Most Recent Updates
September 16, 2021: The UK Royal College of Obstetricians and Gynaecologists released a statement urging "all pregnant [individuals] eligible for the COVID-19 booster vaccine to take up the offer."
"There have been more unvaccinated pregnant [individuals] becoming seriously ill from COVID-19, particularly in their third trimester, and an increased number...admitted to hospital and intensive care. The RCOG is recommending all pregnant women receive both doses of the either Pfizer or Moderna mRNA COVID-19 vaccine, and have the booster vaccine if they are eligible."
"We also urge all pregnant [individuals] to have the flu jab this winter, which can be given alongside the COVID-19 vaccine. It is possible to get infected with flu and COVID-19 at the same time and this could make someone who is pregnant severely unwell."
September 16, 2021: According to CDC data: Cases of COVID-19 among Pregnant Women by Week of Diagnosis (data were collected from 120,459 women):
September 7, 2021: Study assessed Pfizer COVID-19 vaccine effectiveness during pregnancy:
10,861 vaccinated; 10,861 unvaccinated matched controls
During a median follow-up of 77 days, 131 infections were documented in the vaccination group and 235 infections in the control group
The estimated vaccine effectiveness for documented infections was:
67% (40–84%) in days 14–20 after the FIRST dose
71% (33–94%) in days 21–27 after the FIRST dose
Estimated vaccine effectiveness from 7 days through to 56 days after the SECOND dose was:
96% for any documented infection (89–100%)
97% (91–100%) for infections with documented symptoms
89% (43–100%) for COVID-19-related hospitalization
"In summary, the BNT162b2 mRNA vaccine was estimated to have high vaccine effectiveness in pregnant [individuals], which is similar to the effectiveness estimated in the general population"..."Our findings make it plausible that the vaccine effectiveness estimated in the general population for future variants may be used to infer the effectiveness in pregnant individuals for the same variants, particularly for mRNA-based vaccines."
September 4, 2021: Two valuable, regularly updated resources:
Considerations for counselling pregnant persons regarding COVID-19 vaccination: Pregnancy data on thirteen global COVID-19 vaccines (Dr. Liona Poon, academic specialist in Obstetrics and Maternal Fetal Medicine)
Explainer on COVID-19 vaccination, fertility, pregnancy and breastfeeding (Victoria Male, Lecturer in Reproductive Immunology at Imperial College London)
September 2, 2021: Study found that early vs. late third trimester COVID-19 mRNA vaccination appears to “maximize transplacental antibody transfer and neonatal neutralizing antibody levels.” This indicates that getting vaccinated in the early third trimester may offer higher transfer of COVID-19 antibodies to the fetus via the placenta.
September 2, 2021: United Kingdom (UK) Yellow card data indicate there is no current evidence that COVID-19 vaccination while breastfeeding causes any harm to breastfed children or affects the ability to breastfeed.
Of approximately 3,000 Yellow card reports, most individuals reported only suspected reactions in themselves which were similar to reports for the general population, with no effects reported on their milk supply or in their breastfed children.
A small number of individuals reported decreases in milk supply, most of which were transient, or possible reactions in their breastfed child (a number of factors can affect milk supply and infant behavior).
"The symptoms reported for the children (high temperature, rash, diarrhea, vomiting and general irritability) are common conditions in children of this age, so some of the effects reported may have occurred by coincidence."
Overall Key Findings
Pregnant women do not appear to be at an increased risk of infection from COVID-19 over non-pregnant women (i.e. same infection rate).
However, pregnant women appear to have an increased risk of intensive care unit (ICU) admission, mechanical ventilation, and extracorporeal membrane oxygenation (ECMO), as well as death (but overall risk is low).
Rates of pneumonia and preterm delivery may also be increased compared to pregnant women without infection, but these results are inconsistent.
There is a significant racial disparity; pregnant Hispanic and non-Hispanic Black women experience even higher risks of complications from COVID-19 infection.
Regarding fetal and neonatal health, current results are reassuring and indicate newborns of mothers who contract COVID-19 appear to be born healthy.
Current evidence also indicates the virus does not readily cross the placenta or infect the fetus. Although there are case reports of this occurring, the event appears to be rare and likely depends on severity of infection.
Preliminary research indicates COVID-19 infection in early pregnancy does not appear to increase the risk of miscarriage, but more research is necessary.
Infant infection from exposure to an infected parent or caregiver likely accounts for most infections reported in newborns; majority of these infections appear to be asymptomatic or mild.
There is currently no evidence that COVID-19 infection can be transferred to the baby through breast milk; breast milk of previously infected mothers appears to contain COVID-19 antibodies (no reason to separate mother and baby after delivery).
There is currently no long-term data on how COVID-19 infection during pregnancy could affect women or their babies.
Pregnant and breastfeeding women may choose to be vaccinated when eligible and should have a risks and benefits discussion with their health care provider.
As of September 13, 2021 more than 158,465 pregnant women have been vaccinated in the U.S. and entered into CDC's v-safe registry. Side effects of vaccines in pregnant women are similar to those expected among the non-pregnant population. Side effects are generally short-lived; no adverse effects to fetuses have been identified. Fever following vaccination can be treated with acetaminophen to decrease adverse-fever associations risks (talk with health care provider).
Recent reports show that people who received mRNA COVID-19 vaccines during pregnancy and/or while breastfeeding have passed antibodies to their fetuses. These antibodies could help protect babies, but more information is necessary to determine effectiveness of these antibodies and how long they may last.
There is currently no evidence COVID-19 vaccines have any adverse impact on fertility based on mechanism of action (read more below).
There is currently no evidence or mechanism of action in which vaccinated individuals "shed" and/or could cause infertility in other individuals by simply being around them. There is no scientific basis for this as the COVID-19 mRNA vaccines do not replicate and they are not live-attenuated (not a live virus).
Fully vaccinated individuals have low risk of passing infection, including to a newborn. Based on May 13 CDC guidelines, individuals do not need to wear a mask when meeting a baby unless they want to [or at parent request]; talk to pediatrician with any concerns.
In December 2019, health officials in China indicated they had a serious outbreak of a respiratory illness caused by a new type of coronavirus, COVID-19, or “coronavirus disease 2019”.
In February 2020, the virus was given the specific name “severe acute respiratory syndrome coronavirus 2” or SARS-CoV-2. In March 2020, the World Health Organization (WHO) officially declared the outbreak a worldwide pandemic.
This page will refer to SARS-CoV-2 as COVID-19.
Various coronavirus infections during pregnancy – such as severe acute respiratory syndrome (SARS) and Middle-East respiratory syndrome (MERS) – have been associated with a higher incidence of severe illness in the mother and adverse outcomes for the fetus.
Fortunately, current evidence indicates that COVID-19 is significantly less lethal than SARS and MERS and pregnant women may only have a slightly higher risk of certain complications over non-pregnant individuals. However, there is still very little data regarding pregnancy-related outcomes and COVID-19.
The term coronavirus derives from the Latin word corona, which means crown or halo. Under electron microscopy, the virus particles display a crown-like pattern on its outside, similar to spikes, which has resulted in the very common computer-generated image of the virus below. In general, coronaviruses cause illnesses ranging from asymptomatic infection to fatal infection.
There are seven coronaviruses currently infecting humans. COVID-19 is the third coronavirus to cause a major epidemic, after SARS and MERS. However, COVID-19 has infected a far greater number of people than SARS and MERS combined.
Information on the effects of SARS and MERS during pregnancy was being used early in the pandemic to help manage pregnant women with COVID-19. However, more current data has shown several differences between SARS, MERS, and COVID-19, with data indicated COVID-19 is far less lethal in pregnant women compared to SARS and MERS.
Symptoms of SARS consisted of fever, chills, headache, general discomfort, muscle pain, and diarrhea, with an incubation period of around 4.6 days, but a range of 2 to 14 days. Almost all patients contracted pneumonia. Case fatality rate was estimated at 9% to 10%.
Sequencing data show that COVID-19 has a 79% genetic similarity to SARS and about 50% to MERS. However, as of July 5, 2021, COVID‐19 has an overall significantly lower fatality rate, estimated around 1.8% in the United States (2.6% in the UK, 1.8% in Canada, and 3.0% in Australia). Pregnant women appear to have the same fatality rate as non-pregnant women.
Human-to-human transmission occurs through close contact via respiratory droplets; incubation time averages 4 to 5 days but can range from 1 to 14 days. It is estimated almost all infected individuals develop symptoms by 11.5 days.
Infected droplets can also spread to distances of up to 6 feet and deposit on surfaces (fomites). These fomites can then infect healthy individuals who touch the unsanitized surface and then touch their mouth, nose, or eyes.
COVID-19 infection can be described in 3 stages:
Stage 1: Incubation period; may include asymptomatic infection
Stage 2: The virus is detectable and presents with minor or mild symptoms such as a fever
Stage 3: Severe symptoms arise which may require hospitalization and could result in respiratory distress or death
Individuals can experience a complete lack of symptoms to a wide range of acute and long-lasting symptoms. These include fever, shortness of breath, cough, nausea, congestion, runny nose, vomiting, diarrhea, chills, loss of smell, sore throat, headaches, body aches, excessive phlegm, coughing up blood, pneumonia, and blood clotting issues.
Studies of hospitalized patients with COVID-19 indicate that severe pneumonia is common and approximately 17% to 29% of these cases progress to acute respiratory distress syndrome. It is currently estimated that once hospitalized, these patients may have a 4% to 15% fatality rate.
General Pregnancy-Specific Data
Overall, when compared to the non-pregnant population, pregnant women with COVID-19 appear to have an increased risk of hospitalization, ICU admission, mechanical ventilation, and the use of ECMO, as well as death (especially in the third trimester). However, overall risk remains low.
A November 19 study of 252 pregnant women who tested positive for COVID-19 indicated that approximately 5% of all pregnant women with COVID-19 infection develop severe or critical illness. A separate study from July 2021 of 926 pregnatn women indicated this risk appeared to be around 13%. According to the Society for Maternal Fetal Medicine as of November 23, overall low absolute risks appear to be: 2.9 per 1,000 for invasive ventilation, 0.7 per 1,000 for ECMO, and 1.5 per 1,000 for death.
According to a large-scale multinational study published in April 2021, women with COVID-19 diagnosis (compared with those without COVID-19 diagnosis) "were at substantially increased risk of severe pregnancy complications, including preeclampsia/eclampsia/HELLP syndrome, ICU admission or referral to higher level of care, and infections requiring antibiotics, as well as preterm birth and low birth weight. The risk of maternal mortality was 1.6%, [or] 22 times higher in the group of women with COVID-19 diagnosis."
However, "these deaths were concentrated in institutions from less developed regions, implying that when comprehensive ICU services are not fully available, COVID-19 in pregnancy can be lethal. Reassuringly, we also found that asymptomatic women with COVID-19 diagnosis had similar outcomes to women without COVID-19 diagnosis, except for preeclampsia."
Across numerous studies, pre-existing conditions consistently play a role in disease severity, such as obesity, older maternal age, hypertension, diabetes, and asthma. Black and Hispanic pregnant women also appear more likely to experience severe infection and hospitalization.
Stage of pregnancy may also be a factor, similar to influenza, although data is limited. COVID-19 is a pro-inflammatory virus that causes severe and excessive inflammation throughout the entire body. Early pregnancy and near term (third trimester) are considered pro-inflammatory, which could make COVID-19 infection more severe at these stages, but more research is necessary.
The largest cohort of pregnant women tested for COVID-19 worldwide was published in July 2021:
Severe adverse outcomes, defined by maternal death, admission to ICU and/or advanced oxygen support were observed in 9.9% of cases.
Pulmonary comorbidities, hypertensive disorders and diabetes mellitus were significantly associated with an increased risk of severe maternal outcomes.
No difference in the livebirth rate was observed between pregnant women with severe adverse outcomes and patients with an uncomplicated course.
However, a significant increased risk of caesarean section, preterm birth, and neonatal admission to the intensive care unit was observed, highlighting that obstetrical and neonatal outcomes are influenced by the severity of maternal disease.
Blood clot risk remains inconclusive, but appears to be uncommon (despite pregnancy itself increasing the risk of blood clots). A study published in July 2021 indicated that COVID-19 infection can be complicated by coagulopathy (excessive bleeding or clotting), featuring blood clots and other thrombosis events, which has been termed "COVID-19 associated coagulopathy" (CAC). Data concerning CAC in pregnancy is limited, but:
The study above determined that of 1,546 COVID-19 positive pregnancies, 1% developed CAC, indicating CAC appears to be uncommon in pregnancy. However, the authors noted that urgent research is required to determine appropriate anticoagulant dosing and duration in pregnant women with COVID-19 infection.
Pregnant women experience the same symptoms as the general population, and may even be largely asymptomatic. Symptoms include shortness of breath, fever, fatigue, chills, muscle aches, and cough. Infection appears to significantly more common in the third trimester, but this may be due to universal testing as women are admitted for labor and delivery.
Regardless of severity, pregnant women may experience a longer duration of symptoms, as at least one study indicated some COVID-19 positive pregnant women experienced symptoms eight weeks or longer after diagnosis (but many others have no symptoms).
Although most studies to date have indicated pregnant women are not more susceptible to infection than the non-pregnant population, a February 2021 study determined the COVID-19 infection rate in pregnant women in Washington State was 70% higher than similarly aged adults, which could not be completely explained by universal screening at delivery.
Risk of preterm delivery remains inconsistent; while some reports have documented an increased risk of preterm birth, others have not find an association. In some reports, cesarean section was performed to improve the mother’s condition, the baby’s condition, or was triggered for other reasons that may not have been related to infection.
According to a November 2020 CDC report, among 3,912 infants born to women with COVID-19, 12.9% were preterm, which is higher than the national estimate of 10.2%. Among 610 of those infants with testing results, 16 were positive for COVID-19, primarily those born to women with infection at delivery. Eight of those 16 infants were born preterm.
In a large population-based study published in July 2021, COVID-19 diagnosis increased the risk of preterm birth, particularly among those with medical comorbidities. (If the mother's condition deteriorates, preterm birth is often recommended.)
There is also informal and anecdotal reporting of a lack of preterm deliveries overall during the pandemic. This phenomenon could be due to women resting more, staying at home, having more familial support, or lack of infections in general, not just COVID-19 (infection is a primary cause of preterm birth). There may also be a decrease in preterm induction, usually indicated by HCPs for medical reasons.
Despite a possible increased risk of preterm birth, a study published in April 2021 identified no significant differences in abnormal fetal ultrasound and Doppler findings observed between pregnant women who were positive for COVID-19 and controls.
COVID-19 Infection in Early Pregnancy or when TTC
As of September 2021, it does not appear that COVID-19 infection early in pregnancy increases the risk of miscarriage, but laboratory results have indicated it is possible (although likely rare):
At least two studies assessing whether COVID-19 had any impact on early pregnancy loss determined the infection appears to have a favorable maternal course at the beginning of pregnancy and does not appear to increase the risk of miscarriage.
A nationwide study published in June 2021 indicated the risk of pregnancy loss at less than 20 weeks gestation due to COVID-19 was similar to the rate of early pregnancy loss in pregnant women without COVID-19 infection. Although the number of participants was small (n=94), to date, it is the largest study of this type.
However, at least three separate studies (from August/September 2020 and July 2021) identified COVID-19 receptors in the early oocyte and blastocyst; therefore, it is possible that infection in early pregnancy could have adverse effects on the embryo. Significantly more research is necessary in larger populations of women.
A case study published in March 2021 found COVID-19 nucleocapsid protein, viral RNA, and particles in the placenta and fetal tissues of an early pregnancy miscarriage from a pregnant woman who had tested positive for the infection. The study also determined that fetal organs, such as lung and kidney may be targets for coronavirus.
Regarding fertility and trying to conceive (TTC), a study published in June 2021 found that seropositivity to the SARS-CoV-2 spike protein (due to infection) does not prevent embryo implantation or early pregnancy development. The study used in vitro fertilization frozen embryo transfer as a model for evaluating the impact of COVID-19 seropositivity on implantation.
Infection Transmission to Fetus/Newborn
Note: Maternal and fetal blood never directly mix during pregnancy; this exchange takes place in the placenta.
As of September 2021, it does not appear that COVID-19 readily crosses the placenta, enters amniotic fluid or umbilical cord blood, or transfers to the newborn via vaginal delivery (which does occur with other viruses). Further, neonates born to mothers who tested positive for COVID-19 appear to remain relatively healthy (and may receive their mother's COVID-19 antibodies).
However, neonates have tested positive for the virus within 30 minutes of delivery, and the virus has been identified in placental tissue and amniotic fluid. But overall, this appears to be very rare and likely depends on severity of infection, stage of pregnancy, and how long the fetus is exposed to the virus (i.e. time of infection in the mother to time of delivery).
In a study of 86 neonates who were tested for the possibility of vertical transmission, only three were positive. Interestingly, one neonate was negative at the time of delivery but tested positive 24 hours later. This neonate also had amniotic fluid and cord blood tested; amniotic fluid was positive, but the cord blood was negative.
One study examined sixteen placentas from COVID-19 infected women. Third trimester placentas were more likely to reflect a systemic inflammatory or hypercoagulable state (tendency for blood to clot). Despite these changes, all neonates tested negative for the virus and were discharged within four days.
In contrast, a separate study that examined twenty-one third trimester placentas of women who tested positive for COVID-19 did not find any major adverse effects on placental structure and pathology, and another study from December 2020 identified no placental or fetal transfer of the virus.
However, more recent findings indicate placental damage may occur even if neonates are born healthy. A study published in August 2021 found that a significant proportion of placentas where COVID-19 occurred during pregnancy showed histopathological findings suggesting placental damage.
The timing in which fetuses may be infected in utero is not known or understood. While some reports indicate there is no evidence of vertical transmission of COVID-19 when the infection occurs during the third trimester, this may only be because delivery occurs so shortly thereafter.
Two stillbirths have been documented from severe infection, one in the second trimester and one in the third trimester, indicating possible transmission. Further, at least one fetal demise has been identified in a woman who contracted COVID-19 in the first trimester.
Note: Overall, data regarding risk of stillbirth and COVID-19 are inconsistent, but it does appear to be rare. While some reports have indicated a slight increased risk, others have not found an association. Further, in at least one study that indicated an increased risk, this increase was thought to be due to factors other than COVID-19 infection (more in Prenatal Care/Appointments).
Therefore, it is likely (although rare) that vertical transmission could happen during any trimester but additional research and clarification between COVID-19 positive newborns and timing of infection in the mother is necessary.
Regarding the postpartum period, transmission can occur from the mother to the newborn. According to a U.K. study of 66 newborns who tested positive for COVID-19, 17 were suspected of contracting the infection from their mother after delivery.
The authors indicated that despite these numbers, the newborns did not experience severe illness, and the benefits of remaining with the mother after delivery appear to outweigh the possibility of infection. Symptoms in these newborns included high temperature, poor feeding, vomiting, a runny nose, cough and lethargy.
According to the CDC, there are two types of tests (decisions about testing are made by state or local health departments or healthcare professionals).
The most used test for current infection is the RT-PCR (real time reverse transcription-polymerase chain reaction, a type of NAAT). This type of test is used to identify the genetic material of a virus (see Resources). Specimens are collected from the patient’s nose or throat using nasopharyngeal or oropharyngeal swabs.
It is often recommended that if the first test is negative, but the disease is highly suspected, a second test should be performed. A negative result can be confirmed through two negative tests in a row, spaced at least 24 hours apart. Researchers do not yet know the most optimal timing to administer the test (especially in newborns).
HCPs may also use a chest CT scan for COVID-19 diagnosis, as this has been reported to be superior in early diagnosis compared with RT-PCR. The CT can show what is called “ground glass”, or white spots on the lungs that indicate the infection is present. For pregnant women, the diagnostic value of the CT may outweigh possible radiation risk to the fetus (read Radiation).
Women should have a risks and benefits conversation with their HCP regarding any imaging scans during pregnancy.
Some health care facilities may universally test all pregnant women prior to delivery, as pregnant women can also be asymptomatic, similar to non-pregnant individuals.
Management and Treatment
The American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) have developed an algorithm to aid practitioners in assessing and managing pregnant women with suspected or confirmed COVID-19 (read more).
Overall: There is no definitive treatment regimen for pregnant women with COVID-19; therefore, all management is currently individualized based on disease severity, stage of pregnancy, and risks and benefits of any medications.
It is also recommended that every pregnant woman with COVID-19 be monitored carefully due to possible complications, even if a woman initially presents without symptoms.
Formally, and depending on severity, recommendations include isolation, infection control procedures, diagnostic testing, oxygen therapy if needed, antibiotics (secondary bacterial infection risk), fetal and uterine contraction monitoring, and an individualized delivery plan.
Antiviral Medication: Currently, there is no specific drug for COVID-19; further, if a drug does appear to be safe and effective in the non-pregnant population, there is likely no scientific data to guide its use during pregnancy.
Medications such as Type I interferon, lopinavir, ritonavir, and tocilizumab are still being studied in the general population and are not (routinely) recommended for pregnant women; studies on safe and effective treatments for COVID-19 positive pregnant women remain ongoing.
Remdesivir is also not routinely recommended for pregnant women due to a lack of safety data as well as effectiveness. However, it may be used in severe cases under compassionate use and has been linked with initial positive results (very small case studies). Side effects of remdesivir in pregnant woman may include possible liver complications.
Monoclonal antibody treatment: A study published in August 2021 described successful use of of monoclonal antibody treatment for symptomatic COVID-19 in four pregnant patients. The authors found no evidence of pregnancy complications or treatment failure. All four patients avoided progression to severe disease and none required additional COVID-19 related medical visits or hospitalizations.
Blood clotting: Both pregnancy and COVID-19 are associated with an increased risk for blood clotting – to include in asymptomatic women in isolation at home. However, this is also slightly debated as not all studies have found an increased risk. Further, although case reports exists, widespread reporting of blood clotting issues from COVID-19 infection in pregnancy has not been reported.
Some guidance indicates that suspected and confirmed COVID-19 pregnant women should receive preventative low-molecular-weight heparin (LMWH) before and after delivery (unfractionated heparin if delivery is close). Other reviews indicate there is not enough evidence to recommend heparin, and this medication could increase the risk of bleeding.
Delivery: Since there is currently no evidence that vaginal delivery can increase the risk of vertical transmission, mode of delivery should also be individualized and depends on stage of pregnancy, health of the fetus, and the mother’s overall health.
Fetus/Newborn: Prior to delivery, it is recommended that women undergo regular fetal heart monitoring and ultrasounds to monitor growth. Steroids may be considered for fetal lung maturation, depending on gestational age and severity of the mother’s disease.
After delivery, guidelines also conflict on whether the newborn should be separated from the (infected) mother to prevent infection transmission. However, most obstetric organizations agree the benefits of the mother and baby being together outweigh the possible risks of transmission. Women and their HCPs should have individualized discussions regarding infant separation for mothers suspected or confirmed to have COVID-19.
Antibody Transfer to Fetus after Infection (via Placenta and/or Breast Milk)
Current data on COVID-19 antibody transfer to the fetus/newborn after maternal infection during pregnancy:
All types of COVID-19 infections – asymptomatic, mild, severe –initiate antibody transfer across the placenta.
Antibody levels from mild COVID-19 infection during pregnancy appear to decline more quickly than after severe infection (may be faster decline for asymptomatic, but this has not been studied).
A longer interval between infection and delivery provides more time for effective transplacental transfer of antibodies (e.g. two months better than two weeks; also likely depends on severity of infection).
However, infection in early pregnancy may not provide lasting antibody protection to fetus/newborn (vs. infection in late pregnancy) as this interval could be too long.
Antibody levels passed to a newborn after COVID-19 infection during pregnancy have been shown to decline in infants approximately 6 to 11 weeks after birth.
Despite this decline, passive immunity may persist in infants up to six months of life.
Infection in early to mid-pregnancy + vaccination later in pregnancy appears to be safe and produces strong antibody transfer across the placenta (and is recommended).
COVID-19 infection during pregnancy also transfers antibodies to colostrum and breastmilk; these antibodies are effective at neutralizing the virus.
Of note, it is currently unclear how long this lasts, but at least one study indicated antibodies were present in breast milk up to 10 months after a positive COVID-19 test. However, this amount and level of protection is likely highly variable, depending on stage of pregnancy during infection, severity of infection, whether the infant is exclusively breastfed, and length of time the infant is breastfed.
Women who attend their prenatal appointments should be assessed for fever each time and evaluated for signs and symptoms of a respiratory infection.
Women need to express any concerns they have with their HCP, to include their appointment schedule (virtual or in person), fetal monitoring, what they should do in-between appointments if they suspect infection, and what to do if they experience contractions, especially if nearby hospitals have changed their procedures.
Women should continue to see their HCP when recommended, or when they feel they may be experiencing a concern.
At least one study noted an increase in the stillbirth rate in one U.K. hospital during the pandemic. Of note, none of the stillbirths were indicated in women who tested positive for COVID-19. This indicates that a decrease in appointments, prenatal care, routine screenings, or ultrasounds may have occurred that led to this increase.
Women also need to tell their HCP how they are coping with the pandemic. Increasing isolation, preventative measures, anxiety about their health and the health of their baby, and a significant amount of uncertainty can increase women’s risk for depression and anxiety during pregnancy and the postpartum period.
Pregnant women and those trying to conceive should also consider being vaccinated against COVID-19, although this is a completely personal choice (see more information below).
Vaccine Safety & Effectiveness Data in Pregnancy (and Breastfeeding) and Antibody Transfer to Fetus
There are currently three COVID-19 vaccines authorized for use in the U.S.: Two are mRNA vaccines (Pfizer-BioNTech and Moderna) and one is an adenoviral-vector vaccine (Janssen) [of Johnson & Johnson]. Second doses of Pfizer and Moderna vaccines are given 21 days and 28 days after the first dose, respectively (in the U.S.). The Johnson & Johnson vaccine is only one dose.
Although pregnant women were excluded from the original clinical trials, as of September 13, 2021 more than 158,465 pregnant women have received at least one COVID-19 vaccination, and numerous safety and effectiveness studies and reviews have been published since the vaccine rollout began in December 2020.
Vaccines are effective at preventing infection during pregnancy, as well as related complications. According to a Mayo Clinic study, vaccinated pregnant women were less likely to experience COVID-19 infection compared to unvaccinated pregnant patients in their cohort. In an Israeli study published in July 2021, mRNA vaccines were shown to be 78% effective at preventing infection in pregnancy (15,000+ participants). An additional study published in September 2021 determined the Pfizer vaccine to be 96% effective after two doses for preventing any documented infection in pregnancy (20,000+ participants).
An additional study published in March 2021 found that COVID-19 vaccination may offer protection against maternal ICU admission, mechanical ventilation or ECMO, maternal death, and vertical transmission; vaccination may also help reduce preterm birth, cesarean section, stillbirth, mother-infant separation at birth, and possible interruption of breastfeeding (due to infection).
Vaccination during pregnancy also offers protection against COVID-19 variants. In a study published in May 2021, pregnant vaccinated women developed cross-reactive immune responses against COVID-19 variants of concern. Further, while pregnant women admitted to the hospital in the UK during the Delta period had an increased risk of pneumonia, no fully vaccinated pregnant women were admitted between February 1, 2021 and July 11, 2021.
To date, vaccination in pregnancy is not associated with adverse maternal or fetal outcomes. Rates of adverse events such as miscarriage, preterm birth, stillbirth, birth defects, gestational diabetes, preeclampsia/gestational hypertension, eclampsia, intrauterine growth restriction, and neonatal deaths are less than or within expected background rates for the same events in non-vaccinated pregnant women.
United Kingdom (UK) reporting on vaccine safety from Yellow Card data published in August 2021 indicated that more than 55,000 pregnant individuals in the UK had been vaccinated against COVID-19. Data do not suggest an increase in miscarriage, stillbirth, birth defects, or birth complications.
A pre-print published on August 9, 2021 indicated that among 2,456 pregnant persons who received an mRNA COVID-19 vaccine preconception or prior to 20 weeks’ gestation, the cumulative risk of pregnancy loss from 6–19 weeks’ gestation was 14.1%, similar to the background rate of pregnancy loss in an unvaccinated pregnant group. These data suggest receipt of an mRNA COVID-19 vaccine preconception or during pregnancy is not associated with an increased risk of pregnancy loss.
Side effects are similar to those experienced by the non-pregnant population. Side effects of dose one or dose two of either the Pfizer or Moderna vaccines are similar to the non-pregnant population and can include pain at the injection site, fatigue, headache, chills, nausea, muscle pain, and/or fever.
According to the CDC, most systemic post-vaccination symptoms are mild to moderate in severity, occur within the first three days of vaccination, and resolve within 1–2 days of onset. These symptoms are more frequent and severe following the second dose.
A study published in August 2021 assessed short-term reactions among pregnant and lactating individuals in the first wave of the COVID-19 vaccine rollout and determined average maximum temperature was 100.6 °F/ 38.1 °C after dose 1 and 100.7 °F/38.2 °C after dose 2 (including 1051 pregnant individuals). This same study also indicated that decreased milk supply for less than 24 hours was reported by 339 lactating individuals after the first dose (5.0%) and 434 individuals after the second dose (7.2%).
However, at least one case study published in August 2021 documented that very rare side effects are possible. The case study indicated that a pregnant woman was diagnosed with immune thrombocytopenia (can lead to bleeding or bruising) in the first trimester, which occurred thirteen days after initiating the COVID-19 vaccination series. "High-dose oral corticosteroids were started, and she was discharged home with significant improvement in platelet count on her fourth day of hospitalization with no subsequent complications."
The fetus does not get exposed to the spike protein. Study that assessed antibodies in babies after the mother was COVID-19 vaccinated during pregnancy shows evidence the vaccine itself does not cross the placenta, only the mother's antibodies (IgG). If the vaccine had crossed the placenta, researchers should have seen IgM antibodies, but none of the infants from vaccinated mothers had this type of antibody.
No placental antibody concerns have been identified. Among fifteen women who received at least one dose of Pfizer (including five breast-feeding women and two women vaccinated in early pregnancy), none had placental anti-syncytin-1 binding antibodies at either time-point following vaccination (May 2021). This means the vaccine did not cause antibodies toward a placental protein, adding further evidence to its safety in pregnancy. The study also determined that mRNA was not detected in breastmilk.
No placental harm has been identified. Study published in May 2021 found no evidence that mRNA COVID-19 vaccination during pregnancy harms the placenta (84 vaccinated individuals, 116 controls). "Placental examination in women with vaccination showed no increased incidence of decidual arteriopathy, fetal vascular malperfusion, low-grade chronic villitis, or chronic histiocytic intervillositis compared with women in the control group. Incidence of high-grade chronic villitis was higher in the control group than in the vaccinated group."
Vaccination produces COVID-19 antibody transfer to the fetus. Several studies have detected antibodies in umbilical cord blood, amniotic fluid, and in newborns after maternal vaccination. Further, this antibody transfer is assessed to be greater than antibody transfer after COVID-19 infection in pregnancy.
A study published in May 2021 found that mRNA-based COVID-19 vaccines in pregnant women lead to maternal antibody production as early as 5 days after the first vaccination dose, and passive immunity to the neonate as early as 16 days after the first vaccination dose.
Vaccination during pregnancy plus initiation of breastfeeding (prenatal antibodies + breastfeeding antibodies) is likely the most effective strategy, but both methods alone may offer an infant protection. The exact strength and length of that protection requires more research.
There is limited information on the most "ideal" timing for vaccination in pregnancy, but it is recommended pregnant women get vaccinated when they can. However, several studies indicate that vaccination late in the second trimester or early in the third trimester could provide more time for antibody transfer (vs. vaccination too close to delivery).
Placental transfer (during pregnancy) likely offers more protection (IgG; antibodies “more durable”) compared to vaccination while breastfeeding (IgA, some IgG; see box) but each method protects differently.
Placental transfer offers systemic protection (gets into blood; antibodies may last as long as 6 to 12 months); breastmilk transfer offers mucosal protection, but is not long lasting; however, being breastfed every few hours would offer some level of sustained [IgA, IgG] protection.
At least two studies published in March and April 2021 found robust secretion of COVID-19 antibodies in breast milk. One study found these antibodies remained up to 6 weeks after vaccination and the second study determined they were present up to 80 days after vaccination. Antibodies found in breast milk of these women showed strong neutralizing effects, suggesting a potential protective effect against infection in the infant.
A third study indicated that significantly elevated levels of specific IgG and IgA antibodies in human milk started approximately 7 days after the initial vaccine dose.
However, it is unclear if maternally transferred antibodies via breastmilk will offer protection against COVID-19. IgA antibodies produced in breastmilk after vaccination appear to resist an infant’s gastric phase of digestion but are degraded during the intestinal phase; IgG antibodies may be prone to degradation in both phases of digestion. More research is necessary to determine if the antibodies produced in breastmilk after vaccination are effective at preventing infant infection, and if they are, for how long.
More data is necessary, but breast milk IgA could prevent infection and transmission of infection at the mucosal surface (mouth, throat) for as long as breastfeeding continues.
A study published in August 2021 assessed antibodies in breastmilk after COVID-19 vaccination, include those lactating for two years or more. The study found that all vaccinated study participants ( n=94) who were breastfeeding had IgG antibodies and 89% of them had IgA antibodies against COVID-19 in their milk. Further, IgA and IgG antibody concentrations in the milk of mothers who were breastfeeding for 24 months or longer were significantly higher than in mothers with breastfeeding periods less than 23 months.
Infant side effects are rare, and may be coincidental. According to UK Yellow card data published in September 2021, there is no current evidence that COVID-19 vaccination while breastfeeding causes any harm to breastfed children or affects the ability to breastfeed. Of approximately 3,000 Yellow card reports, there were a small number of reports regarding symptoms in breastfed children. These included high temperature, rash, diarrhea, vomiting and general irritability. However, these are common conditions in children of this age, so determining whether the vaccine caused these effects is very difficult.
Current long-term safety information:
There are currently no data regarding long-term outcomes of infants whose mothers were vaccinated during pregnancy or while breastfeeding. However, researchers do have present data and decades of other research that indicate long-term unexpected adverse outcomes in infants are unlikely:
Currently, there are four large datasets from three countries that have not found higher rates of adverse birth outcomes after COVID-19 vaccination in pregnancy. Adverse outcomes detected are occurring at the same rate as unvaccinated pregnant individuals.
There is currently no evidence the vaccine itself (e.g. spike protein) crosses the placenta. IgM antibodies have not been detected in babies after maternal vaccination. IgM is made by the body when it is "infected"; it does not cross the placenta (see box, above). Therefore, if a newborn had IgM antibodies after maternal vaccination, that would indicate the vaccine itself crossed the placenta and "infected" the fetus for the fetus to have made its own IgM antibodies, but this has not been detected due to vaccination.
Vaccine mRNA has not been detected in placenta or breastmilk (estimated half-life of 8 to 10 hours).
Lipid nanoparticles are not expected to be a concern (prior drugs using LNPs were unable to cross placenta in animal studies).
Polyethylene glycol is not absorbed orally (no breastfeeding concerns).
There is no plausible mechanism for intact, complete, functional viral S proteins to be distributed into the milk.
Latest Organizational Recommendations
The latest organizations recommendations regarding pregnancy and COVID-19 vaccination from:
U.S. Centers for Disease Control and Prevention
American College of Obstetricians and Gynecologists
Society for Maternal-Fetal Medicine
UK Royal College of Obstetricians and Gynaecologists
The Society of Obstetricians and Gynaecologists of Canada
The Royal Australian and New Zealand College of Obstetricians and Gynaecologists
CDC: On August 11, 2021, the U.S. Centers for Disease Control and Prevention (CDC) formally announced new guidance to officially recommend COVID-19 vaccination for all people aged 12 years and older, including people who are pregnant, breastfeeding, trying to get pregnant now, or might become pregnant in the future. CDC further added:
No safety concerns were found in animal studies.
No adverse pregnancy-related outcomes occurred in previous clinical trials that used the same vaccine platform as the J&J/Janssen COVID-19 vaccine.
COVID-19 vaccines do not cause infection, including in pregnant individuals or their babies.
Early data on the safety of receiving an mRNA COVID-19 vaccine (Moderna or Pfizer-BioNTech) during pregnancy are reassuring.
Early data suggest receiving an mRNA COVID-19 vaccine during pregnancy reduces the risk for infection.
Vaccination of pregnant individuals builds antibodies that might protect their baby.
Read the full announcement here.
American College of Obstetricians and Gynecologists: On July 30, 2021, ACOG updated their COVID-19 Vaccination Practice Advisory to recommend "that all eligible persons, including pregnant and lactating individuals, receive a COVID-19 vaccine or vaccine series." They further added:
"Pregnancy testing is not a requirement prior to receiving any EUA-approved COVID-19 vaccine.
Claims linking COVID-19 vaccines to infertility are unfounded and have no scientific evidence supporting them. ACOG recommends vaccination for all eligible people who may consider future pregnancy.
COVID-19 vaccines may be administered simultaneously with other vaccines, including within 14 days of receipt of another vaccine. This includes vaccines routinely administered during pregnancy, such as influenza and Tdap."
Society for Maternal-Fetal Medicine: On July 30, 2021, SMFM updated their Provider Considerations for Engaging in COVID-19 Vaccine Counseling With Pregnant and Lactating Patients on 30 July to recommend "that pregnant and lactating people be vaccinated against COVID-19". They further added:
"Vaccination is the best method to reduce maternal and fetal complications of SARS-CoV-2 infection. Counseling to support the recommendation for vaccination should include available data on vaccine efficacy, as well as data on vaccine safety during pregnancy and lactation."
UK Royal College of Obstetricians and Gynaecologists (RCOG): On July 22, 2021, RCOG released the following statement: "Health chiefs are encouraging more pregnant women to come forward for their COVID-19 vaccine, as new data from Public Health England (PHE) show for the first time that 51,724 pregnant women in England have received at least one dose...On 16 April 2021, the Joint Committee on Vaccination and Immunisation (JCVI) advised that pregnant women should be offered the COVID-19 vaccine at the same time as the rest of the population, based on their age and clinical risk group."
The Society of Obstetricians and Gynaecologists of Canada (SOGC): On May 25, 2021, SOGC revised and reaffirmed their original guidance from December 2020:
"Pregnant individuals should be offered vaccination at any time during pregnancy or while breastfeeding if no contraindications exist.
All available COVID-19 vaccines approved in Canada can be used during pregnancy and breastfeeding, but the SOGC recommends following provincial and territorial guidelines on type of vaccine to prioritize for pregnant and breastfeeding individuals.
The decision to be vaccinated is based on the individual’s personal values, as well as an understanding that the risk of infection and/or morbidity from COVID-19 outweighs the theorized and undescribed risk of being vaccinated during pregnancy or while breastfeeding. Individuals should not be precluded from vaccination based on pregnancy status or breastfeeding.
Given that pregnant people are at increased risk of morbidity from COVID-19 infection, all pregnant persons should be eligible to receive a COVID-19 vaccination."
"Global surveillance data from large numbers of pregnant women have not identified any significant safety concerns with mRNA COVID-19 vaccines given at any stage of pregnancy. Furthermore, there is also evidence of vaccine-induced antibodies in cord blood and breastmilk, which may offer protection to infants through passive immunity."
V-safe is a smartphone-based tool that uses text messaging and web surveys to provide personalized health check-ins after you receive a COVID-19 vaccine. Through v-safe, you can quickly tell CDC if you have any side effects after getting a COVID-19 vaccine. Depending on your answers to the web surveys, someone from CDC may call to check on you and get more information. V-safe will also remind you to get your second COVID-19 vaccine dose if you need one.
V-safe COVID-19 Vaccine Pregnancy Registry: The registry is collecting health information from people who received COVID-19 vaccination in the periconception period (within 30 days before last menstrual period) or during pregnancy. The information is critical to helping people and their healthcare providers make informed decisions about COVID-19 vaccination. Participation is voluntary, and participants may opt out at any time.
Vaccine Adverse Event Reporting System (VAERS): VAERS is a U.S. early warning system to detect possible safety problems in U.S.-licensed vaccines. VAERS is co-managed by the Centers for Disease Control and Prevention (CDC) and the U.S. Food and Drug Administration (FDA). VAERS accepts and analyzes reports of adverse events (possible side effects) after a person has received a vaccination. Anyone can report an adverse event to VAERS.
COVID-19 Vaccines International Pregnancy Exposure Registry: The C-VIPER is open to any woman who is 18 years of age or older, pregnant, and vaccinated against COVID-19 during pregnancy.
The best way to prevent the virus is to avoid being exposed.
Pregnant woman should:
Seek care immediately if experiencing a medical emergency. Emergency symptoms can include trouble breathing, persistent pain or pressure in the chest, new confusion, inability to wake or stay awake, or bluish lips or face. This is not an inclusive list, and women should always call their HCP or visit an emergency room when necessary.
Avoid unnecessary traveling, use of public transportation, and contact with sick people
Wear a mask (to protect others) in public settings
Quit smoking (risk factor for infection)
Follow personal and social distancing rules
Regularly wash hands for at least 20 seconds (if soap and water are not readily available, use a hand sanitizer that contains at least 60% alcohol)
Avoid touching their eyes, nose, and mouth with unwashed hands.
Do not skip prenatal care appointments or other health appointments that may be necessary
Tell their HCP if they get tested in a location other than their HCP's office
Make sure to have at least a 30-day supply of prescription medications
Learn about stress and coping
Get adequate sleep and physical exercise
Go outside in open areas for walks, fresh air, and a change of scenery
Any pregnant woman who has traveled in a state or country with a high rate of COVID-19 infection or who has had close contact with an individual with confirmed infection should be tested and quarantined.
Women should refer to the CDC and ACOG COVID-19 web pages below for additional information (see Resources).
Partners, family members, and other adult family members who live with a pregnant woman need to practice the same hygiene and social distancing habits and procedures as they do.
This includes maintaining a distance of at least 6 feet from other individuals, wearing a mask in public settings, washing hands for at least 20 seconds, and regularly disinfecting commonly touched surfaces in the office or at home.
Household transmission of COVID-19 is common and occurs early after illness onset.
CDC advises that persons should self-isolate immediately at the onset of COVID-like symptoms, at the time of testing as a result of a high risk exposure, or at time of a positive test result, whichever comes first.
All household members, including the infected person case, should wear masks within shared spaces in the household.
Symptoms can include:
Fever or chills
Shortness of breath or difficulty breathing
Muscle or body aches
New loss of taste or smell
Congestion or runny nose
Nausea or vomiting
Emergency symptoms can include trouble breathing, persistent pain or pressure in the chest, new confusion, inability to wake or stay awake, or bluish lips or face. This is not an inclusive list, and individuals should always call their HCP or visit an emergency room when necessary.
Infected persons should also:
Stay home. Most people with COVID-19 have mild illness and can recover at home without medical care. Individuals should remain at home unless they need to seek medical care.
Get rest and stay hydrated.
Stay in touch with an HCP and seek emergency medical care for difficulty breathing.
Avoid public transportation, ride-sharing, or taxis.
Individuals should refer to the CDC COVID-19 page for additional detailed information and resources.
Considerations for counselling pregnant persons regarding COVID-19 vaccination; pregnancy data on thirteen global COVID-19 vaccines (Dr. Liona Poon, academic specialist in Obstetrics and Maternal Fetal Medicine)
Explainer on COVID-19 vaccination, fertility, pregnancy and breastfeeding (Victoria Male, Lecturer in Reproductive Immunology at Imperial College London)
Total cases in the United States/COVID tracker (U.S. Centers for Disease Control and Prevention
COVID-19 Home Page (U.S. Centers for Disease Control and Prevention)
COVID-19 Testing Page (U.S. Centers for Disease Control and Prevention)
Management Considerations for Pregnant Patients With COVID-19 (Society for Maternal-Fetal Medicine)
COVID-19 Vaccination of Pregnant or Lactating People (U.S. Centers for Disease Control and Prevention)
Provider Considerations for Engaging in COVID-19 Vaccine Counseling With Pregnant and Lactating Patients (Society for Maternal-Fetal Medicine)
How Do We Know the COVID-19 Vaccines Are Safe and Effective? One Expert Explains. (American College of Obstetricians and Gynecologists; December 2020)
How does the RT-PCR test work? (International Atomic Energy Agency)
Novel Coronavirus 2019 (COVID-19): Practice Advisory (American College of Obstetricians and Gynecologists; December 2020)
Management Algorithm (American College of Obstetricians and Gynecologists and Society for Maternal-Fetal Medicine)
COVID-19 FAQs for Obstetrician-Gynecologists, Obstetrics (American College of Obstetricians and Gynecologists)