The Bottom Line

Nausea and Vomiting of Pregnancy (NVP) severity varies dramatically from woman to woman – and even within the same pregnancy – depending on time of day and the presence of associated symptoms.

Although health care providers (HCP) do you use certain factors for the diagnosis of Hyperemesis Gravidarum (HG) – the most severe form of NVP – there is no scientific hard line for when NVP becomes HG.

Due to this inconsistency, some women with severe NVP are likely overlooked, and therefore do not receive a proper diagnosis or timely medical care. This can be incredibly detrimental, as early recognition and treatment is strongly associated with better outcomes.

Women should tell their health care providers (HCP) exactly how they feel, and how their symptoms are affecting their lives, even if no dehydration or weight loss is present. Although these are important clinical signs that HCPs look for to assess severity, they are not the only ones that should be considered. A woman’s emotional and mental health can be significantly affected even with mild-to-moderate NVP.

Women have options available to help them manage their NVP – no matter the severity. Women should be treated individually, based on their tolerance for their own symptoms, the effect on their families, social, and work lives, and their overall physical, mental, and emotional health.

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When women present to their HCP with NVP in early pregnancy, HCPs attempt to assess the severity of their symptoms to determine if medical intervention is necessary. 

However, HCPs often view NVP severity as quantifiable physical and measurable health effects, such as weight loss, dehydration, and/or malnutrition, but they should also include emotional, social, and mental health, as well as its associated symptoms and overall quality of life.

Although the "beginning" and "end" of NVP is somewhat predictable (although still a wide range), severity is not; otherwise it would be easier to manage as women would get much earlier care and attention from their HCPs.

Therefore, while there is no way to determine early in pregnancy (4 to 6 weeks) the severity of NVP a woman may experience, it does generally track toward progression until about 9 to 11 weeks of pregnancy, at which point it peaks, and begins to subside until 16 to 22 weeks.

Photo by C. Z. Shi on Unsplash

However, it can also come in waves, with some days or weeks better than others. This is due to the combination of different associated symptoms that NVP causes, as well as the cumulative effect from other early pregnancy-related symptoms, and how women are managing these symptoms at any given time.

For example, at the same time as nausea and/or vomiting, women may also be dealing with headache, constipation, acid reflux, extreme fatigue, dizziness, low blood sugar, exhaustion, and bloating – all of which can impact the severity of a woman's nausea and vomiting.

Fortunately, severe symptoms/complications can be prevented through early engagement with an HCP.

Women with NVP should find an HCP who understands and empathizes with women with this condition.

Women need to find an HCP who understands the nuances of NVP, treats the physical, emotional, and mental health aspects of the condition, and does not discard a woman's concerns simply because she has managed to stay hydrated and avoid weight loss. All aspects of this condition should receive attention, not just the clinical signs.


There are no real definitions for what constitutes mild, moderate, or severe. However, at least one review indicated that up to 30% of women will experience “severe” NVP (“severe” was not defined).

An earlier review estimated that 20% of women had 100 to 300 hours of nausea per pregnancy and a further 10% experienced 300 to 700 hours, which may be associated with vomiting at least 40 times.

However, NVP severity is also very subjective and individualized to each woman. Women tolerate their symptoms differently and for longer periods of time. While one woman can vomit and move on seconds later, many other women may struggle the rest of the day.

Women need to make sure their HCP agrees with how they view their symptoms. While clinical signs may or may not be present, if a woman is well hydrated and has maintained her weight, she could still be significantly struggling, and women should do their best to communicate this to their HCP, who can determine the best management plan forward.

Photo by S L on Unsplash

All levels of severity of NVP need to be assessed and monitored by an HCP, as NVP can progress quickly in some cases.

Further, even mild NVP can affect the daily lives of entire families and communities, from childcare to work productivity, future pregnancies, and romantic, social, and professional relationships, as well as a woman's physical and mental health.

Women with mild NVP have also reported experiencing the same psychosocial problems as women with severe symptoms. Further, women may require medical help with their symptoms even if they are not vomiting.

Additionally, although somewhat rare, severe nausea and vomiting during early pregnancy can be associated with other conditions (i.e. molar pregnancy, hyperemesis gravidarum), and an HCP will want to rule these out.

NVP versus HG

There is no consistently agreed upon point at which NVP becomes Hyperemesis Gravidarum (HG). Currently, this diagnosis is based mostly on a variety of possible signs and symptoms as well as the experience and discretion of the HCP.

As a result, women who do not fit exact current definitions of HG may be overlooked for medical attention.

Further, this lack of definition makes it difficult to assess the difference between NVP and HG in published research.

Hyperemesis Gravidarum current diagnostic guidelines:

Although no overall agreement exists, HG is most often defined as the occurrence of greater than three episodes of vomiting per day, ketones in the urine, more than 5% of body weight loss, muscle contractions and wasting, low potassium, malnutrition, dehydration, and electrocardiographic abnormalities. Read more.

There are, however, clear distinctions between mild NVP and those who need immediate and continuous medical attention. The purpose of attempting to define HG is to try to identify these women so they may receive the proper level of care on a more immediate basis (read Hyperemesis Gravidarum). 

Several studies have indicated that early recognition and management of all severities of NVP can prevent a delay in diagnosis of HG and reduce the likelihood of hospital admission through proper management and control of symptoms.

Potential Tools

The research community has identified several potential ways to “quantify” the effects of NVP on a woman’s life, generally using a 12- or 24-hour time frame. However, because severity may change often, women should consider using these questionnaires more than once per week.

Five of these questionnaires are described here, but are very dated and not readily available for use by the general population of pregnant women to fill out or provide to their HCP outside of a clinical or research setting.

However, the PUQE scoring questionnaire can be viewed here.

A readily available questionnaire for use by pregnant women to download, fill out, and provide to their HCP has much better value, especially because NVP can be very difficult to describe, especially with 4-week intervals between appointments. Some women may not have full, in-depth conversations with their HCPs about their pregnancies until close to 10 or 12 weeks.

The Hyperemesis Education and Resource Foundation has a PDF available for download that women can print, fill out, and provide to their HCP. Women should also make note that if they fill this out during week 7, their symptoms could be markedly different by week 10 (in either direction).


Due to the potential fast progression of NVP, women should not hesitate to call their HCP in between appointments when their NVP is becoming more than they can handle. Further, women should not wait until they are severely dehydrated or have lost too much weight before asking for help. Symptoms are much easier to tolerate when they are managed from the beginning.

Women should not let an HCP tell them their symptoms are not "severe" simply because they are not vomiting. Constant, unrelenting nausea can wreak absolute havoc on a woman's life, even if she manages to stay nourished and hydrated. While dehydration and other physical signs are unquestionably important clinical signs to assess, they should not be the only complications HCPs look for when determining level of care.

In addition to the above, women should call their HCP immediately if they:

  • Experience severe nausea, vomiting, abdominal pain, and/or weight loss

  • See blood in vomit, which could be red or black

  • Cannot keep fluids down; experience symptoms of dehydration

  • Pass only a small amount of urine or urine is a dark color

  • Have a fever

  • Have a rapid heart rate

  • Experience dizziness, faintness, tiredness, or confusion

Women should consider sharing their NVP experience (below), especially how they felt, how long it lasted, what may have caused or contributed to their symptoms, severity of their symptoms, and anything they did that relieved symptoms, even if only temporarily.


Partners of pregnant women, and others who support them, should recognize that NVP severity can be quite variable. It can change day-to-day, and overall severity can change week-by-week. Further, NVP often progresses in severity from the time it starts to about 9 to 10 weeks of pregnancy. From that point, it may remain relatively stable at that severity until symptoms start to fade, which could be anywhere between 16 and 22 weeks (read more).

The woman's perception of the severity of her symptoms also matters; she is the one constantly coping with them on a day-to-day basis. She can eat fine one day and absolutely struggle another. She still deserves positive emotional support through out these weeks/months. Partners/family members should also remain patient, as it can take weeks for the woman to feel somewhat normal again on a regular basis.

However, support and symptom acknowledgement from partners, family members, and friends can significantly improve a woman's ability to handle her symptoms – physically, mentally, and emotionally. Partners should regularly ask how she is doing, how she is feeling, if she is coping okay, or if she needs additional help from her HCP or those around her.


Nausea and Vomiting of Pregnancy (Gastroenterol Clin North Am. 2011 Jun)

Nausea and Vomiting of Pregnancy-What’s New? (Auton Neurosci. 2017 Jan)

Morning Sickness: Nausea and Vomiting of Pregnancy (American College of Obstetricians and Gynecologists)

Nausea and Vomiting of Pregnancy: Committee Opinion 189; January 2018 (American College of Obstetricians and Gynecologists)

Problems of the Digestive System (American College of Obstetricians and Gynecologists)

Screening for Perinatal Depression: Committee Opinion 757 (American College of Obstetricians and Gynecologists)


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