We all know there are many aspects of pregnancy that are not so pleasant, and one of them is nausea and vomiting. Here’s a summary of ACOG’s Clinical Management Guidelines for Obstetrician-Gynecologists. A better understanding of how to manage and treat nausea and vomiting of pregnancy can significantly improve quality of life for expecting parents.
Definition, Incidence and Diagnosis
- Nausea and vomiting of pregnancy is a common condition, with prevalence rates for nausea of 50-80%, and for vomiting and retching of 50%.
- A woman’s perception of the severity of her symptoms, her desire for treatment, and the potential effect of treatment on her fetus all influence clinical decision making.
- Hyperemesis gravidarum appears to represent the extreme end of the spectrum of nausea and vomiting of pregnancy, with an incidence of 0.3-3% of pregnancies. It is the most common indication for admission to the hospital during the first part of pregnancy, and second only to preterm labor as the most common reason for hospitalization during pregnancy.
- The timing and onset of nausea and vomiting is important. Indeed, symptoms of nausea and vomiting of pregnancy manifest before 9 weeks of gestation in virtually all affected women.
- If a patient experiences nausea and vomiting for the first time after 9 weeks of gestation, other conditions should be considered in the differential diagnosis (such as gastrointestinal conditions, conditions of the genitourinary tract, metabolic conditions, or neurologic disorders).
Causes and Risk Factors
- While the causes of nausea and vomiting of pregnancy are unknown, various theories have been proposed.
- Because of the close temporal relationship between peak human chorionic gonadotropic (hCG) concentrations and peak symptoms of nausea and vomiting of pregnancy, hcG coming from the placenta has been considered a potential factor. Another hormone known to influence nausea and vomiting of pregnancy is estrogen.
- Another theory is that nausea and vomiting of pregnancy is an evolutionary adaptation that developed to protect the woman and her fetus from potentially dangerous foods. This could explain why some women experience temporary aversions to certain tastes and smells.
- Some risk factors for hyperemesis gravidarum have been identified. These include women with increased placental mass (for example, multiple gestation), a family history of motion sickness, migraine headaches, family history, or history of hyperemesis gravidarum in a previous pregnancy.
Maternal and Fetal Effects of Nausea and Vomiting of Pregnancy
- While death from nausea and vomiting of pregnancy is rarely reported today, significant morbidity related to hyperemesis gravidarum has been reported.
- In addition to increased hospital admissions, some women experience significant psychosocial stressors caused by nausea and vomiting of pregnancy, including higher levels of depression and anxiety.
- In terms of fetal effects, with mild or moderate vomiting, and even hyperemesis gravidarum, there is little apparent effect on pregnancy outcome.
Clinical Considerations and Recommendations
What nonpharmacologic therapies exist?
- It is important to remember that treatment of nausea and vomiting of pregnancy begins with prevention.
- Two studies found that women who were taking a multivitamin at the time of fertilization were less likely to need medical attention for vomiting. Therefore, the standard recommendation to take prenatal vitamins for 1 month before pregnancy may reduce the incidence and severity of nausea and vomiting of pregnancy.
- There is little published evidence regarding the efficacy of dietary changes for prevention of treatment of nausea and vomiting of pregnancy.
- However, recommendations include frequent, small meals to avoid a full stomach, avoiding spicy or fatty foods, eliminating supplemental iron and substituting folic acid for iron-containing prenatal vitamins, and eating bland or dry foods, high-protein snacks, and crackers in the morning. Ginger has been associated with improvement in nausea.
- Another common recommendation is to avoid sensory stimuli such as odors, heat, humidity, noise, and flickering lights that may provoke symptoms.
What pharmacologic therapies exist?
- Early treatment of nausea and vomiting is recommended to prevent progression to hyperemesis gravidarum. For instance, it may be beneficial for women with a history of nausea and vomiting of pregnancy in their previous pregnancy to initiate antiemetic therapy before the onset of symptoms.
- Treatment of nausea and vomiting of pregnancy with Vitamin B6 (pyridoxine) alone or vitamin B6 (pyridoxine) plus doxylamine in combination is safe and effective as first-line pharmacotherapy. Consult with your doctor if you feel like you might benefit from pharmacological treatment.
- Intravenous hydration should be used for patients who cannot tolerate oral liquids for a prolonged period or if clinical signs of dehydration are present.
When is hospitalization needed?
- When a woman cannot tolerate liquids without vomiting and has not responded to outpatient management, hospitalization for evaluation and treatment of dehydration and electrolyte imbalance is recommended.
The purpose of this document was to summarize the best available evidence about the diagnosis and management of nausea and vomiting of pregnancy. Find ACOG’s full article here.
