From the Guidelines
Nausea during pregnancy should be managed with dietary changes, vitamin B6, and doxylamine as first-line treatments to reduce the risk of progression to hyperemesis gravidarum. The management of nausea in pregnant patients involves a stepwise approach, starting with diet and lifestyle modifications, such as eating small, frequent meals, avoiding spicy or fatty foods, and consuming ginger products (tea, candies, or capsules 250mg four times daily) 1. Staying hydrated is also crucial. If symptoms persist, vitamin B6 (10-25mg every 8 hours) can be tried, which can be combined with doxylamine (Unisom) for more severe cases, as recommended by the American College of Obstetricians and Gynecologists (ACOG) 1.
For patients with more severe nausea and vomiting, prescription medications like Diclegis (doxylamine/pyridoxine combination) or antiemetics such as promethazine (12.5-25mg every 4-6 hours) or ondansetron (4-8mg every 8 hours) may be considered, though these should be discussed with a healthcare provider first 1. It's essential to note that early treatment of nausea and vomiting of pregnancy may reduce progression to hyperemesis gravidarum, a condition that can lead to dehydration and electrolyte imbalances 1.
Key considerations in managing nausea during pregnancy include:
- Identifying and avoiding specific triggers, such as certain foods with strong odors or activities
- Using the Motherisk Pregnancy Unique Quantification of Emesis score to quantify the severity of vomiting during pregnancy 1
- Considering the use of H1-receptor antagonists, such as doxylamine, promethazine, and dimenhydrinate, as safe first-line pharmacologic antiemetic therapies if needed 1
- Recognizing that nausea during pregnancy results from hormonal changes, particularly elevated hCG and estrogen levels, which affect the digestive system and trigger the brain's vomiting center 1.
From the Research
Nausea and Vomiting in Pregnancy
- Nausea and vomiting of pregnancy (NVP) is a common condition that affects up to 85% of pregnant women, with mild and moderate cases not associated with major increase in fetal or maternal risks, but having a major impact on the quality of life of the mother 2.
- Severe NVP and hyperemesis gravidarum (HG) are associated with increased maternal and fetal risks, from in utero growth restriction to developmental delay 2.
- The fetal safety of the doxylamine/pyridoxine combination, H1blockers, and metoclopramide has been documented, with reassuring studies on the fetal safety of ondansetron, although some studies claim increased fetal risk 2, 3.
Treatment Options
- Initial pharmacologic treatment for HG includes a combination of doxylamine and pyridoxine, with additional interventions including ondansetron or dopamine antagonists such as metoclopramide or promethazine 3.
- Mirtazapine is a useful drug in the context of HG, acting on noradrenergic, serotonergic, histaminergic, and muscarinic receptors to produce antidepressant, anxiolytic, antiemetic, sedative, and appetite-stimulating effects, and is not associated with an independent increased risk of birth defects 3.
- Ginger, vitamin B6, antihistamines, metoclopramide, pyridoxine-doxylamine, and ondansetron are associated with improved symptoms compared with placebo, with corticosteroids may be associated with benefit in severe cases 4.
Management and Diagnosis
- Nausea and vomiting of pregnancy should be distinguished from nausea and vomiting related to other causes, with the woman's perception of the severity of her symptoms playing a critical role in the decision of whether, when, and how to treat NVP 5, 6.
- Treatment in the early stages may prevent more serious complications, including hospitalization, with safe and effective treatments available for more severe cases, and mild cases of NVP may be resolved with lifestyle and dietary changes 5, 6.