It is estimated that about 75% of pregnant women will experience some degree of “morning sickness.” Half of all expectant mothers will have both nausea and vomiting and the other 25% will have only nausea.
The most severe cases of nausea and vomiting in pregnancy (NVP) are called hyperemesis gravidarium (meaning “excessive vomiting during pregnancy”). Fortunately, these cases are rare, occurring in only about 1% of pregnancies, and even more rarely (one in 500), may require hospitalization if acidosis, dehydration or other systemic effects are present.
For most women, taking a multivitamin starting early in pregnancy may decrease nausea and vomiting. Treatment of NVP with ginger has also been suggested as a nonpharmacologic option.
The American College of Obstretricians and Gynelcologists (ACOG) states that with respect to more severe symptoms, vitamin B6 may be suggested first, and doxylamine, an antihistamine medication found in over-the-counter sleep aids, may be added if vitamin B6 alone does not relieve the symptoms.
ACOG, in a brochure answering common questions about morning sickness, also states “drugs that combat nausea and vomiting may be prescribed” but does not specify any particular drug. In a 2004 practice bulletin, ACOG does refer to certain classes of drugs such as antihistamine receptor blockers, phenothiazines, and benzamides as being safe and efficacious to take for more severe cases of morning sickness during pregnancy.
It is noteworthy that ACOG in its 2004 bulletin did not include Zofran (ondansetron) as a recommended medication for morning sickness—for severe cases or otherwise. Zofran has now been linked in several studies to an increased risk of birth defects (principally cleft palate, cleft lip, and cardiac malformations) when taken during the first trimester of pregnancy.