Background  

More than one-half of all pregnant women suffer from nausea and vomiting during pregnancy (NVP), primarily during the first trimester.

Methods  

Prospectively ascertained information on drug use during pregnancy was obtained from the Swedish Medical Birth Register during the period July 1, 1995 to 2002. Antiemetics (antiemetic antihistamines, dopamine modulators, and ondansetron) primarily used for NVP were studied, and women reporting the use of these drugs were compared with all women who gave birth during the study period.

Results  

Use of these antiemetics was reported in 4.5% of the pregnant women – 86% of whom reported their use before the first antenatal visit (usually weeks 10–12). Meclozine, followed by other antihistamines, accounted for 68% of the drugs reported. Young maternal age, multiparity, non-smoking, and a period of unwanted childlessness increased the probability of using any of the antiemetics during pregnancy. Women with a low education used these drugs more often than women with a relatively higher education. Neonates born to women who used any of the antiemetics had a reduced risk for low birthweight, prematurity, being small-for-gestational age, and having a malformation. No specific differences were observed with respect to the outcome following a comparison of different antiemetic drugs.

Conclusions  

Women using antiemetics as a rule have a better delivery outcome than other women, probably due to an effect of a well-functioning placenta, which is associated with NVP. There were no signs of any significant teratogenicity of the drugs studied, but for some drugs the number of exposures was low.