Relationship between vitamin use, smoking, and nausea and vomiting of pregnancy.

BACKGROUND Nausea and vomiting in pregnancy (NVP) is a common complaint but risk factors for NVP are not well characterized. METHODS Occurrence of NVP was studied by questionnaires given to pregnant women at their first visit to the antenatal care unit and were returned around gestational week 28. RESULTS Analysis of 3675 completed questionnaires was made. Nausea and vomiting in pregnancy was reported by 79% of the women, approximately half of which had been vomiting. Various therapies (drugs, acupuncture, acupressure) were tried by 18% of the women with NVP, of which the majority used drugs, most notably antihistamines (specifically meclozine). Hospitalization occurred in 1% of all women. Nausea and vomiting in pregnancy caused 28% of all sick-leaves during the first 28 weeks of pregnancy. Low maternal age and parity 1+ independently increased the risk for NVP. Smoking before pregnancy and using vitamins in early pregnancy were associated with a decreased risk for NVP. Women working outside the home had a lower rate of NVP than housewives and women out of work. CONCLUSIONS Nausea and vomiting in pregnancy is a common complaint with a significant impact on leave of absence from work. The study identifies a number of factors that are related to the occurrence of NVP and that may give hints on the etiology of the condition.