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.