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