Objectives: Nausea and vomiting of pregnancy (NVP) is frequent, affecting up to 70–85% of pregnant women. However, severity of NVP especially in clinical practice is often uncertainly assessed and thus both under- and overdiagnosing is probable. Furthermore, risk factors for NVP, although recognized, are not well established. The aim of our study was to evaluate the severity of NVP with a structured questionnaire and evaluate associative risk factors. Study design: Sample of 2411 women were recruited from maternity health care clinics. Severity of NVP was assessed with pregnancy-unique quantification of emesis (PUQE) questionnaire. Age, previous pregnancies, previous deliveries, previous miscarriages including ectopic pregnancies, previous pregnancy terminations, nationality, pre-pregnancy body mass index, smoking, marital status and employment were used as explanatory factors. Results: Altogether 88.0% of the women reported some level of NVP, of which 6.4% was severe, 52.2% moderate and 29.4% mild. Daily duration of NVP was four hours in 12 h in 45.0%. Further, 18.8% of the women had vomiting episodes three times and 37.4% retching episodes three times in 12 h. Women with two previous pregnancies had increased risk for more severe NVP (OR 2.17, 95%CI; 1.34–3.51, p < 0.0001). Older women had increased daily duration of nausea (OR 1.03, 95%CI; 1.00–1.06, p = 0.004) but lower number of vomits (OR 0.93, 95%CI; 0.93–0.97, p < 0.0001) and lower number of retching (OR 0.93, 95%CI; 0.90–0.96, p < 0.0001). Smokers had shorter daily duration of nausea (OR 0.49, 95%CI; 0.33–0.73, p < 0.0001), but higher number of vomiting episodes compared to non-smokers (OR 1.83, 95%CI; 1.26-2.66, p = 0.021). Conclusions: Women suffered from NVP very frequently. The daily duration of NVP was moderately long, in nearly half of the women four hours or more. In addition, retching was more frequent than vomiting. From studied risk factors, few associations with different aspects of NVP emerged, but only multiparity was associated with the severity of NVP. As NVP affects several women during pregnancy, in future, the impact of NVP on quality of life, future family planning and health costs should be evaluated.
