Predictors of inter-individual variation in nausea and vomiting in pregnancy in two samples of women attending a pregnancy clinic

Problem: The aetiology of nausea and vomiting in pregnancy is still not well understood. Background: Previous research suggests that its incidence and severity are influenced by many different factors, including demographic, lifestyle and psychosocial factors. Aim: This study aimed to test the effect of multiple factors (use of combined oral contraception (COC) on meeting the father, sex of the foetus, age when pregnant, parity, education, life standard/income, smoking before pregnancy and BMI) on levels of nausea and vomiting in pregnancy. Methods: We collected data from two independent samples of women attending the same pregnancy clinic in the Czech Republic (Study 1, N = 448; Study 2, N = 508) and tested the effect of multiple factors using two different methodological designs: retrospective self-report (Study 1) and self-reports on their current state (Study 2). Findings: In Study 1, we found that lower levels of nausea and vomiting were reported by women who used COC when they met their partner, as well as in those who smoked before pregnancy. In Study 2, we found that younger women and women who reported higher household income had relatively severe NVP symptoms. Discussion: We discuss the pros and cons of the two methodological approaches, as we found different predictors in two otherwise comparable samples. Conclusion: We suggest that future studies use longitudinal designs and combinations of both current and retrospective measures of nausea and vomiting in pregnancy.