Existence and severity of nausea and vomiting in pregnancy (NVP) with different partners

Nausea and vomiting in pregnancy (NVP) is a widespread condition which may impact on the quality of life. Our objective was to understand the role of the placenta, which is mostly made up of fetal cells, in NVP. We examined the relationship between NVP and different partners in the same women. If a paternal contribution to placental function affects NVP, this could shed light on the genetics of the most common condition in pregnancy. We assessed nausea and vomiting in two groups of 100 women counselled by the Motherisk Program in Toronto, using a score from 1 (none) to 5 (severe with hyperemesis). The first group had ≥2 pregnancies with the same partner; the second had ≥2 pregnancies with ≥2 partners. Scores were averaged across pregnancies, partners and overall. Regression was used to separate numbers of pregnancies and partners. The 100 women having one partner reported an average score of 3.1 in their 261 pregnancies, which was similar to the score of 3.0 in 319 multi-partner pregnancies (p = 0.508). There was a positive (but weak) correlation between gravidity and NVP score (Spearman's rho = 0.21, p < 0.001) but not between partner and score. There was a linear increase in scores from 2.7 in the first pregnancy, to 4.0 in the tenth (rho = 0.948, p < 0.01). After controlling for number of pregnancies, number of partners was not associated with NVP scores (p = 0.302). NVP severity tends to increase with each successive pregnancy. Different partners have no impact on NVP severity.