Nausea and vomiting in pregnancy: effects on maternal diet, health, and birth outcomes. An investigation using the Norwegian Mother and Child Cohort Study

Abstract

Background: Nausea and vomiting in pregnancy (NVP), sometimes referred to as morning sickness, is a common condition which accompanies gestation, particularly during the first trimester. Prevalence for this condition is estimated to be 50-90% of all pregnancies. There is currently no clear understanding of the aetiology of NVP, although pregnancy hormones are often suspected as being involved. Limited research has been conducted on consequences for mother and offspring suffering NVP. The aim of this study was to evaluate the diet, gestational health, pregnancy, and birth outcomes for women with NVP or nausea alone (NP), as compared to symptom-free (SF) women. Data material: >51,000 pregnancies from the Norwegian Mother and Child Cohort Study (MoBa), merged with the Medical birth registry of Norway (MBRN). Results: The results showed the NVP group of women were significantly younger, shorter and heavier than the SF group. The NVP group had the highest proportions with an education =12 years, with an income <300,000 NOK, and being non-smokers 3 months prior to and during pregnancy. They also had the highest total mean energy intake, with the highest absolute intake of all macronutrients, except for monounsaturated fat and fibre. Significantly more women in the NVP group increased their intake of meat, vegetables, water, and sugar-containing or artificially sweetened soft drinks as a result of the pregnancy. By contrast, significantly more SF women introduced probiotic containing dairy foods and chocolate. The NVP women had the highest proportion experiencing dietary change, by either representing the highest proportion eating more or less than before the pregnancy. Women with NVP and NP had higher odds for gestational complications such as pelvic girdle pain (PGP), high blood pressure and proteinuria, yet reduced odds for pregnancy complications such as preterm birth, and low birth weight infants. The NP and NVP women had higher odds for having female infants.When we analysed the association between NP/NVP and PGP further, we found that the NP/NVP women with PGP during pregnancy had a higher prevalence of PGP also 4-6 months post-partum compared to the SF group. This association suggests a common pathway between NP/NVP and PGP. Conclusions: We found women with NVP to be characterised by high intakes of carbohydrates and added sugar, primarily from sugar-containing soft drinks. These women also had a higher degree of dietary change compared to SF women. Women with NP and NVP were found more likely to develop pregnancy complications, yet displayed mostly favourable delivery and birth outcomes. An association found between NP/NVP and PGP during pregnancy and post-partum is shown here for the first time.