Researchers have discovered a link between morning sickness and the chance of pregnancy loss. Women who experienced nausea and vomiting during early pregnancy were less likely to have a miscarriage. The findings are in a study that was just published in the journal JAMA Internal Medicine.
Morning sickness is a symptom of early pregnancy that results in nausea and vomiting. Despite the name, symptoms can occur at any time during the day. At least 80% of pregnant women are affected. Morning sickness symptoms usually subside by the 16th week but some women experience nausea and vomiting late into the pregnancy. The exact cause of morning sickness is unknown but current theories point to hormone fluctuations or protecting the fetus from pathogens. Researchers have long believed that morning sickness is a sign of a healthy pregnancy but the theory has been difficult to test. Most past studies consisted of women with clinically recognized pregnancies, eliminating any early miscarriages from the dataset.
A team of researchers, in collaboration with the National Institutes of Health, analyzed information from a previous study on aspirin use during pregnancy. The study had included women with very early pregnancies and all of the participants kept diaries on pregnancy symptoms. The team found that women who had experienced nausea with or without vomiting were at least 50% less likely to have a miscarriage. There was no significant difference between women who only had nausea and women who also experienced vomiting.
The findings show a link between morning sickness symptoms and the risk of miscarriage. Nausea, with or without vomiting, was associated with healthier pregnancies. The team still isn’t sure what causes this protective benefit; the source and purpose of morning sickness is still a mystery. For now, it appears that nausea is generally a positive sign when it occurs in early pregnancy.
Stefanie N. Hinkle et al. Association of Nausea and Vomiting During Pregnancy With Pregnancy Loss. JAMA Internal Medicine (2016).