Women who have experienced morning sickness and have probably disliked the feeling while praying for it to stop, may be surprised by the results of this new study.
The NIH study finds that both nausea alone and nausea with vomiting are linked to a lower risk of miscarriage in the first eight weeks of pregnancy.
Other studies have found the same link, but thjs new one goes a step further in illustrating it in a large number of women trying to conceive.
The reasons for the connection aren’t so clear yet, but it may have to do with keeping a woman from eating the wrong things, or as always, with the fluctuating hormones in the early months of pregnancy.
The study, published in JAMA Internal Medicine, included nearly 800 women with either one or two miscarriages in the past, and who were not pregnant at the time the study began.
This factor is important since most other studies on the subject looked at women who were already pregnant. They monitored the women for pregnancy, and had them log their symptoms over time. The team also tracked how many pregnancies ended in miscarriage or went to full term.
By week two of pregnancy, one-fifth of the women reported nausea with or without vomiting. By week eight, the numbers of nauseous women had grown considerably: 57% reported nausea alone, and 27% reported nausea with vomiting.
Among all of the women, 188 pregnancies ended with miscarriage and as suspected, morning sickness was linked to a significantly reduced risk.
Nausea by itself was linked to a 50% reduced risk of miscarriage, and nausea with vomiting was linked to a 75% reduced risk of miscarriage.
There are a couple of theories that support this study: One is that the hormone human chorionic gonadotropin (hCG), which rises in pregnancy and is what pregnancy tests are based on, may be responsible. The other reason has to do with evolution. According to the authors, “symptoms may be part of an evolutionary advantage to change one’s dietary intake, increase consumption of carbohydrate-rich foods, or avert intake of potentially teratogenic substances.” In plain English, this means that the nausea may envo pregnancy-friendly eating habits and perhaps the avoidance of potentially poisonous substances.
It’s important to understand though that there are successful pregnancies that don’t involved morning sickness, and there are unsuccessful pregnancies that do.