Why pregnant women experience morning sickness

Anytime a woman in her reproductive years complains about being nauseated, the first thing people ask is “are you pregnant?”!  This is because morning sickness or nausea and vomiting is usually one of the first signs that a women is pregnant. Approximately 85% of all pregnant women experience some degree of nausea and vomiting in the first trimester (0-12 weeks) of pregnancy. 

Despite its name, morning sickness can occur at any time during the day. Symptoms usually appear within 4-7 weeks and usually resolve by 16-20 weeks. It is not clear why early stages of pregnancy cause women to experience nausea and vomiting and there is much speculation as to why some women experience it and some do not. One theory suggests it is a way for a woman to avoid substances that may be harmful for her baby and women who experience nausea are more likely to have a healthy pregnancy with a decreased risk of miscarriage. The massive surge of hormones produced during pregnancy is usually considered responsible for a few reasons, one being that the liver has a harder time processing these hormones and another is certain hormones lead to the slowing of the digestive system which can also aggravate morning sickness.  

Morning sickness becomes a medical problem when the nausea/vomiting is severe and continues past the 16th week. This is called hyperemesis gravidarum and occurs in less than 2% of all pregnancies. Medical attention is needed as it can result in dehydration, malnutrition, and the body becoming more acidic which can endanger the growing fetus. Your healthcare practitioner will also want to rule out any liver, gallbladder, or pancreatic disease, thyroid issues, and molar pregnancy if your symptoms are severe and prolong into the second trimester. 

The triggers that lead to morning sickness differ among women. Some common triggers include: 

  • low blood sugar
  • strong smells
  • constipation
  • vitamin and nutritional deficiencies
  • lack of exercise
  • stress
  • anxiety
  • normal pregnancy related changes in the digestive system.  

Sometimes simply changing when you take your prenatal vitamin or iron supplement (i.e., from the morning to the end of the day) can take away feelings of nausea but unfortunately this will not be the case for every woman. See this post about natural treatments for morning sickness. 

Related posts:
How to treat morning sickness naturally
How to satisfy your pregnancy cravings
Non-food cravings during pregnancy