Morning Sickness
In this condition factsheet:
The Facts on Morning Sickness
Many pregnant people (up to 85%) experience a period of nausea and vomiting. In the vast majority of cases, it's unpleasant but not dangerous.
About 2% of expectant parents will vomit so severely that they lose weight and become dehydrated, requiring hospital treatment. This severe form of morning sickness is called hyperemesis gravidarum. Although this condition could be life-threatening if left untreated, it can be remedied by treatment during a brief hospital stay.
When a person has morning sickness, it can be severe enough that it affects usual daily activities (e.g., working, caring for children). Although it's called "morning sickness," the nausea and vomiting may occur at any time of day.
Causes of Morning Sickness
While the exact causes of morning sickness aren't known, it's probably linked to pregnancy hormones. People who suffer morning sickness tend to have higher levels of these hormones than those who don't.
It's possible that nausea and vomiting during pregnancy is an ancient mechanism for protecting the fetus from poisons. With the enormously rich and varied diet we eat today compared to our ancestors, it's no surprise that such a protective system could become a bit confused and start rejecting all sorts of healthy food.
One piece of evidence for this idea can be found in research showing that people who suffer from vomiting during pregnancy actually have lower rates of miscarriage than those who don't. Research shows higher levels of 2 hormones (thyroxine and human chorionic gonadotropin) in people with morning sickness. Higher levels of estrogen are found in people suffering from hyperemesis gravidarum.
Other possible causes of morning sickness include infection of the digestive tract and the use of prenatal multivitamins containing iron.
People who suffer nausea from the birth control pill, motion sickness, and migraines are more likely to develop morning sickness during pregnancy.
Symptoms and Complications of Morning Sickness
Morning sickness doesn't necessarily strike in the morning. While vomiting is at its worst for many people between 9 am and noon, it can continue through the day, or may even appear on a completely different schedule. Vomiting is more likely after meals.
This is essentially a problem of early pregnancy. Some people begin vomiting within days of conception, but typically morning sickness starts about 6 weeks after the end of the last menstruation. Actual vomiting is often preceded by nausea lasting a week or 2.
About 80% of sufferers will feel better by Week 12 of the pregnancy, and most will stop vomiting by the end of Week 16. Occasionally, some nausea returns just before delivery. Like morning sickness itself, this is in no way a dangerous or bad sign. A very few people have morning sickness throughout pregnancy – again, this is unfortunate but not dangerous.
Hyperemesis gravidarum is essentially morning sickness so severe that it affects the birth parent's nutrition and, therefore, the baby's health. It usually leads to dehydration and can also lead to liver or kidney damage. Fortunately, most pregnant people are closely monitored by their doctors, and these complications are almost always caught early on.
You should see a doctor right away if your nausea and vomiting is accompanied by abdominal pain, fever, a fast heartbeat, dizziness when standing, or if your vomit contains blood.
