Everything you need to know about morning sickness

What is morning sickness?

Between 80 and 90 percent of women experience morning sickness, which is now called nausea and vomiting during pregnancy (NVP) because many women have these symptoms all day long.

When does morning sickness start?

Nausea or vomiting usually begins around four weeks’ gestation and will subside for most women by 13 weeks. However, some women have NVP for the entire pregnancy. For a small proportion of women (about three percent), NVP is so severe that they experience significant weight loss and dehydration, and may require hospitalization (a condition called hyperemesis gravidarum), according to Carolyn Lane, a family physician from the Low Risk Maternity Clinic in Calgary.

What causes morning sickness?

Nobody knows for sure, but NVP may occur because of a combination of factors, including rising hormone levels and changes in the way food moves through the gut. Women with higher levels of pregnancy hormones, such as those carrying twins or with abnormal placental growth, also have a higher incidence of nausea.

Morning sickness symptoms and outcomes

“A bit of nausea is actually a good sign and may be associated with better pregnancy outcomes,” says Lane. “If the pregnancy is developing normally and all the pregnancy hormones are there, you are more likely to experience some NVP.” However, if a woman is vomiting so much she becomes dehydrated and her electrolytes are off balance, NVP is potentially harmful. “Women need to discuss their symptoms with their caregiver and work together to try and reduce nausea and vomiting.”

Morning sickness remedies

Lifestyle and dietary changes, such as getting enough rest and eating smaller amounts of food throughout the day, instead of three large meals, may help ease NVP. “There’s no hard and fast rule about what a woman should eat to avoid nausea,” says Lane. “Women should follow their own cues; that may mean sticking to carbohydrates, such as bread, fresh fruit and vegetables, if that’s all they can stomach.”

Sea bands, the acupressure wristbands worn to relieve seasickness, have been shown to be effective for NVP, so they’re worth a try, says Lane.

Morning sickness prescription drugs

Diclectin (a combination of vitamin B6 and antihistamine) is the most commonly prescribed drug for NVP. It has been tested in pregnancy and proven safe for mother and baby, and Lane does not hesitate to prescribe it, although some research suggests it's ineffective.  Still, many women say the pill, which has a pink silhouette of an expectant mom stamped on it, was a lifeline during pregnancy. For severe NVP, treatment has to be tailored to the individual, says Lane, including intravenous hydration to replenish lost fluids for extreme cases.