Why does morning sickness happen and what can I do to help?

Morning sickness happens because of a rapid rise in pregnancy hormones, most notably human chorionic gonadotropin (hCG) and a placental hormone called GDF15, both of which affect the areas of the brain that control nausea. It affects up to 80 percent of pregnancies, usually starting before 9 weeks and easing by the second trimester for most women.† It is uncomfortable, but research increasingly links it to a healthy, developing pregnancy rather than something going wrong.

The hormone behind the nausea

According to Mayo Clinic, nausea and vomiting during pregnancy are believed to be tied to hCG, a hormone the body starts producing shortly after a fertilized egg implants in the uterine lining. Women with more severe morning sickness, including hyperemesis gravidarum, tend to have higher hCG levels, as do women carrying twins or multiples.

A newer piece of the puzzle comes from a landmark 2023 study published in Nature. Researchers found that a placental hormone called GDF15 acts directly on the brainstem's nausea center, and that a woman's sensitivity to it, not just how much the placenta produces, largely determines how sick she feels. Women with naturally low GDF15 levels before pregnancy tend to be more sensitive to the hormone's rapid rise in early pregnancy, which helps explain why severity varies so much from woman to woman, and even from pregnancy to pregnancy in the same woman.

Why it's actually a reassuring sign

Research from the NIH's Eunice Kennedy Shriver National Institute of Child Health and Human Development found that among women with a history of pregnancy loss, those who experienced nausea and vomiting in early pregnancy had a meaningfully lower risk of miscarriage than those who didn't. The researchers describe this as one of the strongest pieces of evidence to date supporting a protective association between morning sickness and pregnancy outcomes.

"One of the challenges in pregnancy is building that trust… and feeling heard."

— Dr. Tosin Odunsi, MD, MPH, FACOG, Obstetrics and Gynecology Physician

What actually helps day to day

According to ACOG's practice bulletin on nausea and vomiting of pregnancy, taking a prenatal vitamin starting three months before conception may ease the incidence and severity of morning sickness, and this is one of the guideline's highest-confidence recommendations. ACOG also notes that dietary and lifestyle changes are often enough to manage mild cases, before turning to other options.

Our clean-label prenatal with 5-MTHF and iron bisglycinate is formulated with ScentCert technology specifically to reduce scent-triggered nausea, and supports healthy folate and iron status during pregnancy.† For nausea that shows up regardless of prenatal timing, our organic ginger and vitamin B6 nausea lozenges are formulated for discreet, on-the-go relief.†

Always consult your healthcare provider before starting any new supplement, especially during pregnancy, breastfeeding, or while managing a medical condition.

"I remember how isolating pregnancy nausea felt before anyone had language for it. That's part of why we build products around real experience, not just a lab bench."

— Amy Suzanne Upchurch, Founder and CEO of Pink Stork

Explore the rest of this series

• Does morning sickness severity mean anything about the baby's sex?
• What foods commonly trigger morning sickness nausea?
• What is the best time to take prenatal vitamins to avoid nausea?
• Is morning sickness different with your second pregnancy?

Pink Stork Nausea Sweets are USDA Organic and cGMP-certified, and Total Prenatal is third-party tested at ISO 17025 accredited labs, with 50,000+ verified Amazon reviews across the brand.

Frequently asked questions

Why does morning sickness happen if I'm healthy?

It's driven by rapidly rising pregnancy hormones, primarily hCG and GDF15, acting on the nausea centers of the brain. Research links it to normal, healthy placental development rather than a sign of a problem.

Does morning sickness mean the pregnancy is healthier?

Research from NIH found that among women with a history of pregnancy loss, experiencing nausea and vomiting in early pregnancy was associated with a lower risk of miscarriage. That said, not experiencing nausea does not mean something is wrong.

When does morning sickness usually start and stop?

Symptoms almost always begin before 9 weeks of pregnancy and typically ease by the end of the first trimester, though some women experience symptoms longer.

Can taking a prenatal vitamin help before I'm even pregnant?

ACOG's clinical guidance notes that taking a prenatal vitamin for one to three months before conception may reduce the incidence and severity of nausea and vomiting once pregnancy begins.

† These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Always consult your healthcare provider before starting any new supplement, especially during pregnancy, breastfeeding, or while managing a medical condition. Keep out of reach of children.