Does morning sickness severity tell you the gender of your baby?

Several large studies have found a small statistical association between more severe morning sickness and carrying a female fetus, but the research is inconsistent, the effect is modest, and it isn't reliable enough to predict your baby's sex.† Medical tests, not symptom severity, are the only accurate way to know.

What the research actually found

A study of 4,320 pregnancies, published in Archives of Gynecology and Obstetrics, found that women carrying a female fetus reported a statistically higher frequency of nausea and vomiting in the first trimester than women carrying a male fetus, though the difference in average scores was small.

A much larger study of more than 91,000 women, part of the Japan Environment and Children's Study and published in the Journal of Epidemiology, found higher odds of both having and having severe nausea and vomiting among women with female pregnancies compared with male pregnancies, and similarly higher odds among twin pregnancies compared to singleton pregnancies.

That's a real, replicated pattern across large datasets. But it's a population-level statistical association, not a reliable individual predictor. Plenty of women carrying boys have severe morning sickness, and plenty of women carrying girls have none at all.

Why the link might exist at all

One proposed explanation involves GDF15, the placental hormone identified in 2023 research published in Nature as a key driver of pregnancy nausea. Fetal sex may subtly influence placental hormone production, which could partly explain the pattern researchers keep finding, though this hasn't been definitively proven as the mechanism behind the sex-based difference specifically.

The bottom line

If you want to know your baby's sex, a blood-based cell-free DNA test or an anatomy ultrasound will tell you far more reliably than how you're feeling. Symptom-based folklore, including morning sickness severity, food cravings, and bump shape, isn't supported as a prediction method by current evidence.

Whatever your morning sickness looks like, our organic ginger and vitamin B6 nausea lozenges are formulated to help ease occasional upset stomach and morning sickness on the go.† Pairing them with Pink Stork's Total Prenatal, formulated for first-trimester sensitivity, covers both the nutrition and the nausea side of early pregnancy.†

For the full mechanism behind why morning sickness happens at all, see our guide on why morning sickness happens and what actually helps.

Always consult your healthcare provider before starting any new supplement, especially during pregnancy.

Frequently asked questions

Does worse morning sickness mean I'm having a girl?

Large studies have found a statistical association between more severe nausea and carrying a female fetus, but it's a modest, population-level pattern, not a reliable individual predictor. Many exceptions exist in both directions.

Is there any real science behind the "worse sickness, more likely a girl" idea?

Yes, in the sense that multiple large studies have found the pattern, including one with over 91,000 participants. But "statistically associated" is very different from "predictive for you," and the effect size is small.

What's the most accurate way to find out my baby's sex?

Medical tests, including cell-free DNA blood tests as early as 10 weeks or an anatomy ultrasound around 18 to 20 weeks, are the reliable methods. Pregnancy symptoms are not.

Why might fetal sex affect nausea at all?

One theory involves placental hormone production potentially differing subtly by fetal sex, though the exact mechanism behind the population-level pattern researchers have observed isn't fully settled.

† 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.