Nausea During Pregnancy: More Likely to Have a Girl?

Also read: Nub theory: This is how you can see the gender on an ultrasound

What causes nausea during pregnancy?

Nausea is a common symptom of pregnancy. Until recently, however, the exact cause of this nausea was not fully understood. Hormonal changes (HCG hormone) were often blamed in the past, but a recent discovery (2023) has found the culprit: the GDF15 protein.

Whether a pregnant woman experiences nausea is related to her sensitivity to the hormone GDF15. Researchers found that the severity of symptoms is directly linked to the amount of the hormone the expectant mother was exposed to before pregnancy, and to the amount of the hormone produced by the fetus.

In other words, the lower the GDF15 levels in a woman's body before pregnancy, the greater the risk of her getting sick if those levels rise once she is pregnant. And the more GDF15 the fetus produces, the more severe the nausea and vomiting are likely to be.

Also read: What can you do about pregnancy nausea and vomiting?

More nausea in a girl?

A 2021 study found that GDF15 levels were significantly higher in the blood and cerebrospinal fluid (CSF) of women carrying a female fetus than in women carrying a male fetus. However, the authors found no reason for the increase in GDF15 levels.

In the scientific literature, an association has repeatedly been established between women who suffer from hyperemesis gravidarum (severe nausea and vomiting with or without hospitalization) and the fact that they are carrying a female fetus. A study conducted at Harvard University in 2020 extended these results to women with daily, but less severe, nausea. In the study, women who were carrying a female fetus reported a greater frequency of nausea and vomiting during the first trimester of pregnancy than women who were carrying a male fetus.

Also read: When can you see the gender on an ultrasound?

So there's probably some truth to it, but while morning sickness is more common in women who are pregnant with a girl, it's important to remember that any woman can experience it, regardless of the sex of her baby.

Nearly 75% of pregnant women experience morning sickness in early pregnancy and only 49% give birth to a girl each year.

Sources:
https://newscientist.nl
https://www.ncbi.nlm.nih.gov
http://onlinelibrary.wiley.com
https://www.ncbi.nlm.nih.gov