Ladies, Rejoice! An Explanation for Morning Sickness


man's hand on woman's pregnant belly

For some women who become pregnant, severe morning sickness can be debilitating and even cause a miscarriage. It’s called hyperemesis gravidarum or HG for short.  Until now, we didn’t know what caused this and some doctors believed it was all in the woman’s mind. The researcher who traced the problem to a hormone was motivated by her own suffering from HG.   

What causes the nausea and vomiting is the hormone GDF-fifteen which is made regularly by the body but just not at such high levels. Once the woman is pregnant, the placenta and fetus up the production.  

The higher the level of GDF-fifteen, the worse the morning sickness. It signals the brain to lower food intake because it senses cellular stress, a normal part of pregnancy. The suppression of appetite causes nausea which leads to vomiting.  

Women with lower levels of the hormone were more resistant to its effects and the same for women who’ve been pregnant before and older women.  They also found that women with an uncommon genetic variant of the GDF 15 naturally produced higher levels of the hormone and suffered from HG.  

Researchers believe nausea falls off later in pregnancy because the woman’s body becomes tolerant to higher levels of the hormone.  This could lead to new ways to prevent morning sickness – through helping build a woman’s tolerance to the hormone before she gets pregnant.  If that’s the case, pregnant moms can just focus on their next craving: pickles or ice cream or both? 

We are Drs. David Niesel and Norbert Herzog, at UTMB and Quinnipiac University, where biomedical discoveries shape the future of medicine.   For much more and our disclaimer go to or subscribe to our podcast. Sign up for expanded print episodes at or our podcasts at:  Medical Discovery News ( 

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