Sunday, December 17, 2023

Mornings with no sickness?

Today I learned that scientists have figured out that one hormone is the cause for "morning sickness," which does not actually always happen in the morning. I knew the all-day part before, but the hormone identification part I did not. From the NYT: "Scientists Pinpoint Cause of Severe Morning Sickness." 

Scientists from the study, in Nature, attribute morning sickness to the hormone GDF15. I tried to read the study to get a better understanding of what they are saying, but I really understood nothing. I tried to read the abstract, too, but it still made little sense. 

This is a big deal partially because throwing up is bad and inconvenient, especially if you are pregnant, but also because there is a severe form of morning sickness that can hospitalize pregnant women. It is called hyperemesis gravidarum, and it causes unrelenting vomiting and nausea throughout pregnancy. It affects 2% of women. Like many things that affect pregnant women, and women in general, the scientific establishment has a tendency to ignore them as just women going crazy. 

Perhaps because nausea and vomiting are so common in pregnancy, doctors often overlook hyperemesis, dismissing its severe symptoms as psychological, even though it is the leading cause of hospitalization during early pregnancy, experts said. Although celebrities like Kate Middleton and Amy Schumer have raised the condition’s profile in recent years by sharing their experiences, it remains understudied.

The link at the end of the quote is to an editorial by Jessica Grose, who writes a Times newsletter on "American family, culture, politics and the way we live now." Grose brings up that research on women-specific illnesses is tremendously underfunded, and cites several examples. She also brings up that for a long time, it has been completely acceptable to "psychologize" women's illnesses. Fejzo, the first author on the GDF15 study, is mentioned several times. In 1999, Fejzo actually did have hyperemesis gravidarum:

During her second pregnancy, Fejzo was so sick that she couldn’t swallow a teaspoon of water, lost 15 pounds and ultimately miscarried. Her doctor, Callahan wrote, told Fejzo that “women make themselves sick during pregnancy to gain the sympathy of their husbands, and later, that her illness was a ploy for attention from her parents, who were helping with her medical care.”

An interesting aspect of this is that GDF15 is not "all bad." A rare blood disorder found in Sri Lankan women, which gave them abnormally high levels of the hormone before pregnancy, also meant that they didn't have any nausea or vomiting. Researchers from the study point out that this might be due to them being hyperexposed to GDF15 before pregnancy, and that this mechanism may be used to prevent morning sickness.

Curing morning sickness is apparently very fraught, because of the dark history of it. In the 1950s, a drug called thalidomide (content warning on link) started to be used to treat morning sickness. What ensued is described as "the biggest man‐made medical disaster ever." The drug worked, but a side effect is that your child can become deformed and likely die shortly after birth. The risk, according to the GDF15 study, is that hormonal treatments may "cross the placenta" and with that bring the risk of teratogenesis (deformation). Discussion on using the GDF15 hormone to control morning sickness and hyperemesis begins on line 307 of the study in Nature linked above. It is interesting, but it is out of my abilities to summarize it. 

The article was by Azeen Ghorayshi, a reporter for the Times covering "the intersection of sex, gender, and science," which is a pretty interesting beat, I think. Browsing her articles, I found this interesting piece: "Guess Which Sex Behaves More Erratically (at Least in Mice)." The answer is male mice, according to one new study. This clashes with the standard that excludes female mice from research due to their hormones making them unpredictable.