Is nausea during pregnancy a good sign?

Answers from Yvonne Butler Tobah, M.D.

It's not clear if nausea during pregnancy, also called morning sickness, is a good sign.

The cause of nausea and vomiting in pregnancy is currently unknown. Studies have suggested that nausea and vomiting in pregnancy might be due to hormones, evolutionary adaptation or psychological causes. A recent study of more than 2,400 pregnant women associated nausea and vomiting during the first trimester with a reduced risk of early pregnancy loss — particularly for women age 30 and older. However, this finding has not been proved in all cases.

What's the possible connection between nausea and vomiting during pregnancy and a reduced risk of pregnancy loss? Shortly after a fertilized egg attaches to your uterine lining, your body begins producing the hormone human chorionic gonadotropin (HCG). HCG has been linked to nausea and vomiting—women with severe morning sickness (hyperemesis gravidarum) have higher HCG levels than other pregnant women. Women pregnant with multiples, who are more likely to experience morning sickness, also have higher HCG levels.

Similarly, estrogen, another hormone that increases during pregnancy, is associated with an increased frequency of nausea and vomiting during pregnancy. It's possible that nausea and vomiting during pregnancy might indicate that you're experiencing the normal climb in pregnancy hormones needed for a healthy pregnancy. However, high pregnancy hormone levels aren't consistently associated with nausea and vomiting.

Keep in mind that a lack of nausea and vomiting during pregnancy isn't cause for concern. Some women with healthy pregnancies never experience morning sickness.

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Yvonne Butler Tobah, M.D.

Aug. 04, 2016