Study links morning sickness to lower miscarriage risk

Newborn twins whose mother didn't experience morning sickness
Newborn twins whose mother did not experience morning sickness. (courtesy of Joyce Lutz)

By Hannah Moulthrop

Expectant mothers experiencing morning sickness may have less cause to worry about a miscarriage, a new study by the National Institutes of Health suggests. That does not mean women who feel well should be concerned, doctors say, warning that morning sickness does not measure how a pregnancy will fare.

Joyce Lutz, a Hyde Park  accountant, is not among the approximately 80 percent of women who suffer from morning sickness during pregnancy.

“I didn’t have nausea. I never threw up actually,” said Lutz. “It was more just the discomfort of not knowing what I felt like [eating]. “

Lutz, who delivered her twin boys Saturday, experienced what she said her doctor described as general malaise. No food was appealing or off-putting, which made it difficult to decide what to eat when she felt famished.

“It’s interesting she had twins because I think, in theory, she should have felt worse than an average person, but she felt fine,” said Dr. Whitney B. You, maternal fetal medicine specialist at Northwestern Medical Group and a professor at Northwestern University Feinberg School of Medicine. “So, I think it’s good evidence that while one feeling bad might offer some reassurance, I don’t think that not feeling bad should be a point of anxiety,” said You, who is not Lutz’s doctor.

Researchers from the National Institutes of Health found that among women with one or two prior miscarriages, those who have nausea are 50 percent less likely to have a miscarriage and those who have nausea and vomiting are 75 percent less likely to miscarry than women who did not have any morning sickness.

The study, published in JAMA Internal Medicine, reports finding stronger evidence that morning sickness may guard against miscarriages than earlier research.

Dr. Stefanie N. Hinkle, one of the study authors and a staff scientist at Eunice Kennedy Shriver National Institute of Child Health and Human Development, said earlier studies were limited by relying on women reporting their pregnancy symptoms retroactively and by missing early miscarriages that occurred before the data were collected.

“Our study enrolled women preconception while they were trying to get pregnant and therefore collected data prospectively on women’s symptoms in their earliest weeks of pregnancy and we’re also then able to look at the association with the very early pregnancy losses,” Hinkle said in an email.

Hinkle and her colleagues are curious about what might make morning sickness protective for a pregnancy.

“There have been some hypotheses that women may change their lifestyle habit in response to feeling nauseous and that this could prevent risky behaviors that have been linked to an increased risk for pregnancy loss, such as smoking and alcohol intake. However, we ruled out these factors along with other lifestyle factors such as caffeine and stress. So ultimately, more research is needed to understand this mechanism,” Hinkle said.

The study tracked the nausea symptoms of 797 women prior to conception through their 36th week of pregnancy. But other experts cautioned against using the findings as predictive for miscarriages.

Dr. Samuel Z. Williams, professor and the director of a program that treats chronic miscarriage at the Albert Einstein College of Medicine Montefiore Medical Center, cautioned that while, “It is true that, in a large population, those women with morning sickness are more likely to have a healthy pregnancy while those women without morning sickness are more likely to have a miscarriage, however, on an individual patient basis it is very difficult to use this as a guide to predict the pregnancy outcome.”

Williams said in an email that many of his patients who did not have any nausea progressed through a healthy pregnancy and delivery, while other patients with terrible nausea and vomiting may have miscarried.

Using self-reported symptoms recorded in a daily diary for weeks two through eight and then a monthly questionnaire for the 12th through 36th week of pregnancy means the NIH study involved data related to a woman’s experience of how she felt.

“One person might feel extraordinarily nauseated and it may not affect their life in any way, shape or form and somebody might just feel a little bit nauseated and for them it’s intolerable,” said Northwestern’s You.

She noted that while there are valid scales to measure nausea, it is ultimately a subjective measurement.

You urged women not to be afraid of treating their morning sickness. She said they don’t have to suffer through nausea or vomiting to have a healthy pregnancy. Treating their symptoms and feeling better will not mean anything has gone wrong, she added.

Photo at top: Joyce Lutz’s twin boys were born on Saturday. (Courtesy of Joyce Lutz)