High Fat Diet during Pregnancy increases Risk of Stillbirth

“Eating for two” is no excuse to divulge nutritional necessities, as most women already know—but a recent study has shown that not only is it unhealthy for the mother to consume a fatty diet while she is pregnant, it is also dangerous for the baby.

Consuming a high-fat diet during pregnancy may increase the chance of stillbirth, according to new research at Oregon Health & Science University, as well as other adverse outcomes.

The study reports that a pregnant woman eating the typical American diet—high calorie, high fat—has a decrease in blood flow from her own body to the placenta, where the fetus gets its nourishment.

The study was performed at the OHSU Oregon National Primate Research Center, which houses the Japanese macaque, a monkey whose placental structure is very similar to that in humans.

Frias and colleagues observed twenty-four pregnant Japanese macaques that consumed either a diet containing 32% calories from fat or a control diet with 14% fat calories for at least four years.

The researchers discovered that monkeys that consumed a high-fat diet underwent a significant decrease in blood flow from the uterus to the placenta—a reduction of 38% to 56%—and a rise in placental inflammation, regardless of whether the monkeys were obese or slender. The risk of stillbirth was higher, however, when the monkeys were obese with hyper-insulinemia, or pre-diabetes.

"This study demonstrates that maternal diet during pregnancy has a profound influence on both placental and fetal development. The high-calorie, high-fat diet common in our society has negative effects on placental function and may be a significant contributor to adverse pregnancy outcomes, such as stillbirth," said Antonio Frias, M.D., principal investigator and assistant professor of obstetrics and gynecology (perinatology/maternal-fetal medicine) in the OHSU School of Medicine.

Previous studies have proven that virtually all undesirable outcomes during pregnancy—abnormal fetal growth, preeclampsia, preterm labor, and stillbirth—are in some way connected to an abnormally developed or damaged placenta.

Additionally, maternal obesity has previously been associated with placental inflammation and dysfunction, as well as an increased risk of stillbirth. With these results in mind, the researchers conjectured that consumption of a fatty diet during pregnancy may increase the risk of placental inflammation and the risk of stillbirth.

Further studies are needed to determine precisely how a high-fat diet reduces placental blood flow, the researchers reported.

They will also investigate whether dietary changes and diet supplementation improve pregnancy outcomes in both monkeys and humans.

The study is published in the June edition of the journal Endocrinology.