WASHINGTON - A new study has found that women who lie on their backs late in their pregnancies could be increasing their risk of stillbirth.
Researchers at the University of Auckland in New Zealand say that when an expectant mother rests in a supine position, her unborn baby's heart rate and activity level change, indicating that the fetus is responding by decreasing the amount of oxygen it takes in.
Investigators studied 29 healthy women in their third trimester of pregnancy. The women were asked to lie in different positions for 30 minutes at a time. The fetal behavior state, a measure of fetal health, was recorded for each position.
Researchers found that lying face up late in pregnancy can add stress to the fetus and may reduce the amount of oxygen, possibly contributing to stillbirth.
If a woman has an underlying health conditions, say investigators, that could add to the risk of stillbirth.
The findings were published in the Journal of Physiology .
Each woman in the study was followed through birth and each baby was born healthy.
According to the World Health Organization, more than 18 babies out of 1,000 are stillborn, mostly in low- and moderate-income countries.