Late pregnancy snoring could harm mother and baby alike

By Dr. Ananya Mandal, MDOct 27 2011

Nearly half of pregnant women may develop snoring by their final trimester and this could lead to dangerous health problems for mother and baby, Australian sleep researchers have shown. According to professor of medicine, Colin Sullivan, research found woman who started snoring during the later stages of pregnancy were at increased risk of developing high blood pressure.

“It's like they are being woken up a lot during the night-time rather than having a restful sleep,” said Professor Sullivan, who will present his findings at the Australasian Sleep Association conference in Sydney. He explained that high blood pressure was bad for the mother and also linked to babies having restricted growth or reduced blood flow through the placenta causing oxygen deprivation.

Professor Sullivan’s study with the Fertility First treatment centre that followed 30 women throughout their pregnancies found that by the third trimester nearly half were snoring for 20 per cent of the night and six were snoring for more than half the night. But the women were not always aware they snored. A study his team did of 2,000 pregnant women found half reported snoring. But further testing with Annemarie Hennessy, from the University of Western Sydney, found not all women who said they snored did, and 24 per cent who believed they did not snore did.

Another study also being presented tomorrow found a more serious form of snoring, sleep apnea, was linked to babies having reduced growth. The study leader, Alison Fung, from the Mercy Hospital for Women in Melbourne, said that if her results were replicated by a larger study they could potentially be used to help prevent stillbirth and other complications in pregnant women. Obese women were known to be more at risk of stillbirth and were also more at risk of developing sleep apnea.

“There's not much we can do about obesity … but if we found some of the complications associated with it can be treated that would be very exciting,” Dr Fung said. In the past, sleep apnea had been rarely studied in pregnant women because it largely affected men, but the hormones and weight gain in pregnancy put women at extra risk, she said. “Pregnancy is a particularly stressful time…You are putting your body through a stress test of life,” she said.

Pregnant women tend to snore because of the increased levels of the hormone progesterone, which causes increased stuffiness in the airways and congestion in the nasal passage. Their diaphragm also rises as the baby grows inside the uterus, reducing their lung capacity. Increased swelling in late pregnancy and weight gain, the biggest link to sleep apnea in the general population, also play a role. Dr Fung said pregnant women could try to prevent snoring by lying on their side to help them breathe faster and protect against airway collapse. They could also consider a continuous positive airway pressure mask to keep their airways open.