Sleep apnea and pregnancy complications

Pregnancy is a time of rapid change in women's bodies. Sleep apnea can be more common due to weight gain and fluid retention (Restless legs syndrome is also more common - but that is for a separate post). This article discusses research presented at the American Thoracic Society's 2017 International conference. I did not attend this meeting. Researchers studied > 1.5 million pregnant women with a history of sleep apnea. The results showed that in women with obstructive sleep apnea there was a greater risk of serious pregnancy complications, longer hospital stays, and admission to the intensive care unit than mothers without the condition. However, treatment of sleep apnea was not determined, so it's not known if that would reduce the risk.

Sleep-disordered breathing in pregnancy

I've blogged before here, here, and here about pregnancy and breathing disorders in sleep. We know that the prevalence of sleep-disordered breathing (SDB) symptoms increases the further along in the pregnancy. This could be due weight gain and swelling that occurs as pregnancy progresses.

Some studies have shown an association between SDB and pregnancy-related illnesses like high blood pressure, gestational diabetes, and pre-term birth. However, many of these studies relied on subjective assessment of SDB. This study was done to look at the relationship of objectively assessed SDB and certain pregnancy-related illnesses. A home sleep study was performed on pregnant women twice - once between 6 - 20 weeks and again between 28 - 37 weeks. Results showed that 30% of the pregnant women had SDB early pregnancy. However, there was no relationship between SDB and maternal high blood pressure (called preeclampsia), preterm birth, or extremes of birthweight (low or high). There was a relationship between SDB severity and risk of developing gestational diabetes, even after controlling for confounding factors like age, race, body-mass index, hx of chronic high blood pressure, etc.

Despite the observed relationship between sleep-disordered breathing and gestational diabetes, the study authors pointed out that there is no evidence that treatment of the SDB in the short term improves maternal or neonatal outcomes.

Sleeping position may affect pregnancy outcome

I was always taught that pregnant women should avoid sleeping on their back. This is especially true as you get closer to term date. As the baby gets bigger, it and the uterus can compress the inferior vena cava, the main vein that brings blood back to the mom's heart. Less blood into the heart means less blood out of the heart, which can harm the baby.

Here is a article about a study that showed that sleeping on the back while pregnant was associated with stillbirth. Researchers think that the stillbirths occurred because the babies were low birth weight - possibly due to reduced blood flow to the placenta during back sleeping. Researchers speculate that sleeping on the sides may reduce rates of stillbirth.

Obstructive sleep apnea and pregnancy

This article discusses research about obstructive sleep apnea (OSA) and pregnancy. Pregnant women have a higher chance of developing pre-eclampsia, a condition that leads to protein loss in the urine and high blood pressure in pregnancy. OSA also increases the risk that the newborn will require neonatal care in an ICU. Screening for OSA when pregnant may help prevent some of these problems.

Sleepiness in third trimester common, but may signal underlying obstructive sleep apnea

This article discusses research showing that sleepiness during the third trimester is common, but may not be normal. Some of the sleepiness could be due obstructive sleep apnea (OSA). The authors conclude that screening for sleep related breathing disorders should be done in pregnant women, and I agree. Especially if a pregnant woman has known OSA but is not using CPAP. Untreated OSA can increase risk for a small baby, called intrauterine growth retardation.

Pregnancy, High Blood Pressure, and Sleep-Disordered Breathing

Pregnant women snore more and have more nasal congestion than non-pregnant women. And pregant women with high blood pressure (a.k.a. gestational HTN) or pre-eclampsia (a.k.a. gestational HTN with protein in the urine) have even more snoring and nasal congestion. Some studies have suggested that women with getstational HTN or pre-eclampsia have a high prevalence of obstructive sleep apnea (OSA).

In this month's Sleep Journal , there is an article about pregnant women with gestational HTN and OSA. Study participants were at least 18 years old during their first and only pregnancy and had gestational HTN or pre-eclampsia. Controls were matched for gestational age and had no high blood pressure or protein in the urine. Results showed that women with gestational HTN were more obese than controls. There was a higher frequnecy of self-reported regular snoring and nasal congestion in women with gestational HTN vs controls. The women with gestational HTN also reported lower sleep quality but there was no difference in daytime sleepiness between the two groups. Sleep studies showed that women with gestational HTN had less total sleep time, lower sleep efficiency, and a lower percentage of REM sleep than the controls. Finally, 50% of women with gestational HTN had OSA compared to 12% of pregnant women without gestational HTN.

The authors point out that the higher OSA frequency in the women with gestational HTN could be due to the higher obesity rates, as OSA and obesity go hand-in-hand. But these findings are important because even mild OSA can affect blood pressure in non-pregnant patients. And recent data have shown that short-term relief of mild OSA with CPAP can improve blood pressure in pre-eclamptic patients. Therefore, it is important to screen pregnant women with gestation HTN for snoring, sleep quality, and OSA.