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.

Pre-eclampsia, fetal activity levels, sleep-disordered breathing, and CPAP

Pre-eclampsia occurs high blood pressure and protein in the urine develops in a woman at least 20 weeks pregnant. It is associated with maternal death and fetal growth restriction. Some studies have shown an association of sleep disordered breathing (SDB), like obstructive sleep apnea (OSA), with pregnancy-induced high blood pressure. Pre-eclampsia goes away with delivery. However, if it's too early, delivery is delayed as long as possible.

Fetal movements are a normal part of pregnancy. Frequent movements are good, lack of movements is bad. In the Journal Sleep is a study where researchers quantified fetal movements in pregant patients with and without pre-eclampsia. They then did sleep studies on those with moderate to severe pre-eclampsia and observed some of them on CPAP for one night.

The results showed that pre-eclampsi reduced fetal movements. CPAP also raised fetal activity in women with pre-eclampsia, even thought the pre-eclampsia did not go away. The results are a little hard to interpret, because both pre-eclamptic and control patients had OSA based on the charts in the study, and the controls did not receive CPAP.

But if the results hold up in larger, better defined studies, treating women with pre-eclampsia with CPAP if they have sleep disordered breathing may allow obstetricians to delay delivery until a safer time.

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.

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.