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.