Obstructive sleep apnoea (OSA) affects 11 per cent of pre-menopausal women though it often remains undetected. Women may present differently than men, and the classic findings of snoring, witnessed apnoeas and sleepiness may not be observed. Factors which predispose to OSA include polycystic ovarian syndrome, obesity, retromicrognathia, and hypothyroidism. OSA may contribute to neurocognitive dysfunction, depression, hypertension and metabolic syndrome. Emerging evidence indicates that snoring and OSA increase during pregnancy. For normal women with normotensive, low-risk pregnancies the prevalence of OSA is very low. Among normotensive pregnant women with high risk pregnancies, the prevalence of OSA is high and is even higher among those with gestational hypertension/preeclampsia during pregnancy. Incident snoring, which is a marker for OSA, is associated with an increased risk of developing gestational hypertension. Recent studies indicate that OSA per se is an independent risk factor for gestational hypertension/pre-eclampsia and may contribute to other poor obstetrical outcomes. The diagnostic test of choice for OSA is a polysomnography with electroencephalogram. Milder degree of disease than what is usually considered clinically significant among men or non-pregnant women appears to be relevant for foetomaternal outcomes. There seems to be benefit for blood pressure control to treating even milder degrees of OSA with CPAP, both acutely and over the 9 months of pregnancy. Chronic hypertensive women should be strongly considered for diagnosis and treatment of OSA prior to or beginning as early as possible in pregnancy to help maintain blood pressure control. Increasing awareness of OSA among maternal health care providers is important given the potential benefits for pregnancy and other health-related outcomes associated with identification and treatment of OSA.