Alison M. Fung

Effects of Maternal Obstructive Sleep Apnoea on Fetal Growth: A Prospective Cohort Study

Objective The objective of this study is to determine whether obstructive sleep apnea (OSA) is associated with reduced fetal growth, and whether nocturnal oxygen desaturation precipitates acute fetal heart rate changes. Study Design We performed a prospective observational study, screening 371 women in the second trimester for OSA symptoms. 41 subsequently underwent overnight sleep studies to diagnose OSA. Third trimester fetal growth was assessed using ultrasound. Fetal heart rate monitoring accompanied the sleep study. Cord blood was taken at delivery, to measure key regulators of fetal growth. Results Of 371 women screened, 108 (29%) were high risk for OSA. 26 high risk and 15 low risk women completed the longitudinal study; 14 had confirmed OSA (cases), and 27 were controls. The median (interquartile range) respiratory disturbance index (number of apnoeas, hypopnoeas or respiratory related arousals/hour of sleep) was 7.9 (6.1–13.8) for cases and 2.2 (1.3–3.5) for controls (p<0.001). Impaired fetal growth was observed in 43% (6/14) of cases, vs 11% (3/27) of controls (RR 2.67; 1.25–5.7; p = 0.04). Using logistic regression, only OSA (OR 6; 1.2–29.7, p = 0.03) and body mass index (OR 2.52; 1.09–5.80, p = 0.03) were significantly associated with impaired fetal growth. After adjusting for body mass index on multivariate analysis, the association between OSA and impaired fetal growth was not appreciably altered (OR 5.3; 0.93–30.34, p = 0.06), although just failed to achieve statistical significance. Prolonged fetal heart rate decelerations accompanied nocturnal oxygen desaturation in one fetus, subsequently found to be severely growth restricted. Fetal growth regulators showed changes in the expected direction- with IGF-1 lower, and IGFBP-1 and IGFBP-2 higher- in the cord blood of infants of cases vs controls, although were not significantly different. Conclusion OSA may be associated with reduced fetal growth in late pregnancy. Further evaluation is warranted to establish whether OSA may be an important contributor to adverse perinatal outcome, including stillbirth.

Obstructive sleep apnea and pregnancy: the effect on perinatal outcomes.

Obstructive sleep apnea (OSA) is characterized by repeated episodes of upper airway obstruction, resulting in hypoxemia, hypercapnia and sleep fragmentation. Pathophysiological sequelae include sympathetic activation, increased oxidative stress and a generalized inflammatory response, culminating in endothelial dysfunction. These are the proposed mechanisms that mediate the increased risk of hypertension and cardiovascular disease among patients with OSA outside of pregnancy. It is intriguing to consider the consequences of these events on pregnancy outcomes. There is a growing literature on the impact of maternal OSA on hypertensive disorders of pregnancy, gestational diabetes and impaired fetal growth. The data, while promising, require confirmation with larger numbers to verify the findings. OSA may be an important mediator of the poor perinatal outcomes associated with maternal obesity; moreover, one which may be amenable to treatment. This review discusses OSA and summarizes the current literature linking OSA with adverse perinatal outcomes.

Subjective reports versus objective measurement of sleep latency and sleep duration in pregnancy.

This study compared self-reported sleep latency (SL) and total sleep time (TST) to objective measures on polysomnography (PSG) during pregnancy. Thirty-three women in the third trimester (T3) of pregnancy, 16 women in the first trimester (T1) of pregnancy, and 15 non-pregnant women underwent overnight PSG, and shortly after awakening reported their perceived SL and TST. Results showed that, on average, the T3 group slightly overestimated their TSTs, whereas the T1 and non-pregnant groups underestimated TSTs when compared with objective measurement. All groups overestimated SL, and perceived SL was closest to the first epoch of 10 min of uninterrupted sleep or the first epoch of slow-wave sleep, rather than the first epoch of sleep (the current definition used for diagnostic sleep studies). The wide variation in discrepancies between estimation and PSG measurement for both TST and SL shows that self-reports made by both pregnant and non-pregnant women tend to be unreliable, which has important implications both clinically and for the many studies based on self-reported sleep patterns in pregnancy.

Dichorionic triamniotic triplet pregnancy complicated by twin anemia polycythemia sequence: the place of fetal therapy.

Monochorionic twins as part of a high order multiple pregnancy can be an unintended consequence of the increasingly common practice of blastocyst transfer for couples requiring in vitro fertilisation (IVF) for infertility. Dichorionic triamniotic (DCTA) triplets is the most common presentation, and these pregnancies are particularly high risk because of the additional risks associated with monochorionicity. Surveillance for twin-to-twin transfusion syndrome, including twin anemia polycythemia sequence, may be more difficult, and any intervention to treat the monochorionic pair needs to balance the proposed benefits against the risks posed to the unaffected singleton. Counseling of families with DCTA triplets is therefore complex. Here, we report a case of DCTA triplets, where the pregnancy was complicated by threatened preterm labour, and twin anemia polycythemia sequence (TAPS) was later diagnosed at 28 weeks. The TAPS was managed with a single intraperitoneal transfusion, enabling safe prolongation of the pregnancy for over 2 weeks until recurrence of TAPS and preterm labour supervened. Postnatal TAPS was confirmed, and all three infants were later discharged home at term corrected age, and were normal at follow-up. This case highlights that in utero therapy has an important role in multiple pregnancies of mixed chorionicity, and can achieve safe prolongation of pregnancy at critical gestations.

Electroconvulsive Therapy in Pregnancy

Modified Electroconvulsive Therapy (ECT) is a highly effective treatment in psychiatry despite variable community views. It is considered a first-line treatment option for severe depression (associated with high suicide risk, catatonic signs, and/or psychotic symptoms), functional catatonia, and severe psychotic agitation (acute mania or psychosis). It is also an effective treatment option for depression that is unresponsive to multiple trials of antidepressant medications with response rates close to 70 % in some studies. The current evidence suggests that pregnant women who present with the above indications for ECT should not per se be excluded from accessing ECT. There are specific considerations associated with ECT use in pregnancy and this chapter will summarize the principles of safety and effective use of ECT in pregnant patients to optimize perinatal outcomes. The chapter will not go into details of ECT electrophysiology and techniques that can be accessed from other texts and guidelines.

Sleep‐disordered breathing in hypertensive disorders of pregnancy: a BMI‐matched study

Sleep‐disordered breathing is more common in hypertensive disorders during pregnancy; however, most studies have not adequately accounted for the potential confounding impact of obesity. This study evaluated the frequency of sleep‐disordered breathing in women with gestational hypertension and pre‐eclampsia compared with body mass index‐ and gestation‐matched normotensive pregnant women. Women diagnosed with gestational hypertension or pre‐eclampsia underwent polysomnography shortly after diagnosis. Normotensive controls body mass index‐matched within ±4 kg m−2 underwent polysomnography within ±4 weeks of gestational age of their matched case. The mean body mass index and gestational age at polysomnography were successfully matched for 40 women with gestational hypertension/pre‐eclampsia and 40 controls. The frequency of sleep‐disordered breathing in the cases was 52.5% compared with 37.5% in the control group (P = 0.18), and the respiratory disturbance index overall did not differ (P = 0.20). However, more severe sleep‐disordered breathing was more than twice as common in women with gestational hypertension or pre‐eclampsia (35% versus 15%, P = 0.039). While more than half of women with a hypertensive disorder of pregnancy meet the clinical criteria for sleep‐disordered breathing, it is also very common in normotensive women of similar body mass index. This underscores the importance of adjusting for obesity when exploring the relationship between sleep‐disordered breathing and hypertension in pregnancy. More severe degrees of sleep‐disordered breathing are significantly associated with gestational hypertension and pre‐eclampsia, and sleep‐disordered breathing may plausibly play a role in the pathophysiology of pregnancy hypertension in these women. This suggests that more severe sleep‐disordered breathing is a potential therapeutic target for reducing the prevalence or severity of hypertensive disorders in pregnancy.