OBSTETRICS Prospective trial on obstructive sleep apnea in pregnancy and fetal heart rate monitoring Sofia A. Olivarez, MD; Bani Maheshwari, MD; Meghan McCarthy, MD; Nikolaos Zacharias, MD; Ignatia van den Veyver, MD; Lata Casturi, MS; Haleh Sangi-Haghpeykar, PhD; Kjersti Aagaard-Tillery, MD, PhD OBJECTIVE: Obstructive sleep apnea (OSA) involves episodic nocturnal ap- neas. Using polysomnography, we examined the predictive capacity of screening questionnaires (Berlin) in pregnancy. Incorporating simultaneous fetal heart rate monitoring (FHM), we examined the association of maternal apnea with FHM abnormalities. STUDY DESIGN: We enrolled 100 pregnant women at 26-39 weeks of gestation with OSA screening and baseline data ascertainment who underwent polysomnography and FHM for 3 hours. The rela- tionship between maternal characteristics, OSA, and FHM was ex- plored with multivariate analyses that were controlled for potential confounders. RESULTS: When compared with polysomnography, sensitivity and specificity by Berlin screening was 35% and 63.8%, respectively; the snoring component of the Berlin correlated better with oxygen desaturation 95% ( P = .003). Body mass index was a significant confounder (r s = 0.44; P  .0001). No associa- tion was observed between FHM abnormalities and OSA parameters. CONCLUSION: In pregnancy, the Berlin questionnaire poorly predicts OSA. It is unclear whether fetal compromise during maternal apnea is a mecha- nism in OSA that is related to pregnancy outcome. Key words: fetal heart rate monitoring, obstructive sleep apnea, polysomnography, pregnancy Cite this article as: Olivarez SA, Maheshwari B, McCarthy M, et al. Prospective trial on obstructive sleep apnea in pregnancy and fetal heart rate monitoring. Am J Obstet Gynecol 2010;202:552.e1-7. O bstructive sleep apnea (OSA) is characterized by episodes of air- flow limitation that cause intermittent hypoxia. 1 Studies have observed that in nonpregnant patients, it is an indepen- dent risk factor for hypertension, coro- nary artery disease, and atherosclero- sis. 2-4 Although the true prevalence rate in pregnancy is unknown, many physio- logic changes contribute to increased risk for OSA. 5-8 To date, few studies have investigated OSA in pregnancy, and most studies have failed to adjust for po- tential maternal confounders. 1,6-8 The diagnosis of OSA is established by polysomnography, but time and expense limitations have lead to the development of several validated screening tools, which includes the Berlin question- naire. 9,10 Although the Berlin question- naire has been shown to have a positive predictive value as high as 89%, recent analyses suggest the predictive perfor- mance of the questionnaire may be quite variable; the sensitivity and specificity range from 57-86% and 43-97%, respectively. 10-14 Among pregnant women, snoring, which is a risk factor for OSA, increases through latter gestation; although not all “snorers” have OSA, it has been associ- ated with adverse pregnancy outcomes, intrauterine growth restriction, and pre- eclampsia. 15-18 Furthermore, maternal apnea episodes have been associated with fetal heart rate decelerations that may be a contributing factor to docu- mented adverse pregnancy outcomes. 19 We hypothesized that the Berlin ques- tionnaire is a valid tool for the screening of OSA in pregnancy, when compared with the gold standard, polysomnogra- phy. We therefore sought to investigate the performance of the Berlin question- naire among pregnant women in a large, prospectively acquired cohort. We also sought to investigate the suggested asso- ciation between sleep-related maternal apnea events and changes in fetal oxy- genation status, as measured by fetal heart rate monitoring (FHM). METHODS Basic study design Institutional review board approval was obtained from both Baylor College of Medicine and the Harris County Hospital District. All pregnant women during the 9-month study interval who were admitted to the antepartum ser- vice at the Ben Taub General Hospital were approached for participation in the study. Enrollment was halted when we reached an initial cohort of 100 women. Inclusion criteria included singleton pregnancy with unrelated condition for antepartum admission and gestational age 26 weeks by best obstetric estimate (with at least 1 con- firmatory sonogram). Exclusion crite- ria consisted of hospital stay 4 hours From the Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology (Drs Olivarez, Maheshwari, McCarthy, Zacharias, van den Veyver, Sangi-Haghpeykar, and Aagaard-Tillery), and the Department of Pulmonary-Critical Care (Ms Casturi), Baylor College of Medicine and Ben Taub General Hospital, Houston, TX. Received June 24, 2009; revised Sept. 20, 2009; accepted Dec. 7, 2009. Reprints: Kjersti M. Aagaard-Tillery, MD, PhD, Baylor College of Medicine, 1 Baylor Plaza, Jones 314, Houston, TX 77030; aagaardt@bcm.tmc.edu. Authorship and contribution to the article is limited to the 8 authors indicated. There was no outside funding or technical assistance with the production of this article. 0002-9378/$36.00 © 2010 Mosby, Inc. All rights reserved. doi: 10.1016/j.ajog.2009.12.008 Research www. AJOG.org 552.e1 American Journal of Obstetrics & Gynecology JUNE 2010