Pregnancy and perinatal outcomes in women with polycystic ovary syndrome and twin births: a population‐based cohort study

• Published in: BJOG : an international journal of obstetrics and gynaecology Vol. 122; no. 10; pp. 1295 - 1302
• Main Authors: Løvvik, TS, Wikström, A‐K, Neovius, M, Stephansson, O, Roos, N, Vanky, E
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01-09-2015
• Subjects: Adolescent; Adult; Apgar Score; Cesarean Section - statistics & numerical data; Childbirth & labor; Cohort Studies; Cohort study; Female; Humans; Infant, Low Birth Weight; Infant, Newborn; Medicin och hälsovetenskap; Obstetrics; Odds Ratio; Perinatal Mortality; Polycystic Ovary Syndrome; Pre-Eclampsia - etiology; Pregnancy; Pregnancy Complications - etiology; Pregnancy Outcome; Pregnancy, Twin; Premature Birth - etiology; preterm birth; Registries; Regression Analysis; Twins; Young Adult; preterm birth; twins; pregnancy outcome; Cohort study; polycystic ovary syndrome
• ISSN: 1470-0328; 1471-0528; 1471-0528
• DOI: 10.1111/1471-0528.13339

Objective
To investigate pregnancy and perinatal outcomes in twin births among women with and without polycystic ovary syndrome (PCOS) diagnosis.
Design
Population‐based cohort study.
Setting
Sweden.
Population
We identified 20 965 women with twin births between 1995 and 2009 of whom 226 had a PCOS diagnosis through linkage between the Swedish Medical Birth Register and the Swedish National Patient Register.
Methods
Calculating risk ratios (RR) with 95% confidence intervals (CI) using a log‐binomial regression model and hazard ratios (HR) with 95% CI for preterm birth.
Main outcome measures
Preterm birth, low birthweight, caesarean section, pre‐eclampsia, Apgar score <7 at 5 minutes and perinatal mortality.
Results
PCOS diagnosis in twin pregnancy was associated with increased risk of preterm delivery (51% versus 43%, RR 1.18 [95% CI 1.03–1.37]), particularly spontaneous preterm delivery (37% versus 28%; RR 1.30 [95% CI 1.09–1.55]) and very preterm birth (<32 weeks) (14% versus 8%, RR 1.62 [95% CI 1.10–2.37]). Twins of PCOS mothers had more often low birthweight (48% versus 39%, adjusted RR 1.40 [95% CI 1.09–1.80]). This difference disappeared when adjusting for gestational age. No risk difference was found for caesarean section, pre‐eclampsia, low 5‐minute Apgar score or perinatal mortality.
Conclusions
The risk of preterm delivery in twin pregnancies is increased by having a PCOS diagnosis. This should be considered in risk estimation and antenatal follow‐up of twin pregnancies.