A study by researchers at McGill University has identified polycystic ovary syndrome (PCOS) as an independent risk factor for gestational diabetes (GDM), gestational hypertension (GHTN) and preeclampsia (PEC) of pregnancy. After controlling for all potential confounding effects, women with PCOS were at a two-fold higher risk of developing GDM, a 50% increased risk for the development of GHTN and a 30% increased risk of developing PEC, compared to women without PCOS.
The condition, known to lead to multiple reproductive complications, including infertility, affects one in 10 women of childbearing age. PCOS was already known for its association to other adverse perinatal conditions, such as insulin resistance. However, there remains significant gaps in understanding the correlation between the syndrome and neonatal complications.
"We discovered that PCOS is a risk factor for morbidity in pregnancy," explained Dr Michael Dahan, Assistant Professor in McGill's Department of Obstetrics and Gynecology and lead author of the study. "We are now able to precisely determine the relative risk in pregnancy related to the disease process itself by controlling for underlying conditions, which previous studies were unable to do."
For the study, ‘Polycystic ovary syndrome as an independent risk factor for gestational diabetes and hypertensive disorders of pregnancy: a population-based study on 9.1 million pregnancies’, published in the journal Human Reproduction, the researchers wanted to know whether PCOS confers an independent risk for the development of GDM, GHTN and PEC based on analysis of the Healthcare Cost and Utilization Project Nationwide Inpatient Sample (HCUP-NIS) database. This retrospective population-based study used data from the HCUP-NIS over 11 years from 2004 to 2014. A dataset of all deliveries between 2004 and 2014 inclusively was created. Within this group, all deliveries to women with PCOS were identified as part of the study group (n=14 882), and the remaining deliveries were categorised as non-PCOS births and comprised the reference group (n=9,081,906).
At baseline, more pregnant women with PCOS had obesity (22.3% vs. 3.5%, p<0.001), had chronic hypertension (HTN) (8.4% vs. 1.8%, p<0.001), had pregestational diabetes (4.1% vs. 0.9%, p<0.001) and had treated thyroid disease (12.6% vs. 2.4%, p<0.001). Women with PCOS were also more likely to have undergone IVF treatment (2.4% vs. 0.1%, p<0.001), have multi-gestation pregnancies (5.9% vs. 1.5%, p<0.001), and more multiple gestations (MGs) in the PCOS group were the result of IVF treatment than the non-PCOS groups (12.3% vs. 2.3%, p<0.001).
In all pregnancies, women with PCOS were more likely to develop gestational diabetes (adjusted odds ratio (aOR) 2.19, 95% CI 2.02–2.37), pregnancy associated HTN (aOR 1.38, 95% CI 1.27–1.50, p<0.001), GHTN (aOR 1.47, 95% CI 1.31–1.64), PEC (aOR 1.29, 95% CI 1.14–1.45) and superimposed PEC (aOR 1.29, 95% CI 1.04–1.59) after controlling for confounding effects (age, race, income level, insurance type, obesity, IVF use, previous caesarean section, chronic HTN, pregestational diabetes, thyroid disease, MG, smoking and recreational drug use).
Odds ratios were comparable between all pregnancies and singleton pregnancies only. In women pregnant with multiple foetuses, PCOS only conferred a statistically significant increased risk of developing GDM (aOR 2.33, 95% CI 1.92–2.83, p<0.001). However, there was a trend toward an increased risk for developing pregnancy associated HTN (aOR 1.92, 95% CI 0.99–1.42, p=0.058).
"PCOS is the most common hormonal condition among reproductive age women," added Dahan. "It is important to consider the risk of other co-existing conditions frequently encountered in women with PCOS, as these risks are additive and place them at a significantly increased risk of adverse pregnancy outcomes."
Further research will be undertaken to investigate the role of specific interventions in PCOS on modifying risk in pregnancy and delivery.
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