What is the recommended management for a pregnant woman with polycystic ovary syndrome?

Management of Pregnant Patients with PCOS

Pregnant women with PCOS require intensified surveillance for pregnancy complications—particularly gestational diabetes, preeclampsia, and preterm birth—with early glucose screening, close blood pressure monitoring, and individualized weight management as the cornerstone of care.

Preconception and Early Pregnancy Assessment

Before or immediately upon pregnancy recognition, women with PCOS should undergo comprehensive metabolic screening:

• Perform a 75-g oral glucose tolerance test at preconception or within the first 20 weeks of pregnancy if not done preconceptionally, then repeat at 24-28 weeks 1
• Assess blood pressure, renal function, and thyroid function prior to pregnancy 2
• Calculate BMI and establish baseline weight, as obesity significantly worsens maternal and fetal complications in PCOS 3
• Screen for cardiovascular risk factors including lipid profile, as PCOS increases long-term cardiovascular disease risk 4

The evidence strongly supports that obesity and insulin resistance are the primary drivers of adverse pregnancy outcomes in PCOS, not PCOS itself 3, 1. This distinction is critical because it directs management toward modifiable risk factors.

Weight and Lifestyle Management During Pregnancy

Weight management during pregnancy should focus on preventing excessive gestational weight gain rather than weight loss, as even modest pre-pregnancy weight reduction of 5% improves metabolic and reproductive outcomes 2, 4.

• Implement a balanced diet with appropriate caloric intake for pregnancy, avoiding aggressive caloric restriction 2
• Encourage at least 150 minutes per week of moderate-intensity physical activity unless contraindicated 4
• Monitor weight gain according to Institute of Medicine guidelines based on pre-pregnancy BMI 2

Pharmacological Considerations

Metformin Use in Pregnancy

Metformin appears to be safe during pregnancy according to ACOG guidelines, though its role in preventing pregnancy complications remains uncertain 2, 5:

• Metformin may be continued or initiated during pregnancy for women with documented insulin resistance or glucose intolerance 4
• Evidence is insufficient to recommend metformin specifically for preventing gestational diabetes or preeclampsia in PCOS 6, 7
• The decision to use metformin should be individualized based on metabolic status and pre-pregnancy use 1

Medications to Avoid

• Discontinue thiazolidinediones (rosiglitazone, pioglitazone) as safety data in pregnancy are inadequate 2
• Stop clomiphene citrate once pregnancy is achieved 2
• Avoid oral contraceptives during pregnancy 2

Surveillance for Pregnancy Complications

Women with PCOS face significantly elevated risks requiring enhanced monitoring 6, 3, 7:

Maternal Complications to Monitor:

• Gestational diabetes mellitus: Screen early (before 20 weeks) and again at 24-28 weeks with 75-g OGTT 1
• Pregnancy-induced hypertension and preeclampsia: Monitor blood pressure at every prenatal visit, with lower threshold for additional testing 6, 3
• Preterm birth: Assess cervical length if indicated by clinical factors 3

Fetal Complications to Monitor:

• Fetal growth abnormalities (both small-for-gestational-age and large-for-gestational-age): Perform serial growth ultrasounds in third trimester 3
• Increased NICU admission rates: Coordinate with neonatology for delivery planning if complications arise 3

Delivery Planning

• Cesarean section rates are elevated in PCOS pregnancies 3, 7
• Delivery timing should be based on standard obstetric indications, with consideration for metabolic complications if present 1
• Ensure delivery occurs at a facility equipped to manage potential maternal and neonatal complications 3

Postpartum Management

• Repeat glucose screening at 6-12 weeks postpartum with 75-g OGTT, as women with PCOS and gestational diabetes have markedly increased risk of type 2 diabetes 1
• Resume or initiate long-term metabolic management including lifestyle modification and metformin if indicated 1
• Screen for postpartum depression, as PCOS is associated with higher rates of mental health disorders 4, 1

Critical Pitfalls to Avoid

• Do not assume normal glucose screening in early pregnancy excludes gestational diabetes risk—repeat testing at 24-28 weeks is mandatory 1
• Do not neglect blood pressure monitoring even in normotensive women, as preeclampsia risk is substantially elevated 6, 3
• Do not attribute all pregnancy complications to PCOS alone—obesity and insulin resistance are the modifiable culprits requiring aggressive management 3, 1
• Do not discontinue metabolic surveillance postpartum—lifelong cardiovascular and diabetes risk remains elevated 1