In a woman at 41 weeks gestation (post‑term), what is the most likely maternal complication?

Maternal Risks in Post-Term Pregnancy at 41 Weeks

The most significant maternal risk associated with post-term pregnancy at 41 weeks is cesarean section, with rates increasing from 18.6% with induction at 39 weeks to 22.2% with expectant management beyond 41 weeks. 1

Primary Maternal Complication: Cesarean Delivery

Cesarean section is the predominant maternal risk when pregnancies extend to 41 weeks and beyond. The evidence demonstrates that:

• At 41 weeks specifically, expectant management increases cesarean delivery risk compared to induction (22.2% vs 18.6%, representing a 16% relative risk reduction with induction). 1
• As cesarean deliveries accumulate across pregnancies, rates of hysterectomy, blood transfusion, adhesive disease, and surgical injury increase in a dose-response pattern. 2
• The increasing cesarean delivery rate has directly contributed to increasing prevalence of placenta accreta spectrum in subsequent pregnancies, which causes severe and often life-threatening maternal hemorrhage. 2

Secondary Maternal Risks

Hypertensive Disorders

Post-term pregnancy significantly increases the risk of gestational hypertension and preeclampsia:

• The incidence of hypertensive disorders is substantially lower with induction at 39 weeks compared to expectant management (9.1% vs 14.1%, representing a 36% relative risk reduction). 1
• Women with hypertensive disorders during pregnancy face increased cardiovascular disease risk both acutely and long-term, with persistent postpartum hypertension and metabolic syndrome occurring within the first year after delivery. 2

Hemorrhagic Complications

While blood transfusion is a potential complication, the evidence shows:

• Postpartum hemorrhage rates show no significant difference between induction and expectant management in most studies. 3
• However, antepartum hemorrhage and placental abruption risks increase with prolonged pregnancy. 1
• Planned delivery allows better preparation and management of potential bleeding complications. 3

Infectious Complications

• Intraamniotic infection risk increases with prolonged pregnancy, particularly when combined with membrane rupture. 2
• Maternal sepsis can occur in up to 6.8% of complicated cases. 2
• Endometritis and postpartum infection risks are elevated with expectant management. 2

Adherent Placenta Risk

While placenta accreta spectrum is mentioned as a consequence of multiple cesarean deliveries 2, there is no direct evidence linking post-term pregnancy at 41 weeks to adherent placenta as an acute complication. The relationship is indirect—post-term pregnancy increases cesarean risk, and accumulated cesareans increase future placenta accreta risk.

Clinical Management Implications

The American College of Obstetricians and Gynecologists recommends induction at 41 weeks, as this approach reduces cesarean delivery rates compared to expectant management. 3

Key management principles include:

• Induction of labor at 41 weeks reduces perinatal mortality, stillbirth, and cesarean delivery compared with expectant management or induction starting at 42 weeks. 4
• All patients should be delivered by 42 weeks' gestation, as prolongation beyond this involves unacceptable increases in fetal and maternal risk. 3, 5
• Assess cervical favorability using the modified Bishop score, and use cervical ripening agents if the cervix is unfavorable (Bishop score <5). 3
• Allow at least 12 hours after cervical ripening, membrane rupture, and oxytocin before considering cesarean delivery for "failed induction" in the latent phase. 3, 6

Critical Pitfalls to Avoid

• Do not underestimate the cumulative maternal morbidity risk—studies show 60% maternal morbidity rates in high-risk scenarios with expectant management. 2
• Do not delay delivery waiting for spontaneous labor—infection and hemorrhage risks increase with time. 2
• Cesarean section should be reserved for obstetric indications, not performed electively at 42 weeks. 3

Answer to the multiple choice question: A. Cesarean section is the most significant maternal risk, with the strongest evidence base demonstrating increased rates with expectant management at 41 weeks. 1, 3, 4