Common questions about late-term and postterm pregnancy

Area of Science:

• Maternal-Fetal Medicine
• Obstetrics
• Perinatology

Background:

• Late-term pregnancy is defined as 41 weeks, 0 days to 41 weeks, 6 days' gestation, and postterm at 42 weeks' gestation.
• Accurate dating via early pregnancy ultrasonography is crucial for identifying late- or postterm pregnancies.
• Management of low-risk late-term pregnancies requires balancing maternal preference with induction versus expectant management.

Purpose of the Study:

• To evaluate the risks and benefits of induction versus expectant management for late-term pregnancies.
• To determine the optimal timing for interventions in pregnancies reaching 41 weeks' gestation.

Main Methods:

• Comparison of outcomes between induction at 41 weeks' gestation and expectant management.
• Review of evidence regarding antenatal testing protocols for late-term pregnancies.
• Consideration of maternal preferences in management decisions.

Main Results:

• Induction at 41 weeks' gestation shows a small absolute decrease in perinatal mortality compared to expectant management.
• Induction is associated with reduced fetal and maternal risks without increasing cesarean delivery rates.
• Antenatal testing, while not definitively preventing intrauterine fetal demise, is often employed due to low risks.

Conclusions:

• Induction at 41 weeks' gestation is a viable option for low-risk pregnancies, offering benefits over expectant management.
• Expectant management, if chosen, typically involves twice-weekly antenatal surveillance starting at 41 weeks.
• Induction may be deferred until 42 weeks if antenatal surveillance remains reassuring.