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Post-Term Pregnancy

Posted on January 6, 2014

Pregnancy is considered “at term” when gestation has lasted 37 complete weeks. Post-term pregnancy, delivery after 40 weeks, is technically defined by some practitioners as delivery at or beyond 42 weeks gestation, and affects about 10% of all deliveries.

Vaginal delivery at or near term is often the best option in an uncomplicated pregnancy. All interventions to artificially control the timing of delivery (induction of labor, caesarean section) are associated with risk, albeit small, of certain complications. The same holds true with allowing a pregnancy to continue beyond 40 weeks. Post-term babies may be larger in size and weight, a condition known as macrosomia. This brings an increased risk of complications, such as respiratory compromise, cord compression, shoulder dystocia, and other orthopedic or neurologic injuries. There is also a risk to the mother, as a large baby can lead to prolonged labor that can cause perineal injury, hemorrhaging, and may require a cesarean section.

Carrying a baby past the due date can also be associated with reduced placental perfusion. The placenta, which supplies the baby with nutrients and oxygen from the mother, begins aging after the 40th week of gestation. This can result in the decrease of blood flow through the placenta as calcium deposits accumulate on the surface of the placenta. Lastly, there is an increased risk of the fetus passing fecal matter (which is not supposed to happen until after birth) and subsequently breathing it in, a condition known as meconium aspiration.

If you have any questions about a situation where you believe post-term pregnancy injury has occurred, we welcome your call.