Effect of parity and advanced maternal age on obstetric outcome

To examine the effect of parity on obstetric outcome in women aged 40 years or older.

A retrospective cohort of 16,427 singleton pregnancies delivered between 1998 and 2001 was studied. Obstetric outcomes in women aged 40 years or older versus women younger than 40 years were compared for both nulliparous and multiparous women.

Of the 15,727 pregnancies (95.7%) that satisfied the inclusion criteria, 606 (3.9%) were in women aged 40 years or older. Advanced age was independently associated with cesarean delivery, birth and spontaneous preterm labor before 37 weeks, and low birth weight neonates in nulliparous women, but only with preterm birth before 37 weeks and cesarean delivery in multiparous women.

Obstetric outcome in women aged 40 years or older was influenced by parity. Cesarean delivery and preterm birth before 37 weeks were independently associated with older age irrespective of parity. Advanced age is a risk factor for preterm birth.