Late pregnancy termination within a legislated medical environment

To review the indications and outcomes for abortion beyond 20 weeks' gestation within an environment of legislated notifiable pregnancy termination.

In Western Australia legislation allowing abortion > or = 20 weeks' gestation for serious maternal-fetal conditions was enacted in May 1998. Late abortions are only permitted in a single state institution and are notifiable by law. All pregnancy terminations > or = 20 weeks' gestation performed since this legislation were prospectively identified with the indications and outcomes reviewed.

During the study period, 219 women underwent abortion > or = 20 weeks' gestation, representing 0.5% of all abortions in the state. Comparison with 438 contemporanous medical abortions for fetal anomaly at 14-20 weeks' gestations was made. Misoprostol was the primary abortifacient for both. The median maternal age for termination at 14-20 weeks was 32 years (interquartile range (IQR) 27, 36) and 30 years (IQR 26, 34) at > or = 20 weeks' gestation (P < 0.001). There was no significant difference in maternal gravidity or parity. The principal indications for terminations > or = 20 weeks were: karyotypic (28.8%); cardiac anomalies (15.5%) and neural tube defects (11.9%). Cardiac anomalies represented 5.0% of fetal anomaly terminations at 14-20 weeks (P < 0.01). The median time for medical abortion was 15.4 h (IQR 11.5, 23.2) at 14-20 weeks' gestation compared with 18.3 h (IQR 13.3, 26.1) at gestations greater than 20 weeks (P < 0.001). A total of 13.2% of terminations were performed at gestations beyond 24 weeks.

Abortion > or = 20 weeks' gestation under medically regulated legislation is used primarily for serious fetal anomalies. The women are younger and the abortion duration is greater for late pregnancy termination compared with those conducted at earlier gestations. The majority of late terminations occur < 23 weeks' gestation and the incidence has remained stable since the legislation was enacted.