Intra-amniotic pressures following vaginal gemeprost prior to first and second trimester termination of pregnancy.

Intra-amniotic pressures were measured following 1 mg gemeprost for cervical preparation before first trimester vacuum aspiration (n = 10) and following 2 mg gemeprost before second trimester dilatation and evacuation (n = 15). Twenty-five women, matched for gestational age and parity, who did not receive gemeprost served as controls. Compared to control values (2-8 mmHg), basal intra-amniotic pressure (IAP) was significantly increased after 1 mg and 2 mg of gemeprost (median 20.0, range 4-45 mmHg, median 20.0, range 8-60 mmHg, respectively). Uterine contractions were recorded in 8 of 10 subjects after 1 mg (median delta IAP 28.0, 95% CI 10.0-42.6 mmHg) and 14 of 15 subjects after 2 mg (median delta IAP 52.5, 95% CI 26.7-60.3 mmHg). Gemeprost produces an increase in uterine contractility which may be additional to cervical softening properties and which may be responsible for the adverse effects of pain and bleeding experienced by some women prior to termination.