Amniotic fluid and maternal plasma prostaglandins in hypertonic saline-induced abortion

Intraamniotic instillation of 20% sodium chloride solution was carried out in 12 women within the 16th to 18th weeks of pregnancy. PgE2 and PgF2 alpha levels were monitored both in amniotic fluid 5 and 11 h following NaCl instillation as well as in the maternal plasma within the 5-h interval up to 36 h after instillation had been performed. A significant increase was observed of both PGE2 and PGF2 alpha concentrations in the amniotic fluid of all women who underwent induction of abortion. PgF2 alpha in amniotic fluid was increasing abruptly during the time of abortion, reaching the value of 249.7 +/- 19.6 ng/l (n = 12; P less than 0.001). Maternal plasma PgF2 alpha showed a continuous mild increase from 20.4 +/- 5.5 ng/l before to the maximum level, recorded 36 h after instillation, ranging within 205 +/- 1.0 ng/l (n = 4; P less than 0.001). A statistically significant increase in the levels of PgE2 and PgF2 alpha in both amniotic fluid and maternal plasma suggests that the release of primary PGs is a pathognomonic event for initiating labor pains, maturation of the cervix in abortions induced via intra-amniotic instillation of hypertonic NaCl solution.