Prostaglandin-F2 alpha levels in normal saline-induced mid-trimester abortions

In 20 mid-trimester abortion seekers induced by extra-amniotic instillation of normal saline, serial estimation of prostaglandin F2 alpha (PGF2 alpha) in the plasma and extra-ovular space were carried out. It was observed that PGF2 alpha was undetectable in both plasma and the extra-ovular space prior to the onset of induction, and was first detected in the extra-ovular fluid 2 hours after the onset of induction, prior to oxytocin infusion. In the subsequent samples, the prostaglandin concentration in plasma as well as in the extra-ovular fluid was found to rise, with levels in the latter showing a more significant rise with time as compared to the former. Thus, this study confirms the hypothesis that the mechanism of action of extra-ovular normal saline instillation in mid-trimester termination of pregnancy is the result of separation of fetal membranes from the uterine wall, leading to the release of prostaglandins which, in turn, causes uterine contractions leading to abortion.