The effect of prostaglandin F2alpha on the placental progesterone level in midtrimester abortion.

A gas chromatograph method has been used for the determination of placental progesterone levels in 14 patients aborted at midtrimester by intra-amniotic instillation of prostaglandin F1alpha, also from a control group (five patients) aborted surgically by dilatation and suction. The results showed that the mean %/- S.E. of placental progesterone in the prostaglandin group was 1.45 mug +/- 0.09 per 1 Gm. of placental tissue, whereas the mean +/- S.E. of the placental progesterone in the surgically aborted group was 5.22 +/- 0.31 mug per 1 Gm. of placental tissue. The difference between the two groups was significant: P EQUALS 0.0001. This low level of placental progesterone in the prostaglandin abortion group could explain the sharp decline of the progesterone levels in the peripheral blood during abortion by intra-amniotic instillation of prostaglandin F2alpha, as observed by our group1, 2 and others.3(-5)