Fetal pathology and mechanism of fetal death in saline-induced abortion: a study of 143 gestations and critical review of the literature

Morphological changes in the placenta and decidua after induction of abortion by extra-amniotic prostaglandin

Seventeen placentae from second trimester abortions induced by the injection of extra-amniotic prostaglandin have been examined. The extraplacental membranes, the chorionic plate of the placenta, the placental intervillous space and the placental villi were normal in all cases. In all but one specimen lesions were, however, noted in the decidua, these including focal decidual necrosis, intradecidual haemorrhage, thrombosis of maternal vessels and dilatation and congestion of the maternal vasculature. Similar decidual lesions were also seen in placentae from spontaneous and surgical second trimester abortions and it is concluded that prostaglandins do not produce any specific lesions in the placenta or decidua. It is suggested that the negative findings of this study indicate that prostaglandins do not induce abortion by either direct injury to the placenta or by provoking utero-placental ischaemia.

Hormone changes in relation to the time of fetal death after prostaglandin-induced abortion

The changes in unconjugated estradiol-17beta and estriol, progesterone and chorionic somatomammotropin (HCS) in peripheral plasma have been studied in 18 women at 30-minute intervals following intra-uterine prostaglandin E2 administration for therapeutic termination of second trimester pregnancy. The hormonal changes were related to the time of fetal death detected by the disappearance of fetal heart pulsations. Prostaglandin E2 was given by the intra-amniotic route with urea (5 patients) or with intravenous oxytocin (5 patients), or by the extra-amniotic route with intravenous oxytocin (8 patients). Fetal death occurred rapidly with intra-amniotic PGE2, but usually at a late stage with extra-amniotic PGE2. Three fetuses in the extra-amniotic group died at or just before abortion. A variety of fetal heart changes were noted and the time of fetal death did not appear to influence the time of abortion within each treatment subgroup. Estradiol and estriol showed a sligh but persistent fall over 24 hours prior to induction of abortion. A more rapid fall usually occurred after induction, with a consistent fall around the time of fetal death. Progesterone and HCS usually fell much less before and immediately after fetal death. A marked rise in estradiol sometimes occurred before fetal death, particularly in the intraamniotic PGE2 and urea subgroup. Estriol levels declined more rapidly before than after fetal death, whereas fetal death had less consistent effects on the other hormones. All hormones had usually fallen considerably at the time of abortion, and in some individuals marked fluctuations in hormone levels were seen.

Midtrimester prostaglandin-induced abortion: gross and light microscopic findings in the placenta

A systematic gross and light microscopic study was done of 60 placentas, spontaneously delivered following induction by intra-amniotic PGF2alpha administration. The main findings were: high incidence of marginal and basal decidual hemorrhage, widespread degenerative changes in the decidua and chorionic villi, intervillous congestion and thrombosis and significant underfilling of the fetal vasculature. These changes are discussed in terms of the possible factors underlying the mechanism of prostaglandin-induced abortion.

Massive subchorial thrombohaematoma (Breus' mole)

Ten placentae with massive subchorionic thrombohaematomas are reported. This lesion, which is composed of maternal clotted blood, separates the chorionic plate of the placenta from the villous chorion and is traversed by the main cotyledonary branches of the fetal circulation. In some instances it dissects into the layers of the chorionic plate. In anatomical terms it is identical to the lesion which has been described in early pregnancy under the title of Breus' mole. Previous reports suggested that the lesion was confined to early pregnancies and was a consequence of fetal death. In our series all ten placentae were from pregnancies of at least 25 weeks' maturity and six were more than 30 weeks. Seven infants were liveborn and three survived the neonatal period. Differential diagnosis is discussed along with aetiology, which is still obscure although earlier theories implicating fetal death may be discounted.