A study was undertaken in order to investigate the clinical observation that patients who underwent midtrimester abortion using intra-amniotic PG F2alpha in combination with hyperosmolar
urea, always aborted a dead fetus. Ten Caucasian primigravidae, aged between 16 and 22 years old and whose pregnancies ranged between 14 and 23 weeks in duration, were studied. The patients were randomly divided into two equal groups. The one group received
urea and PG F2alpha intra-amniotically whereas the other received PG F2alpha alone. Blood was drawn for measurement of plasma
estradiol,
progesterone and
human placental lactogen (HPL) prior to injection of the
abortifacients and at regular intervals thereafter for a period of 120 min. The five patients who received the combination regime of treatment (
urea + PG F2alpha) showed a rapid decline in the plasma concentrations of these
hormones and induction of abortion was followed by
fetal death within 35 min in all cases. In contrast, the five patients who received intra-amniotic PG F2alpha alone, did not (with a single exception), demonstrate this rapid decline in the plasma concentrations of the
placental hormones measured. Also with the same single exception, these fetuses, although stillborn, were alive two hours after inducing abortion.