Fetectomy in monkeys (Macaca mulatta): retention of the placenta past normal term.

Abstract

At Gestation Day 65-143, fetectomy was performed in 13 monkeys (Macaca mulatta), leaving the placentas in place. The uterus and abdomen were then closed, and the monkeys were subsequently observed for placental expulsion. 9 of the 13 monkeys retained the placentas past normal term. 11 placentas were recovered after spontaneous expulsion and 1 by surgery, indicating that the maternal instinct to eat the placenta was lacking in the absence of a live infant. Placenta weights were near or more than those expected at the time of fetectomy but below that of normal term placentas. Histological examination of the placentas recovered 17-108 days postfetectomy revealed viable trophoblasts in 10 samples with variable areas of nonneoplastic cytotrophoblastic hypertrophy and hyperplasia in 8 of the 10 specimens.