Reaction of Rat Mother to Retention of Near Term Dead Fetuses

Abstract

Corey 1 reported that death of the mother almost invariably took place in cases which involved retention of older (larger) dead rat fetuses. He stated that, “Near-term fetuses which have been either separated from the maternal blood supply in the uterus or placed in the maternal peritoneal cavity bring about the early death of the mother.”Death occurred in his cases from 1–3 days after the operation. The present work does not confirm these findings.

Albino rat females were caused to retain varying numbers of near term dead fetuses, both in utero and in the body cavity. The uteri were exposed through a medial ventral abdominal incision to allow easy access to both horns of the uterus. The fetuses nearest the Fallopian tube were killed through an incision in the uterine wall, at the periphery of the placenta, just large enough to insert a needle. The end of the needle was bent to form a complete loop in order not to injure the tissue unnecessarily. It was possible to free the entire placenta by rotating such a needle between the placenta and uterine wall. This procedure carefully done does not injure the embryo or embryonic membranes. Abortion of the killed fetuses was prevented by ligation of the uterus. Sterile precautions were always employed.

Two fetuses measuring 19 mm. (c-r) were killed. The remaining young, but one, were not disturbed during the operation. The one was removed as a control. Four days after the operation a litter of 6 healthy young were born. These were nursed by the mother and given excellent care. Apparently the 2 retained dead fetuses produced no disturbance in the general behavior of the mother.