Increased depth of trophoblast invasion after chronic constriction of the lower aorta in rhesus monkeys.

Objective: Our purpose was to investigate whether a reduction in uteroplacental perfusion pressure would produce changes in trophoblast-uterine interactions at the cellular level.

Study Design: Strictures were placed around the abdominal aortas of rhesus monkeys at 116 +/- 7 days of pregnancy to reduce uteroplacental perfusion pressure. Placental bed biopsy specimens were obtained at cesarean section, and cytotrophoblasts were identified by means of an anticytokeratin antibody.

Results: In monkeys without aortic strictures, interstitial trophoblast invasion was restricted to the outer half of the endometrium. Endovascular trophoblast invasion involved the entire endometrial portion of uterine vessels and extended through the subjacent half of their myometrial segments. In seven of nine monkeys with aortic strictures the depth of interstitial trophoblast invasion was substantially increased and extended throughout the entire decidua and at least a portion of the myometrium. In contrast, the pattern of endovascular trophoblast invasion was identical to that observed in the placental beds of control animals.

Conclusion: These results suggest that uteroplacental perfusion pressure or oxygen content may be important physiologic factors controlling the depth of interstitial cytotrophoblast invasion.