Divergent trophoblast invasion and apoptosis in placental bed spiral arteries from pregnancies complicated by maternal anemia and early-onset preeclampsia/intrauterine growth restriction

Abstract

Impaired trophoblast invasion into spiral arteries is associated with early-onset intrauterine growth restriction and preeclampsia. We compared trophoblast invasion into spiral arteries in pregnancies with maternal anemia or early-onset preeclampsia/intrauterine growth restriction and related these findings to trophoblast apoptosis. Full-thickness uterine wall samples were obtained from women with early-onset preeclampsia/intrauterine growth restriction (n = 6), normal pregnancies (n = 5), and chronic anemia (n = 8). Trophoblast invasion into the walls of spiral arteries was quantified by morphometric analysis of paraffin sections stained with anticytokeratin 18, antiactin, and anticytokeratin 18 neoepitope (M30) antibodies. Trophoblast invasion into spiral arteries was increased in anemic pregnancies (mean [SD]: 206 [46] cell profiles/mm2) and severely impaired in preeclamptic/intrauterine growth restriction pregnancies (17 [6]), compared with normal subjects (149 [52]). Spiral artery lumen area was increased in anemia (0.07 [0.03] mm2) versus normal pregnancies (0.09 [0.04] mm2) and reduced in preeclampsia/intrauterine growth restriction (0.04 [0.02] mm2). Trophoblast apoptosis was similar in anemic (4.2% [3.4%]) and normal (5.0% [1.9%]) pregnancies but increased in preeclampsia/intrauterine growth restriction (12% [5.6%]). Trophoblast invasion into the placental bed in early-onset preeclampsia/intrauterine growth restriction is limited by increased apoptosis, resulting in narrower spiral arteries, which is in contrast to findings in anemia.