Placental histology and placental/fetal weight ratios in pregnant women with sickle cell disease: relationship to pregnancy outcome.

Although the adverse effects of sickle cell disease on pregnancy outcome are well recognized, the contribution of placental pathology to these events remains controversial. Placentas from single, term deliveries of 21 women with sickle cell (SS) disease and 63 low-risk control women with hemoglobin AA, matched for maternal age, gestational age, and parity, were examined and findings correlated with neonatal outcome. Gross and microscopic examinations of these placentas were performed by a pathologist unaware of the pregnancy outcome. All placentas were weighed, and the relative placental weight was calculated and examined for the presence of infarction, villous sclerosis, and intervillous fibrin deposits. The mean birth weight of infants of the SS women was significantly lower than that of the low-risk controls (2830 +/- 310 g versus 3415 +/- 250 g, P < .05). The mean placental weight was also lower in the SS group compared with controls (445 +/- 78 g versus 568 +/- 86 g). The mean relative placental weight for the SS women was 12.9 +/- 4% and for the controls, 15.2 +/- 3.4%. Moderate-to-severe villous sclerosis, infarction, and intervillous fibrin deposits were present in 7 of 21 SS placentas but absent in placentas of low-risk controls. These 7 pregnancies with SS disease and abnormal placental findings had small-for-gestational-age infants, and their relative placental weight was less than 10%. We conclude that in SS disease, relative placental weight less than 10% and placental lesions of moderate-to-severe villous sclerosis, intervillous fibrin deposits, and infarction are associated with small-for-gestational-age infants.