Objective: To study associations between placental histopathology and neonatal outcome in preeclampsia (PE).
Study design: The cohort consisted of 544 singleton pregnancies complicated by PE and managed at Karolinska University Hospital, Stockholm, Sweden during 2000-2009. Evaluation of placental histopathology was made by one senior perinatal pathologist, blinded to outcome. Clinical outcome was obtained from prospectively collected medical registry data and medical records. Main outcome measures were intrauterine fetal death, smallness for gestational age, admission to neonatal unit, major neonatal morbidity (defined as presence of intraventricular hemorrhage ≥ grade 3, retinopathy of prematurity ≥ grade 3, necrotizing enterocolitis, cystic periventricular leucomalacia and/or severe bronchopulmonary dysplasia) and neonatal mortality. Logistic regression analyses including gestational age were performed.
Results: Abnormal placental weight, both low (adjusted odds ratio (OR) [95% confidence interval] 5.2 [1.1-24], p = 0.03) and high (adjusted OR 1048 [21-51 663], p < 0.001) for gestational age, was associated with major neonatal morbidity in preterm infants. Accelerated villous maturation was less prevalent in intrauterine fetal death pregnancies (adjusted OR 0.18 [0.04-0.77], p = 0.02). Decidual arteriopathy increased the odds for admission to neonatal care (adjusted OR 2.7 [1.1-6.5], p = 0.03). Infarction involving ≥5% of the placenta was associated with intrauterine fetal death and small for gestational age infants (adjusted OR's 75 [5.5-1011], p = 0.001 and 3.2 [1.7-5.9], p < 0.001; respectively). No relations between histological variables and neonatal mortality could be found.
Conclusion: Placental pathology in PE reflects adverse perinatal events and deviant placental weight predicts adverse neonatal outcome in preeclamptic women delivering preterm. Placental investigation without delay can contribute to neonatal risk assessment.