Researchers in the Netherlands have identified that assessing the effects of maternal and fetal vascular malperfusion can lead to faster identification of infants at high risk of developing retinopathy of prematurity (ROP). The study, led by Salma El Emrani, BSc, from Leiden University Medical Center, suggests that evaluating placental factors can enhance the current ROP risk profile.
ROP, a condition resulting from abnormal vessel development, affects 10% to 25% of premature neonates born before 32 weeks of gestation. Current screening primarily relies on low gestational age and birthweight, with some countries including oxygen therapy, cardiorespiratory support, and sepsis as additional risk factors.
Maternal and Fetal Vascular Malperfusion
Maternal vascular malperfusion encompasses histologic changes affecting maternal circulation to the fetus, such as decreased uterine and intervillous blood flow. Fetal vascular malperfusion includes pathological lesions caused by umbilical cord obstruction, leading to reduced perfusion of the villous parenchyma and fetal hypoxia.
The study involved 591 neonates with a gestational age of 32 weeks or less, or a birthweight of 1,500 grams or less. Clinical data were collected retrospectively, and placentas were examined prospectively to identify maternal vascular malperfusion (e.g., abruption, infarct, distal villous hypoplasia) and fetal vascular malperfusion (e.g., thrombosis, fetal hypoxia).
The primary outcome was ROP, with secondary outcomes including gestational age, birthweight, duration of mechanical ventilation, postnatal corticosteroids, sepsis, and necrotizing enterocolitis.
Key Findings
The analysis revealed that maternal vascular malperfusion was associated with higher gestational age, lower birthweight, and increased rates of being small for gestational age. Fetal vascular malperfusion was associated with lower birthweight, increased rates of being small for gestational age, and lower duration of mechanical ventilation.
In placentas without inflammation, increased rates of distal villous hypoplasia (44% vs. 31%) and hydrops parenchyma (7% vs. 0%) were observed in neonates with ROP. Multivariate regression analyses identified three placental factors independently associated with ROP: distal villous hypoplasia (OR = 1.7; 95% CI, 1.0–3.0), severe acute histologic chorioamnionitis (OR = 2.1; 95% CI, 1.1–3.9), and funisitis (OR = 1.8; 95% CI, 1.0–3.1).
Clinical Implications
The investigators suggest that these newly identified risk factors are a valuable addition to the ROP risk profile. "Evaluation of these placental risk factors shortly after birth can aid in identifying high-risk infants in an earlier stage than currently possible," they stated. This confirmation can then be used for personalized neonatal treatment to prevent ROP from developing. The researchers also propose that these placental risk factors may serve as targets for placental therapy to prevent ROP in vulnerable premature neonates.
