Do Hypertensive Pregnancy Disorders Affect Preterm Infant Neurodevelopment?

Maternal hypertension is independently associated with risk for adverse neurodevelopment outcomes in preterm infants, according to research results published in JAMA Network Open.

Multiple studies have suggested a link between hypertensive disorders of pregnancy (HDP), including preeclampsia, gestational hypertension, and chronic hypertension, and brain development and behavioral disorders in children. However, there is contradictory evidence on this association in preterm infants.

In a cohort study, researchers studied the impact of maternal HDP on neurodevelopment in preterm infants.

The researchers included data from preterm infants, ie, those born at gestational age (GA) 32 weeks or less, from the Cincinnati Infant Neurodevelopment Early Prediction Study (CINEPS) in the current analysis. Participants were enrolled from level 3 and 4 intensive neonatal care units (NICUs) between September 2016 and November 2019.

Maternal antenatal and postnatal information, as well as infant characteristics, were recorded. HDP-exposed infants were defined as those with diagnosed maternal chronic hypertension or pregnancy-induced hypertension (PIH).

Magnetic resonance imaging (MRI) was performed, and the scans were analyzed for brain injury and development in preterm infants, using the global brain abnormality score (GBAS). The Bayley Scales of Infant and Toddler Development (BSID) was used to assess neurodevelopment of infants, including cognitive, motor, language, socioemotional, and adaptive behavior.

The primary outcome was BSID cognitive composite score. Secondary outcomes included BSID language and motor composite scores.

A total of 395 infants (median GA, 29.6 weeks; birth weight, 1230 g; 53.2% infant boys) were included in the study, of whom 170 (43%) were classified as HDP-exposed, 134 (34%) were PIH-exposed, and 104 (26%) were preeclampsia-exposed. A total of 162 mothers were diagnosed with HDP.

The HDP and non-HDP groups were comparable, except for maternal age, multiple gestations, histologic chorioamnionitis, and antenatal magnesium therapy. There were only a few differences between the preeclampsia or PIH and the non-HDP groups.

Overall, 341 infants (87%) completed BSID at 22 to 26 months corrected age. Cognitive scores were similar between the HDP-exposed and non-HDP groups (mean BSID, 90.63 vs 90.55; difference, 0.08; 95% CI, -3.52 to 3.57; P =.97). All participants had available GBAS scores, which were comparable between the HDP-exposed and non-HDP groups (median GBAS, 5 vs 4; difference, 1.00; 95% CI, -1.03 to 0.10; P =.21).

After adjusting for confounders, HDP had a negative impact on cognition (β_estimate, -3.69; 95% CI, -6.69 to -0.68; P =.02) and language (β_estimate, -4.07; 95% CI, -8.03 to -0.11; P =.04).

Preeclampsia was also found to negatively affect cognitive (β_estimate, -4.85; 95% CI, -8.63 to -1.07; P =.01) and language scores (β_estimate, -6.30; 95% CI, -11.49 to -1.09; P =.02).

Apart from lower cognitive (β_estimate, -4.93; 95% CI, -8.32 to -1.55; P <.01) and language scores (β_estimate, -6.34; 95% CI, -10.92 to -1.77; P =.01), PIH also affected motor scores (β_estimate, -3.62; 95% CI, -7.05 to -0.19; P =.04).

Brain abnormalities mediated 24% of the total effect of HDP on lower cognitive scores (β_estimate, -0.82; 95% CI, -1.72 to -0.13; P =.02). Results of a mediation analysis showed the direct effect of HDP on adverse cognitive development, but it was not statistically significant (P =.07). Birth weight also did not have a significant effect on cognitive BSID scores (β_estimate, -0.44; 95% CI, -1.26 to 0.20; P =.19).

Study limitations included its observational nature; some diagnoses of HDP being based on the clinical definition of hypertension and not ascertained by obstetricians; and possible selection bias, based on infants who returned to the center for follow-up.

“[The study results emphasized] the clinical importance of recognizing HDP as a risk, enabling targeted risk management strategies for closer monitoring and aggressive early intervention in affected populations,” the researchers concluded.