SAN DIEGO — Female gender in extremely-low-birth-weight infants has a positive influence on the neurodevelopmental outcome at 18–22 months, increasing the Bayley-II Mental Developmental Index scores by 8–10 points, Dr. Regina A. Gargus reported at the annual meeting of the Society for Developmental and Behavioral Pediatrics.
“The persistence of this effect over time will need to be reassessed in longer-term studies,” said Dr. Gargus, medical director of the Dennis Developmental Center at Arkansas Children's Hospital, Little Rock.
The finding is important because the influence of gender alone on the outcome of extremely-low-birth-weight (ELBW) infants has not been described.
In a study Dr. Gargus conducted during her fellowship at Brown University, Providence, R.I., she and her associates reviewed prospectively collected data from the neonatal intensive care unit (NICU) course and follow-up visits of 71 female and 53 male ELBW infant survivors who were admitted to Women and Infants Hospital of Rhode Island in Providence from January 1, 2000 to December 31, 2001. The infants had a gestational age of less than 32 weeks and a birth weight of less than 1,000 g, and they participated in developmental assessments at 18–22 months. Infants who were born with chromosomal or major congenital anomalies were excluded from the study.
The investigators analyzed the data for demographic characteristics, Score for Neonatal Acute Physiology-Perinatal Extension II (SNAP-PE II) scores, neonatal course, perinatal morbidities, and 18-month outcome.
Most of the medical characteristics did not differ between the two groups, but the mean number of days on oxygen was significantly greater in the male population (65.9 days vs. 50.6 days). The incidence of chronic lung disease was 1.5 times greater in males compared with females, but other comorbidities were not different between the two groups.
Bivariate analysis revealed that female gender was associated with decreased neurodevelopmental impairment and increased Bayley-II Mental Developmental Index scores.
Multivariate regression analysis, adjusted for gestation, chronic lung disease, SNAP-PE II, and level of maternal education, revealed that Bayley-II MDI scores were associated with female gender. Overall, the MDI scores of females were 8–10 points higher than the scores of their male counterparts.