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Updated: Jun 12, 2026

Modeling Posthemorrhagic Hydrocephalus of Prematurity in Rats
Published on: March 28, 2025
Factors associated with small head circumference at birth among infants born before the 28th week
Thomas F McElrath1, Elizabeth N Allred, Karl Kuban
1Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Brigham and Women's Hospital, Boston, MA, USA.
Objective:
We sought to identify risk factors for congenital microcephaly in extremely low gestational age newborns.
Study Design:
Demographic, clinical, and placental characteristics of 1445 infants born before the 28th week were gathered and evaluated for their relationship with congenital microcephaly.
Results:
Almost 10% of newborns (n = 138), rather than the expected 2.2%, had microcephaly defined as a head circumference >2 SD below the median. In multivariable models, microcephaly was associated with nonwhite race, severe intrauterine growth restriction, delivery for preeclampsia, placental infarction, and being female. The risk factors for a head circumference between <1 and >2 SD below the median were similar to those of microcephaly.
Conclusion:
Characteristics associated with fetal growth restriction and preeclampsia are among the strongest correlates of microcephaly among children born at extremely low gestational ages. The elevated risk of a small head among nonwhites and females might reflect the lack of appropriate head circumference standards.
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