Survival of infants and children born with severe microcephaly, Texas, 1999–2015

Abstract

Background Severe microcephaly is a brain reduction defect where the delivery head circumference is <3rd percentile for gestational age and sex with subsequent lifelong morbidities. Our objective was to evaluate survival among 2,704 Texas infants with severe microcephaly delivered 1999–2015. Methods Infants with severe microcephaly from the Texas Birth Defects Registry were linked to death certificates and the national death index. Survival estimates, hazard ratios (HR) and confidence intervals (CI) were calculated using the Kaplan–Meier method and Cox proportional hazards models stratified by presence versus absence of co‐occurring defects. Results We identified 496 deaths by age 4 years; most (42.9%) occurred in the neonatal period, and another 39.9% died by 1 year of age. Overall infant survival was 84.8%. Lowest infant survival subgroups included those with chromosomal/syndromic conditions (66.1%), very preterm deliveries (63.9%), or co‐occurring critical congenital heart defects (44.0%). Among infants with severe microcephaly and a chromosomal/syndromic co‐occurring defect, the risk of death was nearly three‐fold higher among those with: proportionate microcephaly (i.e., small baby overall), relative to non‐proportionate (HR = 2.84, 95% CI = 2.17–3.71); low‐birthweight relative to normal (HR = 2.72, 95% CI = 1.92–3.85); critical congenital heart defects (CCHD) relative to no CCHD (HR = 2.90, 95% CI = 2.20–3.80). Trisomies were a leading underlying cause of death (27.5%). Conclusions Overall, infants with severe microcephaly had high 4‐year survival rates which varied by the presence of co‐occurring defects. Infants with co‐occurring chromosomal/syndromic anomalies have a higher risk of death by age one than those without any co‐occurring birth defects.

Racial and ethnic differences in infant survival for hydrocephaly—Texas, 1999–2017

“…This was calculated in days from birth until the death of an infant or until the infant was aged 1 year, with censoring at 1 year. Based on prior work (Benjamin et al, 2021(Benjamin et al, , 2023Marengo et al, 2014Marengo et al, , 2023Martin-Giacalone et al, 2023;Vendola et al, 2010), infants without death records were assumed to have survived to their first birthday. Several independent variables were considered, including maternal race and ethnicity (non-Hispanic White [White], non-Hispanic Black [Black], Hispanic, and additional groups), maternal age at delivery (<35 years or ≥ 35 years), maternal education at delivery (less than high school [<12 years] high school [12 years], and more than high school [>12 years]), preterm birth (gestational age < 37 weeks or ≥ 37 weeks at delivery), birthweight (<2500 grams or ≥ 2500 grams), clinical classification for infants with hydrocephaly (isolated, chromosomal or syndromic, and multiple), and birth year (1999-2011 or 2012-2017) (Supplement A).…”