Gestational age-specific sex difference in mortality and morbidities of preterm infants: A nationwide study

Abstract

This study aims to determine whether male sex has adverse effect on mortality and morbidities in very low birth weight infants (VLBWI) <30 weeks of gestation and to ascertain this sex effect, stratified by gestational age, adjusting for perinatal risk factors. This is a population-based study from Korean Neonatal Network for VLBWI born at 23+0 and 29+6 weeks of gestation between January 2013 and December 2014. The primary outcome was gestation-specific sex difference in the occurrence of mortality, combined morbidities, and individual morbidity. A total of 2228 VLBWI were enrolled (males, 51.7%). Mortality was not different between sexes. The risk of bronchopulmonary dysplasia and combined morbidities was significantly higher in males ≤25 weeks of gestation (odds ratio [OR] 2.08, 95% confidence interval [CI] 1.35–3.20 and OR 2.00, CI 1.19–3.39, respectively). Males had a significantly higher incidence of periventricular leukomalacia at 23 and 29 weeks of gestation. The risk of severe retinopathy of prematurity was higher in females >25 weeks of gestation. Although both sexes have similar risk for mortality, male sex remains an independent risk for major morbidities, especially at ≤25 weeks of gestation. The risk of each outcome for males has a specific pattern with increasing gestational age.

Let’s call the whole thing off: evaluating gender and sex differences in executive function

“…A number of environmental exposures occurring either during prenatal or early postnatal development have been shown to affect executive function, including dietary changes, and exposure to toxins, infection/inflammation or glucocorticoids (GCs) being the most well-studied. For health outcomes in general, an emerging theme suggests that male offspring tend to be more adversely affected by early life adversity than females [102][103][104][105][106], an observation documented in both humans and animal models. To what extent this applies to executive function shall be discussed here.…”

Retinopathy of Prematurity Among Very Low-Birth-Weight Infants in China: Incidence and Perinatal Risk Factors

“…Previous studies have shown that male sex is associated with worse respiratory outcomes, such as RDS and BPD, as well as IVH and ROP. 39 Lingappan et al 40 thought that hormonal, physiological, and developmental differences between males and females might lead to sexspecific outcomes; recently, there have been fewer studies on this topic. The effects of sex difference on fetal and later infant retinal vascularization need further evaluation.…”

Trends in sex-specific differences in outcomes in extreme preterms: progress or natural barriers?

“…In the past two decades, cohort studies of preterm neonates (born before 37 weeks’ gestation) reaffirmed the ‘male disadvantage’ that was first described in 19711 2; mortality was usually, but not always, found to be significantly higher in preterm boys than girls 2–10. Important morbidities associated with preterm birth, such as bronchopulmonary dysplasia (BPD),3 5 9 11 intraventricular haemorrhage (IVH),6 9 12–14 periventricular leukomalacia (PVL),11 retinopathy of prematurity (ROP)15 16 and infection6 17 are also reported to occur at higher rates in preterm boys than girls. The difference in outcomes between the sexes was attributed to biologic differences between preterm boys and girls such as slower fetal development, less hospitable intrauterine environment and different sex steroids exposure 18–20…”