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"Masculinizing" effect on respiratory morbidity in girls from unlike-sex preterm twins: a possible transchorionic
Eric S Shinwell1, Brian Reichman, Liat Lerner-Geva
1Department of Neonatology, Kaplan Medical Center, PO Box 1, Rehovot 76100, Israel. eric_s@clalit.org.il
Insights
Male premature infants face higher risks for mortality and respiratory issues. However, in unlike-sex twin pairs, this male disadvantage appears transferable to female infants, suggesting intrauterine influences on fetal development.
Area of Science:
- Neonatalogy
- Perinatal Medicine
- Fetal Development
Background:
- Male preterm infants exhibit higher rates of respiratory and neurologic morbidity and mortality compared to females.
- Female infants in unlike-sex twin pairs show birth weights closer to their male co-twins than to females in like-sex pairs.
Purpose of the Study:
- To investigate if male disadvantage in preterm infants impacts respiratory distress syndrome (RDS) incidence in female infants from unlike-sex twin pairs.
- To explore potential intrauterine factors affecting fetal lung development and their sex-specific outcomes.
Main Methods:
- Population-based study using the Israel Neonatal Network data.
- Included 8858 very low birth weight infants (500-1500g) from 24 to 34 weeks' gestation.
- Compared morbidity and mortality in male/female singletons, like-sex twins, and unlike-sex twins using multivariable analyses.
Main Results:
- Male singletons and like-sex twins had increased risks for mortality, RDS, pneumothorax, bronchopulmonary dysplasia, and brain hemorrhages.
- No significant difference in respiratory morbidity was observed between males and females in unlike-sex twin pairs.
- The male disadvantage persisted for mortality and periventricular-intraventricular hemorrhage in unlike-sex pairs.
Conclusions:
- The observed differences in morbidity and mortality highlight a male disadvantage in preterm infants, not a female advantage.
- This male disadvantage may be transferred to female co-twins in unlike-sex pairs, potentially via intrauterine paracrine mechanisms.
Objectives:
Preterm male infants are at a disadvantage when compared with female infants regarding the incidence of respiratory and neurologic morbidity and mortality. At term, female infants from unlike-sex twin pairs have birth weights that are closer to their male co-twins than to girls from like-sex twin pairs. We hypothesized that if the male disadvantage is mediated via factors that affect fetal lung development, there may be a potential effect on the incidence of respiratory distress syndrome and its complications in female infants from unlike-sex pairs.
Patients And Methods:
In this population-based study we used data from the Israel Neonatal Network, which included data from 8858 very low birth weight (500-1500 g) infants of 24 to 34 weeks' gestation. The incidence of morbidity and mortality was compared in male and female infants from singletons and like-sex and unlike-sex twin pairs. Multivariable analyses were used, accounting for relevant confounding variables.
Results:
Male singletons and like-sex twins were at increased risk for mortality, respiratory distress syndrome, pneumothorax, bronchopulmonary dysplasia, periventricular-intraventricular hemorrhage, and periventricular leukomalacia. However, in unlike-sex twin pairs, no difference was seen in the incidence of respiratory morbidity between male and female twins. The male disadvantage was maintained for mortality and periventricular-intraventricular hemorrhage.
Conclusions:
These findings suggest that the difference in morbidity and mortality between male and female premature infants represents a male disadvantage as opposed to a female advantage and that this disadvantage may be transferred from boys to girls in unlike-sex twin pairs, perhaps via an intrauterine paracrine effect.
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