Perinatal & Pediatric
Association Between Neonatal Abstinence Syndrome Incidence and Male Twin Birth Patterning in the US Parvati Singh* Parvati Singh Alaxandria Crawford
The patterning of male twin live births in a population may respond to adverse socioecological conditions, characterized by research as “collective optimism”. In concordance with expectations from the theory of selection in utero which posits that populations respond to adverse circumstances by altering the sex ratio of offspring, studies show a decline in male twins following increased suicides at the population level. The quantification of “collective optimism” through suicides, however, does not offer a direct link to birth outcomes. We use the monthly incidence of births diagnosed with Neonatal Abstinence Syndrome (NAS, withdrawal condition in newborns resulting from prenatal exposure to addictive substances) as a direct indicator of population-level exposure to harmful substances in-utero, and examine consequent changes in the patterning of male twin live births in the US. We utilize national monthly counts of male twin live births, male singleton live births from CDC WONDER, and national monthly counts of NAS births from the National Inpatient Sample database (2003-2019, 204 months). Our analytic data comprise a total of 1,129,713 male twin live births, 333,291 NAS births and 33,850,336 male singleton births, with a monthly mean of 5538, 1634 and 165,933 respectively. We apply ARIMA time-series methods to examine whether male twin live births decline within 0-4 months following higher-than-expected increase in monthly counts of NAS births, controlling for male singleton births and autocorrelation. Results from time-series analyses indicate a decline in male twin births 4 months following increased NAS births in the US, with 100 additional NAS births preceding a decline in 12 male twin live births 4 months later. Our findings contribute to our understanding of the complex interplay between societal challenges and reproductive outcomes, and underscore the potential impact of substance use crises on the biological responses within populations.
