Are Male Neonates More Vulnerable to Neonatal Abstinence Syndrome Than Female Neonates?

Unger, Annemarie; Jagsch, Reinhold; Bäwert, Andjela; Winklbaur, Bernadette; Rohrmeister, Klaudia; Martin, Peter R.; Coyle, Mara; Fischer, Gabriele

doi:10.1016/j.genm.2011.10.001

« Previous Next »Gender Medicine: The Journal for the Study of Sex & Gender Differences
Volume 8, Issue 6 , Pages 355-364, December 2011

Are Male Neonates More Vulnerable to Neonatal Abstinence Syndrome Than Female Neonates?

Annemarie Unger, MD
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
- Address correspondence to: Annemarie Unger, MD, Department of Psychiatry, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
Reinhold Jagsch, PhD
- Department of Psychology, University of Vienna, Vienna, Austria
Andjela Bäwert, MD
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
Bernadette Winklbaur, PhD
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
Klaudia Rohrmeister, MD
- Department of Paediatrics, Medical University of Vienna, Vienna, Austria
Peter R. Martin, MD
- Addiction Center, Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, Tennessee
Mara Coyle, MD
- Department of Pediatrics, Warren Alpert Medical School of Brown University, Providence, Rhode Island
Gabriele Fischer, MD
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria

Accepted 10 October 2011. published online 16 November 2011.

Abstract

Background

Prior studies have shown an increased vulnerability among males to adverse outcomes during the postnatal period. Most children exposed to opioids and other medications in utero develop neonatal abstinence syndrome (NAS), yet individual predisposition for NAS is poorly understood.

Objective

This investigation examined the role of neonatal sex in the postnatal period for neonates exposed to standardized opioid maintenance treatment in utero with a focus on NAS regarding severity, medication requirements, and duration.

Methods

This was a secondary analysis of data collected in a prospective randomized, double-blind, double-dummy, multicenter trial (MOTHER study) that examined the comparative safety and efficacy of methadone and buprenorphine during pregnancy. A total of 131 neonates born to opioid-dependent women randomized at 6 US sites (n = 74) and 1 European site (n = 37) were analyzed. Sex-based differences in birth weight, length, head circumference, NAS duration, NAS severity, and treatment parameters of full-term neonates were assessed.

Results

Males had a significantly higher birth weight (P = 0.027) and head circumference (P = 0.017) compared with females, with no significant sex difference in rates of preterm delivery. No significant sex-related differences were found for NAS development, severity, or duration, or medication administered, and there were no significant differences in concomitant drug consumption during pregnancy (P = 0.959).

Conclusions

This unique prospective study shows similar postnatal vulnerability for both sexes, suggesting that factors other than sex are the major determinants of clinically significant NAS. ClinicalTrials.gov identifier: NCT 00271219.

Key words: buprenorphine , methadone , neonatal abstinence syndrome , opioid dependence , pregnancy , sex differences