Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Narrowing of Sex Differences in Infant Mortality in Massachusetts


OBJECTIVES: To examine whether the improved survival of preterm infants has influenced the known male excess in infant mortality.

STUDY DESIGN: We analyzed sex-specific infant mortality using linked birth and death certificates for all 619,811 live born infants in Massachusetts between 1989 and 1995.

RESULTS: Between 1989 and 1995 the male excess in infant mortality decreased by 50%, from 1.6/1000 to 0.8/1000 live births (LB). This narrowing resulted primarily from a more rapid decline in neonatal mortality among male infants (1.5/1000 LB) than among female infants (0.9/1000 LB). The largest declines in the male excess in neonatal mortality occurred among very premature infants (GA ≤ 30 weeks) and resulted primarily from a more rapid decrease in male deaths from respiratory distress syndrome.

CONCLUSIONS: The narrowing of the sex difference in mortality between 1989 and 1995 suggests that newer treatments like antenatal steroids, and surfactants may have differentially benefited male infants.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Get just this article for as long as you need it


Prices may be subject to local taxes which are calculated during checkout

Figure 1
Figure 2
Figure 3


  1. Naeye RL, Burt IS, Wright DI, et al. Neonatal mortality, the male disadvantage. Pediatrics 1971;48)6):902–906.

    CAS  PubMed  Google Scholar 

  2. Khoury MJ, Marks JS, McCarthy BJ, et al. Factors affecting the sex differential in neonatal mortality. Am J Obstet Gynecol 1985;151(6):777–782.

    Article  CAS  Google Scholar 

  3. Fanaroff AA, Wright LL, Stevenson DR, et al. Very low birth weight outcomes of the National Institute of Child Health and Human Development Neonatal Research Network, May 1991 through December 1992. Am J Obstet Gynecol. 1995;173(5):1423–1431.

    Article  CAS  Google Scholar 

  4. Hammoud EI . Studies in fetal and infant mortality. Am J Public Health. 1965;55(8):1152–1163.

    Article  Google Scholar 

  5. Chen SJ, Vohr BR, Oh W . Effects of birth order, gender, and IUGR on the outcome of VLBW in twins. J Pediatr. 1993;123(1):132–136.

    Article  CAS  Google Scholar 

  6. Singh GK, Yu SM . Infant mortality in the US. Am J Public Health. 1995;85(7):957–964.

    Article  CAS  Google Scholar 

  7. Hobar JD, Lucey J . Evaluation of neonatal intensive care technologies. In: The Future of Children, Vol. 5 (1): Low birth Weight, David and Lucille Packard Foundation, Los Altos, CA, 1995, p. 139–161.

  8. NIH Consensus Development Panel. Effect of corticosteroids for fetal maturation on perinatal outcomes. JAMA 1995;273(5):413–417.

    Article  Google Scholar 

  9. Palta M, Weinstein MR, McGuinness G, et al. A population study. Arch Pediatr Adolesc Med 1994;148:1295–1301.

    Article  CAS  Google Scholar 

  10. Schoendorf KC, Kiely JL . Birth weight and age-specific analysis of the 1990 US infant mortality drop. Arch Pediatr Adolesc Med 1997;151(2):129–134.

    Article  CAS  Google Scholar 

  11. Horbar JD, Wright E, Onstad L . Decreasing mortality associated with the introduction of surfactant therapy: an observational study of infants weighing 601 to 1300 grams at birth. Pediatrics 1993;92(2):191–196.

    CAS  PubMed  Google Scholar 

  12. Spinillo A, Capuzzo E, Ometto A, et al. Value of antenatal corticosteroid therapy in preterm birth. Early Hum Dev 1995;42(1):37–47.

    Article  CAS  Google Scholar 

  13. Crowley P, Chalmers I, Kierse MJ . The effects of corticosteroid administration before preterm delivery: an overview of the evidence from controlled trials. Br J Obstet Gynaecol. 1990;97:11–25.

    Article  CAS  Google Scholar 

  14. Torday JS, Nielsen HC . The sex difference in fetal lung surfactant production. Exp Lung Res 1987;12:1–19.

    Article  CAS  Google Scholar 

  15. Miller HC, Futrakul P . Birth weight, gestational age and sex as determining factors in the incidence of RDS of prematurely born infants. J Pediatr 1968;72(5):628–635.

    Article  CAS  Google Scholar 

  16. David RJ . The quality and completeness of birthweight and gestational age data in computerized birth files. Am J Public Health 1980;70(9):964–973.

    Article  CAS  Google Scholar 

  17. Alexander GR, Himes JH, Kaufman RB, et al. A United States national reference for fetal Growth. Obstet Gynecol 1996;87(2):163–168.

    Article  CAS  Google Scholar 

  18. International Classification of Diseases. 9th Revision Clinical Modification: ICD-9-CM 4th ed. Vols. 1, 2, and 3 New York: McGraw-Hill; 1994.

  19. National Center for Health Statistics. National Vital Statistics Reports Vol 47, No 23 Hyattsville, MD: National Center for Health Statistics; 1999.

  20. National Center for Health Statistics. Monthly Vital Statistics Reports Vol 46, No (S)2 Hyattsville, MD: National Center for Health Statistics; 1997.

  21. Hamvas A, Wise PH, Yang RK, et al. The influence of the wider use of surfactant therapy on neonatal mortality among Blacks and Whites. N Engl J Med 1996;334(25):1635–1640.

    Article  CAS  Google Scholar 

  22. Kleinman JC, Fowler MG, Kessel SS . Comparison of infant mortality among twins and singletons: United States 1960 and 1983. Am J Epidemiol 1991;133(2):133–143.

    Article  CAS  Google Scholar 

  23. Graybill FA, Iyer HK . Regression Analysis. Belmont, CA: Duxbury Press; 1994.

    Google Scholar 

  24. Jobe AH, Mitchell BR, Cunkel JH . Beneficial effects of the combined use of prenatal corticosteroids and postnatal surfactant on preterm infants. Am J Obstet Gynecol 1993;168:508–513.

    Article  CAS  Google Scholar 

  25. Modanlou HD, Beharry K, Padilla G, et al. Combined effects of antenatal corticosteroids and surfactant supplementation on the outcome of very low birth weight infants. J Perinatol 1996;16(6):422–428.

    CAS  PubMed  Google Scholar 

  26. Kleinman JC . Methodological issues in the analysis of vital statistics. In: Kiely M, editor. Reproductive and Perinatal Epidemiology. Boca Raton, FL: CRC Press; 1991.

    Google Scholar 

  27. National Center for Health Statistics. US Decennial Life Tables for 1989–91. Vol II, State Life Tables No 2. Massachusetts, Hyattsville, MD: National Center for Health Statistics; 1998.

Download references

Author information

Authors and Affiliations


Rights and permissions

Reprints and Permissions

About this article

Cite this article

Bhaumik, U., Aitken, I., Kawachi, I. et al. Narrowing of Sex Differences in Infant Mortality in Massachusetts. J Perinatol 24, 94–99 (2004).

Download citation

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


Quick links