Neonatal mortality by order of birth and age of parents

Am J Hyg. 1938 Sep;28(2):244-70. doi: 10.1093/oxfordjournals.aje.a118441.


PIP: A study of all infants born in New York State, exclusive of New York City, in 1936 has been made with the intent of investigating the effects of order of birth and age of paretns of neonatal mortality. The study revealed these results. 1) Of the 82,140 infants, 2563 (31.2/1000 livebirths) died before 1 month of age. 2) Firstborn infants, as well as those of higher birth orders, were found to have a considerably higher mortality than the intermediary births. The rate for 1st births was 32.1; for 2nd births it was 26.0. It rose gradually for births of orders 2, 3, and 4, and sharply beginning with 5th births. The rate for infants of order 10 and over was 55.2, more than twice the rate for 2nd births. 3) More than 1/2 of the neonatal deaths (54%) were found to occur among infants born prematurely, while less than 3% of the surviving infants for the 1st month of life were premature. The frequency of prematurity was 42.9/1000 livebirths. 4) The mortality of premature births was extremely high (389.2), and it rose with order of birth. The rate was a minimum for 1st births (329.4) and rose to a rate of 644.4 for infants of order 10 and over. However, the frequency of premature births/1000 livebirths started high for 1st births (49.3), was a minimum for 5th births (36.0), and increased thereafter. 5) The neonatal mortality of infants carried to fullterm was only 15.2/1000 livebirths. Thus, the rate for prematurely born infants was 25 times as high as the rate for fullterm infants. The handicapping of the 1st born is very marked for the latter. The rate for fullterm 1st births was 44% higher than the rate of 2nd births. 6) The neonatal mortality for male infants was consideralby higher for than female infants for every order of birth. 7) Premature births were more frequent in urban communities than in the rural part of the state. However, the mortality among the premature was higher in the rural areas thanin the cities. 8) When stillbirths were added to neonatal deaths, the total loss (late fetal and neonatal mortality) presented the same variation by birth order as neonatal mortality. The rate for the total loss was 58.4 and the frequency of prematurity was 55.5/1000 total births. 9) Neonatal mortality of infants born to very young mothers and to older mothers is considerably higher than that of infants born to mothers ages 20-30. The lowest rate was recorded for mothers ages 27-28. 10) The same trend of mortaltiy by age of mother was observed in practically every order of birth. It started high for young mothers of every birth order, dropped gradually to a minimum, and then rose to very high rates for old mothers. Neonatal mortality seems to be independently correlated with the 2 factors of birth order and maternal age.

MeSH terms

  • Adolescent
  • Age Factors*
  • Americas
  • Birth Order*
  • Demography
  • Developed Countries
  • Developing Countries
  • Family Characteristics*
  • Family Relations
  • Fetal Death*
  • Infant
  • Infant Mortality*
  • Infant, Premature*
  • Maternal Age*
  • Mortality*
  • New York
  • North America
  • Parents*
  • Paternal Age*
  • Population Characteristics*
  • Population Dynamics*
  • Population*
  • Rural Population*
  • United States
  • Urban Population*