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Assessment and Evaluation of the High Risk Neonate: The NICU Network Neurobehavioral Scale
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Published on: August 25, 2014

Birth intervals and perinatal health: an investigation of three hypotheses

J E Miller1

  • 1Office of Population Research, Princeton University.

Family Planning Perspectives
|March 1, 1991
PubMed

Insights

Short birth intervals increase infant health risks. Avoiding less than two years between births can decrease risks of low birth weight and neonatal death by 5-10%.

Area of Science:

  • Perinatal health
  • Reproductive epidemiology
  • Public health

Background:

  • Infants born within 12 months of a previous birth exhibit elevated health risks.
  • Potential contributing factors include prematurity, maternal selection, and maternal depletion.

Purpose of the Study:

  • To investigate the factors behind increased health risks associated with short birth intervals (less than 12 months).
  • To quantify the impact of prematurity, maternal selection, and maternal depletion on perinatal outcomes.

Main Methods:

  • Analysis of data from Hungary, Sweden, and the United States.
  • Statistical control for confounding effects of prematurity.
  • Examination of three hypotheses: confounding by prematurity, selection bias, and maternal depletion.

Main Results:

  • Prematurity is the primary contributor to excess risks in closely spaced births, especially for late fetal death.
  • Even after controlling for prematurity, short intervals (conception within months of prior birth) elevate risks of low birth weight, preterm birth, and neonatal death.
  • A 5-10% reduction in low birth weight and neonatal death is projected by avoiding birth intervals shorter than two years.

Conclusions:

  • Short interpregnancy intervals pose significant risks to infant health, with prematurity being a major mediator.
  • Maternal factors beyond prematurity also contribute to adverse outcomes in closely spaced births.
  • Extending birth intervals to at least two years is a viable strategy for improving infant health outcomes.

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