Recreational exercise and occupational activity during pregnancy and birth weight: a case-control study

Am J Obstet Gynecol. 2001 Feb;184(3):403-8. doi: 10.1067/mob.2001.109392.


Objective: Our purpose was to investigate the impact of exercise and occupational activity on birth weight.

Study design: This case-control study involved singleton infants at > or = 34 weeks' gestation without congenital anomalies. Case subjects had birth weights at <15th percentile for gestational age, and 2 control subjects were selected per case subject. Data were collected by self-completed questionnaire and analyzed by means of logistic regression.

Results: Relative to those who participated in structured exercise 3 or 4 times per week during the third trimester, the odds of lower birth weight were substantially increased for those who exercised > or = 5 times per week (adjusted odds ratio, 4.61; 95% confidence interval, 1.73-12.32) and modestly increased for those at the other extreme, who engaged in structured exercise < or = 2 times per week (adjusted odds ratio, 2.64; 95% confidence interval, 1.29-5.39). Other factors of importance to birth weight were maternal height, prepregnancy body mass, pregnancy weight gain, smoking in the third trimester, and nulliparity.

Conclusions: Structured exercise frequency during late pregnancy is a determinant of birth weight.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Body Height
  • Body Weight
  • Case-Control Studies
  • Embryonic and Fetal Development / physiology
  • Exercise / physiology*
  • Female
  • Humans
  • Infant, Newborn
  • Infant, Small for Gestational Age / physiology*
  • Logistic Models
  • Maternal Age
  • Multivariate Analysis
  • Occupations
  • Pregnancy
  • Pregnancy, High-Risk
  • Regression Analysis
  • Risk Factors
  • Surveys and Questionnaires
  • Weight Gain
  • Work / physiology*