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Oregon PRAMS: Presentations

Association Between Maternal Smoking and Breastfeeding at 10 Weeks

Kenneth D. Rosenberg, MD, MPH, Zhiwei Yu, MPH, Alfredo S. Sandoval, MS, MBA
Oregon Department of Human Services, Office of Family Health, Portland, Oregon
Background. Maternal smoking may be associated with decreased likelihood of initiating breastfeeding and decreased duration of breastfeeding. There is some evidence that maternal smoking decreases the volume of breast milk.

Methods. Oregon PRAMS (Pregnancy Risk Assessment Monitoring System) surveys a stratified random sample of Oregon resident mothers 2-6 months after a live birth. This data comes from women surveyed from November 1998 through October 1999; the babies were born 8/1/98-8/9/99. Responses were weighted for oversampling (race/ethnicity and low birthweight), nonresponse and noncoverage. Duration of breastfeeding (not necessarily exclusive breastfeeding) was assessed by asking "For how many weeks did you breast-feed your new baby?" Over 99% of PRAMS responses occurred after the baby was 10 weeks old.

Results. Of 2919 women surveyed, 1867 responded (response rate = 64.0%). 83.6% of Oregon women initiated breastfeeding. 59.5% of Oregon women were still breastfeeding at the time the baby was 10 weeks old. In a multivariate model, the only significant predictor of women not breastfeeding at 10 weeks was smoking in the third trimester of pregnancy: ORa=1.92 (95% CI 1.33, 2.78).

Conclusions. Maternal smoking is strongly associated with decreased breastfeeding at 10 weeks. This is supported by parallel work * that we have done linking newborn metabolic screening (containing infant feeding data) and birth certificate data. Postpartum smoking is highly correlated with smoking during pregnancy and may be the real cause of decreased breastfeeding. These findings are biologically plausible because smoking mothers may have lower milk output and decreased prolactin levels than nonsmoking mothers.

Public Health Implications. There is a need for more programs to assist pregnant women who wish to stop smoking. Helping mothers to quit smoking should increase infant health in many ways, including increasing breastfeeding duration. Breastfeeding support programs should expect that women who smoke may need supplemental support to continue breastfeeding.

*GW Letson GW, KD Rosenberg KD and Wu L. Association between smoking during pregnancy and breastfeeding at about two weeks of age in Oregon, 1998. Journal of Human Lactation, in press.

Submitted for presentation at CDC Maternal and Child Health Epidemiology Workskop, December 2002.