Maternal smoking, urinary cotinine levels and birth-weight

Area of Science:

• Obstetrics and Gynecology
• Environmental Health
• Pediatrics

Background:

• Maternal smoking during pregnancy is a significant public health concern.
• Accurate assessment of tobacco smoke exposure is crucial for understanding its impact on fetal development.
• Urinary cotinine is a validated biomarker for nicotine exposure.

Purpose of the Study:

• To investigate the association between active and passive maternal smoking and infant birth weight.
• To compare the accuracy of self-reported smoking habits versus urinary cotinine levels in assessing tobacco smoke exposure.
• To evaluate the utility of urinary cotinine assays for monitoring smoke exposure in pregnant women.

Main Methods:

• Interviews were conducted with 300 pregnant women regarding smoking habits at 16 and 32 weeks' gestation and postpartum.
• Urine samples were collected during pregnancy and labor for cotinine level estimation.
• Statistical analysis correlated smoking data and cotinine levels with infant birth weights.

Main Results:

• Both self-reported maternal smoking and urinary cotinine levels were significantly associated with lower birth weights.
• Urinary cotinine levels showed a stronger correlation with reduced birth weight (25g decrease per µg/mg creatinine) compared to self-reported smoking (12g decrease per cigarette).
• Passive maternal smoking was associated with a non-significant decrease of 66g in mean birth weight.

Conclusions:

• Urinary cotinine is a more reliable biomarker than self-report for quantifying tobacco smoke exposure in pregnancy.
• Assessing urinary cotinine levels can effectively monitor pregnant women's exposure to environmental tobacco smoke.
• Findings underscore the detrimental effects of both active and passive smoking on fetal growth and birth outcomes.