The volume of milk produced by mothers who smoked cigarettes (n = 11) and control subjects who did not smoke (n = 29) was compared after the delivery of their preterm infants (28 to 32 weeks gestation). Milk production was significantly less among those who smoked, with or without adjusting for age, race, parity, gravidity, weight-for-height, prior nursing experience, customary alcohol and caffeine intake, infant birth weight, and pumping frequency. Each mother maintained her milk production using an electrical breast pump and without the stimulus of her infant suckling at the breast. Daily frequency and duration of breast pump usage were similar in the two groups. At 2 weeks postpartum, 24-hour milk volumes were 406 ± 262 mL for mothers who smoked and 514 ± 338 mL for control subjects. Between 2 to 4 weeks postpartum, the mean change in 24-hour milk volume (milliliters per 24 hours) of control subjects increased (+113 ± 179 mL, P < .005), whereas milk volume of mothers who smoked cigarettes remained unchanged (-47 ± 122 mL, P = .25). The percentage change in milk volume between 2 and 4 weeks for the combined groups was significantly related to four factors: pumping frequency, change in daily pumping frequency, day of initiation of pumping, and smoking status. Total and protein nitrogen, lactose, calcium, and phosphorous concentrations did not differ in milks from mothers who smoked cigarettes and mothers who did not smoke. Fat concentrations were lower in the milk from mothers who smoked cigarettes. Reduced milk volume and fat concentrations may explain the reported early weaning of breast-fed infants by women who smoke cigarettes.
- Received April 6, 1992.
- Accepted June 25, 1992.
- Copyright © 1992 by the American Academy of Pediatrics