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Clin Endocrinol (Oxf). 1982 Oct;17(4):363-8.

Suppressed prolactin but normal neurophysin levels in cigarette smoking breast-feeding women.


The hormonal responses to breast-feeding were studied during the first 3 post-partum weeks in ten women smoking more than fifteen cigarettes/day and in a control group. Basal PRL levels were significantly lower in smokers compared with non-smokers, but suckling induced acute increments in serum PRL and oxytocin-linked neurophysin, which were not influenced by smoking. The lactational pattern was normal, but smokers weaned their babies significantly earlier compared with non-smokers. Heavy cigarette smoking women have lower basal PRL levels and this may shorten the period of lactation.


Hormonal responses to breastfeeding were studied during the 1st 3 postpartum weeks in 10 women smoking more than 15 cigarettes/day and in 10 nonsmoking controls. All had had uncomplicated pregnancies resulting in term deliveries of infants weighing above 2800 gm. Mean age, parity, and infant birthweights were 26.5 years, 2, and 3390 gm in smokers and 28 years, 2, and 3615 gm in nonsmokers. The only significant clinical difference was earlier weaning in smokers. Mean serum prolactin (PRL) was consistently lower in smokers. Basal levels differed significantly on the 1st day and in repetitive samples on the 21st postpartum days, when the difference was significant prior to and 120 minutes after breastfeeding. The difference after 12 hours of abstinence from smoking was also significant. Increments in serum PRL during breastfeeding were not significantly different between smokers and nonsmokers, and not influenced by abstinence from smoking. Basal levels and sucking-induced increments of oxytocin-linked neurophysin (hNp2) were similar in smokers and nonsmokers and were not influenced by abstinence from smoking. At the 3rd week, mean basal vasopressin-linked neurophysin (hNpl) was .31 ng/ml in nonsmokers and .40 ng/ml and .37 ng/ml respectively in smokers abstaining and not abstaining. Neither smoking nor breastfeeding induced any significant alteration in serum hNpl. Serum nicotine and plasma adrenaline but not dopamine or noradrenaline increased significantly during smoking. Basal levels of catecolamines were not significantly altered after abstinence from smoking. The lower basal PRL levels of heavy smokers may shorten the period of lactation.

[Indexed for MEDLINE]

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