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. 2015 May;10(4):197-202.
doi: 10.1089/bfm.2014.0164. Epub 2015 Apr 1.

Maternal neuroendocrine serum levels in exclusively breastfeeding mothers

Alison M Stuebe  1 , Samantha Meltzer-Brody, Brenda Pearson, Cort Pedersen, Karen Grewen
Affiliations

Maternal neuroendocrine serum levels in exclusively breastfeeding mothers

Alison M Stuebe et al. Breastfeed Med. 2015 May.

Abstract

Background: Low milk supply is a common cause of early weaning, and supply issues are associated with dysregulation of thyroid function and prolactin. However, hormone levels compatible with successful breastfeeding are not well defined, limiting interpretation of clinical lab results. In this study we sought to quantify ranges for thyroid-stimulating hormone (TSH), free thyroxine (T4), total T4, and prolactin in a cohort of exclusively breastfeeding women.

Materials and methods: Women planning to breastfeed were recruited in the third trimester of pregnancy. Maternal endocrine function was assessed before and after a breastfeeding session at 2 and 8 weeks postpartum. We used paired t tests to determine whether values changed from the 2- to 8-week visit.

Results: Of 52 study participants, 28 were exclusively breastfeeding, defined as only breastmilk feeds in the prior 7 days, at both the 2- and 8-week study visits. Endocrine function changed with time since delivery: the TSH level was higher, whereas total T4, free T4, and prolactin levels were lower, at the 8-week visit than at the 2-week visit (by paired t test, p≤0.01). We found a wide range of prolactin values at the 8-week visit, with a 5th percentile value of 9 ng/dL before feeding and 74 ng/dL at 10 minutes after feeding.

Conclusions: Neuroendocrine function changes during the first 8 weeks after birth, and a wide range of values is compatible with successful breastfeeding. Further studies are needed to define reference values in breastfeeding women.

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Figures

<b>FIG. 1.</b>
FIG. 1.
Prolactin trajectories for 28 exclusively breastfeeding mothers at 2 and 8 weeks postpartum. Color images available online at www.liebertpub.com/bfm
<b>FIG. 2.</b>
FIG. 2.
Correlation between number of breastfeedings per day and prolactin levels at (A) baseline, (B) 10 minutes after starting feeding, and (C) 10 minutes after the end of feeding and (D) the ratio of postfeeding:baseline prolactin levels among 28 exclusively breastfeeding women at 8 weeks postpartum.
See this image and copyright information in PMC

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