Time-course of leptin levels in term and preterm human milk.
OBJECTIVE
To compare the time-course of breast milk leptin levels between term and preterm pregnancy.


METHODS
Open longitudinal prospective randomised study.


METHODS
RIA of leptin levels in milk from 33 mothers (term pregnancy: n=24; preterm: n=9) at three postpartum intervals: 2-3 days, 4-5 days and 6 weeks (intervals A, B and C), combined with serum in 23 mothers (term: n=17; preterm: n=6) in interval A. Milk samples were sonicated before incubation.


RESULTS
Interval A leptin levels were approximately tenfold higher in serum than in milk (term: 13.24+/-2.48 vs 1.34+/-0.14 ng/ml, P<0.0001; preterm: 4.46+/-1.05 vs 0.63+/-0.18 ng/ml, P<0.0005), and higher in term than in preterm serum (P=0.03). Milk levels were higher in the term vs preterm group in intervals A (P<0.01) and B (P<0.05). In the term group they declined significantly from interval A to interval B (P<0.05) but did not vary significantly in the preterm group. Serum levels correlated with maternal body mass index; milk levels showed only moderate correlation with maternal and infant weight or body mass index.


CONCLUSIONS
The reasons for the presence and differential longitudinal expression of leptin in human milk after term and preterm pregnancy remain unknown. A hypothesis, requiring further study, is that persistently lower leptin levels in preterm milk act as a compensatory release of a brake on neonatal growth.
Department of Obstetrics, Zurich University Hospital, Frauenklinikstrasse 10, CH-8091 Zurich, Switzerland.
J
J
Bielicki
R
R
Huch
U
U
von Mandach
D000328:Adult; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D020738:Leptin / Q000097:blood / Q000378:metabolism*; D016014:Linear Models; D008137:Longitudinal Studies; D008895:Milk, Human / Q000378:metabolism*; D049590:Postpartum Period / Q000378:metabolism; D011446:Prospective Studies; D011863:Radioimmunoassay
D020738:Leptin