Initiation of lactation in women after preterm delivery


Address for correspondence:
Mark Cregan
Department of Biochemistry
The University of Western Australia
35 Stirling Highway
Crawley, 6009


Background.  Lactogenesis II describes the onset of copious milk secretion, and the success of lactogenesis II has been determined in women by measuring the changes in the composition of mammary secretion in the immediate postpartum period.

Aim and methods.  Therefore, the aim of this study was to determine the success of lactogenesis II at day 5 postpartum in women expressing milk for their preterm infants (n = 22) by measuring the lactogenesis II markers (milk citrate, lactose, sodium and total protein) and comparing them with women breastfeeding full-term infants (n = 16).

Results.  There were no significant differences between the means (± SD) of the lactogenesis II markers for preterm (4.3 ± 0.7 mM; 147 ± 10 mM; 12 ± 6 mM; 14.0 ± 1.5 g/l, respectively) and term (3.4 ± 1.4 mM; 126 ± 17 mM; 30 ± 13 mM; 15.3 ± 2.5 g/l, respectively) women. However, variation about the mean was greater in preterm women (coefficient of variation for citrate, 40%; lactose, 14%; sodium, 42%; and total protein, 17%) compared with term women (17%, 7%, 33%, and 10%, respectively). All lactogenesis II markers were within 3 SD from the means for the term women and thus these women were considered to have successfully initiated their lactation. Only 18% of preterm women had all four lactogenesis II markers within 3 SD from the mean for term women. The remaining 82% of preterm women had at least one of the markers of lactogenesis II at pre-initiation concentrations (36% had 1 marker, 32% had 2 markers, and 14% had 3 markers). Furthermore, these women had significantly lower 24-hr milk production than those preterm women that had all four markers within 3 SD from the mean of the term women.

Conclusions.  It was concluded that 82% of preterm women had a compromised initiation of lactation, and this was not uniform in all women.