Maternal perception of the onset of lactation is a valid, public health indicator of lactogenesis stage II.

Test weighing is the "gold standard" for documenting lactogenesis stage II. However, this method is impractical for use in population studies. Maternal perception of the timing of the onset of lactation may be a useful proxy for lactogenesis stage II. This study seeks to validate maternal perception of the onset of lactation as a marker of lactogenesis stage II. Women (n = 60) were recruited after cesarean delivery. Beginning at 24 h postpartum (pp), the onset of lactation was assessed 3 times daily by both test weighing and maternal perception. Delayed onset of lactation was defined as follows: 1) milk transfer < 9.2 g/feeding at 60 h pp and 2) maternal perception >/= 72 h pp. Misclassification analyses were conducted. Multivariate logistic regression, bivariate analyses and Cox survival analyses were used to evaluate the determinants and consequences of delayed onset of lactation, using both definitions. The sensitivity and specificity of delayed maternal perception as an indicator of delayed lactogenesis were 71.4 and 79.3%, respectively. Four risk factors for low milk transfer were significant (P: < 0.05) or nearly significant (P: </= 0.08) predictors of delayed perception of the onset of lactation. The effects of low milk transfer and delayed maternal perception on breast-feeding duration were similarly modified by intended breast-feeding duration. The magnitude and directionality of the ss coefficients for the milk transfer and perception variables were consistent. On the basis of these results, we conclude that maternal perception of the onset of lactation is a valid public health indicator of lactogenesis stage II.