STRESS DURING LABOR AND DELIVERY AND EARLY LACTATION PERFORMANCE

The amount of stress experienced by both the mother and fetus during l abor and delivery varies considerably and is likely to be different in primiparous and multiparous women. In this study we explored relation s between the birth experience and lactation performance of 40 women. Stress hormones were measured in serum or plasma during pregnancy, par turition (cord and maternal blood), and lactation. Milk samples were obtained and breast-feeding frequency was recorded each day during the first 2 wk postpartum. Four outcomes were used as markers of lactogen esis: the time when the subject first felt fullness in the breasts, 24 -h milk volume on day 5 postpartum, milk lactose concentration on day 5, and the day of appearance of casein in the milk as determined by ge l electrophoresis. There were significant intercorrelations among the outcome variables, except for milk lactose. Compared with multiparous women, primiparous mothers experienced a delay in breast fullness and lower milk volume on day 5. In multiple regression analyses excluding subjects who had cesarean deliveries (n = 5), markers of both fetal an d maternal stress during labor and delivery (cord glucose concentratio n and maternal exhaustion score) were associated with delayed breast f ullness and casein appearance; delayed casein appearance was also asso ciated independently with a longer duration of labor. Milk volume on d ay 5 was lower in women with higher exhaustion scores, and, in multipa rous women, those who breast-fed less frequently on day 2. The milk la ctose concentration was inversely related to pregnancy weight gain. Th ese results indicate that primiparity, long labor, stress to the mothe r and fetus during labor and delivery and elevated cord concentrations are risk factors for delayed lactogenesis.