Abstract

The umbilical venous plasma prolactin concentrations of three groups of term infants were compared immediately after birth. Samples were taken following seven vaginal deliveries, eight emergency caesarean sections performed during labour, and 12 elective caesarean sections before labour. Mean concentrations of prolactin were significantly lower in the elective caesarean section group compared with the labour groups. This result indicates that the fetal hypothalamic–pituitary axis is stimulated during labour which could explain the increase in plasma prolactin concentrations at birth.