Abstract
Follicle-stimulating (FSH) and luteinizing hormones (LH) were measured by radioimmunoassay in 133 serum samples after parturition from 10 normal healthy women. All cases were investigated at weekly intervals till resumption of menstruation and during the first menstrual cycle. The postpartum period, defined as the time between delivery and resumption of menstruation, was divided into: lactation, partial lactation and non-lactation periods. Low or non-detectable FSH values were found during the first 2 weeks post partum. Human chorionic gonadotropin (HCG) was detected in the samples obtained during the first 2 weeks after delivery. During the remaining period of sampling, both FSH and LH concentrations were within the range found in the normal menstrual cycle excluding the midcycle peak. No LH values in the range of the midcycle peak could be detected in any of the samples obtained during the three periods. The average serum FSH value during lactation was significantly lower than that found during the period of non-lactation. This significant difference was attributed to the low FSH levels found during the first 2 weeks after delivery. During non-lactation the mean serum FSH concentration was significantly higher than that of the luteal phase but similar to that of the follicular phase of the ovulatory control cycles.