Measurement of Prolactin and Estradiol to Estimate Menses Return of Breastfeeding Mothers

Objective To determine whether the measurement of serum prolactin (PRL) and estradiol (E2) is effective and reliable to estimate the returning time of menses during breastfeedingMethods Serum PRL and E2 were measured in 703 breastfeeding mothers during the period of 2, 3, 4, 5 and 6～9 months postpartum. Radio-immunoassay (RIA) was used to measure the levels of PRL and E2.The cervical mucus, sexual behaviors and vagina bleeding were also monitored since 56 d after postpantum.Results (1) The average level of serum PRL and E2 was 8.16, 3.66, 0.69 in the fully breastfeeding, mixed-feeding and bottle-feeding groups respectively. It showed that 92.55% mother returned menses within 6 months of postpartum in the bottle-feeding group. (2) According to the results, the levels of serum Prolactin and Estradiol were related to the feeding ways, but not completely related to the duration of postpartum. (3) By using the ratio of PRL to E2 to estimate the time of menses return among the breastfeeding mothers, we found that when the ratio became 0.60, the subjects' menses would returen. The sensitivity and the specificity of this method were 89.85% and 90.68% respectively.Conclusion The measurement of serum PRL and E2 is a simple, effective and reliable method to estimate the return time of menses during breastfeeding period. If possible, it should be promoted for clinical use to prepare for their fertility return.