哺乳闭经法（LAM）的指导者认为纯母乳喂养（BF）或近乎纯BF的妇女在产后56天内均可用此法避孕。但有研究发现8％的妇女于产后56天内已有月经复潮，却未阐明月经复潮与排卵的相关性。而产后早期BF的妇女的月经常见排卵的先兆。为了进一步了解BF妇女产后6周～8周阴道出血发生的 Instructors of lactation amenorrhea (LAM) believe that women who are exclusively breastfed (BF) or near-pure BF can use this method for contraception within 56 days of delivery. However, studies have found that 8% of women have had menstrual flow within 56 days after childbirth, but did not clarify the correlation between menstrual reversion and ovulation. The early postpartum BF women’s menstrual common signs of ovulation. In order to further understand the BF women postpartum 6 weeks to 8 weeks vaginal bleeding occurred