Endometrial regeneration after voluntary abortion

Endometrial biopsies were obtained on postabortal days 1 to 36 in 42 women without contraception, in 28 women using oral contraceptives, and in 12 women with intrauterine devices. Tissue samples were examined for day-to-day sequential changes, specifically: a)regenerative, repair, proliferative and secretory activity, b)involution of pregnancy changes, c)inflammation. In the absence of contraception, the endometrium promptly regenerated. The earliest evidence of ovulation was on day 9. One-third of the women ovulated before the first period. Incomplete placental and decidual involution was seen in 45% of patients, but its frequency progressively decreased toward the end of observation. Inflammation seen in 26% was limited to the retained decidua and was, therefore, thought to be a reactive rather than an infectious phenomenon. In women taking oral contraceptives, initial regeneration was also prompt. "On pill" changes resembled the nonpostabortal picture except for a few cases of cystic glandular dilation, or Arias-Stella-like phenomena. Retained decidua and inflammation were more frequent (75% and 68%) than in the noncontraceptive group, and the diminishing trend was not observed. In the intrauterine device group, inflammation was more frequent (83%) than in the other two groups and was not limited to the decidua.