A morphometric study on the endometrial activity of women before and after one year with LNG-IUD in situ

Abstract

The endometrium was studied by morphometry in 34 healthy women before and after one year's use of an IUD releasing levonorgestrel at a rate 20 micrograms/24 hr (LNG-IUD-20). The effect was compared with that of an IUD releasing 2 micrograms levonorgestrel/24 hr (LNG-IUD-2). The appearance of suppressed endometrial proliferative activity and increased inflammatory reaction was similar in the two experimental groups, suggesting that the morphological alterations were independent of the LNG dosage. The result of this study, combined with clinical data, suggests that LNG-IUD-20 could replace LNG-IUD-2 without any additional side effects. The efficacy of LNG-IUD-20 is also likely to last for a longer period than the LNG-IUD-2.

PIP: In Beijing, China, physicians took an endometrial biopsy from 34 healthy women aged 25-37 before IUD insertion (on cycle day 10-12) and after 12 months of IUD use (on the same cycle day) to examine the endometrial effects of two IUDs releasing either 2 mcg levonorgestrel (LNG) daily (LNG-IUD-2) or 20 mcg LNG daily (LNG-IUD-20). Over 12 months, LNG-IUD-20 use was associated with a decrease in the number of glands (3.66-1.46), in the number of glandular mitoses (5.8-0.29), in glandular diameter (6.03-4.17 mcm), in glandular height (3.45-1.69 mcm), and in the number of stromal mitoses (1.9-0.27) (p 0.001), indicating suppressed endometrial proliferative activity. 12-month LNG-IUD-20 use was also associated with an increase in the number of lymphocytes (9.24-12.57), polymorphonuclear leukocytes (PMN) (2.95-5.26), phagocytes (0-0.43), and plasma cells (0-0.2) (p 0.001), reflecting increased endometrial inflammatory reaction. The authors also found that LNG-IUD-20 use over a 12-month period was associated with a greater glandular diameter and number of stromal mitoses than LNG-IUD-2 (4.17 vs. 2.54 mcm and 0.27 vs. 0.06, respectively), while it was associated with a lower number of PMN and lymphocytes (5.26 vs. 12.03 and 12.57 vs. 19.06, respectively) (p 0.05). These differences suggest that the LNG-IUD-20 induces somewhat less atrophy of the glands and somewhat increased proliferative activity in the stroma. Overall, the two IUDs had similar effects on the endometrium, indicating that the LNG dosage was not responsible for the morphological alterations. Advantages of the LNG-IUD-20 include: can be in situ for as long as 5-7 years without losing efficacy; contraceptive effectiveness same as copper IUDs; and slightly fewer morphological changes than the LNG-IUD-2.