Etonogestrel contraceptive implant as emergency contraception: A mechanism of action pharmacodynamic pilot study.

OBJECTIVES

To evaluate the rate of ovulation suppression or delay by the etonogestrel contraceptive implant when inserted as theoretical emergency contraception.

STUDY

DESIGN

We conducted a pharmacodynamic pilot study among healthy, reproductive age females with regular menstrual cycles and proven prior ovulation. Starting cycle day 10, we performed serial ultrasounds on participants until identification of a dominant follicle (≥15 mm). We then inserted contraceptive implants and performed laboratory and ultrasonographic monitoring every other day to identify if ovulation occurred.

RESULTS

Six out of eight participants met pre-established criteria consistent with ovulation suppression or dysfunction after implant insertion.

CONCLUSIONS

Our pharmacodynamic study supports further investigation of the etonogestrel implant as emergency contraception.

IMPLICATIONS: An etonogestrel contraceptive implant is a potential option for an emergency contraception method. Because this study only evaluated a small sample, further research is needed to evaluate suppression in different BMI groups.

GOV IDENTIFIER: NCT05237141.