ABSTRACT

Brache, Vivian, Horacio Croxatto, Régine Sitruk-Ware, Robin A. Maguire, Juan C. Montero, Narender Kumar, Ana M. Salvatierra, Ana-Sofia Tejada, Leila Cochon, Maria L. Forcelledo, Pekka Lähteenmäki, Francisco Alvarez, and Anibal Faundes. 2007. "Effect of a single vaginal administration of levonorgestrel in Carraguard® gel on the ovulatory process: A potential candidate for 'dual protection' emergency contraception," Contraception 76(2): 111–116. (offsite link)

Objective
The study was conducted to evaluate the effect of Carraguard vaginal gel containing 0.75 mg of levonorgestrel (CARRA/LNG gel) administered in a single dose at different stages of follicle development over subsequent follicle rupture and hormonal levels.

Method
Randomized, blinded, cross-over study comparing the effects of a single administration of CARRA/LNG gel or Carraguard (CARRA) gel. Twenty-four healthy women were enrolled in two centers. The gels were administered when the follicle had reached diameters of 12–14, 15–17, and =18 mm in eight women each. Volunteers were followed for one treatment, one washout cycle, and a second treatment cycle. Follicle rupture or nonrupture was assessed by transvaginal ultrasound. Luteinizing hormone, estradiol, and progesterone levels were measured daily for five days following treatment, and three times per week until menses.

Results
No follicular rupture within the five-day period following administration was observed in 74 percent and 30 percent of the CARRA/LNG and CARRA gel treatment cycles, respectively, while ovulation was documented in 4 percent and 61 percent, respectively. The overall proportion of cycles with lack of follicular rupture or ovulatory dysfunction (follicle rupture preceded by an inadequate LH surge) was 96 percent for CARRA/LNG and 39 percent in the CARRA gel cycles.

Conclusion
Single vaginal administration of 0.75 mg LNG in CARRA gel in the late follicular phase is effective for interfering with the ovulatory process.

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