Two studies: benefits seen with limiting OC hormone-free interval.(Gynecology)

MONTREAL -- Limiting the hormone-free portion of OC regimens can reduce side effects and may improve contraceptive effectiveness, according to two studies presented at the World Congress on Fertility and Sterility.

"For a lot of women, the hormone-free days are when they have their PMS, their pain, and their heavy bleeding. That's also when many women have their headaches, and sometimes that's when their acne flares. It's amazing that the 7-day hormone-free interval [HFI] has lasted this long," said Dr. Patricia Sulak, a researcher, consultant, or speaker for Berlex Inc., Barr Laboratories Inc, and Wyeth. all of which market OCs.

In a separate presentation. Angela Baerwald, Ph.D., of the University of Saskatchewan reported evidence of follicular development, endometrial development, increased serum estradiol, and even ovulation during the HFI in women compliant on certain OC regimens.

"The loss of endocrine suppression during this interval provides the rationale for a reduction in the traditional 7-day hormone-free interval and/or the use of continuous hormonal contraception," she said.

Her study, supported by N.V. Organon, a maker of OCs, compared follicular development in 36 women randomized to one of three OC preparations: a monophasic desogestrel, a tricyclic norgestimate, or a monophasic levonorgestrel.

High-resolution transvaginal ultrasonography of the ovaries was performed every third day for 3 consecutive 28-day cycles.

Follicles were monitored for diameters of 10-13 mm (which would indicate they were active) or 14 mm or more (which would mean they had the biologic potential to ovulate).