Most contraceptives available today contain either or both estrogen and progesterone hormones to block ovulation, the phase of the menstrual cycle wherein an egg is released into the uterus. But while effective, hormonal contraception has its drawbacks: an increased potential for blood clots, heart attacks, strokes, mood disorders, and other health risks.

UPD-CS Institute of Mathematics (UPD-CS IM) Ph.D. Mathematics graduate Brenda Lyn Gavina and Associate Professor Dr. Aurelio de los Reyes V, alongside collaborators Dr. Mette Olufsen of North Carolina State University, Dr. Suzanne Lenhart of the University of Tennessee, and Dr. Johnny Ottesen of the Roskilde University of Denmark, analyzed the hormone levels of 23 women aged 20 to 34 years old with regular menstrual cycles. Their research revealed that estrogen-only contraceptives could work just as effectively even if hormone doses were reduced by as much as 92%. Meanwhile, hormone doses in progesterone-only contraceptives could be decreased by as much as 43% while still achieving the same effectivity.

In their study, the researchers developed a modified menstrual cycle model to track natural hormone levels and the effect of hormones taken through contraceptives. They then applied mathematics to determine the lowest amount of hormones needed to prevent ovulation. Apart from finding lower yet effective hormone dosages, they also found that intaking these contraceptives before the tenth day of the menstrual cycle is just as effective in preventing pregnancy as a daily dose.

The study opens new avenues for further research in hormonal birth control. “With the rapid development of new implants and injections providing continuous administration, there is great potential to implement new treatment scheme minimizing dose,” the researchers concluded in their study, published last April 13 in the journal PLoS Computational Biology.

“Reducing the dosage of hormonal contraceptives has been a longstanding objective of safer contraception. Our modeling/computational study suggests an effective and cost-efficient hormonal contraceptive administration.” Dr. de los Reyes said. “We also hope to build on the current model to investigate reproductive health concerns in women like polycystic ovarian syndrome (PCOS) and ovarian cysts. We would like to caution that our model is not directly translatable to clinical setup (or actual patients) as of yet, but the principles and its proof of concept could be potentially implemented to achieve safe and cost-efficient contraception.”