Mathematicians from the University of the Philippines have proven using computer simulations that the dosage of hormonal contraceptives can be reduced by more than 90% without affecting their effectiveness but reducing the risk of side effects. The research was published in the journal PLOS Computational Biology.
The researchers gathered information on pituitary and ovarian hormone levels from 23 healthy women aged 20 to 34, all with regular menstrual cycles lasting 25 to 35 days. Each participant also proved ovulating in the last menstrual cycle.
The researchers used this data to create a mathematical model of a woman’s normal menstrual cycle that allowed them to predict daily hormone levels. They found that birth control pills can work effectively with much lower doses of estrogen or progesterone than currently prescribed. Also, taking hormones at certain times during the menstrual cycle may be more effective than taking them all the time.
“Our results show that it is possible to reduce the total dose by 92% with estrogen monotherapy and 43 percent with progesterone monotherapy; the most effective use of an estrogen contraceptive is in the middle of the follicular phase,” the authors said.
Scientists have also shown that lower doses of each hormone can be used for combined oral contraceptives that use two hormones. They noted that their model did not account for differences in cycle length, which varies from woman to woman and can vary over time.
Previously, researchers used a similar approach to optimize protocols for the treatment of diabetes and prostate cancer, and also selected the optimal hormone dose for IVF.
Despite the many benefits of oral contraceptives (eliminating painful periods, reducing ovarian cancer), they increase the risk of thrombosis, myocardial infarction, and breast cancer. A lower dose of hormones can reduce the number of side effects when taking the birth control pill.