Today, there are many contraceptives that significantly reduce the chances of getting pregnant. However, no form of contraception can be 100% effective. And even with popular hormonal methods of birth control, there is a “failure”.
Experts do not know exactly why such contraceptives sometimes fail, and often, when a woman becomes pregnant while using pills or other hormonal drugs, doctors believe that she neglected the instructions.
Meanwhile, recently, American experts have found that in some cases, the genes of a woman can put her at risk of an unplanned pregnancy, even with the correct use of a hormonal contraceptive.
Researchers at the University of Colorado Medical School, under the direction of Aaron Lazorwitz, decided to turn to pharmacogenomics, which studies the effect of each person’s genetic variation on drug reactions.
Lazorvitsa puzzled why so far no one has investigated the relationship of pharmacogenomics with women's health in this matter. While women mostly use the same hormones to prevent pregnancy, doctors have not studied whether such products will be equally effective for all patients.
Experts studied data on 350 healthy girls, whose average age was 22 years. All of them for at least a year used a contraceptive implant, which allocates etonogestrel. This form of hormonal birth control based on progestins.
Let us clarify that the general collective name of the steroid female sex hormone subclass is progestogens, and synthetic progestogens are commonly called progestins.
It turned out that approximately 5% of participants (18 women) had a special variant of the gene CYP3A7, known as CYP3A7 * 1C.
Despite the fact that none of the women with this variant of the gene became pregnant (at least during the study), they had a lower level of etonogestrel compared with other participants in the study (the average decrease was approximately 23%).
Moreover, in five owners of the CYP3A7 * 1C gene out of 18, the levels of this hormone in the blood were below the threshold value required for the drug to work properly.
As experts explain, the CYP3A7 gene encodes a special enzyme that changes the metabolism of steroid hormones. Typically, this gene is active only in the embryo and is "turned off" before the baby is born. But for some people, it remains active, which in turn leads to more rapid destruction of certain hormones – estrogen and progestin. The latter are most commonly used in hormonal contraceptives.
Further analyzes have shown that this rare variant of the gene caused the expression of enzymes that can destroy steroid hormones.
According to scientists, this may increase the risk of unwanted pregnancy of women during the use of hormonal drugs, especially if she uses low-dose contraception.
"Previously it was assumed that it was the woman’s fault if she became pregnant while using contraceptives. But the new results show that we should listen to our patients and look for the reason including in the genes," says Lazorwitz.
It should be noted that this study should not cause concern among women about the various methods of birth control, as the latter still remain highly effective when used correctly.
Meanwhile, recent work authors emphasize the importance of understanding how a person’s unique genetic code can affect its ability to metabolize certain drugs.
In the future, experts want to conduct additional research and find other genes that may also increase the risk of hormone contraception "failure".
The scientific article on the results of the study was published in the publication Obstetrics & Gynecology.
By the way, earlier the authors of the project "Vesti.Nauka" (nauka.vesti.ru) told about a universal contraceptive for men and women.
In addition, we reported that in Europe, a smartphone application was recognized as an effective contraceptive.
As for hormonal contraceptives, they, as shown by earlier work, may increase the risk of developing breast cancer.