Birth control without hormones? Revolutionary Semen Trapping Antibody Could Change Women’s History

Scientists are working on a revolutionary method that could change birth control forever, eliminating the long list of contraindications and effects that current hormone treatments have for women and focusing on an “antibody” that traps sperm and prevents the penetration of vaginal mucus.

It may sound strange, but there are already a few early tests in sheep that have shown promising results. For them, specially designed antibodies were used to stop the movement of sperm and were 99% effective.

“Although human testing is necessary, these [anticuerpos] can offer women another alternative to hormonal contraception ”, wrote protein engineer and immunologist Bhawana Shrestha and colleagues in their article published in Science Translational Medicine, describing how anti-sperm antibodies could slow sperm on a mission.

“The sperm have to swim through the mucus and up into the upper female reproductive system to reach and fertilize the egg.” explains the team.

“Typically only (about) 1% of ejaculated sperm enter the cervix, even fewer reach the uterus, and only dozens of sperm (of the over 200 million that are ejaculated) reach the vicinity of. the ovum.”they added.

But of all, only one sperm is needed to start a pregnancy.

Currently, the most reliable contraceptive methods are, for the most part, hormonal, because they work by providing constant doses of sex hormones to stop the release of eggs from the ovaries.

The contraceptive pill, the implant and the vaginal ring are some very effective examples in preventing pregnancy, if used correctly.

Sadly, some hormonal contraceptive users experience serious side effects, ranging from weight gain and decreased sex drive to migraines and mood swings, and even depression. There are also associated health risks, such as increased risk of blood clots with the pill and a slightly increased risk of breast cancer.

So it’s understandable that some women are eager to find non-hormonal options to prevent pregnancy (or wonder how long it will take before a male contraceptive method is developed).

“There is a clear need for large-scale clinical trials on new and existing forms of birth control,” Write to Bethan Swift and Christian Becker for The Conversation, two reproductive health researchers from the University of Oxford, who were not involved in the study.

“However, despite this, in reality very little is being invested in making this happen, and there is a tendency to prioritize other areas of research.”. Not all of the improved methods overcome the bureaucratic hurdles of international regulations either.

Funding and access issues aside, this new study, led by Shrestha at the University of North Carolina, takes a different approach to most available contraceptives. The team is focusing on antibodies, the Y-shaped molecules that immune cells make to neutralize infections or foreign particles.

Some women, who are otherwise healthy but have a condition called immune infertility, produce anti-sperm antibodies in their reproductive tract which “they trap the vigorously motile sperm in the mucus and prevent them from reaching the egg “Shrestha and her colleagues explain.

Using these antibodies as a scaffold, the researchers designed an improved antibody set by adding several “binding fragments” to improve the binding properties of the sperm.

These fragments, or binding sites, adhere to a particular cell surface marker that is present in all human sperm, but absent in all other tissues and not found in females. This specificity probably makes the treatment fairly safe, but a lot more research is needed before we are sure.

By testing for antibodies using a “semen escape test,” the researchers quantified the number of sperm that could escape from antibody traps in a plastic tube filled with vaginal mucus.

Compared to the original anti-sperm antibodies, the modified antibodies were at least 8 times better at clumping sperm, preventing them from swimming freely, a process called clumping.

The next test involved injecting antibody solutions, followed by samples of human semen, into the vagina of several sheep. After just two minutes, the antibody treatment had reduced the number of motile sperm in the recovered fluid samples by at least 97%.

For potential use in humans, rather than using a vaccine to train the body’s immune system to produce antibodies, the antibodies would also be administered directly into the vagina.

This can be done in several ways: as a rapidly dissolving film or with “intravaginal rings (IVR) that allow the constant release of [anticuerpos] over a period covering the fertility window for most women to create a contraceptive product similar to NuvaRing but without the hormones “Shrestha and her colleagues write.

There is still some way to go, as the strategy has not been tested in humans and the study did not examine how well the treatment might prevent pregnancy; He only counted the sperm that break up the mucus.

“Actual contraceptive efficacy in men must be determined by rigorous clinical studies”, note the researchers.

If this method proves its effectiveness, we could speak of a new contraceptive which, unlike hormones, would bring other benefits beyond the prevention of pregnancy, such as the return of fertility in a short time, and causing many associated side effects. with the use of hormones they are a thing of the past.

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