Non-hormonal gels have been shown to be effective in helping mucus block sperm with a low risk of side effects

Swedish scientists report that a preventive gel made from all-natural, hormone-free ingredients could become a new method
of contraception without side effects.
This gel strengthens the barrier to cervical mucus and is the first viable alternative
to spermicides and contraceptives.

In tests on ovulating ewes, the gel resulted in an average reduction of 98%
in uterine sperm count compared to untreated control animals.
In contrast, the effectiveness of the pill is thought to be between
91% and 99%.

Of the 8 ewes tested, one found two sperm
in the uterus after using a topical gel developed by KTH.
Thomas Crouzier, a biopolymer researcher at KTH, said the results demonstrate the potential of an unprecedented way to prevent unwanted pregnancies — one that blocks sperm by making mucus, rather than killing sperm cells
like spermicides do.

The mechanism takes advantage of the natural barrier function of cervical mucus to isolate the vagina (where bacteria proliferate) from the uterus and upper genital tract
, Kruzier said.
Cervical mucus also regulates sperm movement
.
Before ovulation, the mucus barrier becomes a more selective gatekeeper, creating exceptions
for carefully selected sperm to enter the uterus.

The researchers altered this dynamic
by crosslinking mucus molecules (proteins that confer mucus lubricating properties) with chitosan.
Chitosan is a fibrous natural substance
commonly used in medical materials such as hydrogels, meshes and sutures.
This combination temporarily thickens the cervical mucus, making it harder for sperm to pass through
.

In laboratory tests using human cervical mucus and sperm, chitosan showed a similar effect
.
It quickly strengthens the mucus barrier, the ability of sperm penetration decreases after one minute, and completely blocks the sperm
after five minutes.

Citing research, Kruzier said it was important that about 50 percent of women thought it was important
that contraceptives were hormone-free.
"This new mechanism of action has the potential to be very effective because it reinforces barriers that already exist in the female reproductive tract
," he said.

Kruzier set up a company called Cirqle Biomedical to conduct further testing, with the goal of conducting clinical tests
.
Cirqle Biomedical has entered into a $360 million partnership with women's health company Organon to develop and commercialize the technology
.

"A vaginal gel like this can be applied in seconds," Krutzier said
.
"We think this product should be available
from seconds to hours before sexual intercourse.
This effect may last for hours, but over time the mucus barrier is naturally replaced and this effect diminishes
.
”