HIV prevention experts say it's time to look at the diaphragm again

Failure to explore the potential of products which provide physical protection
of the cervix—such as the diaphragm—for preventing the transmission of HIV is
depriving women of a promising prevention mechanism that they can control
themselves, according to HIV prevention experts.

In an editorial review published in the September 7, 2001 issue of the journal,
AIDS, lead author Thomas R. Moench, MD, medical director at ReProtect, LLC,
Baltimore, and senior author Nancy Padian, PhD, professor of obstetrics and
gynecology and director of international programs at UCSF’s AIDS Research
Institute, argue that the diaphragm, a once popular birth control method whose
use has declined drastically since the introduction of oral contraceptives,
deserves a second look from researchers.

“Female-controlled HIV prevention technologies are desperately needed,
especially in the developing world where I do much of my work,” said Padian. “
Women often do not have the power to control when or how they have sex. A
diaphragm can be used without their partner knowing about or needing to consent
to its use.”

The review hypothesizes that the cervix is a “hot spot” in terms of
susceptibility to HIV infection and that physical barrier devices like the
diaphragm that protect the cervix may have a greater potential than previously
thought.  “The epithelial surface of the cervix is very thin and fragile—it can
bleed spontaneously or with minor trauma.  The surface of the vagina is much
thicker. It’s covered with something more like skin. Also, the cervix has more
cells with HIV specific receptor sites and these cells appear to reside closer
to the cervix’s surface than in the vagina,” said Moench.
Another factor leading to increased susceptibility noted in the review is the
peristaltic contractions of the uterus that actually aspirate or draw fluids up
into the upper genital track. The upper genital track has been shown to be very
susceptible to HIV and sexually transmitted diseases (STDs).  This rapid upward
movement of fluid is thought both to enhance fertility and to transport HIV and
STD causing pathogens.  The diaphragm is a barrier that blocks the transport of
fluids and keeps them within the vagina where a microbicide—a topical foam,
gel, or lotion that kills the HIV on contact before it infects—could have
greater effect.

Using microbicides concurrently with diaphragms could increase the HIV
preventive qualities of both. “We know that the effectiveness of spermicides—
topically applied, pregnancy preventing, sperm killers—is increased one and one
half times when used in conjunction with a diaphragm. We could reasonably
expect a similar result when the device is used in combination with
microbicides,” said Moench.

Moench also noted that the willingness of women to use a diaphragm is an issue
inhibiting research on its use to prevent HIV.  Few women in the developed
world currently use a diaphragm as a means of contraception. “However, in 1955
before the introduction of the pill, a study by Ryder and Weston showed the 25%
of U.S. women using contraceptive methods used diaphragms. We expect the
acceptability of diaphragms would be high again if they were shown to prevent
HIV,” he said.

“As we look at HIV prevention in the context of the enormous number of women
worldwide at risk for infection, we need to shift our thinking and recognize
that HIV prevention is an aspect of reproductive health.  If we then make the
analogy with contraception, we see that women are offered and use a variety of
different methods,” said Padian, who is currently conducting a study of
diaphragm acceptability in Zimbabwe with very promising initial results.

“In fact, short of a vaccine—something years down the road—there will be no ‘
magic bullet’ or ‘one size fits all’ solution.  We need to consider every
technology, especially something like the diaphragm that has been used safely
for over one hundred years,” added Moench.

Co-author of the review is Tsungai Chipato, MD, professor of obstetrics and
gynecology at the University of Zimbabwe, Harare, Zimbabwe.

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