HIV, pregnancy and TB medication: Do they mix?
Tuberculosis disease is a global killer, infecting 10 million people every year and taking the lives of 1.5 million. Being HIV positive is a risk factor for contracting tuberculosis disease and dying from it. Pregnancy also leaves women vulnerable to the ravages of tuberculosis, and pregnant women who also have HIV are especially at risk.
HIV patients often take the first-line antibiotic isoniazid to
both prevent the transmission of tuberculosis bacteria and to
inhibit the progression of latent tuberculosis disease into
active disease with symptoms. Questions about the safety of
isoniazid in pregnant women arose after a
study, funded by the
National Institutes of Health (NIH), found that women who took
isoniazid during pregnancy experienced poorer fetal or newborn
outcomes than those who waited until they had delivered to begin
the medication. This outcome was unanticipated, as isoniazid has
been recommended for pregnant women with HIV in low-resource
settings for more than 25 years.
Treatment for tuberculosis is critical, as untreated disease
poses a grave threat to pregnant and early postpartum women with
HIV, particularly in impoverished parts of the world such as
sub-Saharan Africa. “Pregnancy suppresses T cells, which
are important in developing the body’s immune
response,” Nicole Salazar-Austin, MD, assistant professor
of pediatrics at Johns Hopkins University School of Medicine and
coauthor of a recent study following up on the NIH study, told
Contagion®. “Pregnancy not only increases the
risk of active TB disease but may mask the symptoms of TB
disease, making it harder to diagnose. HIV compounds this by
further increasing the immunosuppression among these women.
Studies have shown antiretroviral therapy reduces the risk of
TB, but some increased risk persists.”
According to Salazar-Austin, pregnant women with HIV in
lower-resource settings have a risk of contracting tuberculosis
that’s 10 times that of pregnant women who don’t
have HIV.
Salazar-Austin and her colleagues in the Center for Tuberculosis
Research and the Departments of Medicine and Pediatrics at Johns
Hopkins University School of Medicine in Baltimore, along with a
team of investigators in Soweto, South Africa, conducted a study
of 155 pregnant women with HIV. The women were recruited from 10
health clinics in Soweto between 2011 and 2014 and followed
during and after pregnancy. None of the women had tuberculosis
at the time of enrollment. Nearly half of the women had
initiated isoniazid during pregnancy to prevent tuberculosis,
while slightly more than half had not.
Several women dropped out during the course of the study,
resulting in 151 women whose pregnancy outcomes were recorded.
Of the women who took isoniazid during pregnancy, 16% had an
adverse outcome such as low birth weight or congenital
malformation. However, 23% of women who didn’t take
isoniazid reported adverse pregnancy outcomes. The study was
published in
Clinical Infectious Diseases.
While this study does not support the NIH study’s
findings, it does not disprove them either. The authors
acknowledge the limitations of their trial, including that the
sample size was small compared with the NIH study, which
enrolled 956 women.
It’s also possible that the women who took isoniazid in
the Johns Hopkins study were healthier, which could mean better
pregnancy outcomes. Because of these and other limitations, the
authors assert that taking isoniazid while pregnant may entail
some risk, but it’s a chance worth taking. “In
situations where the pregnant woman with HIV is exposed to a
known TB patient, the risk of resulting TB disease and the
resulting poor birth outcomes is high,” said
Salazar-Austin. “This risk likely outweighs the risk of
[isoniazid]-associated poor pregnancy outcomes.”
Additional studies involving
isoniazid and other tuberculosis medications
have recently been completed by other investigators or are in
the planning stages, she added.
Source:
Contagion
