HIV incidence is
high among pregnant and postpartum women and is associated with an increased
risk of mother-to-child transmission (MTCT) of HIV, results of a systematic
review and meta-analysis published in PLOS
Medicine show. The investigators stress the importance of offering repeat
HIV tests to women in high-prevalence settings during pregnancy and
Many women have an
ongoing risk of acquiring HIV during pregnancy and breastfeeding.
Therefore guidelines recommend that women who are identified as HIV negative
during initial antenatal screening should have repeat HIV tests during
pregnancy and postpartum. This rarely occurs, and to better inform prevention
strategies, a team of US investigators performed a systematic review and
meta-analysis of studies examining the incidence of HIV during pregnancy and
postpartum and its association with vertical (mother to child) transmission of HIV.
included studies published or presented to conferences between 1980 and the
autumn of 2013. A total of 47 were included in their analysis.
studies – all involving people in sub-Saharan Africa – looked at incidence
rates among pregnant and postpartum women. A total of 22,803 women were
enrolled in the cohorts. The pooled results showed that HIV incidence was 3.8
per 100 person-years during pregnancy and 2.9 per 100 person-years postpartum.
infection during pregnancy/postpartum was highest in southeast Africa (6.2 per
100 person-years), followed by south Africa (4.8 per 100 person-years), east
Africa (2.7 per 100 person-years) and west Africa (0.7 per 100 person-years).
Incidence was significantly higher in southeast Africa compared to west and east
incidence rates we observed were comparable to, or higher than, those of
non-pregnant ‘high risk’ individuals, including female sex workers…HIV-discordant
couples…and men who have sex with men,” note the authors. “Both biological and
behavioral changes have been hypothesized to explain the potentially higher
risk of HIV acquisition observed during pregnancy and the postpartum period.”
Data on cumulative
incidence rates during pregnancy/postpartum were provided in five studies,
showing this was significantly higher in African compared to non-African
settings (3.6 vs 0.3%; p < 0.001).
Rates of MTCT
among women with incident infections during pregnancy/postpartum were reported
in 13 studies. Vertical transmission rates ranged from 13% in the United States to 58% in
Rwanda, with a pooled rate of 22.7%. Comparison between African and non-African
settings showed a similar rate of vertical transmission (23.6 vs 22%,
respectively). The pooled MTCT rate among women who acquired HIV during
pregnancy was 17.8%, compared to 26.9% among women who acquired HIV postpartum, a
compared the risk of MTCT among women with new infections during
pregnancy/postpartum versus women with chronic HIV infection. Overall,
infection with HIV during pregnancy/postpartum was associated with an almost
threefold increase in the risk of MTCT (OR = 2.8; 95% CI, 0.9-4.7).
among pregnant and postpartum populations was high in this meta-analysis and
may substantially increase risk of MTCT,” conclude the investigators. “Our
results have several implications for antenatal care/PMTCT programs.” First,
all women in high-prevalence settings should be offered repeat HIV tests to
detect incident infections during pregnancy/postpartum. Second, more sensitive
testing assays should be used that detect both HIV antibodies and p24 antigen.
Third, pregnant and postpartum women should receive counselling about the
importance of ongoing condom use. The authors also believe that these women
should be involved in the development of female-controlled methods of
prevention, such as microbicides.