The pregnancy rate among HIV-positive women
in the UK increased significantly between 2000 and 2009, investigators report
in the online edition of AIDS. There
were rises in incidence of first and repeat pregnancies. Younger age, a higher
CD4 cell count and ethnicity were all predictors of pregnancy.
“All HIV-positive women who are pregnant or
planning a pregnancy require a high level of clinical care,” emphasise the
authors. “Demand for services is likely to increase further, particularly as an
increasing number of older women have pregnancies. Older women, particularly
those over 40, are at increased risk of experiencing fertility problems and
pregnancy complications, some of which are also associated with antenatal ART
[antiretroviral therapy] use.”
Becoming pregnant and having an HIV-negative baby are now realistic options for the
majority of HIV-positive women of childbearing age in the UK. With the right treatment and care, the risk of mother-to-child
transmission of HIV can be reduced to below 1%, and developments in
treatment and care have lead to improvements in health, fertility and life
Little is currently known about the
incidence of pregnancy among HIV-infected women in the UK. The characteristics
of women who become pregnant are also poorly understood. Nevertheless, it is
important to understand these issues given the high level of specialist care
that HIV-positive women require during pregnancy.
A team of investigators therefore analysed
data collected from two studies, the UK Collaborative HIV Cohort (UK CHIC) and
the National Survey of HIV in Pregnancy and Childhood. A total of 7853 women
aged between 16 and 49 who received care between 2000 and 2009 were included in
the present study. The number of women receiving care doubled over the course
of the study.
There were 1637 pregnancies among 1291
women. Most women (78%) had a single pregnancy, but 19% had two and 4% had three or
more. The number of pregnancies increased threefold over the course of the
study, from 156 in 2000-01 to 450 in 2008-09.
The proportion of pregnancies among women
aged between 36 and 49 increased from 37% at the beginning of the study to 58%
by its end. The percentage of repeat pregnancies also rose from 30% in 2000-01 to
52% in 2008-09. This increase was highly significant (p < 0.001) and was
seen in all age groups.
In 200-/01, only 46% of women were taking
antiretroviral therapy, but this had increased to 64% by the end of the study.
The rise in the proportion of people taking treatment was reflected by a
steady increase median CD4 cell count, from 338 cells/mm3 to 458
Rates of pregnancy increased in women of
black African or black Caribbean ethnicity, but fell in women of white
ethnicity (p < 0.001).
Almost all the pregnancies involved women
infected with HIV via heterosexual sex (97%).
Incidence of pregnancy increased from 3.4%
in 2000-01 to 4.5% in 2008-09. The likelihood of a women becoming pregnant
increased as the study progressed (RR
per later year = 1.05; 95% CI, 1.03-1.07; p < 0.001).
Predictors of pregnancy included younger
age (p < 0.001) and higher CD4 cell count (above vs below 350 cells/mm3,
p < 0.001). Women of white ethnicity were significantly less likely to
become pregnant than those of black African or black Caribbean ethnicity (p
In the first set of analyses, women who
were taking HIV therapy were less likely to become pregnant, but this ceased
to be the case after the investigators had controlled for confounding factors.
Overall, 1421 pregnancies (87%) resulted in
a delivery, and almost all of these (1401) were live births. There were 126
miscarriages, 63 terminations and four ectopic pregnancies. The proportion of
pregnancies resulting in delivery increased over time (p = 0.05) and the
proportion resulting in termination decreased from 13% at the start of the
study to 3% in 2008/9 (p < 0.001). The investigators believe this is likely
to be because the risk of mother-to-child transmission decreased over the
course of the study. Improved prognosis may also have been a factor.
“HIV-positive women with or planning a
pregnancy require a high level of clinical care and this is likely to continue
particularly as more older women have pregnancies,” conclude the authors.