Transmitted drug resistance in HIV positive pregnant women

Cover of BHIVA 2015 ProgrammePolly Clayden, HIV i-Base

Preliminary data using linkage between three National HIV surveillance databases showed genetic diversity among HIV positive pregnant women in England and Wales. The women had low prevalence of transmitted antiretroviral drug resistance – consistent with other UK and European studies.

Laura Byrne from UCL Institute of Child Health presented these findings at the spring BHIVA Conference 2015.

BHIVA guidelines recommend resistance testing for most pregnant women starting ART. But the prevalence of resistance in pregnant women in the UK had not been investigated before. The study looked at HIV subtype in pregnant women matched to at least one resistance test and transmitted drug resistance in newly diagnosed ART-naive women.

The investigators linked data from three databases: the National Study of HIV in Pregnancy and Childhood (NSHPC) collects data on pregnancies in HIV positive women and their infants; the UK HIV Drug Resistance Database (UKHDRD) collects all results from resistance tests conducted within routine HIV care; and the Survey of Prevalent HIV Infections Diagnosed (SOPHID) is a cross-sectional survey of all diagnosed people receiving HIV care at NHS sites.

Women who had at least one reported pregnancy between 2000 and 2013, delivered of due to deliver by September 2014 in England and Wales were included. Women were matched to resistance test results in UKHDRD via their SOPHID unique identifier. The investigators used the REGA HIV-1 subtyping tool v3 to identify their subtype. They used the IAS 2013 surveillance list to determine major mutations.

There were 14,416 pregnancies during the study period. The median age at conception was 30 years (IQR 26 to 34); 78% of women were black African and only 1.3% likely infected by IDU. The median year of HIV diagnosis was 2004 (range 1982 to 2013). Of the women, 49.9% were matched to >1 resistance test, with year of first resistance test 1996 to 2013. This proportion rose to 58.2% in women diagnosed after 2005. Overall, 63.5% women were classified as naive on their first test.

Factors associated with being matched to >1 resistance test were: having >1 reported pregnancy, aOR 1.65 if 2 pregnancies and aOR 1.98 if > 3 pregnancies; year diagnosed 1985 to 1995 aOR 0.75, 1996 to 2000 aOR 0.56, 2001 to 2005 aOR 0.63 vs 2010 to 2013; woman born in Africa aOR 0.75, woman born elsewhere aOR 0.80 vs London; first pregnancy elsewhere aOR 0.66 vs London; first pregnancy 2000 to 2005 aOR 0.55 and 2004 to 2008 aOR (all comparisons p<0.001).

Of 4929 matched women: 46.6% had subtype C; 13.1% CRF02_AG; 10.6% A: 10.1% B; 8.3% other recombinant forms; 5.3% G; 4.1% D, 0.7% other pure; and 0.7% unclassified.

Overall 5.2% of 1302 women with a resistance test had transmitted drug resistance: 2.8% NNRTI; 1.9% NRTI and 1.2% PI. This rate is similar to that previously observed in the heterosexual population in the UK.


Byrne L et al. Antiretroviral drug resistance in pregnant women living with HIV in England and Wales: Preliminary results from the matching of three national HIV surveillance databases. 21st Annual Conference of the British HIV Association (BHIVA), 21–24 April 2015, Brighton. Oral abstract O27.

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