Introduction Interventions, including commencement of antiretroviral therapy (ARV), have decreased the rate of MTCT to less than 1%. This study looks at women who commenced ARV therapy during pregnancy as this group may be at high risk of MTCT.

Methods A retrospective cohort study of HIV-positive women commencing ARV during pregnancy at a London teaching hospital from January 2004–December 2013.

Results Complete data sets were obtained from 55 HIV-positive pregnant women, (total 59 pregnancies). Median age at diagnosis of HIV was 30.5 (18.2–44.9). 98% contracted HIV through heterosexual contact and one case resulted from MTCT. 26/55 were diagnosed during pregnancy with median gestational age at diagnosis of 16.3 weeks (5.3–37.6). Median gestational age at ARV commencement was 22.8 weeks. Diagnosis during pregnancy was associated with a later start of ARVs (23.4 vs 19.9 weeks, p = 0.02). Viral load at delivery was available in 56 pregnancies from which only 14.3% (8/56) were detectable. 60% (29/48) babies were delivered by Caesarean section (10 emergency and 19 elective). Spontaneous vaginal delivery was achieved in 31% (15/48). Median gestational age at birth was 38 weeks with 21% (10/48) <37 weeks gestation. Average birth weight was 3076g (1100–4096).

Conclusion Antiretroviral therapy commenced during pregnancy, together with a dedicated multidisciplinary team approach, was associated with an extremely low MTCT (1/59). In this small series, no particular drug regimen was associated with prematurity, however this will require further investigation with a larger cohort size.