Surveillance of HIV infection in pregnant women in the United Kingdom and Ireland, 1990-2006

Surveillance of obstetric and paediatric HIV infection in the UK/Ireland is conducted through the National Study of HIV in Pregnancy and Childhood (NSHPC). Pregnancies in diagnosed women delivering/due to deliver 1990-2006 were explored, in relation to demographic characteristics, timing of diagnosis, antiretroviral therapy (ART), pregnancy outcome and delivery. 8208 pregnancies were reported, increasing from 81 in 1990 to 1281 in 2006. Outcomes included 6853 live births, 77 stillbirths, 324 miscarriages, 513 terminations. In 1990-93, 25.8% (71/275) of pregnancies were in black African women, rising to 78.7% (1008/1281) in 2006 (p<0.001); injecting drug use as a risk factor declined from 41.1% (113/275) in 1990-93 to 2.0% (25/1281) in 2006 (p<0.001). Among 7791 pregnancies with known outcome, the proportion of terminations decreased from 32.6% (87/267) in 1990-93 to 3.3% (37/1129) in 2006 (p<0.001). Terminations were more common among women diagnosed before pregnancy rather than antenatally (OR=2.6, p<0.001). The miscarriage rate (4.2%, 324/7791) remained constant over time, and 81.0% (262/324) were before 20 weeks gestation. ART use increased over time, and reached ~98% (986/1010) in 2006 (births only). Among previously diagnosed women, the proportion on ART at conception rose from 5.8% (19/329) before 1997 to 46.4% (1183/2550) after (p<0.001). Most deliveries were by elective caesarean section, with rates highest in 1999 (66.4%, 144/217). Vaginal deliveries increased from 16.6% (36/217) in 1999 to 27.4% (281/1026) in 2006. The number of reported pregnancies increased dramatically between 1990 and 2006, with a changing demographic profile, and substantial changes in availability and uptake of interventions