HIV testing and treatment in the antenatal setting S Coulter-Smith 1 , JS Lambert 1,2 , K Butler 1,3 , M Brennan 1 , M Cafferkey 1 * 1 The Rotunda Hospital, Parnell Sq, Dublin 1 2 Catherine McAuley Research Centre, Mater Misericordiae University Hospital, Nelson St, Dublin 7 3 The Rainbow Team, Our Lady's Children's Hospital, Crumlin, Dublin 12 Abstract Routine linked HIV antenatal screening, with ―opt-out‖, was introduced at the Rotunda in January 1998. This paper reviews the screening and subsequent pregnancy management and outcome in HIV positive women from 1998 to 2006. During this time 225 women (280 pregnancies) were HIV positive and 194 women subsequently delivered at the Rotunda, representing 233 liveborn infants. Overall anti-HIV prevalence was 0.42%, increasing from 0.06% in 1998 to 0.57% in 2006. Of 233 livebirths, 111 (48%) were delivered by spontaneous vaginal delivery (SVD). HIV treatment was started pre-pregnancy in 14 (6 %) pregnancies and antenatally in 208 (90%). The vertical transmission rate in mothers receiving >4 weeks of treatment was 0%. We conclude that routine antenatal HIV screening is effective and significantly benefits the health of mother and child. Introduction Mother to child transmission (MTCT) of Human Immunodeficiency Virus (HIV) can occur in utero, during delivery and post partum through breastfeeding. Without antiretroviral treatment (ART), transmission rates vary from 15-40% depending on maternal viral load, duration of ruptured membranes, the presence of sexually transmitted infections, mode of delivery, prematurity and breastfeeding. 1-3 In developed countries transmission to the infant is almost entirely preventable with a combination of interventions—antiretroviral prophylaxis during pregnancy, intrapartum and to the neonate, elective caesarean section and avoidance of breastfeeding. 4-6 While initial populations identified as HIV positive and pregnant in developed countries were those linked to injecting drug use (IDU), there have been significant changes in such population over the years. Heterosexual transmission is now the major mode of acquisition of HIV infection among women of childbearing years, representing the fastest increasing group of newly infected individuals. 7 The Rotunda was the first maternity unit in the Republic of Ireland to introduce routine linked antenatal HIV (antibody) screening, which commenced on 1st January 1998. Prior to this, most identified HIV infection was linked to IDU and selective testing was performed; however it was soon recognised that more universal testing was necessary for optimal identification. 8 Studies carried out elsewhere had also shown that selective testing was inadequate. 9,10 The introduction of routine testing in Ireland coincided with major demographic changes including significant immigration from sub-Saharan Africa and Eastern Europe. 7 Initially Zidovudine (ZDV) monotherapy was the standard of care for treatment of such women 11 , but by 2002 Ireland had adopted a strategy of offering triple drug antiretroviral therapy (Highly Active Antiretroviral Therapy - HAART) to all women including women who did not require ART for their own health 4,12 . This retrospective study audits our experience of routine HIV screening and management of those identified as infected in the first nine years of our programme.