HIV prevalence in pregnant women in an ethnically diverse population in the UK: 1998-2002.

OBJECTIVE: To describe trends in the prevalence of HIV in an ethnically diverse population of pregnant women in the United Kingdom. METHODS: Data on parental country of birth from national birth registration records were linked to neonatal dried blood spot samples routinely collected for neonatal screening in the North Thames region between 1998 and 2002. Identifiers were subsequently irreversibly deleted prior to establishing maternal HIV status by testing the neonatal samples. RESULTS: A total of 491 213 dried blood spot samples were collected, and 490 879 (99.93%) were tested for HIV. Of these, 1029 were seropositive. There was an overall significant increasing trend (P-value = 0.001) between 1998 and 2002. Maternal region of birth was available for 89.8% of HIV-infected samples, and, among these, 80.5% of mothers were born in sub-Saharan Africa and 11.1% in the UK. The highest prevalences of HIV were in women born in sub-Saharan Africa (2.09%). If both parents were born in the UK, overall seroprevalence was 0.016%. CONCLUSION: HIV infection in pregnant women in the UK continues to occur predominantly in women born in sub-Saharan Africa with prevalence in this group increasing significantly. Although the absolute number of HIV-infected women rose in some other groups, there was no evidence for a statistically significant rise in HIV prevalence in women born outside sub-Saharan Africa. Over 93% of children at risk of vertical transmission of HIV had at least one parent born abroad. This paper underlines the value of data linkage in monitoring HIV prevalence in a diverse population.