Background Mother-support groups (MSGs) are used at hospitals and health centres in Ethiopia to increase uptake of and adherence to PMTCT and reduce vertical transmission of HIV. A study at Dessie Referral Hospital showed that mothers belonging to MSGs had lower vertical transmission rates. The impact on mothers seen at health centres is not known.

Methods Data on the outcome of MSGs on vertical transmission were collected from 15 health centres in Tigray between 2008 and 2011. Data sources included MSG registration log books, regional laboratory DNA/PCR results, and the ART enrollment register. We compared HIV status among babies born to mothers belonging to MSG and those whose mothers did not participate in MSG.

Results A total of 848 HIV-exposed infants (HEIs) were registered between 2008 and 2011. Among 240 HEIs born to mothers enrolled in MSG, 87.5% were tested for HIV and 5.2% were HIV-positive. Among the 608 HEIs whose mothers were not enrolled in MSGs, 44.7% were tested and 11.4% tested HIV-positive (OR = 0.43).

Conclusions The odds of testing positive were 57% lower among HEIs whose mother was enrolled in an MSG compared to those whose mother was not enrolled. The better outcome appears to be due to the support their mothers received from MSGs resulting in better PMTCT and adherence practises as well as high rates of institutional delivery. We are currently collecting more data on PMTCT regimen, HEI testing by age and place of delivery to verify this hypothesis.