Maternal viral load and vertical transmission of HIV-1 in mid-trimester gestation

Background: It is now accepted that the majority of HIV-1 vertical transmis sions occur in late gestation and at the time of delivery. However, there i s wide variation in the prevalence rate of mid-trimester vertical transmiss ion. We assessed the maternal HIV-1 RNA viral load and in utero transmissio n during mid-trimester gestation. Methods: Patients were enrolled when they decided to have their pregnancies terminated between 17 and 24 weeks of gestation. Prostaglandin-induced abo rtion with PGE1 analogue vaginal administration was carried out in all pati ents. Maternal plasma HIV-1 RNA viral load and plasma HIV-1 RNA (qualitativ e) from abortus heart blood were assessed. Results: Amongst 41 HIV-1 seropositive pregnant women not receiving antiret roviral therapy plasma HIV-1 RNA was detected in the abortus heart blood fr om two women (4.9%; 95% confidence interval (CI), 0.6-16.5). Transmission o ccurred in one out of nine (11.1%; 95% CI, 0.3-48.2) with maternal viral lo ad greater than or equal to 100 000 copies/ml versus one out of 32 (3.1%; 9 5% CI, 0.1-16.2) of those with < 100 000 copies/ml (P = 0.39). Conclusions: The frequency of HIV-1 Vertical transmission during mid-trimes ter was approximately 5% as detected by plasma HIV-1 RNA (qualitative) meth od in the fetuses aborted from the prostaglandin termination of pregnancy. During mid-trimester gestation there was no correlation between high matern al viral load and vertical transmission. (C) 1999 Lippincott Williams & Wil kins.