OC31.07: Influence of maternal HIV‐infection on fetal thymus size

Our study aims to reveal the effect of a maternal human immunodeficiency virus infection on the fetal thymus size. The sonographic fetal thymus size was measured retrospectively in 105 pregnancies with maternal HIV-infection and in 615 uncomplicated singleton pregnancies. The anterioposterior thymic and the intrathoracic mediastinal diameter were determined in the three vessel view and their quotient, the thymic-thoracic ratio was calculated. The study group was subdivided into three groups by maternal viral load at the date of ultrasound (<50 cop./ml, 50-1000 cop./ml, > 1000 cop./ml). Furthermore, an association between prognostic factors of the human immunodeficiency virus infection, as lymphocytes counts, CD4/CD8-ratio, medication and the thymus size, was investigated using correlation analyses. Thymus size in pregnancies with HIV-infection was shown to be significantly larger than in uncomplicated pregnancies. The mean TT-ratio in the HIV-positive group was 0.389 and in the control group 0.345 (p < 0.001). There was no association found between any maternal HIV-parameter or medication and size of the thymus gland. Maternal HIV-infection was associated with an increased fetal thymus size. Further consequences of intrauterine HIV-exposure for fetal outcome and the development of the immune system of HIV-exposed uninfected (HEU) infants must be discussed.