This study presents clinical observations in pregnancy made on aborigines of the deep jungle and "outside" populations. Migration out of the jungle results in lowered nutritional status as a result of low socio-economic status in the "outside" aborigine. This, together with food habits, increased family size and higher incidence of helminthic infestations, results in lower mean values of Hb, PVC and MCHC and a higher prevalence of anaemia in pregnancy in the migrant aborigine. A higher population density in the "outside" population resulting in frequent intermingling and increased chances of cross-contamination probably explains the increased vaginal bacterial growth in the "outside" Aborigine women. A higher prevalence of vaginal candidiasis in the "outside" aborigine woman is probably related to exposure to oral contraceptives and broad-spectrum antibiotics. On the other hand, better medical and obstetrical services become more readily available to the "outside" aborigine and this results in a favourable influence on perinatal health.