AbstractSeventy‐two patients were studied with pregnancies of more than 32 weeks, 38 (52.7%) of whom developed either premature labour or pregnancy‐induced hypertension and who were admitted to the high‐risk pregnancy unit of the university hospital in Cali, Colombia.The remaining 34 (47.3%) patients had normal pregnancies and were recruited from smaller hospitals (Selva and Siloi.) in the same city of Cali.Each patient's clinical history included: 1. The level of stress and social support affecting the course of the patient's pregnancy. 2. The patient's lymphocyte activity measured by lymphocyte count on peripheral blood smear. 3. Late hypersensitivity to candidin, all patients having a previous history of candida infection with a positive KOH from a fresh smear. A higher level of stress was found in patients with an obstetric disorder (p<0.005) in whom the relative risk to develop the disorder was 5.1 (95 per cent confidence limits 1.7‐15.6).When the patient had a high level of stress and the social support was inadequate, the relative risk increased to 10.2 (95 per cent confidence limits 1.3−79.0). Absolute lymphopenia was more frequent in those patients with an obstetric disorder (p<0.02) and in 79% of these patients an associated negative candidin test was found.72.7% of the patients with a high level of stress and with inadequate social support showed depression of lymphocyte activity as shown by a negative candidin test combined with absolute lymphopenia in the peripheral blood smear lymphocyte count (<1500 lymphocytes). Psychosocial stimuli, early environmental influences and genetic factors when interacting in a dynamic form, facilitated the depression of lymphocyte activity in those patients with a high level of stress plus inadequate social support. This may be related to the higher relative risk to develop an obstetric disorder shown by this group of patients. The above considerations may induce us to consider both a low socio‐economic status and adolescent pregnancy as risk factors in the obstetric patient. These factors are generators of stress when patients do not have adequate social support in their family or community