Social, economical and family characteristics were studied in 90 women who notified their pregnancy beyond the French legal recommended limit of 3 months (LNP). The development of the children born from these pregnancies was also studied. A group of women notifying their pregnancy within the legal limit of 3 months served as a control. The data were collected at home by nurses from the Service de Protection Maternelle et Infantile visiting the family at the time of notification of the pregnancy and at ages 4, 12 and 36 months. The results showed frequent psychological, economical and social disabilities of women with LNP, presenting high rates of unemployment, low income, unusual ages of pregnancy (44% before 20 years and after 35 years), absence of father, consideration of voluntary interruption of pregnancy. Their offspring had a frequent unfavourable family environment, but their development did not show significant differences at 3 years of age as compared with children of the control group: however they presented signs suggesting a greater vulnerability, and especially frequent language and behaviour disturbances. From these data LNP appears as an indicator of psycho-social vulnerability of the family. Therefore LNP should lead to a systematic visit of the family at home by a social worker in order to assess its degree of psycho-social vulnerability and to provide, when necessary, preventive action directed towards the protection of the child development.