In pregnant women rest is essential to the prevention of some accidents at birth (e.g. prematurity). A survey of 357 women examined and delivered in the maternity department of hospital A. Béclère in 1984 shows that abstention from work is general and prolonged, irrespective of the degree of risk inherent in pregnancy: 50% of women have stopped work 7 weeks before their legal maternity leave. This wide prescription of rest seems to have been requested by the women themselves. Its financial cost to the Social security is negligible, but prescriptions for rest from work have probably not yet ceased to increase.