Objective. To analyze the predictive effect on obstetrical outcome in women with prenatal exposure to diethylstilbestrol (DES) of previous obstetrical history or the specific risk of DES exposure. Patients and methods. We included all in utero DES- exposed women (454 women) followed and delivered at one maternity unit in Paris and compared them with two control women matched for age, parity, number of late fetal losses, number of previous preterm births, number of singleton or twin fetuses, and follow- up, who were managed by the same team or referred for pregnancy complication. Results. DES women had a higher rate of preterm birth (19.2% ) than matched controls (10.5% ), even when considering women with a previous preterm birth or twin pregnancy. The rate of fetal or neonatal deaths were lower in DES- exposed women than in controls. DES women showed a higher rate of severe post partum bleeding (2.8% ) than matched controls (1.5% ) or the global population of women delivered in this maternity unit. Conclusion. A history of prenatal exposure to DESis a major predictor of preterm birth for primiparous women and for those with an adverse obstetrical history. Objective. To analyze the predictive effect on obstetrical outcome in women with prenatal exposure to diethylstilbestrol (DES) of previous obstetrical history or the specific risk of DES exposure. Patients and methods. We included all in utero DES-exposed women (454 women) followed and delivered at one maternity unit in Paris and comparison them with two control women matched for age, parity, number of late fetal losses, number of previous preterm births, number of singleton or twin fetuses, and follow-up, who were managed by the the same team or referred for pregnancy complication. Results. DES women had a higher rate of preterm birth (19.2%) than matched controls (10.5%), even when considering women with a previous preterm birth or twin pregnancy. The rate of fetal or neonatal deaths were lower in DES-exposed women than in controls. DES women showed a higher rate of severe post partum bleeding (2.8%) than matched controls (1.5%) or the global population of women delivered in this ma A history of prenatal exposure to DESis a major predictor of preterm birth for primiparous women and for those with an adverse obstetrical history.