Objective: To analyse treatment outcomes after SET law enforcement and to evaluate the contribution of cryopreservation in a SET policy.
Material: Embryo transfer cycles performed after the law enforcement (SET period) was retrospectively compared to the cycles performed before the law enforcement (DET period).
Results: Pregnancy and delivery rates after fresh transfer of SET and DET periods were comparable (31.7% versus 33.3% and 24.5% versus 26.2%, respectively, NS). Overall twin delivery rate is significantly decreased after the law enforcement (11.3% versus 22.4%, p < 0.001) but not in patients aged 36 to 39 years (20.3% versus 24%, NS). Frozen-thawed embryo cycles allowed similar cumulative pregnancy rate (30.6%, NS). Taking into account all frozen embryos still to be transferred, SET period offers a better overall pregnancy rate than the DET period (36.1% versus 32.3%, p < 0.01).
Conclusions: The Belgian law allowed a dramatic reduction of twin deliveries especially for patients under 39 years. Cryopreservation maintains a similar cumulative pregnancy rate.