[Analysis of risk factors for triplet pregnancy after a simultaneous transfer of triplicate embryos]
Liu Liu1, Wei-hai Xu, Song-ying Zhang
1Assisted Reproductive Unit, Affiliated Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310016, China.
Objective:
To analyze the risk factors for triplet pregnancy after a simultaneous transfer of triplicate embryos.
Methods:
The investigators carried out a retrospective analysis of 769 cycles in which three embryos were transferred in one treatment cycle, including 298 fresh embryo transfer (ET) cycles and 471 frozen-thawed ET (FET) cycles. The impact of patient age and the number of good embryos transferred on the rates of clinical pregnancy and triplet pregnancy was studied according to different cycle types.
Results:
(1) The rates of clinical and triplet pregnancy were significantly higher in the FET group (P < 0.05) than those in the fresh ET group; (2) all patients with a triplet pregnancy in the fresh ET group (n = 6) were younger than 35 years old (P < 0.01). There was no significant difference between the subgroups in the FET cycle according to patient age (P > 0.05); (3) when none, 1, 2 or 3 good embryos were transferred in the fresh ET cycle, the clinical pregnancy rates were 28.3%, 46.7%, 50.6% and 58.7% and the triplet pregnancy rates 0, 2.3%, 4.7% and 6.8% respectively. A similar clinical pregnancy rate (P > 0.05) and a significantly lower triplet pregnancy rate (P < 0.05) were observed when 1 good embryo was transferred versus 2 good embryos (P < 0.05). When 0, 1, 2 or 3 good embryos were transferred in the FET cycle, the clinical pregnancy rates were 38.9%, 54.8%, 59.7%, 63.9% and the triplet pregnancy rates 0, 5.0%, 13.8%, 15.8% respectively. A similar clinical pregnancy rate (P > 0.05) and a significantly lower triplet pregnancy rate (P < 0.05) were observed when 1 good embryo was transferred versus two good embryos (P < 0.05). All triplet pregnancies occurred in cycles in which more than 1 good embryo was transferred (P < 0.05).
Conclusion:
The patients have more triplet pregnancies in the FET cycle than in the fresh ET cycle. In the FET cycle, the patient age is irrelevant. It is recommended that no more than 2 embryos should be transferred. Selective single blastocyst embryo transfer is preferable if there are more than 2 good embryos available for transfer. No more than 2 embryos should be transferred in the fresh ET cycle if good embryos are available and a patient is under 35 years old.
