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Pregnancy And Neonatal Outcomes Of hMG Stimulation With Or Without Letrozole In Endometrial Preparation For Frozen–Thawed Embryo Transfer In Ovulatory Women: A Large Retrospective Cohort Study

Authors Lin J, Wang N, Huang J, Cai R, Fan Y, Kuang Y, Wang Y

Received 14 April 2019

Accepted for publication 2 October 2019

Published 14 November 2019 Volume 2019:13 Pages 3867—3877


Checked for plagiarism Yes

Review by Single-blind

Peer reviewer comments 3

Editor who approved publication: Dr Georgios D. Panos

Jiaying Lin,* Ningling Wang,* Jialv Huang, Renfei Cai, Yong Fan, Yanping Kuang, Yun Wang

Department of Assisted Reproduction, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Yanping Kuang; Yun Wang
Department of Assisted Reproduction, Shanghai Ninth People’s Hospital, Shanghai Jiaotong University School of Medicine, 639 Zhizaoju Road, Shanghai 200011, People’s Republic of China

Objective: Frozen–thawed embryo transfer enables surplus embryos derived from IVF or IVF-ICSI treatment to be stored and transferred in subsequent cycles into a more “physiologic environment”. This study aimed to investigate the clinical effect of letrozole use or hMG stimulation on pregnancy and neonatal outcomes in ovulatory patients undergoing FET.
Methods: This study includes a total of 5901 FET cycles with letrozole use (n = 1569), HMG (n =1827) or letrozole + HMG (n = 2505). In the letrozole group, 2.5 mg of letrozole was administered on menstrual cycle day 3 to 5 for 3 days for patients, and then follicle growth was monitored beginning on day 10. If the follicular diameter was ≥14 mm on the 10th day, no other ovarian stimulation drugs were needed. If the follicular diameter was Results: Compared with the patients undergoing hMG stimulation, the group receiving letrozole or letrozole+HMG stimulation exhibits significantly higher clinical pregnancy rates per transfer (hMG: 47.02% vs letrozole: 52.07% vs letrozole+HMG: 52.26%) and implantation rates (hMG: 31.76% vs letrozole: 34.36% vs letrozole+HMG: 34.24%). In addition, the letrozole group was associated with a statistically significantly lower incidence of miscarriage (hMG: 14.78% vs letrozole: 10.53% vs letrozole+HMG: 14.13%) and ectopic pregnancies (hMG: 1.83% vs letrozole: 0.97% vs letrozole+HMG: 1.58%) than the letrozole + HMG and HMG groups. Neonatal outcomes are similar among the three groups.
Conclusion: Our data demonstrate that the letrozole use may improve clinical pregnancy outcomes and decrease the risk of ectopic pregnancies and miscarriage in ovulatory patients who receive FET cycles.

Keywords: frozen–thawed embryo transfer, Letrozole, ovulation induction, hMG, clinical efficacy

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