Subcutaneous Progesterone in Frozen- Thawed Single Euploid Blastocyst Transfer.

This is a multicenter, randomized, double-blind, double-dummy, active-controlled, non-inferiority clinical study in women aged 35 to 42 years. This study will investigate the safety and efficacy of Progesterone-IBSA to support euploid embryo blastocyst implantation and early pregnancy after frozen embryo transfer (FET) in a modified natural cycle as a treatment for infertile women. Subjects will be randomized to receive either active Progesterone-IBSA or Crinone 8% for luteal and early pregnancy support and these two groups will be compared.