Optimization of Frozen Embryo Transfers by Studying Progesterone on the Day of Transfer
Condition: Infertility; IVF
MeSH terms: Infertility
Study type: Observational

Summary: 
      The number of embryo transfers after freezing has increased over the last 10 years due to
      improvements in embryo freezing techniques and in particular the development of
      vitrification. This has also been made possible by changes in clinical protocols favouring
      freezing in patients at high risk of hyperstimulation and by different methods of endometrial
      preparation to receive embryos after rewarming.

      In fact, embryo transfer requires endometrial preparation to make implantation possible.
      There are various protocols for endometrial preparation. Endometrial preparations in the
      natural cycle, with or without induction of ovulation by FSH, require more regular
      monitoring, and allow the development of a main follicle that will give a corpus luteum that
      will secrete progesterone in the luteal phase, which can be supported by the supply of
      exogenous progesterone. In contrast, endometrial preparations in hormone replacement therapy
      (HRT) cycles are done by administering estradiol orally or transdermally to stimulate
      endometrial growth while blocking the patient's gonadotropic axis, and administering
      progesterone in the luteal phase to differentiate the endometrium. This preparation has the
      advantage of being simpler to monitor and organize.

      There is currently no consensus on a type of preparation that would give better results, and
      although the literature seems to show that there would be more miscarriages in a substituted
      cycle, there does not seem to be any difference in the birth rate per cycle in the end,
      whatever the type of endometrial preparation.

      Some teams have shown that in HRT, there appears to be more miscarriage when the progesterone
      level measured on the day of the frozen embryo transfer is lower, especially below a
      threshold of 9ng/mL. Labarta showed ESHRE in July 2019 that modifying the endometrial
      preparation if the progesterone level is below 9ng/mL on the day of transfer by adding
      subcutaneous progesterone (Progiron) resulted in a lower miscarriage rate, comparable to the
      usual miscarriage rates in spontaneous pregnancy.

      Thus, if the miscarriage rate is higher in HRT than in the natural cycle, and if this is
      related to "luteal insufficiency" characterized by a lower circulating serum progesterone
      level, the hypothesis of this study in the investigator's population would be that the serum
      progesterone level on the day of the frozen embryo transfer would be lower in HRT than in the
      spontaneous cycle.
    


Intervention name(s): bioassay
Intervention type(s): Other
Intervention description(s): Serum progesterone level (ng/ml)
Observational model: Cohort
Time perspective: Retrospective
Sampling method: Non-Probability Sample
Study population: 
        These are MPA patients who have undergone embryo freezing and endometrial preparation for
        embryo replacement.