[Progesterone and frozen-thawed embryo transfer after hormonal replacement therapy for endometrial preparation: An update on medical practices]

Frozen-thawed embryo transfer (FET) has recently become the most frequently performed ART procedure. Many protocols for endometrial preparation are used, without any evidence-based superiority of one protocol above the others. Most French fertility centers mainly use hormonal replacement treatment (HRT) for endometrial preparation for organizational reasons. According to some studies, early pregnancy losses rate is higher with HRT endometrial preparation for FET than with other protocols, leading to new insights in improving outcomes into ART centers. There is a lack of consensual guidelines regarding the use of HRT for FET: there are various protocols, with different dosages, duration and routes for progesterone (PG) prescription. To date, the vaginal route is the most popular around the world as it gives higher intra-uterine concentration of PG because of the first uterine pass. However, recent scientific publications have pointed the importance of PG measurement in order to detect a lack of PG supplementation. Whatever the route of administration, it seems that a significant proportion of patients do not reach adequate PG concentrations for successful implantation and ongoing pregnancy. Timing of the measurement and ideal serum PG rate to reach are yet to be defined. What treatment strategy to adopt according to the results is still under investigation. Individualization of PG doses and routes of administration could lead to a decrease in miscarriages and better outcome.

[Coronary disease in women: The role of sexual hormones]

During their lives, women go through three different phases during which sex hormones play a fundamental role in contributing to specific cardiovascular and coronary risks. To evaluate this risk, we must take into account these various phases with their associated cardiovascular risk factors, and this during three key steps: contraception, pregnancy and menopause. Arterial risk linked to estrogen combined with progestin contraception, depends on the dosage of estrogen. The main cardiovascular risk factor responsible for increasing the risk of myocardial infarction is tobacco, especially after 35 years of age, contraindicating estrogen combined with progestin contraception at the benefit of progestin. Spontaneous dissections and coronary emboli are the most common coronary lesions linked with oestroprogestative contraception. Acute myocardial infarction during pregnancy occurs mostly in the peripartum or postpartum period; and is often caused by spontaneous coronary dissection lesions. Fertility treatment is not associated with an increased risk of developing cardiovascular disease later in life. Hormone therapy during menopause does not increase coronary risk in the first 10 years after menopause and may even have a protective effect, by sustaining arterial integrity. The transdermal route is to be preferred for its metabolic effect. Hormonal treatment during menopause is nonetheless contraindicated in the case of proven coronary disease and uncontrolled cardiovascular risk factors.