Early Pregnancy Loss

EARLY-PREG is an open-cohort clinical study with a preconception, longitudinal, bidirectional and counterfactual design. The aim of this cohort is to investigate the proteomic signatures of maternal-embryonic communication by interrogating a growing biorepository of maternal fluids and tissues collected during the first two weeks after fertilisation. Participants in the EARLY-PREG cohort consist of healthy couples seeking pregnancy, as well as women who are not seeking to conceive. The three main outcomes in the cohort are defined according to menstrual cycles in which conception is achieved and those in which conception is not achieved. Their clinical definitions are as follows: * Pregnancy with a full-term live birth refers to the cycle in which the ovum is fertilised, leading to pregnancy, with beta-hCG levels above the clinical threshold for a positive pregnancy test. * Early pregnancy loss refers to a miscarriage up to 12 6/7 weeks. * Non-pregnancy refers to a menstrual cycle in which conception does not occur, confirmed by a clinically negative beta-hCG test. When referring to the same individual, this is, by definition, considered the counterfactual to the corresponding conception cycle.

A prospective cohort study to explore the optimal time interval between mifepristone and misoprostol administration for medical management of early pregnancy loss. Participants will be followed to assess treatment success, satisfaction, and side effects.

About 1 to 3% of women of childbearing age suffer repeated early spontaneous miscarriages (RCF) defined by at least 3 fetal losses before 14 weeks of gestation. RCFs may be linked to parental chromosomal abnormalities, congenital or acquired uterine abnormalities, hormonal causes (e.g. type 1 and 2 diabetes, ovarian failure), infectious etiology, constitutional or acquired thrombophilia or sickle cell disease. The presence of antiphospholipid antibodies, antithyroid and anti-transglutaminase antibodies in approximately 10% of cases suggests an autoimmune origin for these fetal losses. The role of other antibodies, in particular non-conventional antiphospholipid antibodies, remains to be established. Indeed half of RCF cases are thought to be due to an immunological dysregulation of the mother leading to a decrease in tolerance to the fetus. Several studies have shown immune abnormalities, such as an imbalance of pro and anti-inflammatory cytokines, an increase in cytotoxic cells and a defect in regulatory cells in the blood of patients. The assessment of these immune abnormalities is not currently performed routinely in France in women presenting with recurrent early miscarriages. When one of these known causes is excluded, it is unexplained RCF which represents 50% of RCF. Over half of these women with RCF may be linked to aneuploidies and primary spontaneous recurrent abortions. Assessing the degree of aneuploidy and the genetic origin of foetal losses remains difficult to date, as examination of the miscarriage product is rarely available, due to the spontaneous nature of the loss. An implantation failure (IF) is defined as the absence of pregnancy following the transfer of a good-quality embryo into the uterine cavity. These implantation failures can be due to embryonic factors, maternal factors, or caused by inappropriate stimulation and/or difficult transfers. In the literature, recurrent implantation failure (RIF) is defined as the absence of pregnancy after 3 attempts of transferring good-quality embryos, taking maternal age into account Setting up a prospective cohort of patients with RFC is an essential step in exploring the aetiological factors of RCF and in order to enable better treatment.

A pilot cohort study to preliminarily investigate the efficacy of pretreatment with letrozole 10 mg daily for three consecutive days followed by treatment with misoprostol 800 mcg vaginally for medical management of early pregnancy loss in a US population. Patients will be followed to assess efficacy of this treatment regimen, as well as additional interventions needed, side effects, adverse events, and patient acceptability.