Early Embryonic Mortality in Women

Asymmetry of parental origin in long QT syndrome: preferential maternal transmission of KCNQ1 variants linked to channel dysfunction

“…16 Even if it is unlikely that premature death in males could explain the sex imbalance and the transmission distortion among patients in our population, we cannot exclude that fetal wastage of embryos could occur at very early stage of development, as 50-75% of all human conceptions are lost before the first missed menses. 17,18 It is known that abnormal imprint resetting could lead to early death of embryos 19 and KCNQ1 is a paternally imprinted gene. Nevertheless, it is difficult to conceive the specific loss of male vs female embryos.…”

Regulation of blastocyst formation

“…The first week of development represents a perilous time for the early conceptus as the majority of inseminated oocytes fail to successfully complete this developmental interval to implant to the uterine wall and establish a pregnancy (1)(2)(3)(4)(5). This interval called preimplantation or pre-attachment development (depending upon the species) is uniquely mammalian and encompasses the free-living period of mammalian development during which the early conceptus traverses the oviduct and gains access to the uterine environment (1)(2)(3)(4)(5)(6).…”

“…This interval called preimplantation or pre-attachment development (depending upon the species) is uniquely mammalian and encompasses the free-living period of mammalian development during which the early conceptus traverses the oviduct and gains access to the uterine environment (1)(2)(3)(4)(5)(6). This period culminates in the formation of an embryonic structure called the blastocyst, which is composed of the outer epithelial trophectoderm, a fluid-filled cavity and small group of cells called the inner cell mass, which are the progenitors of the embryo proper (6)(7)(8)(9)(10)(11)(12).…”

“…Although the mouse embryo has been the animal model of choice for most of the experimentation, the e xtension of these studies to the human and domestic agricultural species has stimulated vigorous research activity in these embryo systems leading to explosive growth in the fields of assisted reproductive technology and embryo transfer in humans and other species (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12). Despite these advances, pregnancy rates following embryo transfer remain lower than expectations for all species, and further advances are required to optimize the general application of these technologies (1)(2)(3)(4)(5)(6). Areas of research include; ovarian stimulation; folliculogenesis and oocyte maturation; embryo culture and metabolism; hormonal and growth factor regulation; gamete micromanipulation (intracytoplasmic sperm injection; ooplasmic injection); genomics and gene expression; uterine receptivity and synchronization; embryonic signaling of maternal recognition of pregnancy; organ, gamete and embryo cyropreservation and embryo cloning, transgenesis, and gene targeting in animal species.…”

An investigation of transmission ratio distortion in the central region of the human MHC

“…TRD has been well documented in mice, 1,2 drosophila 3 and flowering plants, 4 but reports in man are somewhat fewer. It is probable, however, that distorter variants do exist across the human genome, as humans have a relatively high level of fetal wastage; speculative reports suggest that 50-75% of all human conceptions are lost before the first missed menses 5,6 and infertility affects one in 10 couples trying to conceive. 7 The maintenance of pregnancy is partly a balance between pro-and anti-inflammatory mediators, 8 designed to prevent an excessive inflammatory response at the feto-maternal interface.…”