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Anembryonic Gestation
A blighted ovum is a pregnancy in which the embryo is reabsorbed or never develops at all. In a normal pregnancy, an embryo would be visible on an ultrasound by six weeks after the woman's last menstrual period. Anembryonic gestation is one of the causes of miscarriage of a pregnancy and accounts for roughly half of first-trimester miscarriages. A blighted ovum cannot result in a viable pregnancy. A blighted ovum or anembryonic gestation is characterized by a normal-appearing gestational sac, but the absence of an embryo. It likely occurs as a result of early embryonic death with continued development of the trophoblast. When small, the sac cannot be distinguished from the early normal pregnancy, as there may be a yolk sac, though a fetal pole is not seen. In anembryonic pregnancy, levels of the pregnancy hormone human chorionic gonadotropin (hCG) typically rise for a time, which can cause positive pregnancy test results and pregnancy symptoms such as tender breasts. Because of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transvaginal Ultrasonography
Vaginal ultrasonography is a medical ultrasonography that applies an ultrasound transducer (or "probe") in the vagina to visualize organs within the pelvic cavity. It is also called transvaginal ultrasonography because the ultrasound waves go ''across'' the vaginal wall to study tissues beyond it. Uses Vaginal ultrasonography is used both as a means of gynecologic ultrasonography and obstetric ultrasonography Obstetric ultrasonography, or prenatal ultrasound, is the use of medical ultrasonography in pregnancy, in which sound waves are used to create real-time visual images of the developing embryo or fetus in the uterus (womb). The procedure is a stand .... It is preferred over abdominal ultrasonography in the diagnosis of ectopic pregnancy. It also can be used to evaluate patients with post-menopausal bleeding. The finding on transvaginal ultrasound of a thin endometrial lining gives the physician a 99% negative predictive value that the patient does not have endometrial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trophoblast
The trophoblast (from Greek language, Greek : to feed; and : germinator) is the outer layer of cells of the blastocyst. Trophoblasts are present four days after Human fertilization, fertilization in humans. They provide nutrients to the embryo and develop into a large part of the placenta. They form during the first stage of pregnancy and are the first cells to Cellular differentiation, differentiate from the fertilized Ovum, egg to become extraembryonic structures that do not directly contribute to the embryo. After blastulation, the trophoblast is contiguous with the ectoderm of the embryo and is referred to as the trophectoderm. After the first differentiation, the cells in the human embryo lose their Cell potency#Totipotency, totipotency because they can no longer form a trophoblast. They become Cell potency#Pluripotency, pluripotent stem cells. Structure The trophoblast proliferates and differentiates into two cell layers at approximately six days after fertilization for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Products Of Conception
Products of conception, abbreviated POC, is a medical term used for the tissue derived from the union of an Egg (biology), egg and a sperm. It encompasses anembryonic gestation (blighted ovum) which does not have a viable embryo. In the context of tissue from a dilation and curettage, the presence of POC essentially excludes an ectopic pregnancy. Retained products of conception ''Retained products of conception'' is where products of conception remain in the uterus after childbirth, medical abortion or miscarriage (also known as spontaneous abortion). Miscarriage with retained products of conception is termed ''delayed'' when no or very little products of conception have been passed, and ''incomplete'' when some products have been passed but some still remain ''Uterus, in utero''. Diagnosis The diagnosis is based on clinical presentation, quantitative Human chorionic gonadotropin, HCG, ultrasound, and pathologic evaluation. A solid, heterogeneous, echogenic mass has a positive p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ovum
The egg cell or ovum (: ova) is the female reproductive cell, or gamete, in most anisogamous organisms (organisms that reproduce sexually with a larger, female gamete and a smaller, male one). The term is used when the female gamete is not capable of movement (non- motile). If the male gamete (sperm) is capable of movement, the type of sexual reproduction is also classified as oogamous. A nonmotile female gamete formed in the oogonium of some algae, fungi, oomycetes, or bryophytes is an oosphere. When fertilized, the oosphere becomes the oospore. When egg and sperm fuse together during fertilisation, a diploid cell (the zygote) is formed, which rapidly grows into a new organism. History While the non-mammalian animal egg was obvious, the doctrine ''ex ovo omne vivum'' ("every living nimal comes froman egg"), associated with William Harvey (1578–1657), was a rejection of spontaneous generation and preformationism as well as a bold assumption that mammals also reproduced v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abdominal Ultrasonography
Abdominal ultrasonography (also called abdominal ultrasound imaging or abdominal sonography) is a form of medical ultrasonography (medical application of ultrasound technology) to visualise abdominal anatomical structures. It uses transmission and reflection of ultrasound waves to visualise internal organs through the abdominal wall (with the help of gel, which helps transmission of the sound waves). For this reason, the procedure is also called a transabdominal ultrasound, in contrast to endoscopic ultrasound, the latter combining ultrasound with endoscopy through visualize internal structures from within hollow organs. Abdominal ultrasound examinations are performed by gastroenterologists or other specialists in internal medicine, radiologists, or sonographers trained for this procedure. Medical uses Abdominal ultrasound can be used to diagnose abnormalities in various internal organs, such as the kidneys, liver, gallbladder, pancreas, spleen and abdominal aorta. If Doppler ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vaginal Ultrasonography
Vaginal ultrasonography is a medical ultrasonography that applies an ultrasound transducer (or "probe") in the vagina to visualize organs within the pelvic cavity. It is also called transvaginal ultrasonography because the ultrasound waves go ''across'' the vaginal wall to study tissues beyond it. Uses Vaginal ultrasonography is used both as a means of gynecologic ultrasonography and obstetric ultrasonography. It is preferred over abdominal ultrasonography in the diagnosis of ectopic pregnancy. It also can be used to evaluate patients with post-menopausal bleeding. The finding on transvaginal ultrasound of a thin endometrial lining gives the physician a 99% negative predictive value that the patient does not have endometrial cancer. If a patient had a prior endometrial sampling that was inconclusive, then a transvaginal ultrasound can be used to triage a woman with post-menopausal bleeding. See also * Gynecologic ultrasonography * Post-menopausal bleeding Vaginal bleeding ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Chorionic Gonadotropin
Human chorionic gonadotropin (hCG) is a hormone for the maternal recognition of pregnancy produced by trophoblast cells that are surrounding a growing embryo (syncytiotrophoblast initially), which eventually forms the placenta after implantation. The presence of hCG is detected in some pregnancy tests (HCG pregnancy strip tests). Some cancerous tumors produce this hormone; therefore, elevated levels measured when the patient is not pregnant may lead to a cancer diagnosis and, if high enough, paraneoplastic syndromes, however, it is unknown whether this production is a contributing cause or an effect of carcinogenesis. The pituitary analog of hCG, known as luteinizing hormone (LH), is produced in the pituitary gland of males and females of all ages. Beta-hCG is initially secreted by the syncytiotrophoblast. Structure Human chorionic gonadotropin is a glycoprotein composed of 237 amino acids with a molecular mass of 36.7 kDa, approximately 14.5kDa αhCG and 22.2kDa βhCG ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fetal Pole
The fetal pole is a thickening on the margin of the yolk sac of a fetus during pregnancy. It is usually identified at six weeks with vaginal ultrasound and at six and a half weeks with abdominal ultrasound. However, it is not unheard of for the fetal pole to not be visible until about 9 weeks. The fetal pole may be seen at 2–4 mm crown-rump length Crown-rump length (CRL) is the measurement of the length of human embryos and fetuses from the top of the head (crown) to the bottom of the buttocks (rump). It is typically determined from ultrasound imagery and can be used to estimate gestatio ... (CRL). References Embryology {{Developmental-biology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embryonic Death
Embryo loss (also known as embryo death) is the death of an embryo at any stage of its development which in humans, is between the second through eighth week after fertilization. Failed development of an embryo often results in the disintegration and assimilation of its tissue in the uterus, known as embryo resorption. Loss during the stages of prenatal development after organogenesis of the fetus generally results in the similar process of fetal resorption or miscarriage. Embryo loss often happens without an awareness of pregnancy, and an estimated 40 to 60% of all embryos do not survive. Moral status There is considerable debate about the moral status of human embryos. These debates are important in relation to abortion and IVF. Some argue that fetuses have the same moral status as infants, children, and adults. However, critics claim that this view is morally inconsistent due to the frequency of embryo loss/miscarriage/spontaneous abortion in general population. Some say that t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gestational Sac
The gestational sac is the large cavity of fluid surrounding the embryo. During early embryogenesis, it consists of the extraembryonic coelom, also called the chorionic cavity. The gestational sac is normally contained within the uterus. It is the only available structure that can be used to determine if an intrauterine pregnancy exists until the embryo can be identified. On obstetric ultrasound, the gestational sac is a dark (Echogenicity, anechoic) space surrounded by a white (Echogenicity, hyperechoic) rim. Structure The gestational sac is sphere, spherical in shape, and is usually located in the upper part (fundus) of the uterus. By approximately nine weeks of Gestational age (obstetrics), gestational age, due to folding of the Trilaminar embryonic disc, trilaminar germ disc, the amniotic sac expands and occupy the majority of the volume of the gestational sac, eventually reducing the extraembryonic coelom (the gestational sac or the chorionic cavity) to a thin layer between t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miscarriage
Miscarriage, also known in medical terms as a spontaneous abortion, is an end to pregnancy resulting in the loss and expulsion of an embryo or fetus from the womb before it can fetal viability, survive independently. Miscarriage before 6 weeks of gestation is defined as biochemical loss by European Society of Human Reproduction and Embryology, ESHRE. Once ultrasound or histological evidence shows that a pregnancy has existed, the term used is clinical miscarriage, which can be "early" (before 12 weeks) or "late" (between 12 and 21 weeks). Spontaneous fetal termination after 20 weeks of gestation is known as a stillbirth. The term ''miscarriage'' is sometimes used to refer to all forms of pregnancy loss and pregnancy with abortive outcomes before 20 weeks of gestation. The most common symptom of a miscarriage is vaginal bleeding, with or without pain. Tissue (biology), Tissue and clot-like material may leave the uterus and pass through and out of the vagina. Risk factors for misc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embryo
An embryo ( ) is the initial stage of development for a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm cell. The resulting fusion of these two cells produces a single-celled zygote that undergoes many cell divisions that produce cells known as blastomeres. The blastomeres (4-cell stage) are arranged as a solid ball that when reaching a certain size, called a morula, (16-cell stage) takes in fluid to create a cavity called a blastocoel. The structure is then termed a blastula, or a blastocyst in mammals. The mammalian blastocyst hatches before implantating into the endometrial lining of the womb. Once implanted the embryo will continue its development through the next stages of gastrulation, neurulation, and organogenesis. Gastrulation is the formation of the three germ layers that will form all of the different parts of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
