What is the role of syncytiotrophoblast during implantation?
The syncytiotrophoblast facilitates implantation of the blastocyst in the maternal endometrium by production of lytic enzymes and secretion of pro-apoptotic factors. Eventually, the expanding syncytiotrophoblast surrounds the embryo entirely.
What is the most common uterine site for implantation in the human?
Implantation begins with apposition of the blastocyst at the uterine epithelium, generally about 2-4 days after the morula enters the uterine cavity. The implantation site in the human uterus is usually in the upper and posterior wall in the midsagittal plane.
What is invasive implantation?
Invasive implantation induces decidualization in primates, which involves hyperplasia and hypertrophy of stromal cells and their secretion of prolactin (PRL), ECM proteins, SPP1, laminin, and fibronectin, invasion by numerous immune cells, and formation of cell–cell contacts.
Does Cytotrophoblast produce hCG?
Cytotrophoblast cells naturally produce hyperglycosylated hCG, which promotes their growth and invasion. Other cells need to be transformed to produce invasive hyperglycosylated hCG.
Which is true about syncytiotrophoblast?
The syncytiotrophoblast is easily identifiable during the first half of pregnancy (Fig. 1) and is characterized by a continuous row of nuclei. During the second half of pregnancy the syncytiotrophoblast becomes thinner to reduce the diffusion distance between maternal and fetal blood.
At which stage implantation takes place?
Implantation takes place about nine days after ovulation. About 25% of women experience bleeding with implantation. 3 At this point, pregnancy has officially begun. If implantation does not take place, the fertilized egg will leave the body, probably during your period.
Does syncytiotrophoblast secrete hCG?
With hatching, the syncytiotrophoblast cells produce hCG, estradiol, and EGF which signal to the uterine epithelium that a blastocyst is about to implant (Fig. 21.1, Panel B) [8,9].
What are the key characteristics of implantation bleeding?
Key Characteristics of Implantation Bleeding Includes: 1 Very light flow 2 Brown or pink colored 3 Usually comes before your next scheduled period 4 Lasts 2–4 days
Can implantation bleeding be mistaken for your period?
If you weren’t trying to get pregnant, you might mistake implantation bleeding for your period. One of the tell-tale signs is the timing. If you’re trying to get pregnant and start to bleed before your period should arrive, you’re probably experiencing implantation bleeding. When Does Implantation Bleeding Happen?
Is it normal to have implantation bleeding 2 weeks after spotting?
If it was more than two weeks before the spotting, then it’s unlikely that you’re experiencing implantation bleeding. Implantation bleeding and other forms of light bleeding are normal during pregnancy. More than 50% of women who experience light bleeding during pregnancy have no issues afterward.