Implantation of an embryo- symptoms and course

Implantation-what is it?

After fertilization, which occurs in the bubble of the fallopian tube, the zygote is transported into the uterine cavity. There the transparent sheath disappears and nesting of the fetal egg takes place. The embryo, which is in the blastocyst stage, enters the endometrium. This usually happens on the top, front or back of its wall. The trophoblast, which is responsible for nourishing the embryo, is formed from cells surrounding the implanted embryo. It is from it at the end of the I. trimester that the placenta then develops.

In order for implantation to be possible, it is necessary for the uterine cavity to “prepare” properly. During the menstrual cycle, the endometrium, thanks to the hormones progesterone and estrogen, becomes thicker and better supplied with blood so that the embryo can more easily “implant” into it. If fertilization and implantation do not occur, the endometrium exfoliates in the form of menstruation.

Embryo implantation-when does it take place?

Nesting of the embryo begins between 6. and the 7th day after fertilization, which is about a week after ovulation, since the egg cell lives for about 24 hours. Implantation itself takes several days, so eventually the embryo implantation occurs around the 12th day after ovulation.

Symptoms of embryo implantation

Some women do not notice any symptoms associated with embryo implantation. In turn, some moms-to-be experience lower abdominal pain, as well as menstruation-like bleeding occurring on its expected date. This is known as implantation bleeding.
implantation bleeding
, which, however, differs from menstruation in intensity and duration. It usually lasts one or two days and is less heavy than a normal menstrual period, and does not contain clots. Implantation bleeding occurs as a result of damage to the small blood vessels, rather than exfoliation of the endometrium.

In addition, implantation may be accompanied by symptoms such as:

• breast soreness,
• nausea,
• Excessive sensitivity to odors,
• Frequent feeling of pushing on the bladder.

If an abnormal embryo implantation and ectopic pregnancy occurs, the woman usually experiences more severe abdominal pain, bleeding and a non-specific increase in beta- HCG levels.

Abnormal embryo implantation

Typically, the blastocyst “implants” within the upper, posterior or anterior wall of the endometrium. If the nesting takes place in an abnormal place, such as the area around the inner cervical outlet, an anterior placenta can develop, which can lead to a dangerous hemorrhage at the end of the pregnancy. It is also a contraindication to natural childbirth. If the fetal egg implants outside the uterine cavity, we have an ectopic (ectopic) pregnancy. It is usually localized in the fallopian tube, but it can also appear, for example, in the peritoneum or cervix. If an ecotopic pregnancy is not detected quickly enough, it can lead to, among other things. For rupture of the fallopian tube.

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Ecotopic pregnancy- symptoms and course

Embryo implantation-when to take the test?

Chorionic gonadotropin, whose beta subunit (beta- HCG) is detected by pregnancy tests, is produced by the syncytiotrophoblast. After the embryo nests, the concentration of beta- HCG rises sharply, so it is recommended that a urine pregnancy test be performed on the date of expected menstruation, which is about 14 days after ovulation. Taking the test too soon can give a false result. After receiving a result indicating that you are pregnant, you should always confirm the correct location of the pregnancy during an ultrasound. This is because it is important to remember that beta- HCG can also be elevated in the course of ectopic pregnancy.

Bibliography: obstetrics and gynecology, vol. 1, G.H. Bręborowicz