A woman is not aware of the precise time of fertilization unless she is receiving IVF or ICSI with the transfer of fresh or frozen embryos (TE). If blastocyst nesting is successful, however, symptoms may appear. Vaginal discharge occurs, including white discharge and implantation bleeding, which should not be confused with the return of menstruation.
Why does nidation cause symptoms?
By fertilization, the oocyte and spermatozoa merge into the fallopian tubes, also called oviducts: the zygote is born. It is already beginning to develop during its migration from the oviduct to the uterine cavity.
Once at the destination, the embryo at the blastocyst stage clings to the walls of the uterus. It is the embryonic implantation or implantation, which begins on the seventh or eighth day after fertilization and lasts until the end of the second week.
The egg adheres to the endometrium to receive oxygen and nutrients from the mother by blood and thus to continue to develop.
For this to happen, a dialogue begins between the mother and the embryo through root-like extensions, which the embryo directs to the uterine mucosa. It breaks the blood vessels of the endometrium in order to form new ones that will allow exchanges.
It is the rupture of the small vessels of the endometrium which causes the characteristic bleeding of the nidation, which the woman can observe in the form of vaginal discharge
During implantation of the embryo, the increase in hormone levels is responsible for the main symptoms of pregnancy. Normally, they are distinguished a little later, around the 2nd or 3rd week after fertilization, although some women feel them earlier.
The vaginal discharge
Among the characteristic symptoms of nidation, the most obvious symptoms are those that affect the female reproductive system more closely.
A few days after the nidation occurs a slight vaginal bleeding, implantation bleeding, which consists of pinkish or brown losses.
While losses are often associated with early pregnancy, although they are not exclusive to this phase.
Rules or bleeding implantation?
Bleeding due to nidation can be confusing with menstruation. In fact, it occurs between the 7th and 10th day after ovulation, which corresponds to the expected time for the return of menstruation if the woman is not pregnant. It is natural to have doubts.
Losses of the nidation are lighter and more liquid than menstruation, with a finer texture. Their color can be pink, red or brown. In all cases, it is less intense than the color of the menstrual blood.
Moreover, the duration of the bleeding depends on each woman. It can be punctual and last only a few hours or manifest in a light and intermittent way for several days. It is not often that it is prolonged more, but it is possible.
The increase in white losses
White losses appear throughout a woman’s life and are not necessarily a symptom of pregnancy.
It is a mixture of cervical mucus and vaginal secretions whose consistency and quantity vary according to the moment of the female cycle. They are more opaque and thicker after ovulation, while at other times they are more abundant and transparent.
However, the noticeable increase in white loss production may actually be a sign of pregnancy, due to the increased HCG hormone , which in turn promotes the secretion of progesterone and estrogen, essential for the good of the pregnancy.
Under the influence of estrogens, the mucosa of the vagina is renewed more rapidly, and the cells are eliminated in more abundant white losses .
It is therefore the increase in white losses, and not the white losses in themselves, which indicate that the woman is actually pregnant. Unlike bleeding implantation, it is a symptom due to the hormones of pregnancy and not directly to the nidation.
Other symptoms associated with implantation
Besides the duration of bleeding, consistency, and color, suffering from other symptoms typical of pregnancy helps to determine whether it is actually nidation or, on the contrary, menstruation.
It should be borne in mind, however, that when pregnant, certain symptoms are similar to premenstrual symptoms and may give rise to additional doubts and confusion.
Some pregnancy-specific symptoms that can be significant if they are confirmed by the rule are:
Colic, on one or two days, accompanied by pains similar to those experienced during menstruation
A slight tension of the breasts, especially towards the areola and the nipple
Genes such as diarrhea or constipation, as well as heartburn
Frequent urge to urinate
A tendency to doze, especially after meals
Nausea and even vomiting, especially on waking, which normally starts the second week
An aversion reaction to certain foods, tobacco, and certain odors
The first cravings, the need for more meals but with less food
Excessive attention to the appearance of signs or changes in the body, combined with the exacerbated desire to become pregnant and to be a mother, may give rise to the fact that we ourselves provoke symptoms of pregnancy, to be pregnant.
In any event, it is recommended to wait at least 12 days after ovulation to perform a reliable pregnancy test
Symptoms of nesting after IVF, ICSI or IA
The design method does not in principle affect the development of the embryo. However, implantation does not take place under the same conditions after IVF or ICSI since the embryos are transferred directly into the uterus.
In the case of artificial insemination (AI), whether it is an IAC (AI with spouse’s sperm) or an IAD (AI with donor sperm), the procedure is less invasive and the nesting of the embryo occurs under the same conditions as for a natural pregnancy.
However, after medically assisted procreation, especially after embryo transfer (TE or TEC, if the embryos have been vitrified), patients should take progesterone supplements to help their endometrium to be receptive to nidation.
Sometimes progesterone causes symptoms similar to those of pregnancy, without it signifying the success or failure of implantation of the embryo. A woman who undergoes fertility treatment is exposed to a false positive result of the pregnancy test.
Brown bleeding may occur, caused by hormonal stimulation, without bleeding from implantation or necessarily pregnancy.