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The duration of gestation is approximately 280 days, ie 40 weeks taking as reference the beginning of the last menstruation. However, the date of birth is unlikely to coincide precisely with the expected one. In principle, it can be said that, if the menstrual cycles are 28-30 days and the pregnancy proceeds normally, the birth of the baby can occur at any time, between two weeks before and two weeks after the expected date.
For a better approximation, however, it is possible to take into consideration some individual factors (such as the date of presumed ovulation or unprotected sexual intercourse), which will then be supported by gynecological evaluation, laboratory analyzes and ultrasound investigations.
going up the uterus, they reach the mature egg cell, released from the ovary during ovulation and available for fertilization.
The fertilized egg is transported by the movement of the hair cells of the tube towards the uterine cavity, where it nestles in the "endometrium" approximately 6-7 days after unprotected sexual intercourse (therefore around the 21st day of a regular menstrual cycle. 28 days, if fertilization took place on the fourteenth day).
At this point, the production of chorionic gonadotropin also begins, the "beta" subunit of which is important for the functioning of the pregnancy test.
Learn more: When to Take the Pregnancy TestThe period in which it is possible for the egg to be fertilized starts 4-5 days before ovulation and ends 1-2 days later. This is possible in consideration of the fact that the mature egg cell, when expelled from the ovary, manages to survive for about 24 hours, while the spermatozoa can remain viable in the female genital system for up to 72-96 hours. Therefore, unprotected intercourse even 3 or 4 days before ovulation can lead to fertilization.