Probably the first indication that the woman is pregnant is the absence of menstruation, which is called amenorrhea. However, this is not an infallible signal, since amenorrhea may occur due to other causes, such as a failure in ovulation, hormonal disorders, anxiety, or other concomitant diseases.
Frequently, the future mother has the feeling that her menstrual period is about to come, but it does not; and, occasionally, there are women who say they "feel" or "sense" that they are pregnant.
Towards the end of the first month after fertilization, she might present more specific symptoms such as nausea (with or without vomiting), sleepiness, weakness, mammary tension, increased frequency in urinating, and abdominal distention.
At this point, a urine or blood test is enough to detect the presence of corionic gonadotrofin, a hormone that is specific to the embryonic tissue and which circulates in the woman's fluids from the moment the embryo comes into contact with her circulatory system. This hormone is detectable in the blood on the 10th day of fecundation, and in the urine, on approximately the 15th day. At the beginning of the pregnancy, the hormone duplicates its concentration in just a day and a half, reflecting the speed of the cellular multiplication during this period.
