A decision could be to make induce the childbirth if it is perceived that the baby is slow. The dates of victory are only one approximated estimation, and the process of form precise to leave with a complica pregnancy because all the women do not have menstrual cycles of 28 days with the ovulation in day 14 after their last menstrual period. Approximately 3.6% of all the women give to light in the date anticipated by LMP, and 4.7% give to light in the day anticipated by ultrasound. The beginning of the pregnancy can be detected of different ways, including several tests of pregnancy that detect hormones generated by the placenta just formed. Clinical tests of blood and urine they can detect a pregnancy shortly after the implantation, that is already in 6-8 days after the fertilization. The homemade tests of pregnancy are personal tests of urine, that normally days cannot at least detect a pregnancy until 12-15 after the fertilization. With both tests clinical and those of the home, it only can detect the state of the pregnancy cannot more detect his age. In the phase subsequent to the implantation, the blastocito secretes a called hormone gonadotropina human corinica that as well, stimulates the corpus luteum in the ovary of the woman to continue producing progesterone.

This acts to maintain the coating of the uterus so that the embryo follows being fed. The glands in the coating of the uterus are swollen in response to blastocisto, and the capillaries will be stimulated to grow in that region. This allows blastocisto to receive the vital nutrients of the woman. The pregnancy tests detect the presence of human corinica gonadotropina.