Pregnancy

The Woman During Pregnancy：The Signs of Pregnancy

Presumptive Signs of Pregnancy
The placenta, which develops in response to the implantation of an embryo, produces a certain hormone called chorionic gonadotropin. This hormone acts upon the ovaries, stimulating them to continue the production of the hormones estrogen and progesterone. As a result, no new eggs are released and no menstruation occurs since the uterine lining does not deteriorate but remains in its place for the duration of the pregnancy. For this reason, a woman who has had sexual intercourse usually suspects that she has become pregnant as soon as she misses her regular menstrual period. However, this sign alone is not conclusive because the menstruation may just be delayed for one reason or another (sometimes for quite a while). The likelihood of a pregnancy increases if she also experiences an enlargement of her breasts, a darkening of the area around the nipples, nausea (morning sickness), and a more frequent need to urinate. Still, all of these so called presumptive signs of pregnancy do not mean definite proof.