Describe the hormonal control of a pregnancy in a human female.

Normal evolution of pregnancy takes place amid major
changes in the endocrine system. Besides the genital tract changes, which are generated
by the development of embryo and fetus, pregnant woman's body will undergo a period when
hormonal activity will be more intense.

The most
solicited endocrine gland throughout the pregnancy is ovary. Ovary will produce a larger
amount of folliculin and progesterone, as well, especially in the first 3-4 months of
pregnancy. Folliculin has a positive trophic action on the uterus and fetal development.
Uterine weight increases during pregnancy by about 35 times and folliculin is the
determining factor of development.

Progesterone
assures fertilized egg viability and it's implantation in the uterine lining and then
favors maintaining and extending the pregnancy.

Besides the
intense activity that takes place throughout the ovary, during 9 months of pregnancy, it
can not cover all needs of sex hormones. The body creates a new source of hormones,
which is represented by the placenta. The placenta will produce progesterone, especially
since the third month of pregnancy,folliculin and a new hormone: gonadotropic hormone.
The action of the new hormone is similar to the pituitary stimulating lutein
hormone.