To understand the various problems related to infertility, one must first recognize the basic functions of the female reproductive tract.
The pituitary is a gland located in the brain and that mainly produces two hormones that act directly on the ovaries (follicle stimulating hormone-FSH and luteinizing hormone-LH).
The ovaries are the female reproductive system organs that produce and release mature eggs. The woman has two ovaries located on each side of the uterus. They are nodular glands which, after puberty, have rough surface, are irregular in size and resemble a large almond shape.
This organ has two basic functions: to produce and store the female gametes (eggs) that are stored within the follicles (primordial and primary).
FSH stimulates follicle growth. LH is responsible for the final maturation of the eggs and subsequent ovulation. They also act as endocrine glands, releasing female sex hormones, estrogens (primarily estradiol) and progesterone.
After ovulation, the eggs must be received by the fallopian tubes, which are two small channels with approximately 10 cm in length leaving the uterus and end in finger-like projections called fimbriae. The fimbriae ‘hover’ over the ovaries, but are not connected to them. After being captured, the egg remains in the fallopian tube for a few days. The meeting of the egg and the sperm (fertilization) usually occurs at the distal fallopian tube.
After fertilization, the embryo is taken along the oviduct by a combination of rhythmic contractions of the muscular walls of the tube. Thus, the embryo is swept toward the uterus where pregnancy can be established through the implantation.
The uterus is a pear-shaped organ, able to undergo major changes during the woman’s reproductive life. From puberty until menopause, the inner layer lining of the uterus (the endometrium) creates an environment suitable for embryo implantation and development during pregnancy.
In order to establish a pregnancy naturally, we have a synchronized reproductive hormone system, a functioning ovary so that there is free ovulation and fallopian tubes that have preserved function so that the egg and sperm can meet. Finally, it is essential that the endometrium is appropriate to allow the implantation of the embryo.
Investigation of Infertility
Classically, a couple should start being investigated for infertility when there is no pregnancy after one year of regular and unprotected sexual intercourse. However, there are some situations where it is recommended to start investigating before this period:
- Existence of known male factor (eg when there is presence of cryptorchidism);
- Existence of high risk of female infertility (eg women over 35 years).
Causes and Diagnosis
The causes of infertility in women may be the following:
- Ovulatory factor
- Tubal factor
- Uterine Factor
- Abortions in repetition
- Early menopause