UTERUS

In the past, the uterus has been blamed for almost every mental and physical ailment from which women have suffered. Nowadays, we have a more rational, although still incomplete, understanding of this vital organ.

FUNCTION

The uterus is composed of two main parts - the corpus or body of the organ, and the cervix or neck - and it is capable of undergoing major changes during a woman’s reproductive life. From puberty to the menopause, the lining of the womb (endometrium) develops each month to provide nutrition for a fertilized egg. If the egg is not fertilized the endometrium is shed during menstruation, and is slowly replaced in the course of the next menstrual cycle.

During pregnancy, the uterus expands to allow the fetus to grow, and provides it with protection and nutrition. At the same time, the large muscle fibbers are prevented from contracting.

The uterus suddenly changes its role when the fetus is mature and begins to contract in order to open the cervix and allow the baby and placenta to pas through. The uterus then contracts tightly to close off the large blood vessels which have been supplying the placenta. After the birth it rapidly returns to its pre-pregnant state, ready to accept another fertilized egg. Rarely, this has been reported as happening as early as 36 days after the birth.

The uterus seems to have almost no function before puberty and after the menopause when it would obviously be unsuitable, both mentally and physically, for a woman to have a baby.

All these changes in the functioning of the uterus are orchestrated by hormones released from the pituitary gland and from the ovaries, and by similar substances called prostaglandin's which are released by the uterine tissue. The way in which these substances interact is still not full-,, understood.

POSITION

In an adult woman the uterus is a hollow organ approximately the size and shape of a small pear, and lies inside the girdle of pelvic bones. The narrow end of the equivalent to the cervix which protrudes into the vagina - the. remainder forms the body of the uterus. This is connected to the two Fallopian tubes which carry the monthly egg from the ovaries. In this way the uterus forms part of a channel between the abdominal cavity and the outside world.

Special mechanisms exist to prevent the spread of infection via this route into the abdominal cavity. Thus the lining of the uterus is shed when a woman menstruates, the cervix secretes antibodies and the acidity of the vagina inhibits the growth of bacteria. The front of the uterus sits on the bladder and the back lies near the rectum. The uterus is normally supported inside the pelvis floor muscles – and by bands of connective tissue and blood vessels from the side wall of the pelvis which are attached to the cervix. At about 38 weeks of pregnancy the uterus usually reaches the lower end of the rib-cage, and about two weeks after the baby is born. the uterus can normally no longer be felt in the abdomen. After the menopause, the uterus shrinks in size.

The variations in size are controlled by the secretions of sex hormones, which also govern the nature of the glandular tissue lining the uterus (the endometrium). During the first half of a woman's menstrual cycle, the endometrium increases in thickness until the egg is released. It then stops growing but begins to secrete substances rich in nutrition to allow further growth of the egg if it is fertilized. If the egg is not fertilized, the endometrium is shed during menstruation.

CONGENITAL VARIATIONS

During the development of the female reproductive organs in the fetus, two tubes of tissue - called Mullerian ducts grow from the side wall of the abdominal cavity and meet centrally. These tubes continue to grow downwards until they fuse with tissue which will later form the lower vagina. The upper portions of the tubes become the Fallopian tubes and the lower central portions fuse to form the uterus and upper vagina.

Very rarely, both the Mullerian ducts fail to form with the result that the adult woman will have a short vagina but no uterus or Fallopian tubes. Nothing can be done to cure this condition although sometimes plastic surgery is performed to lengthen the vagina. Such women are infertile and do not menstruate.

If only one of the Mullerian ducts develops, the woman will have a uterus and vagina but only one Fallopian tube. This does not cause any major - problems.

Another rare occurrence during fetal development is incomplete fusion of the Mullerian ducts. This may result in any abnormality from a double uterus to a small dimple at the top of the uterus. If such abnormalities create difficulties for the woman in carrying a pregnancy to term, plastic surgery can be done to re-form the uterus into a single cavity.

PROBLEMS WITH THE UTERUS

Considering the complex mechanism that governs the normal functioning of the uterus, it is remarkable how few women have any problems.

Obviously, several different conditions can give rise to the same symptoms. For example, bleeding from the vagina between periods or after intercourse is often due to a minor condition such as a polyp which can be easily cured. However, these symptoms are very rarely caused by uterine cancer. This can be completely cured if it is detected early enough, so it is very important for any woman who has these symptoms to seek her doctor's advice.

TREATMENT

It is difficult to diagnose problems that are due to an abnormality of the uterine cavity as this area cannot be examined directly. Therefore a woman may need to have a D & C just to diagnose the cause of a menstrual problem or vaginal bleeding after the menopause. Once the correct diagnosis has been made, the doctor can then prescribe the appropriate antibiotics or hormones.

Unfortunately, doctors are not always able to control abnormal menstrual symptoms in this way. In such cases both the patient and doctor may feel that the only way to cure the symptoms is by a hysterectomy. This will stop a woman having any more periods, and will also make her infertile, but should not otherwise alter her life. However, modern medical therapies are improving and this operation is being performed less frequently. It is hoped that in the future most problems of the uterus will be treated simply with tablets.