The pelvis contains two ovaries in the female, each measuring about 3 cm in length by 1 – 1.5 cm in width. Until the onset of puberty, they remain inactive, but then come to life, being stimulated by hormones called gonadotrophins produced by the pituitary gland. These start to act on the ovaries about two years before the menarche, the time when puberty occurs.
The gonadotrophins consist of two separate hormones. one called the follicle- stimulating hormone (FSH), and the other the luteinising hormone (LH). Both are necessary for the natural progression of ovulation that occurs each month. and pregnancy.
The ovaries contain a large number of Graafian follicles. Each menstrual month, under stimulation from FSH, one of these matures, comes to the surface of the ovary and ruptures in the process known as ovulation. The cavity left fills with fluid, and under the influence of both FSH and LH develops into a white organ called the corpus luteum, which itself starts to excrete a hormone called progesterone. The aim of this hormone is to prepare the uterus for a possible pregnancy. If pregnancy does not occur, the corpus luteum tends to atrophy after 10 days, but it persists for about seven months if pregnancy ensues.
FSH and LH are both produced by the anterior lobe of the pituitary, an endocrine gland located at the base of the brain. Both of these hormones may be measured by the modern methods of radioimmunoassay. They are in peak concentrations at the time of ovulation.
In the past gonadotrophins have been used in women with infertility problems. Their use has sometimes resulted in multiple foetuses in the resulting pregnancies. The use of these hormones for infertility has been largely replaced by bromocriptine that lowers plasma prolactin. a hormone known to prevent ovulation. With prolactin levels reduced, ovulation can return to normal and pregnancy ensue, if this was the basic cause of the infertility problem. LH is very similar to chorionic gonadotrophin, a hormone produced during pregnancy by the placenta (later the afterbirth).
This product can readily be measured in the urine of the pregnant woman. Indeed, most of the simple home  “do-it-yourself” immunochemical pregnancy tests depend on detecting this substance in the woman’s urine. It may be detected about six weeks after the last menstrual period in the event of pregnancy having become established. The ovary secretes important hormones itself.
Oestrogens arc produced by the ovary and corpus luteum in direct response to FSH and LH. Oestrone and oestradiol are the primary hormones, and they readily convert into oestrogen. Oestriol is a breakdown product of oestrogen, and has its main effect on the vagina and cervix, whereas oestrogen mainly acts on the uterus.
During pregnancy, oestriol is secreted, and its detection in the urine is a handy guide as to the efficiency of the placenta in carrying out its work. These hormones have confusing names,but although they are only of academic interest to the reader, they are very important in gynaecology and obstetrics, for they give excellent guidance to the obstetrician as to the progress of the pregnancy. Progesterone is secreted by the corpus luteum under stimulation from LH.
Progesterone has a depressive effect on the higher centres, and has often been incriminated for the common sensations of irritability and depression that trouble many women in the week or so prior to normal menstruation. It may also increase the risk of attacks in epileptics, and even bouts of kleptomania or suicide in susceptible women.
Fortunately, medication is now able to overcome most of these problems. It is also responsible for the outcropping of acne and facial pimples that is notorious at this time, and complained about most volubly by teenage girls. Although the contraceptive pill will often reduce the mental changes, it will tend at the same time to make the skin problems worse, particularly if the pill has a fairly high level of progesterone.
Tests for ovarian function are possible. The vaginal smear takes cells from the upper walls of the vagina, and shows a typical pattern if hormonal secretions are normal or otherwise. The urine may be checked for the metabolites (breakdown products) of oestrogen. The cervical mucus can be examined, and cells will show a typical pattern if hormonal secretions are normal. Similar tests are available for a check on progesterone secretion, the pregnanediol test, and others.
Often taking scrapings from the walls of the uterus (as during a D and C examination) can also yield valuable information on the hormonal levels of the ovaries.