There
are four main reasons why a woman of child bearing age, who
is having unprotected intercourse with reasonable frequency,
might not become pregnant. She may be producing no ova. She
may be producing ova but they are not coming in contact with
the sperm. The ova may be fertilised but are not implanting
in the lining of the uterus. The male sexual partner may be
infertile (see Infertility /Male). She may be producing no ova
because of hormonal imbalance or because her ovaries may be
diseased or have been damaged, by chemotherapy for example,
or removed surgically. Hormone balance is controlled by the
pituitary gland at the base of the brain. More often than not,
there is no clear reason why a woman is not ovulating and deep
psychological issues may be involved. The commonest barrier
between ova, once produced, and sperm, in unprotected intercourse,
is blockage of the Fallopian tubes. These structures carry the
ova to the uterus and are the usual site of fertilisation. The
common causes for this blockage are pelvic inflammatory disease
(see Vaginal discharge) and endometriosis (see Endometriosis).
Implantation of the fertilised ovum may be prevented by disease
of the lining of the uterus. In some women, changes in the cervical
mucous make it impenetrable to sperm. Infertility may be primary
- the woman has never been pregnant - or secondary, she has
been pregnant in the past but is unable to become so again.
In the latter the cause is unlikely to be hormonal, and if a
new partner is involved, particular attention should be paid
to the partner's fertility.
A woman who has had intercourse three times in a year and has not become pregnant should not be considered infertile. A woman who has had regular intercourse over the same period of time and has not become pregnant, merits investigation. A woman nearing the menopause may be investigated sooner. The doctor will carry out a careful history, a physical examination, often an ultrasound of the pelvis, and, even at this early stage, a sample of the partner's semen may be examined for the number and quality of sperm (see Infertility/Male) The woman would keep a chart of her temperature through the month, a small rise in the temperature mid-cycle suggests ovulation and indicates the time when fertilisation is most likely to take place (get a book on the rhythm method of contraception and take the opposite advice on all matters !). If fertilisation does not take place fairly soon, the patient will be referred to a gynaecologist, often at an infertility clinic. Further investigations include laparoscopy (see Endometriosis), examination of the lining of the uterus and an X-ray, using dye, introduced into the uterus, to see if the tubes are blocked. If the tubes are blocked, surgery may be suggested to try to unblock them. Ovulation, if not present may be stimulated by such medications as clomiphene. IVF (in vitro fertilisation) is widely used, in which ova and sperms are mixed outside of the body, and the fertilised ovum is implanted directly in the uterus. This is particularly useful if there is tubal blockage. But, as has been said above, there is often no obvious cause for the infertility. Sometimes women seem to reject the sperm of a particular partner. And, like the watched kettle that never boils, sometimes conception is sought so fiercely that this, in itself, may have an inhibitory effect. |
