Deferring the commencement of a family is a common
choice for women in society today with up to a quarter having their first pregnancy after
age 35. This delayed childbirth allows them to establish careers, find stable
relationships and achieve financial security.
It is vital, however, to appreciate that age can have a significant
effect on ability to become pregnant and to have a normal healthy pregnancy.
Fertility As You Approach 40
The decline in fertility with age is quite remarkable, women under
30 having around a 20 percent chance of becoming pregnant each month while those over 40
have only a 5 percent chance.
While in women the final barrier to having their own children is
menopause at around age 50, sperm quality in men only gradually declines with age and
problems with libido and erections are more associated with other medical conditions
rather than age.
Gynaecological & Obstetric Problems
The older a woman is, the more time she has had to develop
gynaecological conditions such as pelvic infections and endometriosis which have the
potential to decrease chances of becoming pregnant. A laparoscopy may be performed in the
investigation of infertility to screen for these problems.
Women who become pregnant after the age 35 have an increased
incidence of high blood pressure and diabetes during pregnancy.
Ovarian Changes
At puberty, women have around 300,000 eggs in their ovaries. Each
month usually one matures and up to 1000 others cease maturation and are re-absorbed. By
age 40 there may be only several thousand left and they tend to respond poorly to hormonal
signals from the pituitary trying to cause them to mature. This lowered response results
in the ovary producing less oestrogen and progesterone, hormones which are essential for
preparing the lining of the uterus for an embryo to implant and grow.
Oocyte (Egg Changes)
As a woman and her ovaries age, so do the eggs in her ovaries. The
eggs are less able to be fertilised by sperm and they have an increased incidence of
chromosomal abnormalities. Fertilised eggs which chromosomal abnormalities are less able
to continue development causing a lowering of the pregnancy rate and an increase in early
miscarriage if pregnancy occurs. We know this because when women receive donated eggs from
younger women their chances of pregnancy are much greater than had they used their own
eggs.
The eggs of older women, by virtue of their chromosome
abnormalities, also produce newborn babies with a higher risk of chromosome abnormalities
such as Down Syndrome.
Treatment Options
If a specific cause for infertility is found, a particular treatment
may be indicated. If the infertility is unexplained various assisted reproductive
technologies may be tried. These range form the relatively simple superovulation followed
by timed intrauterine insemination (AIH), to the higher technology and more invasive
procedures of gamete intrafallopian transfer (GIFT) or conventional in vitro fertilisation
and embryo transfer (IVF-ET). The QFG Office has information sheets on all these
procedures.
GIFT appears to be the treatment of chose for unexplained
infertility in the older woman. In those 40 years and over GIFT has a pregnancy rate of
around 20 percent each treatment cycle compared with 35-40 percent for younger patients
whereas IVF-ET yields a pregnancy rate of 5-10 percent in 40 years olds compared with 20
percent per treatment cycle in younger patients.
Another option for older women is to use eggs donated by a younger
woman which will yield a higher pregnancy rate and a lower miscarriage rate. Donated eggs
and donors themselves are in short supply and those needing donated oocytes often find
their own donor from within family or friends. There are many sensitive issues to be dealt
with in the use of donated oocytes.
Summary
The decrease in fertility with age is an inescapable fact of life.
Those seeking pregnancy after the age of 40 should seek the advice of their doctor and
explore all options including the medical treatments outlined above, adoption and
child-free living.
The QFG has trained counsellors who are happy to discuss all these
options with you to help you make the decision which is best for you. They may be accessed
through your doctor or the QFG Office.
Keith Harrison,
Queensland Fertility Group
