Human fertility is in crisis. Our lifestyles have unwittingly rounded on our
ability to reproduce, and even with inevitable advances in medicine, experts
foresee a dramatic slump in fertility.
The crisis has many fronts. Sperm counts are in freefall, while sexually
transmitted diseases and obesity both of which seriously harm our ability to
reproduce are rising sharply.
Our environment, stress and the vices we embrace all chip away at our natural
fertility. And the trend towards starting families later in life continues,
landing more couples in fertility clinics than ever before.
But all is not lost. Few aspects of the human body have been studied as
intimately as reproduction, and while much is set by the genetic hand we are
dealt at birth, research suggests that changes to our lifestyles can
dramatically improve our chances of prolonging our fertility.
Here we bring together the latest scientific research on fertility, and how
our life choices affect it.
The impact of smoking on fertility is staggering.
Stop smoking
Last year, a British Medical Association (BMA) report, "Smoking and
reproductive life," listed warning upon the detrimental effects of smoking for
couples trying to have children. It reduces the chances of conceiving by 10 to
40 per cent per cycle, and is responsible for some 5,000 miscarriages every
year.
Men who smoke have lower sperm counts and more malformed sperm than
non-smokers. And genetic defects in the sperm can be carried over into children.
A landmark study published last year added weight to many of the warnings
raised in the BMA report.
Dutch scientists who followed 8,457 women aged 20 to 40 found that smoking
speeds up a woman's reproductive clock, in some cases by 10 years.
"If a smoker is 10 years older, from a fertility perspective, it means a
25-year-old woman has already hit that 35-year-old point at which fertility
begins to spiral downwards," said Allan Pacey, a fertility specialist at
Sheffield University.
The good news is there is evidence to suggest that smoking-induced damage to
fertility may be reversible. While doctors will advise that you can never quit
too soon, you can certainly stop too late.
"To improve the situation, women have to be nicotine-free before the egg
starts developing and maturing," said Dr Laurence Shaw, deputy director of the
Bridge Clinic in London. "If the egg matures while you're still smoking, the
chances of successful implantation are much lower. Giving up when your pregnancy
test is positive will do nothing to improve your risk of miscarriage," he adds.
Unlike many smoking-related diseases, the effect on fertility is down to
nicotine, so nicotine patches can cause all the same problems.
For men, smoking-related sperm damage accumulates over the 90 days it takes
for them to form fully, so quitting for three months will ensure no sperm are at
risk.
Sexually transmitted infections (STIs) often have few, if any, symptoms, so
the damage they cause goes unnoticed until a couple try for children.
Avoid STIs
Chlamydia in particular is on the rise. In 10 per cent of cases, it causes
enough damage to the fallopian tubes to render a woman infertile, yet has no
visible symptoms.
"Women aged 16 to 24 are most prone to chlamydia, but they tend not to have
children at that age, so the first they know about it can be years later," said
Professor Bill Ledger, head of reproductive and developmental medicine at
Sheffield University.
Many physicians think that even rapid treatment with drugs might not help
prevent damage from chlamydia.
Gonorrhea can cause infertility in men and women it blocks the fallopian
tubes and, in men, the vas deferens, which carries sperm.
"Disease is a big factor in infertility, and the message
is simple," said Ledger. "Use a condom."
