Checking your fertility

The following advice will enhance a couple’s chances of conception and delivery of a healthy baby.


Age has a significant effect on the chance of conception per month. The time it takes for both infertile and normally fertile couples to conceive lengthens as age increases.

From 35 years there is a significant drop in the chance of conception per month.

On average it takes three to four months for a 25-year-old woman to conceive if everything else is normal and it takes twice this time for someone who is 35. This doubling of the time it takes to become pregnant over 10 years then doubles again over the next 4 years so that by the time a normally fertile woman is 39 years old. The average time to conception is 15 months.

The male’s age exerts almost no effect until he is well over 55.

There are several reasons for this drop in the chance of conception with increasing age:

  • Follicle atresia – this is the natural aging of the follicles within the ovaries. A follicle is the small structure that encapsulates the egg. Women have a finite number of eggs – after about 7 months of intrauterine life they are all formed, and start to undergo atresia (degeneration) from then. By the time a baby girl is born she has just several hundred thousand eggs remaining. During the next 60 years the ovary will become completely void of follicles. The X chromosome controls this process of aging and, of course, if the woman suffers chromosomal damage (such as by chemotherapy or smoking) there is premature aging and atresia. The use of the oral contraceptive pill has no effect on this aging process.
  • Aging effect on the spindle within the egg. The egg has a spindle on which the chromosomes align themselves in preparation for fertilisation. In eggs from older women the spindle is not as well formed as in younger women so the chromosomes do not line up well. Malfunction of the spindle is the reason why older women are more likely to have a baby who has an extra chromosome, - commonly the pair of chromosome 21 do not split evenly, and then a child with Down syndrome results. 
Click here for further Pregnancy rate information.

Your biological clock - and how to tell its time


For most women, age best predicts the chance of conception per month. However, despite having regular menstrual cycles and normal periods, about 10% of women lose their fertility sooner. These women should think about having a family in their 20’s or very early 30’s.

There are tests which help predict whether a woman may have a faster biological clock. Both tests estimate what is called ‘ovarian reserve’ by measuring the number of follicles developing in the ovary at a particular time. Both tests compare your results with those of other woman of the same age:
  • AMH (Anti-Mullerian Hormone):  AMH is a hormone made by small follicles as they grow in the ovaries. This test is convenient and in-expensive as it uses a simple blood test and can be done at any time in the menstrual cycle.  It is available from all Fertility Associates clinics.  An AMH test can pick up who might lose their fertility more quickly but it does not show who is more fertile than average. AMH does not predict ovarian reserve in women older than 40 or those with Polycystic Ovaries (PCO).   Find out more about AMH here.
  • FSH (Follicle stimulating hormone): Until the advent of AMH, doctors used FSH to estimate ovarian reserve. AMH is more predictive than FSH in women under 40. FSH is still useful in older women and in women nearing the menopause. 

A single test can not give the whole story, which is why we offer the AMH test as part of a consultation with one of our fertility experts. Your own medical history, your family’s fertility history, lifestyle and other investigations are needed to build a comprehensive picture of your fertility now and into the future.

Check you chances of pregnancy with our online Biological ClockTM, click here.

To make an appointment or enquire about any of these tests, please email one of our clinics or call 0800 10 28 28.


Both partners should eat a variety of foods. Choosing more fruit and vegetables, low fat varieties of milk, cheese, yoghurt, meat, bread and cereals is best. Drink at least 6 glasses of water a day.

Should we be taking any vitamins and minerals supplements?

Vitamin and mineral supplements do not make up for poor food choices. They should also not exceed the recommended daily amounts.

Women need to take extra folate (even though your diet may be adequate) for one month before getting pregnant and for the first three months of pregnancy. Folate is a B group vitamin that is found in liver, spinach, silver beet, broccoli, cabbage, oranges and avocados.

Supplements of 0.5mgs a day are recommended for women to prevent neural tube defect e.g. spina bifida.

There is currently a great deal of interest in high protein diets. There is no human evidence on the safety of high protein diets in conception or early pregnancy. There is one study in mice showing an increased risk of miscarriage when mice were fed a high protein diet.

A Normal Body Mass Index

Body Mass Index or BMI is your height in metres squared divided by your weight in kilogrammes. A normal BMI is between 20 and 25 (find out what your BMI is here). Fertility is impaired when a woman’s BMI is below 19 or 28 or above. Pregnancy may still occur, but not at the normal rate, and the miscarriage rate is also higher than average.

If over weight, weight loss may be strongly advised before you start any other treatment programme.

It is just as important to gently increase your daily exercise as to improve your diet.

Women with a low BMI (i.e. under 19 for most women) may also experience impaired fertility. The relationship between weight loss and lack of ovulation is well documented and has been observed in young athletes, ballet dancers and gymnasts. The psychiatric conditions of anorexia nervosa and bulimia are also associated with cessation of ovulation.

Overweight women:

  • have increased ovulation disorders and luteal phase defects
  • have reduced pregnancy and live birth rates
  • may experience medical complications in pregnancy e.g. diabetes and high blood pressure
  • who lose weight through exercise and a healthy diet (average weight loss 5 to 10 kg) have: 

- increased rates of spontaneous ovulation; 
- increased pregnancy rates; 
- reduced miscarriage rate from 75 per cent to 20 per cent, dependent on age; and 
- reduced congenital abnormality (birth defects).

Overweight men:

  • There is inadequate scientific data regarding the effect of excessive weight on male fertility. 

Find out what your BMI is by using our BMI caculator here.



Excessive exercise when you are trying to conceive may not be beneficial for two reasons.

Firstly many women who exercise for many hours each week have irregular or no periods indicating that they are not ovulating. Often a reduction in the amount of exercise may restore the normal menstrual cycle and hence fertility. We do not fully understand why ovulation ceases with either regular strenuous exercise or low body weight but we know it is related to the complex interactions between body fat, brain chemicals and the ovaries.

Secondly, a raised body temperature such as occurs during strenuous exercise, may slightly increase the chances of a heart defect in a baby.

Therefore moderation is the key to exercise when trying to conceive.

Cigarette Smoking

We strongly recommend that couples stop smoking. Some studies of women who smoke have shown:

  • a three times higher incidence of infertility (the decline in fertility is proportional to the number of cigarettes smoked)
  • poorer response to fertility treatment and reduced chance of conception
  • a 50% higher miscarriage rate 
  • earlier onset of the menopause
  • each cigarette smoked by a pregnant woman decreases uterine blood flow for up to an hour, resulting in less oxygen for the baby 
  • a higher rate of intra-uterine growth retardation, congenital abnormalities and infant death
  • male children of smokers have a higher incidence of learning difficulties and behavioural problems.

Some studies of men who smoke have shown:

  • a reduction in sperm counts and normal structure of sperm
  • a higher risk of impotence
  • increased birth defects and a higher incidence of childhood cancer in their children
  • increased incidence of asthma in their children



Caffeine is present in tea, coffee, cola, chocolate, some foods and medicines. There is some evidence that more than 1 coffee a day reduces the chances of conception on an IVF programme. Fertility Associates recommends 1 or less cup of caffeinated beverage a day.


We do not recommend any alcohol during pregnancy.

Recreational drugs

The use of any recreational drugs such as marijuana, ecstasy, cocaine or heroin should be avoided.

Prescribed drugs

Prescribed drugs should not be ceased without consultation with your doctor. We recommend that you advise your practitioner of your desire to conceive in case a change of prescribed drugs is required.

Natural/Alternative therapies

Any preparations taken should be discussed with your doctor

Key Factors in Fertility Fitness

  • stop smoking
  • commence or continue an exercise programme
  • reduce exposure to drugs, caffeine and alcohol
  • reduce exposure to toxins including heavy metals, chemicals and organic solvents e.g. oven cleaners, ammonia-based cleaners and paints
  • take a folate supplement when you are trying to become pregnant and for the first three months of pregnancy.