What can affect the chances of success?

The main factors affecting the chances of a successful pregnancy are:

Weight (female partner)

If you are overweight:

you might not respond as well to the medication used to stimulate your ovaries and as a result produce fewer eggs;
it is more difficult to obtain a clear scan picture during egg collection;
the medication we give you for pain relief and sedation during this procedure can slow your rate of breathing and this can cause complications;
if you do become pregnant, the chance of miscarriage might be higher and there can be more complications in pregnancy, in particular with high blood pressure and sugar tolerance (gestational diabetes).

For all these reasons, we recommend that patients who are very overweight should lose weight before starting treatment. We will not be able to offer you treatment unless you are within the correct weight limit - see table below. If you exceed the recommended weight, we can refer you to a dietitian or you can speak to your GP about local weight loss programmes.

Table 1: maximum weight acceptable for your height
Height	Maximum weight
4 feet 11 / 1.50 metres	10st 7 1bs / 68kg
5 feet 0 / 1.52 metres	11st / 70kg
5 feet 1 / 1.55 metres	11st 3Ibs / 72kg
5 feet 2 / 1.57 metres	11st 6Ibs / 74kg
5 feet 3 / 1.60 metres	12st 1Ibs / 77kg
5 feet 4 / 1.62 metres	12st 4Ibs / 79kg
5 feet 5 / 1.65 metres	12st 8Ibs / 82kg
5 feet 6 / 1.67 metres	13st 2Ibs / 84kg
5 feet 7 / 1.70 metres	13st 5Ibs / 86kg
5 feet 8 / 1.72 metres	13st 10Ibs / 89kg
5 feet 9 / 1.75 metres	14st 4Ibs / 92kg
5 feet 10 / 1.75 metres	14st 8Ibs / 94kg
6 feet / 1.75 metres	15st 6Ibs / 99kg

Group weight loss programmes have been shown to be more effective than individual dieting.

Smoking (both partners)

If you smoke we recommend you to cut down or preferably stop. Smoking has been shown to reduce the chances of conceiving naturally and lowers the success rates of IVF. Cannabis also seriously affects sperm quality and reduces the chance of fertilisation.

If you want help to try and stop smoking, please speak to your GP. You might also want to call the NHS Smoking Helpline on 0800 169 0169.

Alcohol (both partners)

Effects in men

Excessive intake of alcohol, especially 'binge' drinking, can decrease sperm production and the number of moving sperm. Sperm take 72 days to form so the effects of damage take a long time to reverse.

We recommend that you drink less than two units of alcohol per day.

Effects in women

There is no clear evidence that alcohol does or does not affect fertility in women. However as women are advised not to drink alcohol during pregnancy, preparation for PGD may be a good time to review and limit your alcohol intake.

Folic acid intake (female partner)

We recommend you take 400 micrograms of folic acid each day. Folic acid is a vitamin that has been shown to greatly reduce the risk of abnormalities of the brain and spinal cord (anencephaly and spina bifida) in an unborn baby. It has no side-effects and is safe to take during pregnancy.

Folic acid should be started by the beginning of a treatment cycle and continued to the 12th week of pregnancy. It can be bought in pharmacies and supermarkets.