Obviously our way of life has an effect on our general state of health and thus also our fertility. But can it also be proven that certain external factors have an effect (positive or negative) on the chances of success of fertility treatment?
Yes, for some it can. Smoking is a good example.

Smoking and IVF  

"I'll stop smoking when I'm pregnant": it is a known fact that smoking during pregnancy involves many risks.
Less widespread is the knowledge that smoking cessation is an important gain for women who are trying to become pregnant. How come?

• Women who smoke will, according to properly conducted studies (case control studies) take approximately two to three times longer to get pregnant.
• It has also been proven that the breakdown products of nicotine have a negative effect on the reserve of eggs, as a result of which according to several researchers, a woman who smokes may start menopause one to four years sooner. 
• Smoking also increases the chances of genetic abnormalities in the egg, and some researchers also determined an increased risk of miscarriage. 
• There is also an increased risk of an ectopic pregnancy: this is four times higher for heavy smokers (more than twenty cigarettes a day). 

Women who want to become pregnant need to know this. But particularly if you start IVF treatment you should stop smoking: a number of studies have shown that women who smoke need almost twice (!) as many treatment cycles as non-smokers to achieve a pregnancy.
Men should also stop: a smoker's sperm quality is significantly worse than a non-smoker's. The sperm quality of men born from mothers who smoked more than ten cigarettes a day during pregnancy is also less according to research. And finally we also want to mention that passive smoking, i.e. when you smoke in your partner's company, also has a negative effect on her fertility.

Can I drink a glass of wine during my treatment? 

Although there is no clear evidence of the effect of alcohol during pregnancy, a number of large-scale American studies have proven that alcohol is indeed dangerous for a developing foetus, even if consumed in small quantities. The CRG highly recommends that women who are pregnant or want to be pregnant do not drink alcohol.
For women who want to be pregnant, a study has shown that regularly drinking alcohol during IVF treatment results in less eggs being collected. The risk of miscarriage is also twice as high, and affects insemination treatment.
For women who are pregnant: the specific risks for a baby have been summarised under 'foetal alcohol syndrome' (see www.fasstichting.nl). FAS usually concerns a combination of symptoms: the baby's head is too small, lower birth weight and abnormal facial characteristics. Many babies also have a more or less severe mental retardation.
To rule out any risk to the baby we advise no alcohol whatsoever during pregnancy.

I know, I should lose some weight     

Disproportional body weight in women can lead to subtle hormonal disorders and thereby to reduced fertility, usually as the result of disturbed ovulation.
The chances of pregnancy with IVF are also significantly smaller. A recent Dutch study showed that women who are overweight only have a two-thirds chance of becoming pregnant after IVF/ICSI treatment compared to women with a normal weight.
If you are overweight, we recommend you try to lose weight before you start IVF treatment

Coffee, stress?

Currently we cannot give a clear answer as to whether drinking coffee has a negative effect on your chances of becoming pregnant following IVF. Although it has been suggested that coffee increases the risk of miscarriage it is impossible to say so with certainty.
There is little information about the effects of stress either. Although it has been known for years that (psychological) stress has an effect on the operation of the ovaries and can even, in extreme cases, result in the absence of ovulation, the effects of stress on the results of fertility treatment are less clear. Various studies suggest a negative effect, but this proof is not very convincing.
On the other hand, it is clear and has been proven that IVF|ICSI treatment causes psychological stress.

Should I not stay overnight after my transfer?     

Various studies have investigated whether bed rest after the transfer has a favourable effect on the treatment’s chance of success. The outcome was clear: there is no indication that bed rest leads to a greater chance of pregnancy. One study even showed the contrary: that bed rest for 24 hours after transfer results in a lower chance of pregnancy!

Can I continue to exercise?   

Some sports can have an effect on the ovulation or the sperm quality. For instance, deep-sea diving under extreme hyperbaric conditions results in a drastic decline of sperm quality. For women overtraining may result in an absence of ovulation and menstruation.
However, we have no data about the impact of normal physical exercise on IVF|ICSI treatment. If you do practise a sport it is okay to continue, with moderation.

Taking folic acid  

Folic acid is a vitamin and belongs to the so-called Vitamin B complex. It is mainly found in vegetables (spinach, broccoli, sprouts) and in smaller amounts in bread and dairy products. Most is lost when vegetables are cooked. UHT dairy products however, retain most of their folic acid. 

The daily recommended amount of folic acid is 0.2-0.3mg. A balanced diet containing vegetables will provide this.
Various studies have shown that a pregnant woman’s body requires almost double that amount. Additionally, women who are attempting to become pregnant should take an extra supplement of 0.4mg per day to decrease the risk of the child developing spina bifida. Taking folic acid reduces the risk by almost half.
In Europe, between 5 and 20 out of every 10,000 babies are born with some form of neurological defect. Often this results in serious motoric disabilities. In Belgium the incidence is currently around 10 in 10,000 births.

Apart from reducing the risks discussed above, other benefits include a reduction in morning sickness during the first weeks of pregnancy and possibly a reduced risk of premature birth.
Intake of extra folic acid is also believed to reduce the risk of heart and urinary defects in the baby.

All things considered, folic acid should not be omitted from your diet if you are planning a pregnancy.