Lucy Neville-Rolfe was trying for a fourth child but had had ten miscarriages. It was only the chance reading of a newspaper article by her husband that led to her giving up coffee. Her eleventh pregnancy was successful.

The UK Committee on Toxicity of Chemicals in Foods, Consumer Products and the Environment confirmed anecdotal evidence that the daily intake of 300 milligrams of caffeine whilst pregnant can cause low birthweight and even miscarriage. 300 milligrams is the equivalent of four small cups or three mugs of instant coffee, three small cups of brewed coffee, six cups of tea, three cans of energy drink (such as 'Red Bull') or six 50 gram bars of chocolate.

A multi-centre European study into the relationship between caffeine intake and fertility established that women taking over 500mg of coffee a day take longer to conceive after contraception has been stopped (planned pregnancies). In all five countries involved coffee was the main source of caffeine and smoking increased the delay.

The researchers cautioned that:

• the problem could be caused by the cofee or the smoking or an interaction between the two, or

• coffee drinking may simply be a marker for a stressful lifestyle and that the stress may be more significant than the coffee

Norwegian research may explain the link. Making allowances for coffee drinkers' increased tendency to smoke and reduced tendency to eat green vegetables, the study discovered that heavy coffee drinkers had significantly higher levels (18.4% men, 28.9% women) of the chemical homocysteine in their blood plasma. Heavy smokers with high coffee intakes had particularly high levels.

Homocysteine is linked with heart disease and problems in pregnancy.