Why coffee can hinder conception

Scientists may have discovered why drinking coffee makes it harder for women to conceive.

Caffeine, the stimulant in coffee, impairs the transport of eggs from the ovaries to the womb, a study has found. Previous research had already shown that consuming too much coffee can affect female fertility. One study of 9,000 Dutch women found that drinking more than four cups a day cut the chances of conceiving by about a quarter.

But until now the reason for the link had remained a mystery.

The new study, conducted on mice, showed that caffeine inhibits contractions of the Fallopian tubes which are needed to carry eggs to the womb. The stimulant de-activates specialised pacemaker cells in the walls of the tubes.

These cells co-ordinate waves of tube contractions which move the eggs towards the womb.

The research suggests the contractions play a bigger role in egg transport than the beating hair-like cilia that line the walls of the Fallopian tubes. Previously it was thought the reverse was the case. Study leader Sean Ward, pro9fessor at the University of Nevada in Reno, US, said: “This finding goes a long way towards explaining why drinking caffeinated drinks can reduce a woman’s chance of becoming pregnant.”