Scientists say they 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, they found. Previous studies had shown that consuming too much coffee affected female fertility.
Recent research involving 9,000 women found that drinking more than four cups a day cut the chances of conceiving by a quarter. Until now, the reason for the link was a mystery. The new investigation, conducted on mice, showed that caffeine inhibits contractions of the fallopian tubes which are needed to carry eggs to the womb.