Consuming large amounts of caffeinated beverages may lower female fertility, US research indicates. This is because caffeine interferes with the transport of eggs in the fallopian tubes, according to an article in the British Journal of Pharmacology.
Caffeine is considered to be the most consumed substance in the world with pharmacological activity. The main sources of caffeine in our diet are coffee, tea, carbonated drinks (such as cola), chocolate and various dietary supplements.
As the authors of this latest study point out, several studies conducted in the 90s showed that there is a link between caffeine consumption and delayed pregnancy. For example, a European study of women aged 25-44, published in 1997 in the American Journal of Epidemioilogy, found that ladies consuming 501 mg of caffeine per day (which is as much as half a liter of strong coffee can contain) or more waited for slightly longer to get pregnant for the first time than women who do not consume caffeinated products. On the other hand, an American study published in the same journal in 1993 showed that the consumption of more than 300 mg of caffeine per day was 27 percent. lowers the chances of getting pregnant in one monthly cycle.
A gradual decline in fertility, directly proportional to the amount of caffeine consumed, was also observed in a study on non-smoking women, which was published in 1998 in the journal Reproductive Toxicology.
The latest experiments on mice by scientists at the University of Nevada’s Faculty of Medicine explain why this is so.
The mature egg is released into the fallopian tube during ovulation. Its fertilization by sperm occurs most often in the part of the fallopian tube called the bulb. But whether the egg is fertilized or not, it still travels towards the uterus. This is possible due to the movement of the cilia on the cells lining the fallopian tube and the contractions of its smooth muscles.
The rhythmic contractions of the fallopian tubes are generated by free electric waves produced by the so-called Cajal interstitial cells (also found in the intestinal walls). Research has shown that this mechanism also functions in human fallopian tubes.
By conducting experiments on fallopian tubes collected from mice, scientists from the University of Nevada observed that caffeine inhibited the activity of Cajal cells in the wall of the fallopian tube (by activating the so-called ATP-regulated potassium channels). As a result, these cells do not produce electric waves and do not cause rhythmic contractions of the smooth muscles of the fallopian tube.
The researchers explain that this means that caffeine can slow down or block the transport of eggs in the fallopian tube and thus reduce fertility because fertilized eggs do not reach the uterus in a timely manner.
– Our experiments were conducted on mice, but they may be a step towards explaining the causes of delayed pregnancy in women who drink large amounts of caffeinated beverages – comments Prof. Sean Ward. (PAP)