David Baxter PhD
Late Founder
New study shows how caffeine might prevent pregnancy
By Sharon Kirkey, Ottawa Citizen
May 25, 2011
Women trying to conceive should consider quitting coffee cold turkey, according to a study researchers believe explains for the first time why caffeine makes it harder to make babies.
The team discovered that caffeine prevents smooth muscles in the Fallopian tubes from contracting ? and it's those slow, rhythmic contractions that shuttle eggs down the tubes, from the ovaries to the womb.
Numerous studies have linked caffeine consumption to delayed conception. One study found that women who drink more than 300 milligrams of caffeine a day ? the amount found in a little more than two eight-ounce (237-millilitre) cups of brewed coffee ? have a 27 per cent lower chance of getting pregnant in every given cycle, compared to women who don't consume caffeine.
Reporting this week in the British Journal of Pharmacology, researchers from the University of Nevada School of Medicine in Reno found that caffeine had a profound effect on muscle activity in the Fallopian tubes "in concentrations well within what people are drinking," said Sean Ward, a professor of physiology and cell biology.
The finding might help scientists better understand how Fallopian tubes work generally, information that could lead to new treatments for tube-damaging conditions such as chlamydia, the most common bacterial sexually transmitted infection in Canada.
It might also open new insights into ectopic pregnancies ? a medical emergency in which a fertilized egg gets stuck and implants inside a woman's Fallopian tube.
"Caffeine has been reported to be 'the most frequently ingested pharmacologically active substance in the world,' " Ward's team wrote in this week's edition of the British Journal of Pharmacology.
It's long been thought that the egg is transported along the "oviduct," or Fallopian tubes, to the uterus by the wafting of the beating of millions of microscopic hairlike projections called cilia in the ling of the tubes. The cilia, it was believed, propel the eggs towards the womb.
But, in experiments in mice, when Ward's group used inhibitors to stop the smooth muscles in the tubes from contracting, the eggs stopped moving ? even though the cilia kept on beating.
The "beauty" of studying tubes from mice, Ward said, is that the walls are translucent. "You can actually see the eggs inside the wall of the oviduct."
Next the team found that caffeine turns off special "pacemaker" cells that drive the muscle contractions.
The mouse Fallopian tube was exceptionally sensitive to caffeine, Ward said ? even more so than other smooth muscles, including those in the gastrointestinal tract.
However, one world leader in ovarian physiology cautioned that the study was done in mice, and not women.
"We have to be very careful about making huge species leaps from work done in mice to assuming that the same thing happens in humans," said Roger Pierson, a professor of obstetrics and gynecology at the University of Saskatchewan. "But this is really quite an intriguing idea. It makes good physiological sense and bears further investigation."
Ward hopes to collaborate with other researchers using tissue taken from women undergoing hysterectomies to determine whether human Fallopian tubes are equally sensitive to caffeine as tubes taken from mice.
Health Canada recommends that pregnant or breastfeeding women, as well as women who are planning to become pregnant, consume no more than 300 milligrams of caffeine per day.
Ward would go further: "I would suggest that if women are trying to get pregnant, they lay off the coffee, and cola as well," he said.
"The effects of caffeine on the oviduct (Fallopian tube) can be quite sustained."
By Sharon Kirkey, Ottawa Citizen
May 25, 2011
Women trying to conceive should consider quitting coffee cold turkey, according to a study researchers believe explains for the first time why caffeine makes it harder to make babies.
The team discovered that caffeine prevents smooth muscles in the Fallopian tubes from contracting ? and it's those slow, rhythmic contractions that shuttle eggs down the tubes, from the ovaries to the womb.
Numerous studies have linked caffeine consumption to delayed conception. One study found that women who drink more than 300 milligrams of caffeine a day ? the amount found in a little more than two eight-ounce (237-millilitre) cups of brewed coffee ? have a 27 per cent lower chance of getting pregnant in every given cycle, compared to women who don't consume caffeine.
Reporting this week in the British Journal of Pharmacology, researchers from the University of Nevada School of Medicine in Reno found that caffeine had a profound effect on muscle activity in the Fallopian tubes "in concentrations well within what people are drinking," said Sean Ward, a professor of physiology and cell biology.
The finding might help scientists better understand how Fallopian tubes work generally, information that could lead to new treatments for tube-damaging conditions such as chlamydia, the most common bacterial sexually transmitted infection in Canada.
It might also open new insights into ectopic pregnancies ? a medical emergency in which a fertilized egg gets stuck and implants inside a woman's Fallopian tube.
"Caffeine has been reported to be 'the most frequently ingested pharmacologically active substance in the world,' " Ward's team wrote in this week's edition of the British Journal of Pharmacology.
It's long been thought that the egg is transported along the "oviduct," or Fallopian tubes, to the uterus by the wafting of the beating of millions of microscopic hairlike projections called cilia in the ling of the tubes. The cilia, it was believed, propel the eggs towards the womb.
But, in experiments in mice, when Ward's group used inhibitors to stop the smooth muscles in the tubes from contracting, the eggs stopped moving ? even though the cilia kept on beating.
The "beauty" of studying tubes from mice, Ward said, is that the walls are translucent. "You can actually see the eggs inside the wall of the oviduct."
Next the team found that caffeine turns off special "pacemaker" cells that drive the muscle contractions.
The mouse Fallopian tube was exceptionally sensitive to caffeine, Ward said ? even more so than other smooth muscles, including those in the gastrointestinal tract.
However, one world leader in ovarian physiology cautioned that the study was done in mice, and not women.
"We have to be very careful about making huge species leaps from work done in mice to assuming that the same thing happens in humans," said Roger Pierson, a professor of obstetrics and gynecology at the University of Saskatchewan. "But this is really quite an intriguing idea. It makes good physiological sense and bears further investigation."
Ward hopes to collaborate with other researchers using tissue taken from women undergoing hysterectomies to determine whether human Fallopian tubes are equally sensitive to caffeine as tubes taken from mice.
Health Canada recommends that pregnant or breastfeeding women, as well as women who are planning to become pregnant, consume no more than 300 milligrams of caffeine per day.
Ward would go further: "I would suggest that if women are trying to get pregnant, they lay off the coffee, and cola as well," he said.
"The effects of caffeine on the oviduct (Fallopian tube) can be quite sustained."
