Recent news about caffeine, pregnancy and miscarriage is kind of confusing. A complex study from the National Institutes of Health and Ohio State University linked couple’s consumption of more than two caffeinated beverages a day to a risk of miscarriage. Just to be safe, women trying to conceive and pregnant women should limit caffeine intake.
A press release from the NIH says that the study did not attempt to prove a cause-and-effect link.
The press release seems pretty straightforward:
A woman is more likely to miscarry if she and her partner drink more than two caffeinated beverages a day during the weeks leading up to conception … Similarly, women who drank more than two daily caffeinated beverages during the first seven weeks of pregnancy were also more likely to miscarry.
However, women who took a daily multivitamin before conception and through early pregnancy were less likely to miscarry than women who did not. The study was published online in Fertility and Sterility.
For the current study, researchers compared such lifestyle factors as cigarette use, caffeinated beverage consumption and multivitamin use among 344 couples with a singleton pregnancy from the weeks before they conceived through the seventh week of pregnancy.
Contrast that with a report from Slate.com that states: “Don’t be fooled by the scary reports that drinking caffeine before conception causes miscarriages. There is zero evidence to suggest that women (or men, for that matter) need to give up caffeine before or while they’re expecting. If caffeine and miscarriages are causally related—and that’s still a big if—then the risk seems to apply only to women who drink more than two caffeinated drinks per day. If you want to be extra cautious while you’re expecting or trying to conceive, sure, forgo some of the caffeine you might normally have.
Just to be safe, The American Pregnancy Association states: “Due to conflicting conclusions from numerous studies, the March of Dimes states that until more conclusive studies are done, pregnant women should limit caffeine intake to less than 200 mg per day. This is equal to about one 12 oz cup of coffee.”
The researchers in the new study used a hazard ratio, a statistical concept that estimates the chance of a health outcome. In this study, a score of less than 1 indicated a reduced risk for a miscarriage when caffeine is taken daily, and more than 1 indicates an increased risk for pregnancy loss.
There were 344 pregnancies in the study population, 98 of which ended in miscarriage. Women age 35 or above had a miscarriage hazard ratio of 1.96, almost double the risk of younger women. The press release explains:
The study authors cited possible explanations for the higher risk, including advanced age of sperm and egg in older couples or cumulative exposure to substances in the environment, which could be expected to increase as people age.
Both male and female consumption of more than two caffeinated beverages a day also was associated with an increased hazard ratio: 1.74 for females and 1.73 for males. Earlier studies, the authors noted, have documented increased pregnancy loss associated with caffeine consumption in early pregnancy. However, those studies could not rule out whether caffeine consumption contributed to pregnancy loss or was a sign of an unhealthy pregnancy. It’s possible, the authors wrote, that these earlier findings could have been the result of a healthy pregnancy, rather than caffeine consumption interfering with pregnancy. For example, the increase in food aversions and vomiting associated with a healthy pregnancy led the women to give up caffeinated beverages.
Because their study found caffeine consumption before pregnancy was associated with a higher risk of miscarriage, it’s more likely that caffeinated beverage consumption during this time directly contributes to pregnancy loss.
“Our findings also indicate that the male partner matters, too,” Dr. [Germaine] Buck Louis said. “Male preconception consumption of caffeinated beverages was just as strongly associated with pregnancy loss as females’.”
There was some good news in the study, however, because the researchers found that there was a reduce risk of miscarriage if women took a daily multivitamin. During the time before conception, the hazard ratio was only 0.45—what the press release calls “a 55-percent reduction in risk for pregnancy loss. Women who continued to take the vitamins through early pregnancy had a hazard ratio of 0.21, or a risk reduction of 79 percent.”
The researchers’ article cites other studies that found taking vitamin B6 and folic acid reduces the risk of miscarriage.
Slate.com says it’s possible the higher risk of miscarriage among the study’s subjects was because higher caffeine intake is associated with risky behaviors such as drinking and smoking. Scientists are pretty certain smoking cigarettes and drinking alcohol carry a risk for miscarriage, low birth-weight babies and even birth defects.
If you’re a couple trying to conceive, the U.S. Centers for Disease Control has a pretty comprehensive Web package called Preconception Health and Health Care.
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Some research has suggested that caffeine may stimulate thermogenesis - a scientific name for the way your body generates heat and energy from the calories in your food; but nutrition experts say that this effect probably isn't enough to produce significant weight-loss. Caffeine may also reduce your desire to eat for a brief time, but again, there's no good evidence over the long-term that this effect leads to weight-loss. To date, no conclusive clinical studies have been done to determine the long-term effect of caffeine on weight loss, and the smaller studies that have been done show a lot of variability in the outcomes.
Want to hear something shocking?
Having your caffeine fix first thing in the morning will NOT perk you up.
But the good news is, you no longer need to make that sluggish early morning trip to the coffee-maker daily, nor join that long rush hour queue in your go-to café.
If you’re wondering whether we’re pulling some sick April Fool’s joke in the middle of August, there’s actually scientific evidence to all of this.
If you’re trying to lose weight (or at least not gain a few extra pounds), then the best thing to do is eat healthy and go to the gym more religiously, right?
But if you’ve been going at it for a while now and haven’t been seeing much progress, then you may want to look into something else.
Like your coffee consumption.
Now you may ask: what does an innocent cup of joe have to do with weight gain?
Let me tell you.
It’s not as innocent as it seem.
That cup of coffee you buy on your way to work? It may be sneaking in a few extra calories (more than you’d like and expect). And if you buy more than one cup a day, you may be racking up a few calories from a “dessert” that disguises itself as your go-to caffeine fix.