Caffeine has long been on the list of substances that women who are pregnant should not consume. Regardless of the source, be it coffee, soft drinks, or even hot chocolate, caffeine has seemingly always been associated with pregnancy problems. For years though, studies that looked at the impact of caffeine on a woman’s body during pregnancy failed to account for several variables and symptoms that often disguised the true effects of caffeine on a pregnant woman’s body, in particular as its effects relate to miscarriage.

Recently, a study conducted by Kaiser Permanente successfully controlled for these variables, specifically nausea, vomiting, and caffeine aversion, and successfully found a considerable link between caffeine and miscarriage. Unlike previous studies, the once conducted by Kaiser successfully controlled the factors that inspire women to avoid caffeine during pregnancy. As a result, the long-suspected correlation between caffeine and miscarriage was strengthened, especially since it has long been speculated that any correlation was the result of reduced caffeine consumption.

In looking at more than one thousand members, Kaiser found that women who consumed more than 200 milligrams of caffeine or more a day actually increased their risk of miscarriage. This amount, which represents about two cups of coffee or five cans of soda, made consumers twice more likely to miscarry than women who did not consume caffeine during their pregnancy.

By considering other sources of caffeine, including soft drinks, tea, and hot chocolate, researchers were able to establish that the increased risk of miscarriage were in fact due to the consumption of caffeine and not to any other sources. For years, the association between caffeine and miscarriage had been related to caffeine avoidance on the part of healthy women. However, the study clearly indicates that for pregnant women, or women looking to become pregnant, the consumption of caffeine should definitely be eliminated or avoided during pregnancy, especially if they want to avoid a potential miscarriage.

Researchers have long looked at the specifics of how caffeine can affect a developing fetus, and the answers are relatively simple. Caffeine can actually cross from the placenta to the fetus, and when it enters the body, the fetus and its underdeveloped metabolism are not able to break down the caffeine the way adults and older children can. In addition, caffeine might also play a role in improper cell development and a lack of blood flow to the placenta, both of which can increase the risk of miscarriage.

Despite the potential for miscarriage, researchers understand that oftentimes, women who are pregnant need a way of fighting the stress and fatigue that often come with a pregnancy. Their recommendation is to limit the intake of caffeine to no more than a cup or less a day, though they again stress that caffeine should be avoided altogether. One Kaiser representative encouraged women to seek other methods of cheering up and fighting stress, including walking, doing yoga, or snacking on healthy dried fruits.