In fact, caffeine is the short name for a much more complex chemical molecule. In addition to being the most active ingredient in tea and coffee, it is also found in caffeine, cola drinks, chocolate and some medicines. Caffeine is known to be effective in pain relievers, cardiovascular diseases and nervous system diseases.

There are 11 milligrams of caffeine in a 100 milliliter cup of tea, and 41 milligrams in a 100 milliliter cup of coffee.

In an average and healthy individual, the effect of caffeine starts at roughly 250 milligrams and above, and there is no known harm in consuming up to 400 milligrams per day. Caffeine in moderation has many benefits. However, studies have shown that caffeine consumption during pregnancy shortens the baby's height.

A new study published in JAMA Network Open says that children exposed to small amounts of caffeine in the womb are on average shorter than those who do not.

The authors of the study; “Reductions were evident even at levels of caffeine consumption below the clinically recommended 200mg daily guidelines. The clinical significance of this height difference is uncertain and warrants future research."

Slightly lower sizes were recorded, beginning at age 4 and increasing by age 8, "converging to a difference of 0.68 to 2.2 cm," the study says.

Perinatal epidemiologist, PhD, lead author Jessica L. Gleason told CNN; "To be clear, these are not big differences in height, but there are these small size differences between children of people who consumed caffeine during pregnancy," she said.

Gleason said the differences found in the study were revealed in children whose mothers drank less than half a cup of coffee a day while pregnant.