According to a study published in the American Journal of Clinical Nutrition, Pregnant women who consume caffeine- whether it's in the form of coffee or tea, have smaller babies as compared to those who abstain from the stimulant during pregnancy. Even women who took in less than 200 milligrams of caffeine, the safe cut-off during pregnancy, according to the researchers, had significantly increased risk of delivering prematurely or having a low-birthweight baby. Based on the consistent associations the researchers observed, and because many pregnancies are unplanned, they recommend women who are pregnant or seeking to become pregnant to at least limit their intake of caffeinated coffee and tea.
The study, as per the researchers, cannot study the cause and effect. But several previous studies have linked coffee exposure in the womb to negative effects. In most of those studies, coffee was the main caffeinated beverage consumed. For this study, the team of researchers looked at 941 mother-child pairs born in Ireland, where people drink more tea than coffee. Nearly half of the mothers in the study drank tea, while about 40 percent drank coffee.
Every additional 100 milligrams of caffeine consumed daily during the first trimester of pregnancy was associated with a 72-gram lower birth weight, as well as significantly lower gestational age, birth length and head circumference. Women who took in the most caffeine had babies weighing about 170 grams less than those who consumed the least, the researchers found. Whether the caffeine came from coffee or tea made no difference to the results.
So what impact does coffee have on the womb? According to the researchers, high caffeine intake could result in restricted blood flow in the placenta that may subsequently affect foetal growth. Caffeine can also cross the placenta readily, and because caffeine clearance slows as pregnancy progresses, caffeine accumulation may occur in foetal tissues.
Make sure you consume lesser caffeine, or if you wish to consume, consult your doctor as to how many cups you can drink per day.