Caffeine consumption during pregnancy is associated with a higher risk of childhood overweight

In the Norwegian Mother and Child Cohort Study included a total of 50, 943 mothers recruited from 2002 to 2008 and their children, it was found that pregnant women with average (50–199 mg/day, 44%), high (≥200–299 mg/day, 7%) and very high (≥300 mg/day, 3%) caffeine intakes had an increased risk of their child experiencing excess growth in infancy compared with women with low caffeine intake (<50 mg/day, 46%). There was an association between in utero exposure to caffeine  and higher risk of overweight at age 3 years and 5 years, this association persisted at 8 years, only for very high exposures. The researchers concluded that "any caffeine consumption during pregnancy is associated with a higher risk of excess infant growth and of childhood overweight, mainly at preschool ages." 

Source: 
http://bmjopen.bmj.com/content/8/3/e018895