Moderate caffeine consumption during pregnancy does not appear to increase the risk of miscarriage or preterm birth.  Committee opinion defines moderate consumption of caffeine as less than 200 mg. per day.  Brewed coffee contains 137 mg. and brewed tea has 76 mg. in 8 ounces.  Caffeinated soft drinks contain 37 mg. in 12 ounces and milk chocolate has 8 mg. per ounce.