Earlier reports have associated the maternal consumption of caffeine with spontaneous abortions and stillbirths in women who consumed an equivalent to six or more cups of coffee a day during pregnancy and cleft palates, heart defects, and other congenital anomalies if eight or more cups of coffee were consumed. However, all of these studies have since been identified as having statistical flaws.
The most consistent finding regarding caffeine consumption during pregnancy was the possible association with low birth weights. Low birth weights and short gestations were associated with women who consumed four to seven or more cups of coffee or greater than 300 milligrams of caffeine daily. However in one study, no relationship between caffeine consumption and low birth weights was identified after controlling for smoking, alcohol, and demographic factors.
Two studies have suggested the possibility that drinking three or more cups of coffee/day during first month of pregnancy may be a distinct risk factor for miscarriage.
Neonatal withdrawal symptoms following chronic caffeine ingestion during pregnancy have been reported. In one study, when maternal caffeine ingestion ranged from 200 to 1800 milligrams daily (equivalent to approximately 2 to 18 cups of coffee daily), withdrawal symptoms (tremulousness, irritability and vomiting) were observed in newborns. All symptoms generally resolved spontaneously within seven days, and development was considered normal at 9 to 18 months of age in seven of eight infants.