A reproduction/teratology study of brewed and instant decaffeinated coffees.

Sprague-Dawley rats of both sexes were given, in place of their drinking water, full-strength or 50 or 25% dilutions of either brewed or instant decaffeinated coffees for about 6 mo from weaning. These levels are equivalent to the human consumption of about 50, 25, or 12 cups of coffee per day. Controls were given either distilled water, or full-strength or a 25% solution of regular brewed coffee. The rats were bred twice after 91 d to assess reproduction and teratogenicity. The parent animals given decaffeinated coffees and 100% regular coffee drank less than the rats given water, while the rats given 25% regular coffee drank more. No effects on body weight gain or feed efficiency were seen, except that the group given 100% regular coffee gained significantly less weight than the water controls. None of the coffee treatments had a significant effect on reproductive characteristics such as conception rate, number born, or number weaned. During the second pregnancy, no significant effects from the coffee treatments were seen on early embryotoxicity measured in dams sacrificed on d 13 of pregnancy or fetal toxicity in dams sacrificed on d 21. No significant fetal abnormalities due to any of the coffee treatments were observed in either soft-tissue or skeletal examinations, although there was a significant increase in unossified sternebrae in the fetuses from dams given the full-strength regular coffee.