Growth retardation in offspring of female rats treated with morphine prior to conception.

Treatment of female rats with morphine sulfate for 5(1/2) or 10 days, prior to drug withdrawal for 5 days and subsequent mating, results in retarded growth of offspring. The effect is not present at birth but appears at 3 to 4 weeks of age. It occurs even though offspring are not exposed to morphine in utero or postnatally. It is not eliminated by cross-fostering and is apparently of prenatal origin