Dose response to antenatal corticosteroid (AC) exposure in rat offspring.

摘要

The benefits of single course of AC treatment to pregnant woman with risk of preterm delivery are well-established. However, repeated AC courses may impose harmful effects in offspring. The present study was designed to examine the relationship between different doses of AC on postnatal growth in rat offspring. Twenty-four female Wistar rats were mated. The day when vaginal plugs were found was day 1 of pregnancy (P1). On P17, rats were randomly divided into 3 groups and received injections twice/day: Control (CON, n=6) with saline injections for 6 days; moderate (MOD, n=8) with 3 doses of betamethasone (BETA, 2 mg/kg) on P17-P19, saline on P20-P22; and high (HIGH, n=10) with 6 doses of BETA on P17-P22. Delivery occurred on P23-24. The birth weights of 3 groups were in the following order: CON>MOD>HIGH (p=0.08). One litter in CON group (16.7%), 1 in MOD (12.5%) and 2 in HIGH (20%) lost all pups within one week. At weaning, 16.7% of the CON, 37.5% of the MOD and 63.6% of the HIGH litters lost some or all pups. During the pre-weaning period, HIGH pups grew significantly slower than the CON pups (p.01), even with fewer pups per litter, while MOD pup's weights were similar to the other 2 groups. In conclusion, repeated AC treatment impaired pre-weaning growth.