FETAL WEIGHT AND VARIABILITY IN YOUNG ADULT AND AGED PREGNANT MICE
The influence of maternal aging on the reproductive function, especially on the fetal growth, was studied in compairing the number of ova per ovulation, implants and of live fetuses, and the fetal weights on 17th day of pregnancy and their variances, in young adult and aged female mice of CFW strain. It was revealed that the maternal aging not only reduced the number of ova per ovulation and implants and the fetal live rate but diminished the fetal growth. It was also shown that the remarkable increase of the variance of fetal weight in aged pregnant mice and this was principally owing to the enlargement of the within-litter variation. The increase of the embryonic mortality, slow fetal growth and the enlarged within-litter variation of fetal weight in the aged female mice suggested that the maternal environment of the aged pregnant females must be less comfortable than it of young adult pregnant females. And therefore the maternal aging seemed to intensely influence on the maternal environment for fetuses.