Maternal age related pre- and post-implantation fetal mortality: a strain survey

Pre and post-implantation mortality were examined as a function of maternal aging in six inbred mouse strains. These strains were chosen to evaluate the effects of altered immunity (A/J and NZB/J) and premature reproductive aging (CBA). The decline in litter size observed with maternal aging does not appear to be the result of a decrease in the number of ova produced. The frequency of both pre- and post-implantation mortality increases with maternal age in all strains examined. Although the highest levels of pre- and post-implantation mortality were found in the NZB/J strain, which features altered immune responses, results from the A/J females, which also display immune dysfunction were at the other end of the spectrum. Thus, no consistant relationship was seen between altered immune function and fetal mortality. The CBA strain which is characterized by premature reproductive decline and marked maternal age-related fetal aneuploidy also demonstrated high levels of pre- and post-implantation mortality, even in the young maternal age range.