Relationship between maternal age and aneuploidy in in vitro fertilization pregnancy loss.

To determine the fetal loss rate after documented fetal cardiac activity (7-week sonogram) and to evaluate the chromosomal makeup of these losses in IVF pregnancies. Retrospective analysis. University-based IVF center. Two thousand fourteen consecutive IVF pregnancies with documented fetal cardiac activity. Miscarriage rates and karyotypes of pregnancy losses were analyzed. The overall pregnancy loss rate after demonstrated fetal cardiac activity was 11.6% (233/2014). A highly significant increase in fetal loss with advancing maternal age was observed (<30 years = 5.3% vs. 31-34 years = 7.6% vs. 35-39 years = 12.8% vs. > or =40 years = 22.2%). Patients with a multiple gestation were more likely to deliver a live infant, compared with those with a singleton detected at a 7-week sonogram. Of the 233 losses in the study period, cytogenetic analyses were obtained for 74 (31.8%). Three specimens were nondiagnostic. Fifty-two patients had abnormal karyotypes (71.2% [52/71]). Eighty-two percent of the pregnancy losses in women aged > or =40 years were associated with chromosomally abnormal fetuses, compared with 65% of the losses in women aged <40 years (odds ratio, 3.35; 95% confidence interval, 0.96-11.97). Pregnancy loss after documentation of fetal cardiac activity is >10%. This loss is significantly increased with advancing maternal age. The major underlying cause of these losses seems to be chromosomal aneuploidy.