Objective: 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.
Design: Retrospective analysis.
Setting: University-based IVF center.
Patient(s): Two thousand fourteen consecutive IVF pregnancies with documented fetal cardiac activity.
Main outcome measure(s): Miscarriage rates and karyotypes of pregnancy losses were analyzed.
Result(s): 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).
Conclusion(s): 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.