Objective: To describe a case of monozygotic triplet pregnancy following egg donation and the transfer of a single frozen-thawed embryo.
Design: Case report.
Setting: District general hospital and regional department of fetal medicine in northeast England.
Patient(s): A 38-year-old woman with a 2-year history of primary infertility due to severe endometriosis and poor ovarian reserve who conceived after egg donation and transfer of a single frozen-thawed embryo.
Intervention(s): Transfer of a single frozen-thawed embryo and delivery of three identical female infants by emergency caesarean section because of preterm labor at 32 weeks' gestation.
Main outcome measure(s): Review of effect of assisted conception on monozygotic twinning rates.
Result(s): Healthy outcome for all three infants.
Conclusion(s): Assisted reproductive treatments may lead to disturbances in zona pellucida architecture and an increase in monozygotic twinning rates. Couples need to be informed of this and the increased risks associated with these pregnancies before they begin with treatment.