Research Article|Articles in Press

Birth of monozygotic dichorionic twins after a single blastocyst embryo transfer: a case report of genetic determination of zygosity

Open AccessPublished:March 06, 2023DOI:
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      To report a case of monozygotic dichorionic twins after a single cryopreserved blastocyst embryo transfer followed by genetic determination of zygosity postpartum.


      Case report


      University hospital.


      A 26-year-old female with polycystic ovary syndrome and 36-year-old male partner with severe oligozoospermia resulting in a 1.5-year history of primary infertility.


      Controlled ovarian stimulation and ICSI treatment with single cryopreserved embryo transfer at blastocyst stage.

      Main Outcome Measures

      Ultrasound images of the fetuses and short tandem repeat (STR) genotyping postpartum.


      Dichorionic twin pregnancy following a single cryopreserved blastocyst embryo transfer was confirmed at the first trimester screening. Confirmatory testing performed postpartum included STR analysis determining monozygosity and pathology examination reporting dichorionic placental configuration.


      Dichorionic monozygotic twins are thought to arise from the splitting of an embryo before the blastocyst stage. This case suggests that placental configuration of monozygotic twins may not strictly depend on timing of embryo division. Genetic analysis is the only tool to confirm the zygosity.

      Key Words