Sex‐discordant twins despite single embryo transfer: a report of two cases

Abstract

We report two extremely rare cases in which the patients delivered male and female infants that were dizygotic twins (DZT) despite single embryo transfer. : The patient was a 35-year-old woman with a 9-year history of unexplained infertility. In an oocyte retrieval cycle, one blastocyst was transferred; at 26 weeks of gestation, she delivered a 704-g female infant and a 420-g male infant by cesarean section. Because both infants were of extremely low birth weight, they were placed in the neonatal intensive care unit. Congenital anomalies were not found in either infant.: The patient was a 30-year-old woman with a 1-year history of infertility. Hysterosalpingogram revealed bilateral tubal occlusion. In a frozen/thawed cycle one blastocyst was transferred during her natural ovulation cycle. She achieved a pregnancy and delivered a 2,877-g female infant and a 2,544-g male infant at 36 weeks of gestation by cesarean section. The female infant was diagnosed with a neural tube defect. No congenital anomalies were detected in the male infant. We hypothesize that the DZTs might have been the result of concurrent embryo transfer and natural ovulation and intercourse.

Comparisons of pregnancy outcomes between twin pregnancies with and without second‐trimester amniocentesis

“…The latest report found that 10 in 13 set of monochorionic twin had discordant karyotype results 14 . Furthermore, a certain amount of discordant aneuploidy have been reported which most of them involved with sex chromosome 15‐18 . In our center, either monochorionic or dichorionic twins receive amniocentesis by double puncture technique for each sac.…”

The Precise Timing of Embryo Splitting for Monozygotic Dichorionic Diamniotic Twins: When Does Embryo Splitting for Monozygotic Dichorionic Diamniotic Twins Occur? Evidence for Splitting at the Morula/Blastocyst Stage From Studies of In Vitro Fertilization

“…Monozygotic twinning with blastocyst transfer is typically monochorionic, resulting from the division of the ICM within a single trophectoderm (Chida, 1990; Milki et al, 2001; Mio, 2008). When we diagnose DD twins under ultrasonography at 7–11 weeks gestation, we must discriminate between (1) monozygotic DD twins (two half-blastocysts, both with ICM and trophectoderm components from a SET), (2) dizygotic DD twins (a SET with a natural pregnancy: Kyono et al, 2009; Sugawara et al, 2010; Van der Hoorn et al, 2011), and (3) dizygotic DD twins (a two-embryo transfer). In MD twins, we must discriminate between (1) monozygotic MD twins (a SET) and (2) dizygotic MD twins (dual-embryo transfer: blood chimerism; Hackmon et al, 2009; Kuhl-Burmeister et al, 2000; Machin, 2009; Miura & Niikawa, 2005; Souter et al, 2003; Williams et al, 2004).…”

Should sexual intercourse be avoided during the embryo transfer cycle? Life-threatening ruptured heterotopic pregnancy after single thawed embryo transfer: case report and review of the literature

“…However, only one report described HP after SET. They also found four reports (five cases) [10][11][12][13] of a dizygotic twin pregnancy occurring after SET. These were recognized as such because the babies' sex differed.…”