Heteropaternal superfecundation is a rare event where dizygotic twins are conceived by different fathers. This occurs when two separate oocytes, released during the same menstrual cycle- occasionally due to induced hyperovulation- are fertilized by sperm cells from different individuals through separate sexual acts within a short timeframe.

Gestational surrogacy, commonly referred to as “surrogate motherhood,” is an assisted reproductive technology in which a woman carries and delivers a child on behalf of another individual or couple, with no intention of assuming parental responsibilities after birth. In Colombia, this practice has experienced significant growth largely driven by the absence of comprehensive legal frameworks.

We identified a case of heteropaternal superfecundation within a surrogate motherhood case. Following the assisted reproduction technology, a twin pregnancy was confirmed. Following the conclusion of pregnancy, DNA testing was carried out-with prior informed consent- in order to confirm paternity and to exclude biological maternity, by STR analysis (Powerplex fusion). Surprisingly, the paternity inclusion and maternal exclusion was confirmed for one neonate. However, for the second neonate, the maternity was confirmed and the paternity was excluded.  

Despite the contractual prohibition of sexual intercourse during the surrogacy process, and due to the fact that the surrogate mother did not participate as an oocyte donor, she admitted having contact with two other individuals prior to the assisted reproduction procedure. Upon obtaining consent and analyzing DNA samples from these individuals, paternity for the second neonate was confirmed with one of them. Notably, although these newborns share the same womb, they lacked any biological relationship; they originated from two distinct oocytes, one from the surrogate mother and one from a donor, fertilized by sperm cells from two different biological fathers, one of them by IVF and embryo transfer (from the commissioning father) and the second by sexual intercourse.

To our knowledge, this is the first case of twin pregnancy due to heteropaternal superfecundation during a gestational surrogate motherhood case worldwide, where the newborns had no biological relationship among them.

Keywords

Heteropaternal Superfecundation, Surrogacy, Surrogate Motherhood, Assisted Reproduction, In vitro fertilization (IVF)

Authors

• Juan Yunis (Servicios Médicos Yunis Turbay y Cia SAS, Colombia)
• Giselle Cuervo (Servicios Médicos Yunis Turbay y Cia SAS, Colombia)
• Angie Luna (Servicios Médicos Yunis Turbay y Cia SAS, Colombia)
• Luis Mogollon (Servicios Médicos Yunis Turbay y Cia SAS, Colombia)
• Adriana Alayon (Servicios Médicos Yunis Turbay y Cia SAS, Colombia)
• Yesica Pinzon (Servicios Médicos Yunis Turbay y Cia SAS, Colombia)
• Luz Karime Yunis (Servicios Médicos Yunis Turbay y Cia SAS, Colombia)