As the popularity of in-vitro fertilization (IVF) continues to rise, twin pregnancies have become more common in recent years, despite the majority still being the result of natural fertilization. Nonetheless, it is important to acknowledge that there are notable distinctions between singleton and twin pregnancies, starting from the moment of conception all the way through delivery. Both the mother and babies are at an elevated risk of encountering additional complications, necessitating heightened monitoring throughout the entire process.
Fraternal Twins
Fraternal twins, also known as dizygotic twins, are the result of two separate sperm fertilizing two separate eggs that implant at the same time. Unlike identical twins, pregnancies with fraternal twins have two placentas and two amniotic sacs. From a genetic standpoint, these twins are no more similar in appearance than siblings born years apart and can be of the same or different sexes.
Understanding Identical Twins
Identical twins are a fascinating phenomenon that occurs when a single sperm fertilizes a single egg. During this process, the egg splits, and each half develops into a baby that is genetically identical to the other. It is worth noting that identical twins are always of the same sex.
Depending on the timing of the egg split and implantation, each fetus may develop its own placenta and amniotic sac, or they may share one or the other. Both scenarios, sharing a placenta and having separate amniotic sacs, as well as the opposite, pose an increased risk.