- Twinning: nurturing of two conceptuses in the uterus at the same time, giving either dizygotic or monozygotic twins.
Types of Twins
- Dizygotic (fraternal) twins: arise from fertilization of two different oocytes by two different sperms, forming two zygotes that implant as separate blastocysts.
- Dizygotic twins are genetically dissimilar, may be of different sex, and account for about two-thirds of all twins.
- Dizygotic twins usually have separate placenta, chorionic sac and amniotic sac each, though the two placentae may fuse.
dizygotic twins, fetal membranes Dizygotic twins, fetal membranes.