What is a twin pregnancy?
A twin pregnancy is a type of multiple gestation since there is development of two fetuses. Twin pregnancy is also known as univetiline pregnancy or monozygotic. In this type of pregnancy, a single egg is fertilized by a sperm, but later there is a division in two.
Therefore, the two fetuses will have the same genetic load and will be of the same sex. In addition, the blood group, hair color and eye color will be identical in both developed fetuses.
Delivery in cases of twin pregnancy usually occurs around week 37 of gestation, since the space in the uterus is less. This also explains why the birth weight of twins is lower than that of other babies.