quadruplets
Quadruplets are four offspring produced in a single pregnancy. They can occur when four eggs are fertilized by sperm, producing four genetically distinct children (four dizygotic or fraternal siblings). In rare cases, identical or monozygotic quadruplets arise when a single zygote splits into four, or when two zygotes each split into two, yielding two pairs of identical twins. Because of the different possible zygosities, quadruplets may be entirely fraternal or include one or more identical pairs.
Quadruplet pregnancies are uncommon in spontaneous conceptions but are more frequent with fertility treatments such as
Quadruplet pregnancies carry higher risk for mother and babies. They are usually carried to earlier gestational
Long-term outcomes vary with the degree of prematurity and associated conditions. Many quadruplets who survive infancy