A–Z Glossary

Amnionicity

A description of whether twins share one amniotic sac or have separate sacs.

← Back to A–Z Glossary

Search results for: Amnionicity

Identical vs fraternal twins differences

Identical vs fraternal twins differences

The basic biology behind twin types Twin pregnancy begins in one of two broad ways. In a monozygotic pregnancy, a single egg is fertilized by a single sperm, creating one zygote. That early embryo then splits into two separate embryonic lines, which develop into identical twins. In a dizygotic pregnancy, two eggs are released in […]