¿Cómo se FORMA un EMBARAZO GEMELAR? | EMBRIOLOGÍA HUMANA 📚

Gemelar Pregnancy Types and Characteristics

This section discusses the occurrence of twin pregnancies, detailing the two main types: dizygotic (fraternal) and monozygotic (identical) twins.

Dizygotic Twin Pregnancy

• Dizygotic twins result from two separate eggs fertilized by different sperm.

• Each zygote develops independently, potentially leading to separate placentas, amniotic sacs, and chorions.

• Dizygotic twins share about 50% of their genetic material and can be of different sexes.

Monozygotic Twin Pregnancy

• Monozygotic twins originate from a single fertilized egg that splits into two embryos.

• These twins are genetically identical, sharing 100% of their genetic material and are typically of the same sex.

• Depending on when the split occurs, monozygotic twins can have various placental and amniotic configurations.

Monozygotic Twin Pregnancy Division Patterns

This section delves into the different division patterns in monozygotic twin pregnancies.

Early Division

• Early division occurs between days two to four post-fertilization resulting in separate placentas, chorions, and amniotic sacs if implantation is distant.

Intermediate Division

• Intermediate division happens between days five to eight post-fertilization where the embryo blastocyst divides within itself. Twins share a placenta but have separate amniotic sacs.

Late Division

• Late division is rare (1-3% cases) occurring between weeks two to three post-fertilization. Twins share a placenta, chorion, and amnion which poses a higher risk for complications like conjoined twins.