What Does Dichorionic-Diamniotic Twins (DCDA) Mean?
Dichorionic-diamniotic (DCDA) is a twin pregnancy where each fetus has its own placenta and amniotic sac. This means that each embryo has its own individual chorion (the outer membrane that develops into the placenta) and amnion (the inner membrane that fills with amniotic fluid and becomes the amniotic sac).
DCDA twins most frequently occur when two eggs are fertilized by two sperm simultaneously (dizygotic twins), but may also be caused by a single zygote (fertilized egg) splitting into two (monozygotic twins).
Assisted reproductive technologies (ART) can increase the chance of becoming pregnant with twins.
Of all twin pregnancies, DCDA twins have the lowest rate of complications.
FertilitySmarts Explains Dichorionic-Diamniotic Twins (DCDA)
There are two types of DCDA twins: Dizygotic (fraternal) and monozygotic (identical) twins.
Dizygotic DCDA twins
For dizygotic DCDA twins to develop, two eggs must be present for fertilization. Dizygotic twins are two separate fertilized eggs. While this type of twin pregnancy may occur naturally, it is rare. However, it can be more common with fertility treatments such as intrauterine insemination (IUI) or in vitro fertilization (IVF) when multiple eggs are either present (as in the case of IUI) or fertilized and transferred to the uterus as embryos (as occurs in IVF).
Multiple pregnancies with two or more fetuses are a common result of both of these treatments.
Monozygotic DCDA twins
For monozygotic DCDA twins to develop, one fertilized egg, called a zygote, splits into two separate entities 1-4 days following fertilization. This treatment also occurs naturally and may be impacted by other variations of ART. However, it is a rarer occurrence, particularly with DCDA twins.
Complications with DCDA twins
While all twins carry a higher level of risk than a singleton pregnancy, DCDA twin pregnancy is considered to be a lower-risk multiple pregnancy. Because each fetus is contained in its own sac, there is a reduced chance of entanglement or cross-contamination.
However, a woman pregnant with DCDA twins still faces additional pregnancy complications, such as preeclampsia, gestational diabetes, or anemia.