Dichorionic-Diamniotic Twins (DCDA)

Definition - What does Dichorionic-Diamniotic Twins (DCDA) mean?

Dichorionic-diamniotic (DCDA) twins are a pair of fetuses identified by their separate growth in two individual chorinoic and amniotic sacs (the bag of waters that contains the fetus in the uterus). Eventually, each fetus also has it's own individual placenta.

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 splitting into two (monozygotic twins). Assisted reproductive technologies (ART) greatly increase the chance of becoming pregnant with twins.

FertilitySmarts explains Dichorionic-Diamniotic Twins (DCDA)

In order for dizygotic DCDA twins to develop, two eggs must be present for fertilization. While this does occur naturally, it is rare. However, this type of pregnancy is common with fertility treatments such as intrauterine insemination (IUI) or in vitro fertilization (IVF) when multiple eggs are fertilized and transferred to the uterus. Multiple gestation of two or more fetuses is a common result of both of these treatments.

In order for monozygotic DCDA twins to develop, one fertilized egg, called a zygote, splits into two separate entities in the 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.

While all twins carry a higher level of risk then a singleton pregnancy, DCDA twins are considered a lower risk multiples pregnancy. Because each fetus is contained in it’s own sac, there is a reduced chance of entanglement or cross contamination. However, mother’s pregnant with DCDA twins still face additional pregnancy complications, including preeclampsia, gestational diabetes, or anemia.

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