If twins are in two different sacks what kind of twins are they?

Question

twin birth

Answer 1

They can be either fraternal or identical. There is a common misunderstanding about this when it comes to identical twins. I'm a father of identical twins and they had separate sacs and separate placentas.

Usually, with identical twins, an egg gets fertilized, attaches to the uterine wall, and THEN splits. So, there is a single attachment point to the uterus, single sac, single placenta, and so on.

That is not always the case, though. If the egg is fertilized, then splits PRIOR to attachment (within four days of development), then there will be two separate attachment points, two separate sacs, two placentas, etc.

There is also the possibility of one attachment point, one placenta, but two separate sacs.

We were clueless about this at first. Since it was a high-risk pregnancy, my wife had several ultrasounds prior to the delivery. We knew early on that there were two placentas and sacs. So, we assumed that the girls were fraternal. One of the ultrasound doctors asked, "Did your amnio tell you if they were identical or not?" Which floored us. At first we thought maybe he wasn't paying attention to the clearly visible line between our girls, so we politely said, 'they're in two sacs'. He said, 'I know. I can see that. But that doesn't necessarily mean they are fraternal.' And he went on to explain the whole thing. In fact, up to a third of identical twins can have separate sacs.

It was too late to get the amnio tests redone, and we didn't care that much about it at the time since they could be safely tested later.

After they were born we had a DNA test done and it confirmed they are identical.

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Here's some of the technical jargon about identical twins, sacs, and placentas.

Identical twins can have the same or separate amniotic sacs. Depending on the stage at which the zygote divides, identical twins may share the same amnion (in which case they are known as monoamniotic) or not (diamniotic).

Identical twins can have the same or separate placentas. Diamniotic identical twins may share the same placenta (known as monochorionic) or not (dichorionic). All monoamniotic twins are monochorionic.

Therefore, there are three different types of identical (monozygotic) twins:

(same placenta, same sac) monochorionic-monoamniotic
(same placenta, separate sacs) monochorionic-diamniotic
(separate placentas, separate sacs) dichorionic-diamniotic

Answer 2

I am the mother of identical twins and I've done some research on this topic. Twins in separate sacks can be identical or fraternal. Fraternal twins will always come in separate sacks. Identical twins sometimes come in the same sack but mostly they come in separate sacks. It depends on when they embryo splits. It is actually very dangerous for both babies to be in the same sack as there is a high risk of them becoming tangled in the umbilical cords.

Here is just a quick rundown:
Fraternal twins come from two eggs and two sperm, have two sacks and two placentas ALTHOUGH sometimes those placentas may fuse and appear to be one. They have different dna and can be the same or different sexes.

Identical twins come from one egg and one sperm. THey can have :one sack and one placenta; two sacks and one placenta OR two sacks and two placentas, depending on when the embryo splits. The later it splits, the more likely they are to be in the one sack. Conjoined twins split later than other identical twins and have the same sack. Identical twins have the same DNA and will always be the same sex.

For the record, my identical twins had two sacks and one placenta.

Answer 3

Fraternal twins are two different sacks. Identical twins are the same sack. Check out the link below.

Answer 4

Yes, it's rare but it can happen. There was a well-known case in the news a few years ago about a woman taking fertility treatments. The facility collected her husband's sperm in a container that had been previously used, and had not been properly washed. After the woman was inseminated with her husband's sperm from this container she became pregnant, and found out it was twins. What a shock it was almost 9 months later when one twin was white and the other black. They did DNA tests and found the black twin's father was the husband of a different woman using the same facility for fertility treatments. It was a sad case and there was a custody battle between the two couples, but I can't remember which couple got to keep the baby.

Answer 5

Fraternal twins. Identical twins share the same sack. Good luck if it's for you!

Answer 6

Fraternal twins are in two separate sacks.

Answer 7

Fraternal twins, meaning they developed from separate eggs. Identical twins develop when a single egg divides into two separate human being. :o)

Answer 8

Fraternal. I have had 2 sets of twins.

Answer 9

i believe that they came from two seperate eggs that some women produce during their mens. cycles - this will make them fraternal twins not identical twins.

Answer 10

Fraternal twins are created when two separate eggs are fertilized by two separate sperm.