Women who are pregnant with twins sharing a placenta need to be checked more often than women with twins with separate placentas. Frequent checks can pick up early on any potential complications. Twins sharing an inner sac monoamniotic are also at a higher risk of complications during pregnancy because of the chance that their umbilical cords might tangle and cut off their blood supply. These twins are checked even more closely. Medical professionals often recommend that these twins are born earlier than other types of twins.
Medical professionals use ultrasound to work out how many placentas twins have. The earlier the ultrasound, the more accurately it can say how many placentas there are. It gets harder to work out later in pregnancy. After the birth, the placentas should be looked at to confirm or determine what type of twins they are.
Same-sex twins with separate placentas can be fraternal or identical. To find out whether twins are identical or fraternal, you can ask for a genetic test after your babies are born. This is called a zygosity test.
Identical twins are more likely than fraternal twins to get the same illness. If one of a pair of identical twins is diagnosed with a particular disease or health condition, like high blood pressure, the other twin should be checked often for early symptoms. The biological mechanisms that prompt the single fertilised egg to split in two remain a mystery.
Approximately one quarter of identical twins are mirror images of each other, which means the right side of one child matches the left side of their twin.
These babies will be no more alike than siblings born at separate times. The babies can be either the same sex or different sexes, with the odds roughly equal for each. It is proposed that the egg splits in two, and each half is then fertilised by a different sperm. This theory is an attempt to explain why some fraternal twins look identical. Gestation for twins The normal length of gestation for a single baby is around 40 weeks. However, gestation for twins, either identical or fraternal, is usually around 38 weeks.
Since twins are usually premature, they are more likely to have lower birth weights. Prematurity is associated with increased risk of a number of disorders, including jaundice. Giving birth to twins Childbirth can give rise to complications when just one baby is present, so twins present extra potential for difficulties.
It is advised that women carrying twins give birth in hospital, rather than at home. The babies can be delivered vaginally, but caesarean section delivery may be considered a better alternative in some circumstances. Zygosity testing It is difficult to tell if twins are identical or fraternal at birth. Some identical twins may be born with individual sets of membranes, which may lead to the mistaken assumption that the babies are fraternal.
One way to tell the difference is to have the twins DNA-tested. Identical twins share the same genetic information, while fraternal twins share around half. You may be familiar with the most common types of twins — fraternal and identical — but several other rare subtypes exist too. More twins are born than you might think. Read on for more details about twins. The National Library of Medicine says that monozygotic, or identical, twins are conceived from one fertilized egg. This egg separates into two embryos after it has begun to divide.
These two embryos develop into two babies. Genetic materials called chromosomes in both babies are completely identical. This is because both babies come from the same egg and sperm. For this reason, both children are assigned the same sex at birth and share the same genetic characteristics, such as eye and hair color.
Not all twins are identical, of course. More often than not, twins are born with unique physical characteristics. Nonidentical twins are generally known as fraternal twins. A different sperm will fertilize each egg. Since fraternal twins are the result of different eggs and different sperm, they share the same percentage of chromosomes as any other siblings.
Traditionally, the science around twins has taught that identical and fraternal are the only two types. But a third type might exist, called polar body or half-identical twins. Though this has never been confirmed, a research review from suggested that a third twin type would explain why some fraternal twins look so similar.
After the ovaries release an egg , the egg can split into two halves, the smaller of which is called a polar body. This polar body contains all the chromosomes necessary to join with a sperm to create a baby.
Meanwhile, the larger half of the original egg could also be fertilized by a separate sperm. The result? Polar twins. Polar twins share the same chromosomes from their birthing parent, but they get different chromosomes from their non-birthing parent. For this reason, they may or may not be assigned the same sex at birth, and they may look very similar but not exactly identical.
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