Anemia is more than twice as common in multiple pregnancies as in a single birth. Multiple birth babies have about twice the risk of congenital (present at birth) abnormalities including neural tube defects (such as spina bifida), gastrointestinal, and heart abnormalities.
Many studies have found that twin pregnancies also have a higher risk of congenital anomalies than singleton pregnancies [2,3,4]. Approximately 25% of congenital anomalies are attributed to chromosomal abnormalities [5], and twin pregnancies have also been considered to have a high risk of chromosomal abnormalities.
Multiples are about twice as likely as singleton babies to have birth defects, including neural tube defects (such as spina bifida), cerebral palsy, congenital heart defects and birth defects that affect the digestive system.
Because each baby comes from the same egg and sperm, their genetic material (known as chromosomes) is identical. They are assigned the same sex at birth and have the same physical features, including eye and hair color.
Identical twins may differ on a host of diseases and conditions. According to Haseley, “If a genetic change occurs in a gene that affects its function, health concerns may arise.” Twins may differ in their risk of cancer, rheumatoid arthritis, or other conditions.
Identical twins share the same placenta, which may make the risk of cerebral palsy greater when there are complications, such as one twin dying in the womb.
One of the reasons multiple pregnancies are considered higher risk is because 50 percent of them deliver prematurely. A premature delivery occurs prior to 37 weeks of gestation, while a normal full-term pregnancy lasts 38 to 42 weeks.
Identical, or monozygotic (MZ), twins have 100 percent of their genes—including those that influence risk for alcoholism—in common, whereas fraternal, or dizygotic (DZ), twins share (on average) only 50 percent of the genes that vary in the population (see figure). Common Environmental Sources.
Valentina Vassilyeva and her husband Feodor Vassilyev are alleged to hold the record for the most children a couple has produced. She gave birth to a total of 69 children – sixteen pairs of twins, seven sets of triplets and four sets of quadruplets – between 1725 and 1765, a total of 27 births.
Identical twins have 100% of their DNA the same while fraternal twins share only 50%.
Monochorionic-monoamniotic twins are identical twins that share both a placenta and an amniotic sac. This is the rarest and highest risk form of twin pregnancies.
Most twins are born healthy. A twin pregnancy can mean a higher chance of health complications so you'll need extra check-ups. Twins that share a placenta or inner sac need to be checked more closely. It's good to know whether twins are fraternal or identical for health reasons later in life.
Today, the researchers report online in Cell that identical twins' immune systems were too different for the variation to boil down to genetics. Indeed, environment overshadowed inheritance in three-quarters of the measurements, and half showed no measurable genetic influence.
However, for a given pregnancy, only the mother's genetics matter. Fraternal twins happen when two eggs are simultaneously fertilized instead of just one. A father's genes can't make a woman release two eggs. It sounds like fraternal twins do indeed run in your family!
The twin gene is carried by the mother, meaning that it is her genes that determine whether someone may have fraternal twins.
The quick answer to this question is that, in a twin pregnancy, it is the mother's genes that determine twins. First up, giving birth to identical twins is not genetic, but conceiving fraternal twins is. The mother may have the genetic trait of releasing two eggs in one menstrual cycle.
The DNA of monozygotic twins tends not to be 100% identical, and epigenetic and environmental differences further widen the gap between twin pairs. It's not nature or nurture; it's a complex interaction between our genes, our environment, and our epigenetic markers that shape who we are and what illnesses befall us.
High parity – Having one or more previous pregnancies, especially a multiple pregnancy, increases the chances of having multiples. Race – African-American women are more likely to have twins than any other race. Asian and Native Americans have the lowest twinning rates.
There are more twins in the “millennial generation” than any other generation, thanks partly to a twin boom in the '90s. The main reason was a new technology called in vitro fertilization, which in its early days frequently produced twins, triplets and other multiple births.
Monoamniotic-monochorionic Twins
This is the rarest type of twin, and it means a riskier pregnancy as the babies can get tangled in their own umbilical cords. If you have monoamniotic-monochorionic twins, your healthcare provider will monitor your pregnancy closely.
They come from the same fertilized egg and share the same genetic blueprint. To a standard DNA test, they are indistinguishable. But any forensics expert will tell you that there is at least one surefire way to tell them apart: identical twins do not have matching fingerprints.
Monozygotic (identical) twins will have the same blood type, with a few very rare exceptions. Dizygotic (fraternal) twins may have the same blood type, or they may have different types. Therefore, it may be concluded that twins with differing blood types are dizygotic, or fraternal.
A little more than half of twin pregnancies end in preterm delivery (before 37 weeks). While 40 weeks is the full gestation period of the average pregnancy, most twin pregnancies are delivered at approximately 36 weeks (range 32-38 weeks depending on the type of twin pregnancy).
Most practitioners advise women who start their twin pregnancy at a normal weight to gain 37 to 54 pounds. You should gain a little more if you were underweight (between 50 and 62 pounds) and a little less if you were overweight (between 31 and 50 pounds).
While there are risks associated with all twin pregnancies, dizygotic (fraternal) twin pregnancies usually bring about the least amount of complications, carrying the lowest risk of all types of twins.