Statistics of survival
From figures available at least 6000 babies are affected every year in the United States by TTTS and approximately 4000 of them will pass away.
These figures relate to diagnosed pregnancies only - we do not know how many pregnancies that are not diagnosed are lost due to TTTS.
CHANCES FOR SURVIVAL IF PREMATURELY BORN
The Fetal Treatment Program
An early diagnosis of TTTS will give parents an option for various treatments that are available depending on how their case is presentedA team comprised of pediatric surgeons Francois Luks, MD, and Thomas Tracy, MD, of Hasbro Children's Hospital, and maternal-fetal medicine specialist Stephen Carr, MD, of Women & Infants Hospital, performed the procedure, the first of its kind in the Northeast. Three weeks later the team performed a similar operation to try to save 23-week fetuses, after one twin showed signs of heart failure.
Twin-to-twin transfusion syndrome occurs in about 10 percent of identical twins sharing the same placenta, when blood from one fetus (the donor) continually flows to the other (the recipient), endangering the lives of both.
"If the syndrome develops early in pregnancy (before 25 weeks) and nothing is done, there is a very high likelihood that both twins will die," Luks said. Because the circulatory systems of the fetuses are connected, the death of one fetus very often will cause the death of the other. Even if one twin survives, there is a 35 percent risk of severe heart or brain damage.
With this intervention, though, the outlook is brighter. "Survival of at least one twin should occur in 70 percent of cases, and survival of both twins could be seen in half of affected pregnancies. Also, the risk of anomalies in the surviving twin is only about 5 percent," he said.
For the fetal operation, a laser fiber, through a very small telescope inserted into the uterus, is used to close all the blood vessels running from one twin to the other. As a result, the twins are completely separated, with each twin using only his side of the placenta. American physician Julian De Lia, MD, first performed the procedure in 1995. Since then, it has been performed hundreds of times in Europe, but rarely in the United States.
After each of the two procedures in June, the transfusion syndrome was resolved. In the first case, unfortunately, the smaller donor twin was too sick to recover, and died two weeks later. The remaining twin appears to be thriving, and the team expects that a healthy baby will be born to the Providence mother. At this time, doctors are cautiously optimistic that both twins in the second case will live. There are no longer any signs of heart failure in the recipient twin, and the smaller donor twin has grown rapidly since the operation. The mother of this second group of twins, from Falmouth, MA, was referred to the program from New England Medical Center in Boston.
The Fetal Treatment Program is a joint venture of Women & Infants Hospital, Hasbro Children's Hospital and New England Medical Center in Boston. For more than a year, the program's participating physicians and support teams have been preparing to mobilize to perform this and other fetal operations, including treating a baby's cardiac arrhythmia in utero, controlling fetal anemia, or placing plastic shunts to treat a congenital anomaly known as bladder outlet obstruction.
When parents discover they are expecting more than one baby, they're often overwhelmed with emotion . . . and excitement. But multiple births can pose a number of medical challenges and risks. One of these is called Twin to Twin Transfusion Syndrome, a serious condition affecting more than 7,000 infants each year. St. Joseph's Hospital-Milwaukee is the site of an international institute, which performs life-saving surgery to correct this problem before the babies are born. It is the only fetal treatment center in the world specifically dedicated to this disorder.
Twin to Twin Transfusion Syndrome
Twin to Twin Transfusion Syndrome is a disease of the placenta that strikes about 10% of all identical twin pregnancies. In the US, it affects over 7,000 babies—or 3,500 pregnancies—each year. This serious condition occurs when twins (or other multiples) share a single placenta that contains blood vessels which connect the twins. These inter-connections may cause one baby (the recipient) to get too much blood, thereby overloading his or her cardiovascular system. This baby may die from heart failure, while the other baby (the donor) may die from the loss of blood. The tragedy is that these babies are normal. The problem is in the placenta. The death rate for twins who develop TTTS at mid-pregnancy may be as high as 80 to 100 percent. Babies may die in utero, at birth from prematurity or years later from the effects of TTTS. Those who survive suffer from many serious problems, including cerebral palsy. Dr. Julian De Lia developed and pioneered a surgery to combat this problem. The laser-technology surgery dramatically alters the odds for babies with TTTS: in 80 percent of the cases where the operation is performed, at least one twin survives; in 65 percent, both twins live. Less than five percent of the survivors have any disabilities or birth defects, compared to up to 30% with other treatments. In light of the poor prognosis without treatment, these statistics are remarkable.
IDENTICAL TWINS, TRIPS AT RISK
TTTS occurs in 10-15% of pregnancies that are seen with monochorionic-diamniotic twins OR HIGHER ORDER PREGNANCIES. TTTS affects 1 in 100 000 of all pregnancies.
Twin to Twin Transfusion Syndrome is also possible with monoamniotic pregnancies!
What is a monochorionic-diamniotic twin pregnancy?
A pregnancy where identical twins (of the same sex) share one placenta, and have a thin membrane separating them, each in his or her own amniotic sac.
The process of having twins occurs in many ways. Twins may be either "fraternal" or "identical". In fraternal twins, each fetus has his or her own placenta and amniotic sac (bag of waters). In identical twins, the two fetuses may share the same amniotic sac, placenta or both. TTTS occurs in identical twins.
All identical twins share blood vessels through the placenta, but twins with TTTS have an unequal sharing of blood. One twin may not get enough blood while the other becomes overloaded with too much blood. This can lead to heart failure.
- If the egg divides between 4 to 8 days, the result will be identical twins with a common (shared) placenta and each baby will have its own amniotic sac. This is known as monochorionic (one placenta). 10-15% of these pregnancies will develop TTTS.
- If the egg divides between 8 to 12 days, the result will be twins that share one placenta (monochorionic) and one amniotic sac (monoamniotic).
- If the egg divides after 12 days, conjoined twins, also known as Siamese twins, occurs.
Most twins with TTTS have one placenta (monochorionic) and two amniotic sacs (diamniotic). However, it may also occur in pregnancies with only one amniotic sac (monoamniotic).
If you are pregnant with twins please find out from your Obstetrician whether you have a monochorionic-diamniotic or monoamniotic twin pregnancy as TTTS can occur in these types of pregnancies.
Twin to Twin Transfusion Syndrome is possible with monoamniotic twins. Until recently, it was thought that it was less common with monoamniotic twins than with monochorionic, diamniotic twins. However, some recent research showed that the incidence of TTTS is virtually the same in both groups.
Nevertheless, it may be more difficult to diagnose when the babies share a sac. One of the key indicators they use in diagnosing TTTS is the amount of fluid in the two sacs - if one has a whole lot, and the other has very little, that suggests TTTS. However, with only one sac, that is impossible to determine. So the main technique they will use to diagnose TTTS in a monoamniotic pregnancy is size discrepancy. Basically - whether one baby is of drastically different size than the other.
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