Fetal surgery
Thanks to the development of specialized surgical techniques, it's now possible to correct some defects when a baby is still in the womb. Some procedures are still experimental, but they may be the baby's only chance, and many parents see this as a risk worth taking.
Ultrasound-guided surgery
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In the more straightforward types of fetal surgery, thin needles are inserted through a mother's abdomen and womb and into the amniotic sac. Ultrasound allows the surgeon to see the baby and manipulate the needles (only one at a time is used) to take blood or tissue samples or give the baby drugs or blood transfusions as necessary.
Using ultrasound-guided techniques, surgeons are able to treat a growing number of life-threatening conditions. Rhesus and other incompatibilities between the immune systems of mother and baby may be corrected through intrauterine blood transfusions. Drugs to correct fetal heartbeat irregularities and destroy tumours may be injected into the baby; minute drainage tubes (shunts) that prevent further build-up of fluids may be inserted to drain excess fluids from the baby - for instance from the brain in cases of hydrocephalus - and to clear urinary tract blockages. Ultrasound is also used to guide the tiny forceps and scalpels used.
Intrauterine blood transfusions
In some cases of Rhesus incompatibility, in which a mother's blood is Rhesus (Rh) negative and her baby's Rh positive, the baby could become dangerously anaemic. If this happens, she'll need to be given one or more blood transfusions into one of the blood vessels in the umbilical cord to keep her going until she can be delivered safely. Fresh Rh-negative blood will be injected slowly, in amounts related to the baby's estimated weight and the seriousness of the anaemia. Blood transfusions made to a baby in the womb have a good success rate, but in some severe cases, Rh incompatibility causes miscarriage or stillbirth, despite numerous transfusions. Until recently, if transfusions were unsuccessful there was nothing more that could be done. Research is underway, though, to find out whether injecting the baby with donated Rh-negative bone marrow will stimulate him to become Rh negative and so remove the incompatibility. A more uncommon type of incompatibility between a mother and her baby results in the mother producing antibodies that destroy the baby's blood platelets. These platelets help blood to clot, and without them the baby could be in danger of suffering a haemorrhage and dying. This situation can be prevented by giving the baby transfusions of platelets and, in more severe cases, donor antibodies that counteract those of the mother.
Shunts for urinary tract problems
Some unborn babies suffer a condition called hydronephrosis. In this, one of the baby's kidneys becomes swollen with urine because the ureter that drains it is narrow or blocked. If left untreated, this can lead to severe kidney damage; if it affects both kidneys, it can cause kidney failure. Hydronephrosis can sometimes be corrected by the insertion of shunts by fetal surgery.
Open fetal surgery
This is an even more extraordinary technique, used to correct some fetal defects that cannot be treated by ultrasound-guided surgery. It involves opening up a woman's womb and partially removing her baby so he can be operated on. Open fetal surgery has been used to repair diaphragmatic hernias - when a baby has a hole in his diaphragm that allows his intestines to protrude into his chest cavity and damage his lungs - and to remove certain types of tumour.
Posted 30.06.2010
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