INVASIVE PROCEDURE IN FETAL MEDICINEHM Sulchan SofoewanDevision of fetomaternal of Departement of Obstetrics and Gynaecology

INVASIVE ANTENATAL PROCEDURE1. Prenatal diagnosis of congenetal malformation2. Therapy / Surgery

PRENATAL DIAGNOSIS1. Amnoicentesis2. Chorion Villus Biopsy (CVB)3. Fetoscopy4. Ultrasound Guided Fetal Blood Sampling (FBS)5. Fetal Tissue Biopsy6. Intrauteine Fetal Therapy

AMNIOCENTESISPrimary diagnostic technique for antenatal determination of the cytogenetic constitution and inborn errors metabolismAssessment of severity of Rhesus isoimmunisationPrediction of fetal lung maturityDecompression of polyhydramnion

INDICATIONS FOR AMNIOCENTESIS1. Pregnancy of women 35 yrs of age2. Down Syndrome, chromosomal abnormality, multiple major malform or NTD in previous pregnancy3. Pregnancies in women who have x-linked disordes in male relative4. Hematological disorders which can be diagnose by gene probe technique

COMPLICATIONS OF AMNIOCENTESISUltrasound guided amniocentesis has decreased complication ratesUltrasound examination prior amniocentesis for the diagnosis of multiple pregnancies, verification of fetal viability and detection of fetal malformationAbortion risk 0,3-0,5 %, depend on experience of operatorThe test extremely accurate, error rate 0,4%, error caused by contamination of the cultures with maternal cell

ContinueThe cultured failure rate 0,5-1%No longernecessary to perform amniocentesis at 16 weeksImportant to inform patients that the finding of a normal karyotype and normal amniotic fluid alpha-fetoprotein does not guarantee a normal newbornThere are causes of birth defect and mental retardation can not be detected through amniocentesis

CHORION VILLUS BIOPSYFirst trimester CVB became popular in the last decadeWidely use are the transcervical aspiration under ultrasound guidanceMore recently developed ultrsound guided transabdominal placental biopsy

COMPLICATION OF CVBThe indication are similar to amniocentesisThe risk of fetal loss depend primarily on the method and experience of operatorTranscervical approach the risk of fetal loss is 2-6% compare to 0,5-2% with the transabdominal approachFor karyotyping false pos around 2%, false neg around 0,1%Congenital defect such as limb reductin were found in 5 out of 289

FETOSCOPYThe second trimester fetus can be visualised directly through an endoscope introduced transabdominally into the amniotic cavityFor fetal blood sampling, skin biopsy or liver biopsyPrimarily used for the diagnosis of disorders characteristic by small external defect (facial cleft, poly or syndactily etc)For obtaining samples of fetal tissues that expres aepecific genetic characteristic

ContinueFetal blood can be obtained for prenatal diagnosis of haemoglobinopathies, coagulation, metabolic and cytogenetic disorders, immunodifficiencies and fetal infectionFetal lymphocytes are valuable in providing an urgent karyotype within 3 days

RISK AND COMPLICATION OF FETOSCOPYHas been performed in many centres thoughout the world without maternal mortality and significant morbidityThe risk to the fetus is also relatively smallProcedure-related fetal loss is around 5%

PERCUTANEOUS UMBILICAL CORD BLOOD SAMPLING (PUBS)PUBS or Cordocentesis : Umbilical vein is punctured under direct ultrasound guidance, usually at or near its placental origin, and blood is withdrawnObtain fetal blood cells for genetic analysis when CVS or amniocentesis results are confusing or when rapid diagnosis is necesseryFor metabolic and hematological studies, acid-base analysis, viral cultures & immunological studies

COMPLICATIONS OF PUBSSimilar with amniocentesisThe most common were umbilical cord vessel bleeding (50%), hematoma (17%), fetal-maternal hemorrhage (66%), fetal bradycardia (3-12%)Most complications were transitory, with complete fetal recovery; however, fetal death does occur, procedure-related loss rate was 2,7%This rate strongly related to the indication for the procedure

FETAL TISSUE BIOPSYSome genetic condition affecting the fetus can not be diagnosed by molecular genetic techniquesIn this condition, prenatal diagnosis can be performed by direct analysis of fetal tissue obtained by sonographycally guided skin or muscle biopsyFor muscle biopsy to diagnose muscular dystrophy and mitochondrial myopathy

PREIMPLANTATION DIAGNOSISThe identification of genes responsible for certain severe heriditary disease and development of techniques of techniques for IVF have provided access to the early embryoWill allow selection of only healthy embryosInclude diagnosis of single gene disorders such as: cystic fibrosis, sickle cell disease, identificatin of aneuploidy with advances maternal age, or parental chromosome rearrangement

ContinuedSeveral variations: polar body analysis, reasoning that the first polar body is expelled anyway and its removal hould not affect fetal developmentThe 3-day embryo (6 to 10-cell stage), and involves blastomer biopsy through a hole made in the zone pellucidaLoss of one totipotent cell at this stage supposedly has little or no effect on the developing embryo

FETAL THERAPYPregnancy termination:Unfortunately no antenatal therapy available for most congenital anomaliesThe patient and her family still benefit from prenatal diagnosis because it allows an informed decision pregnancy continuationGenetics referral, consultation with a pediatric neurosurgeon, gastrointestinal surgeon, cardiologist or urologistSelective reduction of multiple fetusis results in better outcome

ContinueTwin-twin transfusion syndrome:Complication of monochorionic twin pregnanciesAll monochorionic twins share a placenta which contains vascular anastomoses potentially connecting the two circulationsA small portion have unequal blood flow, unbalanced anastomoses, they have varying degree of discordancy of weight, intravascular volume, hemoglobin concentration, and amniotic fluid volume

ContinueIn the extreme case, one twin is severely growth restricted with no amniotic fluid, while the co-twin is larger, often plethoric and has hydramniosTherapy TTTS are limited, removal of fluid from the sac with hydramnios, occasionally may even reverse the unequal fluid balance between the twinOpening in the amnion separating the fetuses, allowing the fluid to interchangeA more invasive therapy is endoscopic laser ablation of placental vascular anastomosesMore aggressive therapy is selective feticide of the donor twin.

FETAL TRANSFUSIONIsoimmunizationIntraperitoneal red blood cell transfusion for treatment of fetal anemia from red cell isoimmunizationUsing fluoroscopic guidance and a large-bore trocard and needle, blood placed into the fetal abdominal cavity is gradually absorbed by the subdiaphragmatic lymphaticsWith ascites or hydrops, often were not able to absorb enough blood to survive

ContinueIn addition, the procedure described fetoscopically guided intraumbilical blood transfusion, using a 2.4 to 3.0 mm cannula.This was followed by accounts of ultrasonically guided transfusion directly into the hepatic portion of the umbilical vein, or fetal heartOr directed transfusion into the umbilical cord vein using a 22-gauge needle.

PARVOVIRUS INFECTIONA small number of fetuses affected by parvovirus B19 infection will develop severe transient aplastic anemiaFetuses infected before 20 weeks are most likely to develop severe anemia with heart failure and subsequent hydropsWhile unknown number spontaneously recover and survive, other that are severely compromised will dieSome of these can be rescued with blood transfusion

FETAL MEDICAL THERAPYFetal therapy is accomplished by maternal treatment with desired medicationIn other cases, medication is administered directly to the fetus by intramuscular injection or intravenous infusion through the umbilical veinIn fetuses with suspected compromise, thyroid status can be assessed by cordocentesis, and maternal treatment given with PTU that crosses the placenta to supresses the fetal thyroid

ContinueMost arrhytmias are tolerated wthout compromise or the arrhytmia resolves spontaneouslyWhen there is sustained tachyarrhytmia, the fetus may begin to show cardiac decompensation, which can progress to hydropsMaternally administered antiarrhytmic agent cross the placenta in therapeutic dosesDigoxin, verapamil, propranolol, procainamide, quinidin, amiodaron given for fetal arrhytmiasWith fetal hydrops medication is administered directly to the fetus, umbilical cord or IM

FETAL SURGERYFetal surgery is performed in only a few centers by teams trianed in multidisciplinary techniques required for complete care of both mother and fetusRecent technical advances, especially in ultrsound and laparoscopic surgical techniques, make it possible to consider surgical correction of structural fetal malformationThere are a number of requisites that are necessary before surgical intervension is considered

ContinueBecause intervention entails substantial fetal and maternal risk, as well as risk to subsequent pregnanciesEarly experiences with antenatal ventriculoamnionic shunt placement to correct fetal obstructive hydrocephalusThe results of the first 44 procedures reported: fetal death rate was 10%, and 18 of the 34 survivors had serious neurological handicaps

ContinueUrinary shunt: renal agenesis in which association with oligohydramnionThoracic shunt: accumulation of thoracic fluid can also cause pulmonary hypoplasiaCongenital diaphragmatic hernia: antenatal surgical correction of the diaphragmatic defect might restore normal intrathoracic to allow pulmonary developmentSacrococcygeal teratoma: congenital germ cell tumorNeural tube defect: open spine defect