Ob1 Lec - Invasive Techniques (milo)

PRENATAL DIAGNOSIS AND INVASIVE TECHNIQUES TO MONITOR THE FETUS Dr Ramon Gonzales PRENATAL COUNSELLING 1. Couples at risk for fetal or newborn abnormalities because of age or ethnic background 2. history of inherited abnormalities (DM -> CV disease, neural tube defects) 3. underlying maternal distress 4. women whose fetus may be exposed to potentially tetratogenic substances (smoking, alcohol) SCREENING PROGRAMS • questionnaire • maternal age screening? • Maternal serum markers - alpha fetoprotein - hCG - unconjugated estriol ALPHA-FETOPROTEIN • major serum protein of embryo & early fetus • yolk sac (early); GIT liver (later) • concentration of AFP highest both fetal serum and amniotic fluid 13-15 AOG • major source of AFP in amniotic fluid is fetal urine (fetal serum AFP > fetal amniotic AFP; 15200:1) • protein  fetal membrane  maternal circulation • maternal serum AFP is 1/50,000 that of fetal serum • after 13-15th wk, AFP (in fetal serum & amniotic fluid) decreases  inc in maternal serum (200:1) • at 16th to 18th wk AOG measures MSAFP Neural Tube Defects • open neural tube defect – failure of closure of neural axis by 26th to 28th day embryonic life • anencephaly – absence of cranial vault and brain above the base of the skull and orbits – failure of closure at cranial end (lethal during fetal pd) • spina bifida – usually associated motor impairment and hydrocephalus – consists of a hiatus, usually the lumbosacral vertebrae, through which the meningeal sac may protrude, forming a meningocoele – failure of distal closure – compatible with life • encephalocoele – occipital mid-lining effect either cystic or solid in appearance - incomplete skull formation - extrusion of varying amounts of brain tissue - usually associated with either hydrocephaly or microcephaly • increased MSAFP • inc amniotic fluid AFP • inc AchE (acetylcholinesterase) FOLIC ACID SUPPLEMENTATION • reduces risk of NTD by 70 % • HIGH RISK – 4mg/day taken three months prior to pregnancy till the first trimester • LOW RISK – 0.4 mg/day MATERNAL SERUM AFP (MSAFP) • Performed 16-18th wk AOG • 2.0 to 2.5 MOM (multiples of median) abnormal if > 2.5 • elevated MSAFP  sonography  amniocentesis • detect 90% of cases of anencephaly, 80% spina bifida Elevated MSAFP • ultrasound confirm • multiple pregnancy (rule out) • identify other causes of inc MSAFP - ompahlocoele - gastroschisis - duodenal atresia - oligohydramnios - fetal death • if elevation remains unexplained  AMNIOCENTESIS  (1) amniotic AFP (2) AchE (very specific for brain tissue because of neuronal origin  most sensitive and specific for NTD

DOWN SYNDROME • “triple screen” - low MSAFP - low unconjugated estriol - inc hCG *** 57 – 67 % detection rate • “quad screen” - low MSAFP - low unconjugated estriol - inc hCG - inc inhibin A *** 70 % detection rate • quad screen + nuchal transducency (measures thickness of neck if > 6mm, ↑ incidence of down syndrome) • plus biochemical screening 90% detection rate PRENATAL DIAGNOSIS Indications for Prenatal Counseling and Diagnosis include: ***( probably the most common indications for prenatal counseling are advanced AFP screening test, including multiple marker) 1. maternal age 35 y/o and above 2. chromosomally abnormal off spring in previous pregnancy 3. chromosomal aberration in parent 4. down’s syndrome or chromosomal aberration in a close family member 5. a previous child or parent with neural tube defect 6. HR pregnancies esp those at risk for serious Mendelian Disorders (x-linked disorders, autosomal dominant disorders, autosomal dominant disorder, autosomal recessive disorder) 7. abnormal sonographic findings in fetus 8. a previous infant with MCA (multiple congenital anomaly) 9. fetal sex determination among those preganancies at serious risk for X-linked disorders 10. habitual abortions (more than 3 times) 11. previous stillbirths TECHNIQUES FOR DIAGNOSIS Non-invasive 1. X-ray (dwrafism) 2. sonography (18 wks AOG) 3. MRI (oligohydrmnios) Invasive 1. amniocentesis [15 – 20 wks AOG] 2. Chrionic Villi Sampling (CVS) [10 – 13 wks] 3. Percutaneous Umbilical cord Sampling (PUBS) / Cordocentesis AMNIOCENTESIS • Uses spinal needle to puncture abdomen • CYTOGENIC STUDIES (15-20wks  sufficient amount of cells) • Enzyme and DNA analysis (karyotype) • AFP • AchE • Genetic disease • Fetal death • Condition in Rh disease or blood group immunization • Amniotic fluid  centifuge  fetal cells settle (cytogenig studies)  supenantant (amniotic fluid AFP and AchE) • Done in third trimester - Lung maturity - Meconium staining - Chorioamniocentesis Ultrasound evaluation prior to amniocentesis • Placental localization • Fetal viability • Biometric measure Early Amniocnetesis • 11th – 14th week

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success rate > 98%

Genetic Amniocentesis • 16th – 18th week • sufficient fetal cells - cytogenic studies - enzyme and DNA analysis • supernatant fluid - AFP & AchE Complications • Fetal & maternal trauma (placenta umbilical cord, maternal structures) • Amniotic fluid leakage • Vaginal spotting  infection • Chorioamniocitis • Abortion • Preterm labor >Lung Maturity • L/S ratio (34 wk AOG; 1:1) • Increases after the 34th wk, MATURE LUNG 2:1 • Phosphatidyl glycerol – 2nd most surface active…can also tell maturity of lungs • Lamellar body count (more than 20,000: mature) • Foam shake test  amniotic fluid + ethanol (shake for 1 min) tests stability of surfactant to form bubbles >Chorioamniocentesis • Intramniotic infection • Culture • Gram stain - (+) = 93% - (-) = 85.4% ****amniotic fluid should be sterile > Rh disease analysis • indentifies hemolytic anemia • 450 nm optical density • measure products of hemolysis (fetal hemolysis = fetal anemia) CHORIONIC VILLI SAMPLING (CVS) • insert catheter  hit CHORION FRONDOSUM (mitotically active) • 10th – 13th week • prenatal genetic diagnosis • cytogenic studies • biochemical and metabolic diagnosis • fetal infection • karyotype • enzyme and DNA analysis • 97.5% successful in identifying congenital malformations • can be done earlier than amniocentesis • 9th – 12th weeks = distinct structures (1) CHORION FRONDOSUM, (2) CHORION LEAVE Complications of CVS • vaginal bleeding/spotting • chorioamnionitis • fetal maternal hemorrhage • abortion • infection • limb abnormalities (caused by HYPOEFUSION) TRANSCERVICAL vs TRANSABDOMINAL 1. Transcervical – posterior placenta 2. transabdominal – anterior palcenta

Contradictions to TRANSCERVICAL CVS 1. (+) Gonorrhea culture of cervix 2. abdominal sampling

>Limb abnormalities and CVS • if done 8-9 wks • HYPOEFUSION due to Maternal hemorrhage • Embolization fo chorionic villi • Amniotic puncture and limb entrapment PURCUTANEOUS UMBILICAL CORD SAMPLING (PUBS) • CORDOCENTESIS • Access to the umbilical artery or vein depends on placental location and the position of cord insertion into placenta • Umbilical cord near placenta is more stable 1. anterior placenta – needle may traverse the placenta 2. posterior implantation – needle usually passes thru the amniotic fluid before penetrating the umbilical vessels • prenatal diagnosis of blood disorder • isoimmunization and platelet disorder • congenital infections • fetal viral infection • fetal karyotyping (rapid karyotyping 1- 2 weeks only) • metabolic & biochemical analysis • DNA analysis • Fetal hypoxia – blood gases • Fetal therapy – fetal anemia Complications • Fetal loss • Chorioamnionitis • Bleeding • Severe bradycardia Fetal mean Hemoglobin • 16th wk – 11g/dl • 40th wk – 15.5 g/dl • fetal hydrops = hgb deficit .7g/dl >Fetal karyotype • rapid karyotype • useful for later pregnancy when malformation and IUGR is detected by ultrasound IUGR • fetal karyotype • umbilical blood gas ***compared to AGA fetus, SGA presented with hypercapnia, hyperlactosemia, hypoxia  CMM 2007 – Sigma Tau Delta Sorority Hi to all section C especially the subsec of DR GONZALES (kat, tricia,Justin,leigh,auds,karen,marlon,maui,te mea,em,Dinah (pseudobuddy), pam,rhyan,owsang(buddy),ruth,jayhveeh (dinalawa k yung h ;)),blanca,grace (aka bitch), binx, braix ;D(thanks for the inspirational quotes,diane, mark o, aui (kala mo nagbibiro ako sa siargao…mga tao bohol tayo sa break),brian, pat ona,katy,haideeongsun (miss you na kita) Hi kat m Kuya cox tunay sa puso ang laban C3 2007 for me is the best subsec (sa aking opinion lang po) Hi auds salamat sa mga transcriptions, ako naman :D Ann salamat s a picture may pangfriendster na ako…haha Maui cookies ko ha? Leigh maganda pa rin Karen new hairdo Dinah alagaan si dad Pam hello Em isama mo na si…(ok lang sa amin) Buddy…salamat Jayveeh nice haircut….bumata ka ng konti lang…hahaha lambing lang

Ruth, marlon, Justin basta lahat sasama Ate mea ready na akong kumain ng masarap after ng prelims Lahat ng sasama sa tarlac please reunion natin eto… Hi to my buddy, roxy at jena Tiffy salamat sa notes, hi to Barbie at pati na si mary mga kapitbahay ko Hi na rin sa sec D teban, nestle twins, Robbie, rica hello na rin Sa second sem people hi kay meloy,chi-yu, kristine at tin lagunilla, trin,janlo,te kloa,kuya ton at syempre si fritz Hi to batch 2007goodluck to all of us…kaya natin to GOD BLESS!!!!