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بسم الله الّرحمن الّرحیم. Definition : fetus uniforfmly small for gestational age Etiologies of symmetric IUGR: Genetic disorders( e.x : trisomy 18,13,10 ) Fetal infections ( e.x : cmv, para virus ,Rubella) Congenital malformations
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Definition: fetus uniforfmly small for gestational age • Etiologies of symmetric IUGR: • Genetic disorders( e.x: trisomy 18,13,10 ) • Fetal infections (e.x: cmv, para virus ,Rubella) • Congenital malformations • Syndromes( e.x: AIDS embryopathy, Cornelia de lange )
Ultrasonographic findingsin Symmetric IUGR 1-size less than expected for dates 2- structural survey more likely to be abnormal than with asymmetric IUGR ( aneuploidy ) 3- second trimester finding of echogenic bowel associated with IUGR in 10-20% cases. 4- usually a primary fetal abnormality ,not placental insufficiency 5-DOPPLER is not as helpful as in asymmetric IUGR . 6- Does not exhibit “ head sparing “ flow in M.C.A .
Imaging Recommendations 1- know accurate dating 2- early ultrasound is more accurate than LMP or clinical assessment of GA . 3- First trimester CRL measurments accurate to within +/- 0.7 weeks. 4- second trimester dating base on composite of several measurments ( BPD, HC,AC, FL ) 5- second trimester dating accurate to within +/- 1.5 weeks . 6-Third trimester dating accurate to within +/- 3-4 weeks . 7- Look at ossification centers, helps verify dating when patient present late in gestation . Distal femoral epiphysis > 32 w Proximal tibial epiphysis > 35 w
8- Evaluate amnotic fluid volume IUGR + polyhydramnios high risk for trisomy 18 Low fluid poor outcome 9- look at anomalies : Symmetric IUGR has strong associated with aneploidy Multiple anomalies + early onset IUGR triploidy ,trisomy 13,18 10- Look at fetal hands : Clenched fingers trisomy 18 Postaxial ploydactyly trisomy 13 Syndactylytriploidy
Causes of UPI • Placental Disorders • Chronic placental abruption • Placenta previa • Mosaicism ( e.x: localized placental trisomy 16 ) • Marginal or Velamentous cord insertion • Primary placental disorders • Poor placentation
2) Maternal Etiologies A: Behavioral states • Smoking • Cocaine abuse B: Chronic medical condition • Chronic lung disease (chronic obstructive pulmonary disease , Emphysema) • Diabetes mellitus • Chronic hypertension • Collagen vascular disorders ( e.x: lupus ) • Acquired thrombophilias ( e.x: Antiphospholipid antibody syndrome) • Inherited thrombophilias ( e.x: Factor 5 leiden ,prothrombin 20210A mutution)
Development of placenta • First trimester : A: Placental attachment B: Angiogenesis C: Cellular transport mechanism D: Onset of distribution & disposal of various substances between the maternal- fetal circulation by the onset of fetal cardiac activity .
2) The second trimester : A: Trophoblastic invasion in to the uterine B: Vascular remodeling C: Massive increase in total villous sureface area Capacity for maternal – fetal exchange Fetal cardiac output 3) The tird trimester : Establishment of fetal stress especially body fat because of fetus extra uterine existence
Fetal Arterial Doppler 1)Umbilical Artery 2) Middle Cerebral Artery
(2) Middle cerebral artery • MCA is the most accessible cerebral vessel in ultrasound imaging in the fetus. • MCA carries 80% of cerebral flow. • Cerebral circulation is a High-impedance circulation( reverse of Umbilical artery)
Brain Sparing Reflex ( fetal adaptation to oxygen deprivation) Fetal hypoxemia Increase blood flow to the brain ,heart and adrenals Reduction in flow to the peripheral and placenta
Clinical applications of uterine artery Doppler • In vitro fertilization • uterine receptiveness for implantation • Risk assessment for maternal complications of pregnancy • PIH • Pre-eclamptic toxemia • Risk assessment of poor fetal outcome • IUGR • SGA infant
Treatment • Randomised controlled trials are currently in progress • Aim to see if abnormal uterine artery Doppler in early pregnancy can be effectively treated before onset of pregnancy complications • Treatment options: • Aspirine • Vitamins E/C • Low molecular weight Heparine
Fetal venus Doppler • Obtain from fetal central venus circulation • Reflect the physiology status of the right ventricle. • Inferior vena cava and ductusvenosus are the most important