Oligohydramnios and IUGR

Oligohydramnios and IUGR

1. Uterus smaller than date Oligohydramnios & Intrauterine Growth Restriction (IUGR) M. Kamil

2. Amniotic fluid Function Physical space for fetal movement -> important for normal musculoskeletal development Permits fetal swallowing Important for GI tract development Permits fetal breathing Necessary for lung development Prevent umbilical cord compression Protect from trauma

3. Amniotic fluid evaluation Component of fetal testing for 2 nd and 3 rd trimester sonogram. Measurements 2 ways: Single deepest vertical fluid pocket ( nl 2 – 8 cm) AFI - The sum of the deepest vertical pockets from each of four equal uterine quadrants ( nl 5 – 24 cm)

4. Gestational-age-specific nomogram of AFI

5. Oligohydramnios Definition AFI 5 cm (or < 5 th percentile)/ The absence of a fluid pocket 2-3 cm in depth/ Fluid volume of less than 500 mL at 32 – 36 weeks. Anhydramnios – No measurable pocket of amniotic fluid is identified  

6. Etiology Divided into Early onset: Severely decreased since the early second trimester Late onset: Normal volume until near-term or even full-term / after mid pregnancy Prognosis: Depends on underlying etiology and is variable

7. Early onset Fetal abnormality that prevent normal urination - Production B/L renal agenesis – Potter sequence Renal cystic dysplasia - Meckel- Gruber syndrome Renal anomalies – VACTERL association Urinary tract obstruction Sacral agenesis Placental abnormality severe enough to impaired perfusion. Poor placental perfusion PIH – Chronic placental hypoperfusion -> fetal GFR -> Urine output -> Amniotic fluid Preterm premature rupture of membranes (PPROM) in the 2 nd trimester. Usu p/w – fluid leakage (prolonged), vaginal bleeding or uterine contraction. Other causes Drugs – ACEI, PG synthase inhibitors Twin to twin transfusion TRAP (TRAP (twin reverse arterial perfusion sequence) Fetal demise U/S – Should be perform to assess fetal abnormalities  

8. Late onset Fetal growth restriction Placental abnormality Maternal complication Pre-eclampsia Vascular diseases Drugs Postterm pregnancy Amniotic fluid 8% after 40 weeks  

9. Clinical manifestation and diagnosis Uterine size < expected for gestational age Performed ultrasound to assess AF volume AFI 5 cm Single deepest pocket of amniotic fluid 2 cm Gestational age specific nomogram: < 2.5 th percentile A fluid volume of less than 500 mL at 32-36 weeks.  

10. Evaluation Thorough maternal history Targeted physical examination Ultrasound evaluation with fetal biometry and fetal anomalies Fetal growth restriction Aneuploidy - nuchal translucency Placental abnormalities (abruption)  

11. Evaluation (continued) Must r/o PROM Non invasive Invasive Amniocentesis -> Karyotyping Suspected fetal anomalies Most common early oligohydramnios is Trisomy 13 and triploidy

12. Management and Prognosis First trimester Pregnancy usually aborts. We counsel these patients regarding the poor prognosis and inform them of the signs of miscarriage. Serial sonographic examinations are helpful for following the natural history of the process ( eg , worsening oligohydramnios, embryonic/fetal demise, or [rarely] resolution). Second trimester If borderline – generally good prognosis. Serial sonographic examinations are helpful for following the natural history of the process, which may remain stable, resolve, or progress to development of oligohydramnios and/or fetal growth restriction. If oligohydramnios – usually ends with fetal or neonatal death. Women usually chose pregnancy termination because of poor prognosis – usually have anatomical and functional abnormalities -> skeletal deformations, contractures, and pulmonary hypoplasia. Perform fetal anatomic survey - > to look for fetal malformation -> for further management. Administer oral maternal hydration or perform amniofusion if the fetal cannot be visualize adequately. If ROM is uncertain, amniofusion with instillation of indigo carmine dye for dx of PPROM and visualization of fetal anomalies. Serial U/S to monitor amniotic fluid volume, fetal growth and fetal well- being.

13. Management and Prognosis (continued) Third trimester Adverse outcome usually d/t umbilical cord compression, uteroplacental insufficiency, meconium aspiration. Umbilical cord compression and uteroplacental insufficiency -> FHR abnormalities -> C sec delivery and low Apgar score. Duration of oligohydramnios is a prognostic factor. Present in early pregnancy -> higher risk for adverse effect. Present late in pregnancy - > lower risk

14. Evaluation and Management (continued) After diagnosis Doppler U/S of placenta -> to assess for any evidence of fetal distress. Fetal distress -> immediate delivery via C- sec No fetal distress -> should be induced and deliver via vaginally

15. Management Admission for investigation Rule out ROM Amniocentesis - > Karyotyping Doppler ultrasound for fetal distress Evidence of fetal distress- > immediate C-sec If no fetal distress, induced and delivered via SVD Send placenta for pathological examination

16. Complications of oligohydramnios Early onset of oligohydramnios Potter sequence syndrome Limb deformities Abdominal wall defects Pulmonary hypoplasia Cord compression

17. Intrauterine Growth Restriction (IUGR)

18. Intrauterine Growth Restriction (IUGR) Introduction Detection usually on routine U/S Important for prenatal care Confirming diagnosis Determining the cause and severity of fetal growth restriction (FGR) Counseling the parents Closely monitor fetal growth and well-being Determining the optimal time for route of delivery

19. IUGR VS SGA Definition of IUGR : A fetus or infant whose weight is less than the 10 th percentile at a given GA as determined by U/S Or Infants whose growth velocity < expected SGA: An infant with a birth weight at the lower extreme of the normal birth weight distribution. BW <10 th % BW < 2SD below the mean (3 rd %)

20. FGR VS SGA http://datab.us/i/smallforgestationalage

21. Beckmann, C., Herbert, W., Laube , D., Ling, F., Smith, R., & American College of Obstetricians Gynecologists. (2014). Obstetrics and gynecology (7th ed.).

22. Uterine fetal growth pattern Reethiya , L., & Rokeshwar , H.D., Doctrina Perpetua: Guides on Obstetrics. (2015).

23. Types of IUGR Reethiya , L., & Rokeshwar , H.D., Doctrina Perpetua: Guides on Obstetrics. (2015). Pondoral index: Ratio of BW to Length:  

24. Causes and risk factors of FGR Beckmann, C., Herbert, W., Laube , D., Ling, F., Smith, R., & American College of Obstetricians Gynecologists. (2014). Obstetrics and gynecology (7th ed.).

25. Evaluation Assess gestational age on early routine visit. History to assess the risk factors. Physical examination Screening test – serial measurements of fundal height. Fundal height should increase approx. 1cm/week between 20 and 36 weeks Significant discrepancy of > 2 cm may indicate IUGR Ultrasound

26. Evaluation (Continued) Investigation CBC – Hb, WBC (possible infection) TORCHES Screening Look for dysmorphic features Mother urine for substance/ meconium for substance Blood sugar Calcium Bilirubin

27. Ultrasound To assess fetal size and growth. Fetal biometry measurements and compare with standardized table Biparietal diameter Head circumference Abdominal circumference (AC) – false negative < 10% Femur length Evaluation (Continued)

28. Direct studies Invasive studies of the fetus. Amniocentesis for fetal lung maturity Fetal karyotyping and viral cultures and PCRs Evaluation (Continued)

29. Evaluation (Continued) Doppler velocimetry On fetal umbilical artery. Measured by Systolic/ Diastolic ratio Normal at term: 1.8 to 2.0

30. Doppler velocimetry (continued) IUGR secondary to uteroplacental insufficiency Show reversed end- dystolic flow May suggest impending fetal demise

31. Complication Fetal Hypothermia Hypoglycemia Hypocalcemia Perinatal Perinatal asphyxia Hypothermia Hypoglycemia Polycythemia, hyperviscosity meconium aspiration syndrome Neurodevelopment Lower intelligent Learning/behavior disorders Neurologic handicap  

32. Management Diagnosed prior 34 weeks with normal AFI and good fetal well being Postpone delivery until fetus achieve lung maturity Diagnosed at term Prompt delivery Irrespective of period of gestation if fetal has abnormal Doppler studies with oligohydramnios Deliver immediately Severe IUGR with or without abnormal CTG Deliver via C- section.