Intrapartum fetal monitering

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  • 1.ANTEPARTUMFETAL MONITERINGProf. M.C.BansalMBBS., MS., FICOG., MICOG.Founder Principal & Controller,Jhalawar Medical College & Hospital Jjalawar.MGMC & Hospital , sitapura ., Jaipur

2. ANTEPARTUM FETAL MONITORING Two thirds of fetal deaths occur before the onset of labor,many of which are due to uteroplacental insufficiency. No single test can detect abn with 100% accuracy Ideal detection: allows intervention before fetal death ordamage from asphyxia. Preferable: treat disease process and allow fetus to go toterm.DRAWBACK- false positive / negative results may causeundue intervention and lead to premature iatrogenic deliveryor fetal compromise. 3. METHODS OF ASSESSMENTAssessment of Uterine growthFetal movement countingNon stress test- indicator of fetal health.Contraction stress test indicator of U.P func.Fetal Biophysical profileModified Biophysical profileDoppler velocimetryPercutaneous umbilical blood sampling 4. Occurs due to inadequate delivery of nutritive &respiratory substt to fetal tissues.Can be due to:-Inadequate exchangeMaternalFetal uptakewithin placenta dueinadequacy to problemsto-deliver nutrients &oxygen through1. increasedplacentathickness2. reduced blood flow3. decreased sf area 5. SEQUENCE OF FETALDETERIORATION/COMPROMISEGeneralized Fetal Well Being with some Nutritional CompromiseFetal Growth Retardation with Marginal Placental Dysfunction Fetal Hypoxia under Stress cond. with DecreasingRespiratory Function Asphyxia/Death/Residual effects with Profound Respiratory Compromise 6. MATERNAL RISK FACTORS OF UPI1. PRE-ECLAMPSIA , CHRONIC HYPERTENSION2. COLLAGEN VASCULAR DISEASES3. DIABETES MELLITUS4. RENAL DISORDERS5. BLOOD- MATERNAL ANAEMIA, RH SENSITISATION6. HYPERTHYROIDISM7. THROMBOPHELIA8. CYANOTIC HEART DISEASE9. POST DATED PREGNANCY10.FETAL GROWTH RESTRICTION 7. UTERINE GROWTH ASSESSMENTGeneral rule: Fundal height in centimeters = weeks ofgestation (2nd trim.)Johnsons formula = [Ht. of uterus above symphysis (cm) 12 (vx at or above ischial spines)OR 11 (vx below ischial spines)] x 155Exceptions: Maternal Obesity, MultipleGestation, Polyhydramnios, Abnormal FetalLie, Oligohydramnios, Low Fetal Station, and Fetal GrowthRestriction.Abnormalities of fundal height should lead to further 8. FETAL MOVEMENTCOUNTINGMATERNAL PERCEPTION OF REDUCTION IN MOVEMENTS MAYBE A RED FLAG SIGN TO IMPENDING FETAL DISTRESS. 9. 4 fetal behaviour states as described by Nijhuis & colleagues (1982)based on fetal movements, fetal heart rate & eye movements :-1. State 1F- Quiescent state- quiet sleep with narrow oscillatorybandwidth of fetal heart rate.2. State 2F- Frequent gross body movements, cont. eyemovements, wider oscillations of fetal heart rate. (=REM ofneonate)3. State 3F- Continuous eye movements in absence of bodymovements and heart rate accelerations. The existence of suchstate is doubtful4. State 4F- Vigorous body movements with constt eye movementsand heart rate accelerations. 10. USG observations show that fetus has gross body movementsapprox 10% of the time and as many as 30 movements can occur inan hour.Most commonly used method is COUNT TO 10(Moore et all 1989) [Am J Obs-Gyn]Patients are instructed to count until they reach 10 movements.If such 10 movements are noticed in 10 hours, most probably thefetus is in good health. (1 movement in each hour).If mother reports 31wks 90% 17. NST is to be read keeping in account all the variables namely,1. Baseline FHR2. Variability of FHR3. Presence /absence of decelerations4. Presence /absence of accelerationseach one being separately analysed. Normal baseline FHR IS 110-160 bpm.>160 is tachycardia & 36 wks, best option is deliveryb) 40% of total fetal ventricular output directed to placenta obliteration of utero placental circulation increases afterload further hypoxiadilatation & redistribution of MCA blood flowpressure rises in Ductus Venosus due to increased afterload to right side of fetal heart 33. Vessel normally has forward flow throughout cardiac cycle & diastolic flowincreases as gestation advances.So, S/D ratio decreases as gestation advances, from 4 at 20 wks to 0.72 is greater than the normal limits from 26 weeksgestation onwards. 34. Abnormal waveforms can be present for weeks before there is evidence offetal compromise.These are a marker of a high risk situation and should not normally be usedin isolation as an indication for delivery.Most would consider delivering a fetus with absent end-diastolicvelocity from about thirty two weeks gestation followingadministration of corticosteroids.However, reversal of end diastolic blood flow is an ominous sign &predicts severe fetal compromise, possible death, requiring urgentdelivery of the viable fetus. 35. Konjoe & colleagues (2001) [Br J of Obs & Gyn]Doppler studies of MCA showed, hypoxic fetii attempt brain sparing byreducing cerebrovascular impedance & thus reducing blood flow. In growth restricted fetii this effect shows reversal.The effect however, isnt protective, rather indicates negatively on the fetalhealth. 36. INCREASED DIASTOLICFLOW, due to reduced resistance.NORMAL doppler flowHighly reduced resistance, shown byFURTHER INCREASE OFDIASTOLIC FLOW.REVERSAL OF DIASTOLICFLOW, indicative of severe fetalcompromise. 37. F. Daffos (1983-1985)22 G / Finer needle needed.Can be performed at any site on umbilical cord, but placental insertionpreferred.One should avoid piercing through the placenta. 38. INDICATIONSa) Rapid Karyotype In Fetuses Detected With Anomalies On USG.b) Fetal Hemolytic Diseasec) Suspected Fetal Viral Infectiond) Non Immunologic Hydrops Fetalise) Suspected Fetal Thrombocytopeniaf) Twin To Twin Transfusiong) Fetal Heamoglobinopathies 39. RISKS BLEEDING FROM PUNCTURE SITEVASO VAGAL REFLEXFETAL BRADYCARDIA 40. Ideally an obstetrician should adequately inform the patient of allthe pros and cons of any test method being employed, and theefficacy and limitations of the same.In many instances, failing to do so, may cause the patient to haveunreasonable expectations which when unfulfilled may lead toanimosity and disappointment towards the doctor and causemedico-legal problems 41. SOURCES1. WILLIAMS TEXTBOOK OF OBSTETRICS 23RD EDITION.2. PRACTICAL BOOK TO HIGH RISK PREGNANCY 3RD EDITION by FERNANDO ARIAS.