Max MongelliWomen & Childrens’ Health

Nepean HospitalSydney, Australia

Assessment and Management of Abnormal Fetal Growth

Updated December 2009

Max Mongelli 2009

Max Mongelli 2009

Fields to be covered:Fields to be covered:

� Prevention

� Screening

� Diagnosis

� Management

� Long term complications

Max Mongelli 2009

Prevention of IUGRPrevention of IUGR

� Stop smoking� Avoid D & A� Aspirin if indicated� Minimize risk of multiple pregnancy� Minimize risk of infections� Treat thrombophilias� Pre-conceptional counselling

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NotNot effective in prevention:effective in prevention:

� Bed rest� Antihypertensive therapy� Folic acid� Long-chain PU fatty acids� Beta-mimetics

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Prevention of Prevention of MacrosomiaMacrosomia

� Normalise BMI prior to conception

� Early detection of GDM

� Good control of GDM

� ? Moderate exercise during pregnancy

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Screening for Abnormal Screening for Abnormal FetalFetal GrowthGrowth

� Fetal size estimation by palpation alone can be inaccurate

� Better results by measuring the symphysis-fundus height (SFH)

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Technique of SFH Technique of SFH MeasurementMeasurement

� Patient supine, bladder empty.

� Measuring tape should be blank on one side, cm markings on other side. Blank side up.

� SFH measured in cm from top of uterine fundus to the top of symphysis pubis.

� Measurement plotted on reference chart.

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Reference Charts for Antenatal Reference Charts for Antenatal Screening for Abnormal Screening for Abnormal FetalFetal GrowthGrowth

� Unadjusted, population based charts: inaccurate for many women

� Individually adjusted charts: customised growth charts

� Customised charts have lower false positive rates than unadjusted charts.

Max Mongelli 2009

Reference Charts for Antenatal Reference Charts for Antenatal Screening for Abnormal Screening for Abnormal FetalFetal GrowthGrowth

� Unadjusted, population based charts: inaccurate for many women

� Individually adjusted charts: customised growth charts� Customised charts have lower false positive rates than

unadjusted charts.� Better correlation with perinatal outcomes

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Examples of Customized Growth Examples of Customized Growth Charts for Antenatal Screening Charts for Antenatal Screening

Max Mongelli 2009

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Max Mongelli 2009

Max Mongelli 2009

Max Mongelli 2009

Max Mongelli 2009

Antenatal Diagnosis of Antenatal Diagnosis of SGA/IUGRSGA/IUGR

� SFH measurements alone cannot confirm.

� Possibility of IUGR if there is a growth deceleration pattern or a single small SFH measurement.

� Ultrasound examination is indicated if there is clinical suspicion.

Max Mongelli 2009

Max Mongelli 2009

Ultrasound Diagnosis of Ultrasound Diagnosis of SGA/IUGRSGA/IUGR

� Fetal biometry: HC, BPD, FAC, FL

� Can be converted to an estimated fetalweight (EFW)

� Amniotic fluid index (AFI)

� Doppler studies of umbilical arteries

� Screen for fetal anomalies (10% of IUGR)

� Cardiotocography (non-stress test)

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KaryotypeKaryotype

Fetal karyotype may be indicated if:

� IUGR is of early onset

� Severe (< 3rd pct)

� Associated with polyhydramnios

� Structural anomalies are present

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Doppler StudiesDoppler Studies

� Examination of umbilical arteries and MCA

� Proven to reduce PNM by 30%

� Abnormal if absent or reversed diastolic flow

� If abnormal in ductus venosus, fetal risk is very high

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Management of IUGR:Management of IUGR:InvestigationsInvestigations

� FBC, EUC, LFT’s, urate

� LAC, antiphospholipid antibodies

� TORCH/viral studies

� Chromosome studies

� Tests for celiac disease if indicated

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Management of IUGR:Management of IUGR:Conservative or elective Conservative or elective

delivery?delivery?

� Depends on severity of IUGR

� If close to term and fetus not compromised, induction of labour

� If there are signs of fetal distress cesarean section is indicated.

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Management of IUGR:Management of IUGR:ConservativeConservative

� Twice weekly U/S for AFI/flows

� Daily CTG’s

� 2 -weekly EFW measurements

� Antenatal steroids

� Pregnancy should not extend beyond 40 weeks’ gestation

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Complications of IUGR:Complications of IUGR:Short termShort term

� Hypoglycemia

� Hypothermia

� Hyperviscosity syndrome

� Impaired immune function

� RDS / NEC if preterm

� Birth asphyxia

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Complications of IUGR:Complications of IUGR:long termlong term

� Cerebral palsy

� Small decrease in IQ

� Reduced scores for executive cognitive functions

� Risk related to severity of IUGR

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The Barker HypothesisThe Barker Hypothesis

� IUGR fetuses compensate for adverse intrauterine environment by endocrine-metabolic reprogramming

� In adult life this leads to increased risk of hypertension, hypercholesterolemia, IGT, IHD

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Management of Management of MacrosomiaMacrosomia

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Differential Diagnosis of Differential Diagnosis of High SFHHigh SFH

� Macrosomia

� Polyhydramnios

� Multiple pregnancy

� Uterine fibroids

� Pelvic masses

� Maternal obesity

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Diagnosis of Diagnosis of LGA/LGA/MacrosomiaMacrosomia

� Ultrasound biometry

� Conversion to an estimated fetal weight

� Some centres use FAC only

� Cut-off for LGA is EFW>90th pct

� Cut-off for macrosomia 4500 g or 5000 g

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Accuracy of UltrasoundAccuracy of Ultrasound

� Less accurate for big babies

� Sensitivity ranges from 22% to 69%

� May not be more accurate than clinical palpation alone

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Complications of Complications of MacrosomiaMacrosomia

� Birth trauma

� Shoulder dystocia

� Erbs’ Palsy

� Birth asphyxia

� Neonatal hypoglycemia

� Neonatal jaundice

� Hypercalcemia, hypomagnesemia

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Shoulder Shoulder dystociadystocia

� Variable incidence – 0.5%

� Difficult to predict – recurrence risk 10%

� More likely in macrosomia, GDM, post-term, instrumental delivery, prolonged second stage

� 50% have no risk factors

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Complications of Complications of MacrosomiaMacrosomia::Long TermLong Term

� In GDM offspring

� Neurodevelopmental delay

� Reduced head circumference at 3 years of age

� Greater risk of type 2 DM

� Obesity

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Management of Management of MacrosomiaMacrosomia::Vaginal Delivery or C/S ?Vaginal Delivery or C/S ?

� Controversial issue

� Shoulder dystocia difficult to predict

� Some centres use 4500 g or 5000 g

� RCOG does not recommend C/S for suspected macrosomia

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Management of Management of MacrosomiaMacrosomia::Induction of Induction of LaborLabor ??

� Common request from patients

� No evidence that it reduces the risk of shoulder dystocia

� May possibly increase the risk of shoulder dystocia

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Postnatal Management of Postnatal Management of Unexpected/Undiagnosed IUGRUnexpected/Undiagnosed IUGR

� Many cases of IUGR not diagnosed until after delivery

� Confirmation with customised birth weight percentile

� Maternal follow in clinic to exclude underlying medical conditions