Late onset IUGR managment S-Borna.MD, Perinatolgy Dep, Vali-e-Asr hospital,TUMS

Definition: (several different definitions have been used) Abdominal circumference below 10th percentile Weight at birth <2500 g EFW <10th percentile AC <10th percentile EFW <10th percentile with abnormal Doppler indices in the umbilical artery or middle cerebral artery AC <10th percentile with abnormal umbilical artery or middle cerebral Doppler studies.

ACOG (PB 134) usage of terms: (distinguished by the time of identification) IUGR (FGR): Fetus with estimated weight below 10th percentile. SGA: Newborns with weight below the 10th percentile for gestational age.

Categorizing IUGR based on Gestational Age at time of Diagnosis Very early IUGR: Diagnosed <29 weeks Early IUGR: Diagnosed between >29 and <34 weeks Late IUGR: Diagnosed >34 weeks Asymmetric Asymmetric  Late onset  Environmental  Growth arrest  Higher risk for transitional problems  Brain sparing Examples  Chronic hypoxia  Preeclampsia (PIH, PET)  Chronic hypertension  Malnutrition

Consequences: An association between birth weight below the 10th percentile and development later in life of hypertension, hypercholesterolemia, coronary heart disease, impaired glucose tolerance, and diabetes.

I.U.G.R. The role of Doppler (1) Umbilical artery Uterine artery Middle cerebral artery Ductus venosus

Staging of IUGR Stage 0: fetuses with an EFW or an AC <10th percentile. Doppler of the umbilical artery and middle cerebral artery is normal. Stage I: fetuses whose EFW or AC is <10th percentile plus abnormal Doppler flow of the umbilical artery or middle cerebral artery.

Stage II: fetuses whose EFW or AC is <10th percentile plus absent or reversed Doppler flow of the umbilical artery. Stage III: fetuses whose EFW or AC is <10th percentile plus absent or reversed Doppler flow of the ductus venosus. Based on the AFI, the IUGR fetus will be either: “A” AFI <5 cm “B” AFI >5 cm

Staging System and Management Stage 0 SGA: fetuses have a good prognosis. Manage as outpatient with Doppler assessment every 2 weeks. If Doppler remains normal, delivery is recommended at term. If the Doppler becomes abnormal, these fetuses are managed as Stage I IUGR fetuses.

Normal umbilical artery Doppler provides strong evidence of fetal well- being, especially in the absence of risk factors for, or signs of, uteroplacental insufficiency. deliver these fetuses at 39 to 40 weeks of gestation.

Figure 2 The normal umbilical artery flow velocity waveform has marked positive end-diastolic velocity that increases in proportion to systole toward term (A). Moderate abnormalities in the villous vascular structure raise the blood flow resistance and are associated with a decline in end-diastolic velocities (B). When a significant proportion of the villous vascular tree is abnormal (50-70%), end-diastolic velocities may be absent (C) or even reversed (D). Depending on the magnitude of placental blood flow resistance and the fetal cardiac function, reversal of end-diastolic velocities may be minimal (D), moderate (E), or severe (F). In the latter case precordial venous flows were universally abnormal. (Reprinted with permission.36)

Stage I IUGR fetuses have mild growth restriction, and affected mothers without preeclampsia are usually managed as outpatients. Antenatal corticosteroids should be given at time of diagnosis. Twice-weekly antenatal testing is recommended. If NST remains reactive and AFI remains >5 cm, delivery recommended at 38-39weeks. If umbilical artery Doppler becomes absent, these fetuses should be managed as Stage II IUGR.

Decreased diastolic flow (pulsatility index >95 th percentile) in the umbilical artery is a weak predictor of fetal death. perform a BPP twice per week and deliver these fetuses at term w ( NST remains reactive and AFI remains >5) or when the BPP score becomes abnormal.

deliver fetuses with decreased diastolic flow (pulsatility index >95 th percentile) at term. Early term delivery (37 to 38 weeks) if risk factors for, or signs of, uteroplacental insufficiency are present, such as oligohydramnios, preeclampsia or hypertension, renal insufficiency, fetal growth arrest, estimated weight <5 th percentile, or prior birth of a small for gestational age infant.

Figure 2 The normal umbilical artery flow velocity waveform has marked positive end-diastolic velocity that increases in proportion to systole toward term (A). Moderate abnormalities in the villous vascular structure raise the blood flow resistance and are associated with a decline in end-diastolic velocities (B). When a significant proportion of the villous vascular tree is abnormal (50-70%), end-diastolic velocities may be absent (C) or even reversed (D). Depending on the magnitude of placental blood flow resistance and the fetal cardiac function, reversal of end-diastolic velocities may be minimal (D), moderate (E), or severe (F). In the latter case precordial venous flows were universally abnormal. (Reprinted with permission.36)

Stage II IUGR: fetuses managed as inpatients. Fetus should undergo daily antenatal testing with twice- daily NST and daily BPP. If NST remains reassuring and the BPP score remains between 6 and 8 continuation of expectant management is recommended. Antenatal steroids at time of diagnosis. Delivery at 34 weeks. If NST becomes non-reassuring or if BPP score 4 of 8 on 2 occasions at least 4 hours apart, immediate delivery by cesarean section is recommended.

Figure 4 In the ductus venosus blood flow is always antegrade throughout the cardiac cycle under normal circumstances. Pulsatility is less pronounced in waveform patterns obtained at the inlet (A) versus the outlet (B). With impaired cardiac forward function there is a decline in forward flow during atrial systole (C). If progressive atrial forward flow may be lost (D) or reversed (E, F). (Reprinted with permission.36)

: Stage III IUGR: Managed same as Stage II except for delivery at 32 weeks regardless of age at time of diagnosis. Steroids at time of diagnosis. Mg sulfate neuroprotection

Doppler Ultrasound as an Indication for Delivery Delivery solely on the basis of abnormal Doppler studies has not been proven beneficial and, in most cases, fetuses with abnormal Doppler studies do well in the setting of reassuring antenatal testing. If antenatal FHR testing is Category III, then immediate delivery is warranted. BPP<6,DV absent or reverse,pulsatile UM vein

Category III FHR tracings include either: Absent baseline FHR variability and any of the following: - Recurrent late decelerations - Recurrent variable decelerations - Bradycardia Sinusoidal pattern

Delivery Mode for IUGR Fetuses Data support cesarean delivery when there is absent or reversed flow of the umbilical artery because these fetuses rarely tolerate attempts at vaginal delivery. A fetus >34 weeks with an abnormal umbilical artery S/D ratio but a normal BPP is not likely to tolerate labor.

If antenatal testing (nonstress test or biophysical profile) is normal, a trial of labor with continuous intrapartum monitoring is reasonable Women delivering by Caesarean section with risk factors such as obesity, age > 40, or severe preeclampsia should receive prophylactic subcutaneous heparin until discharge to prevent venous Thromboembolism placental pathologic examination.

Recurrence ● There is a tendency to repeat small for gestational age or low birth weight deliveries in successive pregnancies. Growth restriction, preterm delivery, preeclampsia, abruption, and stillbirth can all be sequelae of impaired placental function that may manifest in different ways in different pregnancies

Prevention in subsequent pregnancies any potentially treatable causes of FGR Avoiding a short or long interpregnancy interval low-dose aspirin prophylaxis during pregnancy reduced the risk of recurrent FGR in women at high riskaspirin Whether anticoagulation with unfractionated heparin or low-molecular weight heparin reduces the risk of recurrent placenta-mediated late pregnancy complications, such as growth restriction, is unclearunfractionated heparin

Management of subsequent pregnancies Accurate dating by early ultrasonography is important to establish gestational age and intermittent ultrasound examinations are used to monitor fetal growth. prenatal management is routine. If fetal growth is normal, FGR in a previous pregnancy is not an indication for antepartum fetal surveillance with nonstress tests, biophysical profiles, or umbilical artery Doppler velocimetry