Definition→ Ultrasound estimated fetal weight <10th percentile or birth weight <3rd percentile for gestational age.
Neonates who are small for gestational age (SGA) (ie, birth weight <10th percentile) are also considered growth restricted if maternal risk factors for poor fetal growth (eg, maternal hypertension, preeclampsia) are present.
FGR occurs from a variety of etiologies, including maternal, placental, or fetal factors. Maternal factors include malnutrition (eg, hyperemesis gravidarum), substance use, and conditions leading to vasculopathies (eg, preeclampsia, pregestational diabetes). Fetal conditions include chromosomal aneuploidies and congenital infections.
| Symmetric | Asymmetric | |
|---|---|---|
| Onset | • 1st trimester | • 2nd/3rd trimester |
| Etiology | • Early insult that inhibits cellular growth and expansion. |
• Chromosomal abnormalities (MCC)
• Congenital infection (2nd MCC) | • Uteroplacental insufficiency
• RF: Maternal HTN, tobacco use, DM
• Maternal malnutrition | | Clinical features | • Global growth lag | • Head-sparing growth lag |
The atrial septal defect and this patient's age (>35) are suggestive of an underlying chromosomal abnormality (eg, trisomy 21).
Congenital intrauterine infections (eg, toxoplasmosis, cytomegalovirus) are a less common cause of symmetric growth restriction because first-trimester congenital infections are usually so severe that they often result in spontaneous abortion. If the fetus survives the early infection (particularly through organogenesis), severe malformations will be visualized on the ultrasound (eg, ventriculomegaly, intracerebral calcifications).
Maternal conditions, such as hypertension and pre gestational diabetes mellitus, predispose to abnormal placental development that causes progressive placental dysfunction (uteroplacental insufficiency) during the late second and/or third trimester. The fetus adapts to impaired blood flow and reduced oxygen delivery by redistributing blood to vital organs (eg, brain) and away from non vital organs (eg, abdomen, kidneys), causing a head-sparing growth pattern and associated oligohydramnios
Even when well controlled, hypertension can cause underdevelopment of the spiral arteries in the placenta, resulting in increased vascular resistance and reduced blood flow.
Very high amounts of caffeine (>300 mg) and severe caloric restriction (eg, eating disorder, hyperemesis gravidarum) can lead to asymmetric growth restriction.
Nutrition in pregnancy advices
one of the causes of inadequate weight gain is Hyperemesis Gravidarum
Fetuses with growth restriction have increased risk for intrauterine demise and neonatal morbidity/mortality (eg, preterm delivery).
Inaccurate pregnancy dating can result in an erroneous diagnosis of FGR. Best indicator of dating is first trimester crown rump length
| Management simillar for both types | • Regular nonstress testing • Weekly biophysical profiles • Serial umbilical artery Doppler sonography • Serial growth ultrasounds | | --- | --- |
| Management of neonate | • Monitor/treat complications (eg, hypoglycemia, hypothermia, polycythemia) • Hypoglycemia: frequent screening and frequent feedings • Hypothermia: skin to skin with mother, examinations in incubator • Polycythemia and hypocalcemia: screen if symptoms develop (eg, poor feeding, vomiting, jitteriness) | | --- | --- |
<aside> 💡 Catch-up growth is typically achieved by age 2, but long-term growth and neurodevelopmental abnormalities can occur.
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