Macrosomia: Overview of Fetal Complications 1Macrosomia
Authors: Brielle Cram Reviewers: Nicola Adderley, Crystal Liu, Yan Yu*, Danielle Nelson* * MD at time of publication
(A fetus larger than 4000- 4500 grams)
Size discrepancy between fetal shoulders and maternal pelvic inlet
Anterior shoulder becomes impacted behind the symphysis pubis during delivery
Shoulder Dystocia
(↑risk in infants of diabetic mothers – see slide on Gestational Diabetes)
Injuries acquired as a result of the birthing process in an infant with shoulder dystocia
↑ incidence of preterm birth
Surfactant deficiency
Respiratory Distress Syndrome
Umbilical cord compression
↓ delivery of oxygenated blood to fetus
Hypoxia/Asphyxia
Infant gasping
Perinatal aspiration of stained amniotic fluid
Meconium Aspiration Syndrome
↑ incidence of cesarean deliveries
↓ duration/absence of labour
↓ release of maternal epinephrine and glucocorticoids
↓ activation of epithelial sodium channels on type II pneumocytes
Delayed resorption of fetal lung fluid
Transient Tachypnea of the Newborn
Notes
↑ oxygen demands
Fetal hypoxia
↑ production of erythropoetin
Polycythemia Neonatal Jaundice
Maternal diabetes
↑ intrauterine exposure to
excessive nutrients and glucose
2Fetal Hyperinsulinism
↑ glucose utilization and suppression of hepatic glucose production
Termination of the maternal glucose supply at delivery
Hypoglycemia
Brachial Plexus Injury
Clavicular Fracture
Humeral Fracture
1. Complications of macrosomia ↑ with birth weight. Risk of stillbirth ↑ above 5 kg 2. Most common in the setting of poorly controlled maternal diabetes; however,
hyperinsulinism may be absent if macrosomia is secondary to a different etiology (e.g. post-term fetus, genetic conditions).
Legend:
Pathophysiology
Mechanism
Sign/Symptom/Lab Finding
Complications
Published September 22, 2019 on www.thecalgaryguide.com