SMALL FOR GESTATIONAL AGE

SGA definitionSGA refers to size of infant at birth: IUGR is not synonymous, although the two may be associated.Avergage weight at birth is 7 lbs. LBW < 2500g [5lb 8oz]VLBW 8 lbs 13 oz ( >4000g ) are considered LGA.Macrosomia defined as weight > 9 lb 15 oz ( >4500g ), or above the 97th percentile. During pregnancy, estimate height of the fundus from the pubic bone. This value in centimeters usually correlates with the # of weeks of pregnancy.

Evaluating MacrosomiaUltrasound is less accurateIf the fetus dates are known, the best measurement to evaluate macrosomia is mothers abdominal circumference. Initial abdominal circumference above 70th percentile is strongly associated with delivery of an infant that is LGA. If the fetus dates are unknown, the Femur length/abdominal circumference ratio is an age-independent method of identifying fetus at risk for macrosomia.

LGA Risk FactorsMCC: Diabetic mother, especially poor glycemic control in third trimester. Maternal insulin resistance in 2nd half of pregnancy due to hPL, cortisol and prolactinMaternal obesity - associated with a 3- to 4-fold increased likelihood of fetal macrosomiaPregnancies lasting beyond 40 weeksMale sex - male fetuses are an average of 150 g heavier than appropriately matched female fetuses at each gestational week during late pregnancy Increased maternal ageMultiparityGenetic growth disorders:Beckwith-Wiedemann syndrome, Sotos syndrome#LGA complicationsHigher incidence of stillbirth Polycythemia - significantly higher absolute nucleated red blood cell counts, lymphocyte counts, and packed cell volumes (due to chronic intrauterine hypoxia)Higher risk of dystocia. Depends on size of baby, head circumference and pelvic diameter of the motherErbs palsy, Klumpkes paralysisUsually C-section to safely deliver babyComplications of low blood sugar in baby postpartumCheck babys blood sugar [FIRST] and feed early if hypoglycemic [SECOND]Increased incidence of birth defectsFeeding difficultiesHyperbilirubinemia Maternal complications: Cesarean section, postpartum hemorrhage, shoulder dystocia, perineal trauma, operative vaginal deliveryReferences1.) Peter A. Lee, Steven D. Chernausek, Anita C. S. Hokken-Koelega and Paul Czernichow. International Small for Gestational Age Advisory Board Consensus Development Conference Statement: Management of Short Children Born Small for Gestational Age. Pediatrics 2003. 111:1253-1261.2.) Landon MB, Catalano PM, Gabbe SG. Diabetes mellitus complicating pregnancy. In: Gabbe SG, Niebyl JR, Simpson JL, eds.Obstetrics: Normal and Problem Pregnancies. 5th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2007:chap 37.3.) Michael A. Berk,Francis Mimouni,Menachem Miodovnik, Vicki Hertzberg,andJennifer Valuck. Macrosomia in Infants of Insulin-Dependent Diabetic Mothers. Pediatrics1989;83:61029-10344.) Williams Obstetrics: 23rd Edition: F. Cunningham, Kenneth Leveno, Steven Bloom, John Hauth, Dwight Rouse, Catherine Spong.Via Accessmedicine.com