Labor induction 26,118 (13) 2499 (14) 420 (15) 39 (10) 0.141 Prolonged second stage 6905 (4) 899 (5) 147 (5) 14 (4) <0.001 Chorioamnionitis 13,448 (7) 1778 (1n0) 295 (1n0) 35 (9) <0.001 pH <7.0 925 (0.5) 96 (0.6) 20 (0.7) 4 (1.1) 0.039
Apgar <7 @ 5 minutes 1898 (1n.0) 80 (0.5) 22 (0.8) 10 (2.7) <0.001
ICN admission 4266 (2.2) 123 (0.7) 36 (1n.3) 9 (2.4) <0.00'1
Fractured clavicle 1880 (1.0) 616 (3.5) 125 (4.4) 16 (4.3) <0.001
Mechanical ventilation 2305 (1n.2) 54 (0.3) 11 (0.4) 9 (2.4) <0.001
Hypoglycemia 480 (0.2) 89 (0.5) 31 (1.1) 12 (3.2) <0.001
Hyperbilirubinemia 5829 (3.0) 305 (1.7) 60 (2.1) 12 (3.2) <0.001
Erb palsy 470 (0.2) 224 (1n.3) 74 (2.6) 22 (5.9) <0.001
Neonatal death 402 (0.2) 3 (0) 2 (0.1) 1 (0.3) <0.001 aOutcome data presented as n (%).
ICN = intensive care nursery.
2017; Hehir, 2015). Rates of postpartum hemorrhage, perineal laceration, and maternal infection, which are related complications, are also higher in mothers delivering overgrown newborns. Maternal and neonatal outcomes by birthweight for large babies >4000 g delivered at Parkland Hospital are shown in Table 44-4.
Because current methods fail to accurately estimate excessive fetal size, macrosomia cannot be deinitively diagnosed until delivery. Inaccuracy in clinical estimates of fetal weight by physical examination is often attributable, at least in part, to maternal obesity. Numerous attempts have been made to improve the accuracy of sonographic fetal-weight estimation. Several formulas have been proposed to calculate fetal weight using measurements of the head, femur, and abdomen. Estimates provided by these computations are reasonably accurate for predicting the weight of small, preterm fetuses but are less valid in predicting the weight of large fetuses. In one study of 248 LGA and 655 non-LGA newborns from pregnancies complicated by diabetes, only 23 percent of women diagnosed with an LGA fetus before delivery actually delivered an LGA infant (Scifres, 2015). his resulted in a more than threefold rise in the cesarean delivery rate for suspected LGA birthweights.
From the foregoing, it is apparent that sonographic estimation of fetal weight is unreliable, and its routine use to identiy macrosomia is not recommended. Indeed, the American College of Obstetricians and Gynecologists (2016a) concludes that clinical fetal weight estimates are just as accurate as sonographic ones.