Infants of diabetic mothers with abnormal fetal growth missed by standard growth charts

Abstract

Diabetic pregnancies may result in fetal macrosomia when glycaemia is poorly controlled, and when associated with diabetic vasculopathy, with small for gestational age (SGA) neonates. Both groups of infants have high neonatal morbidity. As fetal growth depends on maternal genetic influences, ethnic group or parity, relying exclusively on population-based growth charts may wrongly categorise the growth pattern of these infants. We compared neonatal morbidity and mortality of a cohort of 214 infants of diabetic mothers (IDM), identified either by population standards or by customised birth weight percentiles (adjusted for maternal height, booking weight, parity, ethnic origin, gestational age at delivery and sex). A total of 68 (31.8%) were diagnosed with macrosomia, 11 (16%) of whom were identified by the customised growth method alone, and 16 were diagnosed as SGA (7.5%), of whom the majority (13 or 81.2%) were identified by the customised growth method alone. None had increased mortality and morbidity.

Application of Customized Birth Weight Curves in the Assessment of Perinatal Outcomes in Infants of Diabetic Mothers

“…Sample size was very small in all three (214, 155 and 212, respectively, vs. 1,921 cases in our study). Our results agree with those of Narchi and Skinner [22] where CC allowed the detection of false-negative LGA (16 vs. 3.8% in our study) and SGA (81.2 vs. 29% in our study), which would not have been identified using non-CC, but these authors were unable to demonstrate a higher risk of perinatal complications in these infants. These results coincide with those of Rowan et al [24], although they only considered women with type 2 DM and did not assess the effect of CC classification on LGA infants.…”

“…We have only found three studies in which CC versus non-CC are used to classify and compare IDM as LGA and/or SGA according to birth weight [22,23,24]. Sample size was very small in all three (214, 155 and 212, respectively, vs. 1,921 cases in our study).…”

Early diagnosis and treatment referral of children born small for gestational age without catch-up growth are critical for optimal growth outcomes

“…These modifying factors can be used to statistically model a corrected birth weight and/or length, and may increase the likelihood of identifying abnormal fetal growth compared with constitutional smallness [30]. This approach to growth assessment adjusts for physiological variation, calculates true growth potential, and creates individually customized fetal, neonatal, and child growth curves and birth weight percentiles [30-33]. Methodology for customized growth assessment is currently being developed and is not yet widely available.…”

Re: Letter by Mongelli and Gardosi

“…Sir, We thank Mongelli and Gardosi for their interest in our paper (Narchi and Skinner 2009). They correctly noted, as we did, that the observed prevalence of complications in neonates diagnosed to be macrosomic by the customised growth method, was higher than in the group diagnosed by the standard population method.…”

“…Dear Sir, In their recent article, Narchi and Skinner (2009) compared the performance of the customised growth charts and population-based charts in newborns of diabetic mothers. While they report, correctly, that customised centiles reduce false positive LGA and SGA babies, we were puzzled by their conclusion that customised centiles do not identify more infants at increased risk of morbidity following a pregnancy complicated by diabetes than standard birth weight centiles.…”