Phenotype of Infants of Mothers with Gestational Diabetes

  1. Patrick M. Catalano, MD,
  2. Alicia Thomas, RD,
  3. Larraine Huston-Presley, MS and
  4. Saeid B. Amini, PHD, MBA, JD
  1. From the Department of Reproductive Biology, Case Western Reserve University, MetroHealth Medical Center, Cleveland, Ohio
  1. Address correspondence and reprint requests to Patrick M. Catalano, MD, Department of Reproductive Biology, Case Western Reserve University, MetroHealth Medical Center, 2500 MetroHealth Dr., Cleveland, OH 44109. E-mail: pcatalano{at}metrohealth.org

The phenotype of the infant of the diabetic mother is generally perceived as being macrosomic or large for gestational age. However, not all infants of women with gestational diabetes mellitus (GDM) are macrosomic and, under certain circumstances, because of the interaction of genes and environment, can present as small for gestational age at birth. In contrast, the macrosomic infant presenting with hypoglycemia may not necessarily be the infant of a woman with GDM, but have an underlying metabolic or genetic dysregulation accounting for a similar phenotype. In this review, we will attempt to review the increasing prevalence of obesity in adults, adolescents, and possibly neonates as well. In an effort to better define macrosomia in the infant of the GDM mother, we will review the body composition analyses of infants of GDM mothers. Last, in addition to well-known factors such as maternal glucose control and overall nutrient availability, we will discuss the independent effect of maternal pregravid obesity on fetal adiposity in the infant of the GDM mother. We will be able to develop rational treatment modalities only if we have a better understanding of the various maternal components and factors relating to growth in these infants.

PHENOTYPE—

The word “phenotype” has its origins in the Greek language: phainein, to show or appear, and typos, a type or mark. In reviewing the definition of phenotype, it became apparent that the meaning of the word has changed over the past few decades. In the 1960s, the standard definition in a medical dictionary was “the outward visible expression of the hereditary constitution of an organism” (1). This definition appeared well suited to descriptions of the fetus of a diabetic mother at that time. For example, in Pedersen's text, the external appearance of the infant of the mother with diabetes is described …

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