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Jornal de Pediatria

Print version ISSN 0021-7557

J. Pediatr. (Rio J.) vol.80 no.4 Porto Alegre July/Aug. 2004 



Growth of preterm newborn infants



Francisco E. Martinez

Full professor, School of Medicine of Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil



At the end of the 19th century and beginning of the 20th century, Stephane Tarnier (1828-1897) and his student Pierre Budin (1846-1907), both obstetricians at L'Hôpital Maternité de Paris, attempted to systematize the care provided to preterm newborns.1 In their lessons, which I recommend reading, they showed concern with thermal control, prevention of infections and nutrition. Nutritional adequacy should be checked by weight gain.1 Budin believed these infants should have a growth rate similar to that of intrauterine growth. After more than one century, these principles have not become old-fashioned.

In the mid-20th century, intrauterine growth curves were created, and seminal data collected by Lubchenco et al. between 1948 and 1961 were published.2 With the passing of time, several other intrauterine growth curves were published and several aspects began to be considered. Quite often, it was considered that curves were built from births and, consequently, they should not represent unborn infants. A cross-sectional study design was used, in which the data were collected from different sources, with sample sizes that were not always appropriate, and in which it was difficult to establish the correct gestational age, different races and even considerations about the effect of the altitude where the data were collected.3 Despite much criticism, these curves provided a lot of information. An important fact is that it was difficult to achieve the growth planned for preterm infants. By comparing the growth of preterm infants with that of the intrauterine fetus, one notes that most preterm infants, even those with appropriate-for-gestational-age weight, have an initial weight loss that places them below the 10th percentile, which characterizes dietary restriction.4 Still today, preterm babies are undernourished in our hospital nurseries, a percentage that reaches nearly 90% after hospital discharge.5

Another method to assess the growth of preterm infants is to compare it with postnatal growth curves, as presented by Anchieta et al. in the current issue of Jornal de Pediatria.6 This type of curve, based on surviving infants, has the advantage of using longitudinal data and predicting the initial weight loss. However, this approach is not free of criticism. These curves obviously depend on neonatal care practices, especially nutritional practices. Since managements fortunately improve, the results become obsolete with time. It is important to pay attention to the time at which the data were collected and to the practices adopted at that time. The restriction on the postnatal use of diuretics and corticosteroids and the new nutritional practices may cause significant changes in future curves.7

If, on the one hand, nutritional deficiency produces long-lasting consequences, on the other hand, the attempt to maintain a growth rate that is similar to that which occurs in utero, with excess supply, may also have its consequences. It has been suggested that acceleration of growth with fortified formulas, comparatively to human milk, may trigger a metabolic syndrome with subsequent hypertension, dyslipidemia, obesity and insulin resistance, acting as a predisposing factor for cardiocirculatory disease.8

Thus, the growth curves published in the current issue are of utmost importance, as they help us to understand more about postnatal growth, may be used to detect infants with growth disorders and help us to plan future intervention studies. However, these curves have to be regularly redesigned, due to the continuous changes in neonatal care. Systematized multicenter registers may provide a continuous database, with the aim of keeping Brazilian postnatal growth curves up-to-date.



1. Budin PC. Le nourrison: alimentation et hygiene. Enfants debile et enfants nes a terme. Paris: Doin; 1900.( )

2. Lubchenco LO, Hansman C, Dressler M, Boyd E. Intrauterine growth as estimated from liveborn birth-weight data at 24 to 42 weeks of gestation. Pediatrics. 1963;32:793-800.

3. Anderson DM. Nutritional assessment and therapeutic interventions for the preterm infant. Clin Perinatol. 2002;29:313-26.

4. Ehrenkranz RA, Younes N, Lemons JA, Fanaroff AA, Donovan EF, Wright LL, et al. Longitudinal growth of hospitalized very low birth weight infants. Pediatrics. 1999;104:280-9.

5. Dusick AM, Poindexter BB, Ehrenkranz RA, Lemons JA. Growth failure in the preterm infant: can we catch up? Semin Perinatol. 2003;27:302-10.

6. Anchieta LM, Xavier CC, Colosimo EA. Crescimento de recém-nascidos pré-termo nas primeiras doze semanas de vida. J Pediatr (Rio J). 2004;80:267-76.

7. Ziegler EE, Thureen PJ, Carlson SJ. Aggressive nutrition of the very low birthweight infant. Clin Perinatol. 2002;29:225-44.

8. Singhal A, Lucas A. Early origins of cardiovascular disease: is there a unifying hypothesis? Lancet. 2004;363:1642-5.

7. Ziegler EE, Thureen PJ, Carlson SJ. Aggressive nutrition of the very low birthweight infant. Clin Perinatol. 2002;29:225-44.