Abstract

INTRODUCTION

There is general consensus that anthropometric measures (mainly birth weight, crown-rump length and head circumference) are useful parameters for monitoring fetal growth and a neonate’s nutritional status.(¹1. World Health Organization. Physical status: the use and interpretation of anthropometry. Report of a WHO Experts Committee. Technical Report Series No. 854. Geneva: World Health Organization; 1995.–⁴4. Usher R, McLean F. Intrauterine growth of live born Caucasians infants at sea level. Standard obtained from measurement of 7 dimensions of infants born between 25 and 44 weeks of gestation. J Pediatr. 1969 Jun;74(6):901–10.) Intrauterine growth parameters are important when establishing short- and medium-term postnatal prognosis.

Population studies as well as studies of selected neonatal groups are needed to assess whether an infant has attained satisfactory growth and nutritional status and to identify at-risk groups. This necessity is corroborated by multiple investigations (including those by Lausman in Canada,(⁵5. Lausman A, McCarthy FP, Walker M, Kingdom J. Screenings, diagnosis and management of intrauterine growth restriction. J Obstet Gynecol Can. 2012 Jan;34(1):17–28.) Polloto(⁶6. Pollato EK, Kilbride HW. Perinatal outcome and later implication of intrauterine growth restriction. Clin Obstet Gynecol. 2006 Jun;49(2):257–69.) and Lagos(⁷7. Lagos SR, Busto ML, Orellana C. Evaluación neonatal del crecimiento intrauterino de recién nacidos en Hospital Regional de Temuco. Comparación con tres estándares nacionales. Rev Chil Obstet Ginecol. 2009;74(4):209–16. Spanish.)) that examine potential neonatal complications from intrauterine growth restriction, such as respiratory distress, hypothermia, hypoglycemia and necrotizing enteritis. Other disorders can also occur in early childhood (cardiovascular diseases, arterial hypertension, diabetes mellitus and kidney problems, etc.). Studies by Manalich,(⁸8. Maãalich R, Reyes L, Herrera M, Melendi C, Fundora I. Relationship between weight at birth and the number and size of renal glomeruli in humans: a histomorphometric study. Kidney Int. 2000 Aug;58(2):770–3.) Susuki,(⁹9. Susuki T, Minami J, Ohrui M, Ishimitsu T, Matsuoka H. Relationship between birth weight and cardiovascular risk factors in Japanese young adults. Am J Hypertens. 2000 Aug;13(8):907–13.) Fattal(¹⁰10. Fattal-Valeski A, Berheim J, Leitner Y, Redianu B, Bassan H, Harel S. Blood pressure values in children with intrauterine growth retardation. Isr Med Assoc J. 2001 Nov;3(11):805–8.) and Perez(¹¹11. Pérez Caballero MD, Valdés Armenteros R, Tasis Hernández M, Cordies Jackson L. Bajo peso al nacer y su relación con la hipertensión arterial en adolescentes y jóvenes. Rev Cubana Med. 2004 Sep;43(5–6). Spanish.) elucidate some of the evidence related to these.

Assessment of birth weight alone, however, started to lose ground after studies by Lubchenco(¹²12. Lubchenco LO, Hansman C, Dressler M, Boyd E. Intrauterine growth estimated for live born birth weight from 24 to 42 weeks of gestation. Pediatrics. 1963 Nov;32:793–800.) and Battaglia and Lubchenco(¹³13. Battaglia FC, Lubchenco LO. A practical classification of newborn infants by weight and gestational age. J Pediatric. 1967 Aug;71(2):129–33.) began to examine weight in relation to gestational age (in weeks) and growth percentile curves, making it possible to identify the following categories: small for gestational age (SGA) if the infant’s birth weight is below the 10th percentile (P10); appropriate for gestational age (AGA) if the infant’s weight is in the 10th–90th percentile range; and large for gestational age (LGA) for infants whose birth weight exceeds the 90th percentile. In light of the lack of any previously established standards, these new standards were rapidly accepted and applied, especially here in the Americas.

As time passed, however, new weight standards related to gestational age (in weeks) were proposed by Latin American authors such as Alarcón,(¹⁴14. Alarcón J, Alarcón Y, Hering E, Buccioni R. Curvas antropométricas de recién nacidos chilenos. Rev Chil Pediatr. 2008 Aug;79(4):364–72. Spanish.) González,(¹⁵15. González PR, Gómez RM, Castro RS, Nien JK, Merino PO, Etchegaray AB, et al. Curva nacional de distribución de peso al nacer según edad gestacional. Chile 1993–2000. Rev Med Chile. Oct;132(10):1155–65. Spanish.) Pazcusso,(¹⁶16. Pazcusso-Lima C, Pazcusso-Lima MR, Colmenares NM, Gavidia R. Patrones de peso al nacer en Venezuela, influencia de la edad maternal y paridad. Rev Obstet Ginecol Venez. 2009 Sep;69(3):162–71. Spanish.) Parra,(¹⁷17. Parra L, Hermoza S, Dávila Ruíz RE, Parra Vergara J, Chumbe Ruiz O, Orderique L. Curvas de crecimiento intrauterino en el Hospital Maria Auxiliadora. Rev Perú Pediatr. 2007 Jan–Apr;60(1):20–9. Spanish.) and Urquía,(¹⁸18. Urquía ML, Alazraqui M, Spinelli HG, Frank JW. Referencias poblacionales argentinas de peso al nacer según multiplicidad de partos, sexo y edad gestacional. Rev Panam Salud Pública. 2011 Feb;29(2):108–19. Spanish.) who presented evidence that P10 figures were higher than those found by Battaglia and Lubchenco.(¹³13. Battaglia FC, Lubchenco LO. A practical classification of newborn infants by weight and gestational age. J Pediatric. 1967 Aug;71(2):129–33.) After 1995, when WHO established criteria to set these standards,(¹1. World Health Organization. Physical status: the use and interpretation of anthropometry. Report of a WHO Experts Committee. Technical Report Series No. 854. Geneva: World Health Organization; 1995.) numerous studies were conducted in Latin America with country-specific populations; Parra,(¹⁷17. Parra L, Hermoza S, Dávila Ruíz RE, Parra Vergara J, Chumbe Ruiz O, Orderique L. Curvas de crecimiento intrauterino en el Hospital Maria Auxiliadora. Rev Perú Pediatr. 2007 Jan–Apr;60(1):20–9. Spanish.) Ticona,(¹⁹19. Ticona Rendón M, Huanco Apanza D. Curva de crecimiento intrauterino de recién nacidos peruanos. Rev Chil Obstet Ginecol. 2008 Jan;73(2):110–8. Spanish.,²⁰20. Ticona Rendón M, Huanco Apaza D, Remirez Atencio C. Identificación de nueva población de riesgo neonatal con curvas de crecimiento intrauterino peruanas. An Pediatr. 2006 Aug;65(2):118–22. Spanish.) and more recently, Villamonte(²¹21. Villamonte W, Jeri M, Lajo L, Monteagudo Y, Diez G. Peso al nacer en recién nacidos a término en diferentes niveles de altura en el Perú. Rev Peru Ginecol Obstet. 2011;57(3):144–50. Spanish.) in Peru; Montoya in Colombia;(²²22. Montoya N. Curvas de pesos al nacer. Rev Salud Pública Colombia. 2007 Jan–Mar;9(1):12 p. Spanish.); San Pedro in Argentina;(²³23. San Pedro M, Grandi C, Larguia M. Estándares de peso para la edad gestacional en 58,706 recién nacidos sanos de una maternidad pública de Buenos Aires, Argentina. Rev Medicina (Buenos Aires). 2001;61:15–22. Spanish.) and Lagos and Juez in Chile.(²⁴24. Lagos R, Espinoza González R, Echevarría P, Orellana JJ. Gráfica regional de crecimiento fetal: comparación con estándar internacional. Rev Chil Obstet Ginecol. 1998;63(5):370–5. Spanish.–²⁶26. Juez G. Curvas de crecimiento intrauterino para el diagnóstico apropiado del crecimiento intrauterino restringido. Rev Med Chil. 1989 Jul–Aug;60(4):198–202. Spanish.)

Intercountry differences observed in their results may be due, among other factors, to variations in features of the population studied, varying demographic and environmental factors, sample size and varying inclusion/exclusion criteria applied by the researchers.(²⁷27. Ayerza Casas A, Rodríguez Martínez G, Samper Villagrasa MP, Ventura Faci P. Nacer pequeão para la edad gestacional puede depender de la curva utilizada. Nutr Hosp. 2011 Jul–Aug;26(4):752–8. Spanish. 28. Vázquez R, Caparro R. Curvas de crecimiento en recién nacidos de altura. Proceedings of XXII Congreso Peruano de Pediatría; 2002; Arequipa, Perú. [Arequipa]: [publisher unknown]; 2002. Spanish. 29. Ray JG, Sgro M, Mamdani MM, Glazier RH, Bocking A, Hilliard R, et al. Birth weight curves tailored to maternal world region. J Obstet Gynecol Can. 2012 Feb;34(2):159–71.–³⁰30. De Souza LR, Urquia ML, Sgro M, Ray JG. One size do not fit all: differences in newborn weight among mother of Philippines and other East Asian origin. J Obstet Gynaecol Can. 2012 Nov;34(11):1026–37.)

In Cuba, the situation of standards relating weight and gestational age has not progressively developed since the curves proposed by Dueãas in 1990.(³¹31. Dueãas E, Sánchez C, Santurio A. Patrones antropométricos en el recién nacido. Havana: Editorial Ciencias Médicas; 1990. Spanish.) Dueãas is important historically and scientifically, not only because he was the first Cuban to design weight percentile curves by week of gestational age, but also because he realized the importance of these curves for identifying newborn infants whose weight for gestational age was less than P10, given this group's greater risk of morbidity and mortality.(³²32. Pittaluga E, Díaz V, Mena P, Corvalán S. Curvas de crecimiento intrauterino para prematuros entre las 23 y 36 semanas de gestación. Rev Chil Pediatr. 2002 Mar;73(2). Spanish.–³⁵35. Hutcheon JA, Platt RW. The missing data problem in the birth weight percentile and threshold for small for gestational age. Am J Epidemiol. 2008 Apr 1;167(7):786–92.) No other weight-for-gestational-age curves have been designed in Cuba since.

We consider Dueãas' curves(³¹31. Dueãas E, Sánchez C, Santurio A. Patrones antropométricos en el recién nacido. Havana: Editorial Ciencias Médicas; 1990. Spanish. 33. Gardosi J. Customized charts and their role in identifying pregnancies at risk because of fetal growth restriction. J Obstet Gynaecol Can. 2014 May;36(5):408–15. 34. Albuiges G. Ponencia sobre recién nacidos pequeãos para la edad gestacional y Crecimiento intrauterino restringido en: Reunión XXII de Ginecología y Obstetricia de la Comunidad Catalana. Ginecol Obst Clínica. 2004;(5):8–21. Spanish.) no longer unsuitable for several reasons. First, they were designed more than two decades ago; second, Dueãas' small study sample was not representative of the universe at that time (as he acknowledges); and third, more recent criteria for constructing such curves have been established. Esquivel, in a comprehensive review of all growth monitoring studies in the country from the 1970s on, concluded that Cuban newborns have been getting bigger.(³⁶36. Esquivel Lauzurique M. Departamento de desarrollo humano: más de cuatro décadas monitoreando el crecimiento de los niãos cubanos. Rev Habanera Ciencias Médicas. 2013;12(1):1–4. Spanish.)

No national or regional studies have been conducted in our country that would allow comparison with the reference values determined in our work. Cuba's 2010 Consensus on Diagnostic and Therapeutic Procedures in Gynecology and Obstetrics(³⁷37. Ministry of Public Health (CU). Consenso de Procederes Diagnósticos y Terapéuticos en Ginecología y Obstetricia. Havana: Ministry of Public Health (CU); 2010. Spanish.) contains no mention of reference weights by gestational age for Cuban infants, but refers only to reports by foreign authors, such as Hadlock(²2. Hadlock FP, Harrist RB, Scharman RS, Deter RL, Park SK. Estimation of fetal weight with the use of head, body and femur measurement– a prospective study. Am J Obstet Gynecol. 1985 Feb 1;151(3):333–7.,³3. Hadlock FP, Harrist RB, Martinez-Poyer J. In utero analysis of fetal growth. A sonographic weight standard. Radiology. 1991 Oct;181(1):129–33.) and Usher,(⁴4. Usher R, McLean F. Intrauterine growth of live born Caucasians infants at sea level. Standard obtained from measurement of 7 dimensions of infants born between 25 and 44 weeks of gestation. J Pediatr. 1969 Jun;74(6):901–10.) among others. Cuba's 2010 Pediatric Consensus refers only to Dueãas' curves.(³⁸38. Ministry of Public Health (CU). Consenso de Pediatría. Havana: Ministry of Public Health (CU); 2010. Spanish.)

For all these reasons and in light of WHO's recommendation that each perinatology service or area construct its own references,(¹1. World Health Organization. Physical status: the use and interpretation of anthropometry. Report of a WHO Experts Committee. Technical Report Series No. 854. Geneva: World Health Organization; 1995.) we decided to formulate weight-for-gestational-age tables and curves for our hospital's area of service.

METHODS

A retrospective longitudinal study was designed whose universe consisted of the 16,018 infants born alive in the maternity unit of the V.I. Lenin University General Hospital in Holguín Municipality, January 2008–December 2012. In 2012, only infants born at 36 weeks or less were included, due to the need to increase the number of cases in this age group.

Included were neonates born in the study hospital living in Holguín Municipality. Neonates from multiple births were excluded. Also excluded were any cases with omissions or errors in gestational age or weight in the infant's records. Infants with histories of conditions that could affect intrauterine growth were not excluded.

The study database was set up with information from the Municipal Statistics Department's registry of live births. Study variables included gestational age, birth weight and sex. Gestational age was determined from date of last menstrual period and corrected, if necessary, by early sonogram (between 13–16 and 20–22 weeks of pregnancy), in accordance with nationally established criteria for antenatal control and followup of all pregnant women.(³⁷37. Ministry of Public Health (CU). Consenso de Procederes Diagnósticos y Terapéuticos en Ginecología y Obstetricia. Havana: Ministry of Public Health (CU); 2010. Spanish.)

Weight was determined in grams. Neonates in the study hospital are weighed immediately after birth in the delivery room by experienced nurses, under direct supervision by obstetricians. The dial scales used are routinely calibrated by the Provincial Metrology Department.

To determine weight curves for gestational age and sex, values were determined for the 3rd, 5th, 10th, 25th, 50th, 75th and 90th percentiles. To smooth the curves, a third-degree polynomial was obtained via weighted least squares regression. Mean weights, standard deviations and weight distribution by gestational age and sex were determined for each of these percentiles.

For data validation, analysis of variance was conducted to compare the years 2008, 2009, 2010 and 2011; no unexpected effects were found to influence results, and the coefficient of variation (CV) for each table was calculated, which was considered to be stable when there was no more than 10% variation in each week of gestation. The normality test was also conducted to determine if weight was normally distributed. Calculations were performed with SYSLAT MY-STAT v.12 (2009) and Excel (Microsoft Office).

Ethics

The study was approved by the scientific council and medical ethics committee of the Holguín Municipal Health Department.

RESULTS

Weight distribution curves by gestational age and sex for the 3th, 5th, 10th, 25th, 50th, 75th and 90th percentiles are displayed in Figures 1 and 2. Mean birth weight for both sexes increased from week 30 to week 42. Table 1 shows a predominance of births in weeks 39 and 40 for newborn girls (29.4% and 27% respectively). Mean weights were 3222 g (SD 381) in week 39 and 3331 g (SD 398) in week 40.

As of week 35, weight variation began to decline in both sexes, as demonstrated by diminishing CVs (Table 2).

Figure 1 shows weight distribution for newborn girls by gestational age (in weeks). At 36 weeks, P10 for this group was 2140 g, and showed a steady rise until week 42. Applying those values, 9.4% of newborn girls fall under P10 and 9.8% above the 90th percentile. Weight distribution for newborn boys by gestational age (Figure 2) shows that P10 was 2200 g at 36 weeks, with increasing values up to week 42. Based on these values, 9.8% of infant boys are below P10 and 8.3% are above the 90th percentile. Applying our cutoffs to the universe of newborns, 47.3% more low birth weight infants were identified than would have been by Dueãas’ curves (1538 vs. 811).

Mean birth weight in most weeks was less for infant girls than for boys, although the mean difference between the two sexes was only 84 g from week 35 to week 42. In the SGA group, a slight predominance of 0.5% was observed for infant boys.

However, in the LGA group, there was a 1.5% predominance for infant girls over boys. The overall results (for both sexes) were 9.6% for SGA, 81.4 % for AGA and 9% for LGA. A comparison of the curves in Figures 1 and 2 indicates that in the 30–36 week group, both curves show the same percentage of SGA.

DISCUSSION

Timely detection of abnormal weight values for gestational age during intrauterine and neonatal development enables better risk assessment for possible early or subsequent disorders.(¹⁰10. Fattal-Valeski A, Berheim J, Leitner Y, Redianu B, Bassan H, Harel S. Blood pressure values in children with intrauterine growth retardation. Isr Med Assoc J. 2001 Nov;3(11):805–8.,¹¹11. Pérez Caballero MD, Valdés Armenteros R, Tasis Hernández M, Cordies Jackson L. Bajo peso al nacer y su relación con la hipertensión arterial en adolescentes y jóvenes. Rev Cubana Med. 2004 Sep;43(5–6). Spanish.)

Our study showed an average weight increase of 26.6% in infant girls and 29.3% in infant boys between weeks 36 and 41, surpassing the results reported by Dueãas (22.2% for both sexes).(³¹31. Dueãas E, Sánchez C, Santurio A. Patrones antropométricos en el recién nacido. Havana: Editorial Ciencias Médicas; 1990. Spanish.) A similar trend was also observed in studies by San Pedro in Argentina(²³23. San Pedro M, Grandi C, Larguia M. Estándares de peso para la edad gestacional en 58,706 recién nacidos sanos de una maternidad pública de Buenos Aires, Argentina. Rev Medicina (Buenos Aires). 2001;61:15–22. Spanish.) and González in Chile(¹⁵15. González PR, Gómez RM, Castro RS, Nien JK, Merino PO, Etchegaray AB, et al. Curva nacional de distribución de peso al nacer según edad gestacional. Chile 1993–2000. Rev Med Chile. Oct;132(10):1155–65. Spanish.) (38.4% and 32.8% respectively; again, for both sexes). The greater increases in mean weights over this period of intrauterine development are important in explaining these studies' higher 10th-percentile values as compared with ours.

The cutoff point for P10 can vary, according to different authors (Ayerza,(²⁷27. Ayerza Casas A, Rodríguez Martínez G, Samper Villagrasa MP, Ventura Faci P. Nacer pequeão para la edad gestacional puede depender de la curva utilizada. Nutr Hosp. 2011 Jul–Aug;26(4):752–8. Spanish.) Alarcón(¹⁴14. Alarcón J, Alarcón Y, Hering E, Buccioni R. Curvas antropométricas de recién nacidos chilenos. Rev Chil Pediatr. 2008 Aug;79(4):364–72. Spanish.)), due to various factors, including study design, specific population characteristics, ethnicity and maternal characteristics (such as weight and height). These authors noted that boys’ birth weights tended to be higher than girls’, which is consistent with our findings. P10 values found by Lubchenco(¹²12. Lubchenco LO, Hansman C, Dressler M, Boyd E. Intrauterine growth estimated for live born birth weight from 24 to 42 weeks of gestation. Pediatrics. 1963 Nov;32:793–800.) were below those reported in studies by Ayerza,(²⁷27. Ayerza Casas A, Rodríguez Martínez G, Samper Villagrasa MP, Ventura Faci P. Nacer pequeão para la edad gestacional puede depender de la curva utilizada. Nutr Hosp. 2011 Jul–Aug;26(4):752–8. Spanish.) González,(¹⁵15. González PR, Gómez RM, Castro RS, Nien JK, Merino PO, Etchegaray AB, et al. Curva nacional de distribución de peso al nacer según edad gestacional. Chile 1993–2000. Rev Med Chile. Oct;132(10):1155–65. Spanish.) and Ticona;(¹⁹19. Ticona Rendón M, Huanco Apanza D. Curva de crecimiento intrauterino de recién nacidos peruanos. Rev Chil Obstet Ginecol. 2008 Jan;73(2):110–8. Spanish.) Lubchenco detected only 2.2% of SGA for both sexes at week 40. The portion of SGA (9.1%) found in our study falls within the range of 7%–11% reported by Latin American authors such as Urquía,(¹⁸18. Urquía ML, Alazraqui M, Spinelli HG, Frank JW. Referencias poblacionales argentinas de peso al nacer según multiplicidad de partos, sexo y edad gestacional. Rev Panam Salud Pública. 2011 Feb;29(2):108–19. Spanish.) Lagos(²⁴24. Lagos R, Espinoza González R, Echevarría P, Orellana JJ. Gráfica regional de crecimiento fetal: comparación con estándar internacional. Rev Chil Obstet Ginecol. 1998;63(5):370–5. Spanish.) and Juez.(²⁵25. Juez G, Luis E, Ventura Junca P, González H, Tapia JL, Winter A. Crecimiento intrauterino en recién nacidos chilenos de la clase media. Rev Chil Pediatr. 1989;60:198–208. Spanish.)

Other studies presented higher cutoff points than ours for P10 at 36 weeks, but these were for both sexes combined. San Pedro of Argentina presented a cutoff point of 2190 g,(²³23. San Pedro M, Grandi C, Larguia M. Estándares de peso para la edad gestacional en 58,706 recién nacidos sanos de una maternidad pública de Buenos Aires, Argentina. Rev Medicina (Buenos Aires). 2001;61:15–22. Spanish.) which was 10 g less than our equivalent cutoff for boys, but higher than ours calculated for both sexes combined. Hadlock in the USA found 2335 g,(²2. Hadlock FP, Harrist RB, Scharman RS, Deter RL, Park SK. Estimation of fetal weight with the use of head, body and femur measurement– a prospective study. Am J Obstet Gynecol. 1985 Feb 1;151(3):333–7.) the Latin American Center for Perinatology in Uruguay indicated 2324 g(³⁹39. Centro latino-americano de Perinatología y Desarrollo Humana (CLAP-OPS-OMS). Sistema Informático Perinatal. Publicación Científica. No 1203. Montevideo: Latin American Center for Perinatology and Human Development; 1990. Spanish.) and Alexander in the USA determined a cutoff point of 2354 g,(⁴⁰40. Alexander GR, Himes JH, Kaufman RB, Mor J, Kogan M. A United States maternal reference for fetal growth. Obstet Gynecol. 1996 Feb; 87(2):163–8.) all values higher than either of our sex-specific cutoffs.

Variability in weeks 36 and 40 in both sexes in our study is consistent with that described by González, who found CVs of 16.6% and 12.1%, respectively, in those weeks,(¹⁵15. González PR, Gómez RM, Castro RS, Nien JK, Merino PO, Etchegaray AB, et al. Curva nacional de distribución de peso al nacer según edad gestacional. Chile 1993–2000. Rev Med Chile. Oct;132(10):1155–65. Spanish.) and by Juez, who reported CVs of 13.9% at 36 weeks and 11.2% at 40 weeks.(²⁵25. Juez G, Luis E, Ventura Junca P, González H, Tapia JL, Winter A. Crecimiento intrauterino en recién nacidos chilenos de la clase media. Rev Chil Pediatr. 1989;60:198–208. Spanish.) CVs in our study approached stability as gestational age progressed.

It is important to note that the low number of neonates born in weeks 30–34 (5.6% of total neonates) is a possible source of bias in our study, and caution should be exercised in interpreting the values calculated for this gestational age. WHO's technical report recommends a minimum of 200 cases for each week of gestation,(¹1. World Health Organization. Physical status: the use and interpretation of anthropometry. Report of a WHO Experts Committee. Technical Report Series No. 854. Geneva: World Health Organization; 1995.) which is extremely difficult to attain in studies in perinatology services and areas with few births. In his work, Alarcón.(¹⁴14. Alarcón J, Alarcón Y, Hering E, Buccioni R. Curvas antropométricas de recién nacidos chilenos. Rev Chil Pediatr. 2008 Aug;79(4):364–72. Spanish.) noted that the Chilean Pediatric Society, in establishing criteria for preparing such growth curves, recommended a minimum of 100 neonates for each gestational age. Our work meets this standard from week 35 on. In an attempt to solve this problem, some authors (such as Pittaluga) have designed curves based solely on neonates born at 36 weeks of gestation or earlier, for greater statistical efficiency. (³²32. Pittaluga E, Díaz V, Mena P, Corvalán S. Curvas de crecimiento intrauterino para prematuros entre las 23 y 36 semanas de gestación. Rev Chil Pediatr. 2002 Mar;73(2). Spanish.)

Our inclusion criteria were also very broad; neonates whose mothers had risk factors that could affect fetal weight (such as pre-eclampsia, hypertension and diabetes mellitus) were not excluded, which could introduce a negative bias in reporting SGA.(⁴¹41. Melamed N, Ray JG, Shah PS, Berger H, Kingdom JC. Should we use customized fetal growth percentiles in urban Canada? J Obstet Gynaecol Can. 2014 Feb;36(2):164–70.,⁴²42. Castaão Castrillón JJ, Villegas Arenas OA. Curvas antropométricas de los niãos controlados en crecimiento y desarrollo en una entidad de salud de primer nivel en Manizales (Colombia) aãos 2005 a 2010. Arch Med (Manizales). 2012 Jan–Jun;12(1):18–30. Spanish.) However, other researchers have also used this design, including González, who studied more than 2 million neonates in Chile without excluding fetal weight risk factors,(¹⁵15. González PR, Gómez RM, Castro RS, Nien JK, Merino PO, Etchegaray AB, et al. Curva nacional de distribución de peso al nacer según edad gestacional. Chile 1993–2000. Rev Med Chile. Oct;132(10):1155–65. Spanish.) and Juez, also in Chile, who likewise included them.(²⁵25. Juez G, Luis E, Ventura Junca P, González H, Tapia JL, Winter A. Crecimiento intrauterino en recién nacidos chilenos de la clase media. Rev Chil Pediatr. 1989;60:198–208. Spanish.)

This study has enabled construction of weight percentile distribution curves and tables by gestation age (in weeks) and sex, specific to the population of Holguín Municipality, Cuba. It also fills an information gap since such curves were not previously available here.

CONCLUSIONS

Values were established for new reference weights by gestational age and sex, enabling formulation of percentile distribution curves and tables. Differences were found when our tables were compared with tables from other countries. The increased detection of newborns under P10 (SGA infants) enables clinical and epidemiological actions that can help reduce morbidity and mortality in this high-risk neonatal group.

ACKNOWLEDGMENTS

We are grateful to Dr Enzo Dueãas Gómez, the first Cuban physician to design weight curves and percentile distribution tables for newborn infants by gestational week and sex, for his guidance in the preparation of this paper.

REFERENCES

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