Original Article
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Risk Factors for the Delivery of Macrosomic Infants at the University Hospital of the West Indies H. Trotman, MBBS, DCH, DM (Paed), MPH1
1 Department of Child and Adolescent Health, University of the West
Indies, Mona, Kingston 7, Jamaica Am J Perinatol 2014;31:927–932.
Abstract
Keywords
► fetal macrosomia ► risk factors ► large for gestational age ► abnormal glucose control
Address for correspondence Helen Trotman, MBBS, DCH, DM (Paed), MPH, Department of Child and Adolescent Health, University of the West Indies, Mona, Kingston 7, Jamaica (e-mail: [email protected]).
Objective The aim of this study is to determine the risk factors for the delivery of macrosomic infants at the University Hospital of the West Indies over a 3-year period. Design and Methods A retrospective, descriptive, case-controlled study was performed. Data were extracted from the maternal medical records of 316 macrosomic infants (weighing 4,000 g) and 316 controls (weighing from 2,500–3,999 g) delivered at the University Hospital of the West Indies. Descriptive analyses were performed comparing maternal characteristics between the two groups. Risk factors were determined using multiple logistic regression models. Results The incidence of macrosomia for the study period was 4.3%. Women who delivered a macrosomic infant were older, taller, and heavier with a greater body mass index at the start of the pregnancy and gained more weight during pregnancy than their counterparts in the control group (p < 0.05). Maternal obesity, height > 164 cm, abnormalities of glucose control, weight gain > 15 kg, gestational age > 40 weeks, and male gender of the infant were found to increase the risk of delivering a macrosomic infant by over 2-fold (p < 0.05). The greatest risk factor was that of having had a previous macrosomic infant which increased the risk of delivering a macrosomic infant by as much as 6-fold (adjusted odds ratio, 6.0; 95% confidence interval, 1.9–18.7). Conclusion The maternal risk factors for fetal macrosomia identified in this study mirror those of previous studies.
There is no general consensus as to the definition of fetal macrosomia. It is defined as the birth weight 4,000 g or 4,500 g regardless of the gestational age.1 The prevalence of fetal macrosomia varies from 0.5 to 15% depending on the weight used.2 Macrosomia has been linked to both maternal and fetal complications. Maternal complications include prolonged labor, cesarean delivery, and postpartum hemorrhage.1,2 Neonatal complications include stillbirth, shoulder dystocia, birth injury, meconium aspiration syndrome, perinatal asphyxia, and neonatal mortality secondary to birth asphyxia.1,3,4
Studies have shown that with increased birth weight, the higher the neonatal and perinatal morbidity rates particularly when the birth weight is 5,000 g. The maternal risk factors that have been associated with fetal macrosomia are weight at first visit, previous macrosomic infant, excessive weight gain in pregnancy, obesity, gestational diabetes, multiparity, postdatism, male fetus, and advanced maternal age.4–7 Similar to international studies, a study in the Caribbean region found that advanced maternal age, multiparity, diabetes, hypertension, and postdatism were maternal risk factors for macrosomia.8
received July 9, 2013 accepted after revision November 21, 2013 published online May 2, 2014
Copyright © 2014 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA. Tel: +1(212) 584-4662.
DOI http://dx.doi.org/ 10.1055/s-0033-1363769. ISSN 0735-1631.
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C. Richardson, MBBS, DM (Paed)1
Fetal Macrosomia at UHWI
Richardson, Trotman
Table 1 Maternal demographics of women who delivered macrosomic infants at the UHWI between 2007 and 2009 versus their control group N
Macrosomic group (mean SD)
N
Control group (mean SD)
p-Value (t-test)
Age (y)
316
29.84 6.1
316
28.34 6.8
0.003
Height (cm)
194
165.5 5.6
228
163.2 6.1
< 0.001
Weight at first visit (kg)
289
81.2 17.7
305
71.6 15.4
< 0.001
Weight gain (kg)
281
12.6 5.6
295
11.1 5.1
< 0.001
Body mass index (kg/m )
193
29.36 5.76
224
26.85 5.67
< 0.001
Gestational age (wk)
316
39.3 1.1
316
39.1 1.1
0.001
2
Abbreviations: UHWI, University Hospital of the West Indies; wk, weeks; y, years.
With the ongoing concern of the increased morbidity and mortality of macrosomic infants, it is important to identify the associated risk factors so that interventions can be made to decrease the incidence of fetal macrosomia. There has been no study to date in Jamaica that has identified maternal risk factors for the delivery of a macrosomic infant. This study aimed to determine the risk factors for the delivery of macrosomic infants at the University Hospital of the West Indies (UHWI) over a 3-year period.
Methods This was a retrospective, descriptive, case-controlled study to determine the risk factors associated with the delivery of macrosomic infants at the UHWI. For the purpose of this study, a birth weight of 4,000 g was used to define macrosomia regardless of gestational age. All macrosomic infants, delivered at UHWI between January 1, 2007 and December 31, 2009 were entered into the study except those with chromosomal abnormalities or congenital anomalies. A normal birth weight infant (2,500 to 3,999 g) born closest in time to the index case was also included in the study and used as the control.
Abnormalities of glucose control: Women who have pregestational diabetes, gestational diabetes or impaired glucose tolerance. Weight gain in pregnancy: This was calculated as the difference in weight between the first and final antenatal clinic visit.
Statistical Analysis Descriptive analyses were performed. Maternal differences between normal birth weight infants and macrosomic infants were determined using Chi-square and the independentsample t-test. Factors found to be associated with the delivery of a macrosomic infant were offered into a multiple logistic regression model to determine risk factors for the delivery of a macrosomic infant. Data were analyzed using the Statistical Package for the Social Sciences (SPSS) version 17 (IBM Corporation, Armonk, NY). Statistical significance was taken at p < 0.05 The UHWI/UWI Ethics Committee granted permission for conducting this study.
Results
Data Collection
Maternal Demographics
The subject population was identified from the labor ward log books, newborn special care nursery log books, and the pathology stillbirth log book. Patients’ charts (both mother and neonate) were retrieved and data on maternal and neonatal demographics were recorded using a data extraction sheet. At the time of the study women attending the antenatal clinic at the UHWI were required to register by the time they had missed two menstrual cycles about 8 weeks gestation, therefore as previously shown9 their weight at entry into the clinic was used as a measure of their prepregnancy weight. All women attending the antenatal clinic at the UHWI received glucose screening between 24 and 28 weeks of gestation.
There were a total of 7,279 deliveries at the UHWI during the study period, January 1, 2007 to December 31, 2009. Out of these, 317 babies had a birth weight of 4,000 g, one case was excluded because of the presence of congenital anomalies giving a rate of 43.5 per 1,000 deliveries for macrosomic infants. There were 34 babies with a birth weight of 4,500 g giving a rate of 4.7 per 1,000 deliveries. The maternal age of women who delivered macrosomic infants ranged from 17 to 44 years with 75% of them being less than 35 years. While in the control group maternal age ranged from 15 to 46 years with 79% of the mothers being less than 35 years. Mothers who delivered macrosomic infants were significantly older than mothers who did not (p < 0.5) (►Table 1). The mean maternal height and body mass index (BMI) at first visit of women who gave birth to macrosomic infants was significantly higher than that of the women in the control group (p < 0.001) (►Table 1). Women who delivered macrosomic babies were older (p < 0.05), taller, and heavier with a
Definitions Hypertension in pregnancy: Women who have chronic hypertension as well as women with hypertensive disorders of pregnancy. American Journal of Perinatology
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Table 2 Maternal characteristics of women who delivered macrosomic infants at the UHWI between 2007 and 2009 versus their control group Macrosomic group n (%)
Control group n (%)
p-Value (Chi-square)
80 (25)
67 (21)
0.129
Multiparity
84 (27)
61 (19)
0.019
Weight gain > 15 kg
83 (30)
66 (22)
0.031
Abnormalities of glucose control
46 (15)
19 (6)
< 0.001
Hypertension in pregnancy
36 (12)
37 (12)
0.499
Maternal age > 35 y
greater BMI at the start of the pregnancy and gained more weight during pregnancy than their counterparts in the control group p < 0.001 (►Tables 1 and 2). There were also significantly more obese women who gave birth to macrosomic infants when compared with controls (p < 0.001) (►Table 3). BMI was not documented for 39% of cases and 29% of controls. Around 30% of women who delivered macrosomic infants had a duration of gestation greater than 40 weeks compared with only 22% of women who delivered normal birth weight infants (p ¼ 0.001). Significantly more women who delivered macrosomic infants had abnormalities of glucose control compared with their counterparts in the control group, (p < 0.001) (►Table 2). Mothers in the macrosomic group accounted for 68% of the women with gestational diabetes, 90% of those with pregestational diabetes, and 64% of those with impaired glucose tolerance. Overall 156 (49%) women who had a macrosomic infant were delivered by lower segment cesarean section (LSCS) compared with 93 (29%) women in the control group (p < 0.001) (►Table 4). The most common indication for elective LSCS in the macrosomic group was presumed macrosomia (estimated by ultrasound) 38% while in the control group it was the history of a previous LSCS 40%. There was no significant difference in the emergency LSCS rate between the two groups (48 vs. 45%). Of the women who delivered vaginally a significantly greater proportion of women who
Table 3 Body mass index of women who delivered macrosomic infants at the UHWI between 2007 and 2009 versus their control group Macrosomic group n (%)
Control group n (%)
Underweight
3 (2)
6 (3)
Normal
45 (23)
92 (41)a
Overweight
66 (34)
68 (30)
Obese
79 (41)
58(26)a
Abbreviation: UHWI, University Hospital of the West Indies. a p < 0.001.
delivered macrosomic infants experienced shoulder dystocia 15% compared with 2% in controls (p < 0.001) (►Table 4). Around 10% of mothers who delivered macrosomic infants had postpartum hemorrhage as compared with 6% of controls p < 0.05 (►Table 4).
Neonatal Demographics There was a male preponderance 201 (64%) in the macrosomic group as opposed to 161 (51%) in the control group (p ¼ 0.001). The birth weights of the macrosomic population ranged from 4,000 to 5,100 g with a mean standard deviation (SD) of 4,219 207 g. The majority, of the cases, (89%)
Table 4 Outcomes of women who delivered macrosomic infants at the UHWI between 2007 and 2009 versus their control group Macrosomic group n (%)
Control group n (%)
p-Value (Chi-square)
Prolonged second stage
4 (3)
9 (4)
0.36
Cesarean delivery
156 (49.4)
93 (29.4)
< 0.001
Emergency LSCS
75 (48)
42 (45)
0.66
2(0.7)
1(0.3)
0.478
24 (15)
5 (2)
< 0.001
Postpartum hemorrhage
32 (10.1)
18 (5.7)
0.015
Length of stay > 3 d
46 (15)
36 (11)
0.14
Instrumentation Shoulder dystocia
a
Abbreviations: d, days; LSCS, lower segment cesarean section; UHWI, University Hospital of the West Indies. a Percentages based on vaginal deliveries. American Journal of Perinatology
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Abbreviations: UHWI, University Hospital of the West Indies; y, years.
Fetal Macrosomia at UHWI
Richardson, Trotman
Table 5 Risk Factors for the delivery of a macrosomic infant at the UHWI between 2007 and 2009 Variable
Odds ratio
95% Confidence interval for odds ratio
p-Value
Male gender
2.1
1.3–3.2
0.001
Multiparity
1.3
0.8–2.3
0.264
Maternal weight gain > 15 kg
2.1
1.27–3.4
0.004
Maternal height > 164 cm
1.99
1.3–3.0
0.002
Obesity
2.14
1.3–3.5
0.003
Abnormal glucose control
2.78
1.2–6.5
0.018
Previous macrosomia
6.10
1.9–19.1
0.002
Gestational age > 40 wk
2.28
1.4–3.7
0.001
Abbreviations: UHWI, University Hospital of the West Indies; wk, weeks.
fell within the range between 4,000 and 4,499 g. In the control group the birth weights ranged from 2,500 to 3,920 g with a mean SD of 3,206 334 g. There were three stillbirths and all were within the macrosomic group. Of these one mother was diagnosed with pregestational diabetes and chronic hypertension and another with gestational diabetes. There were no neonatal deaths in either group.
Risk Factors for Macrosomia When significant risk factors found to be associated with the delivery of a macrosomic infant were offered into a multiple logistic regression model, maternal obesity, maternal weight gain of > 15 kg, maternal height > 164 cm, abnormal glucose control in the mother, a previous history of having a macrosomic infant, gestational period > 40 weeks, and male gender of the infant remained independent risk factors for the delivery of a macrosomic infant (see ►Table 5).
Discussion This study showed that the incidence of macrosomia was 4.3% for babies weighing more than 4,000 g and 0.5% in babies weighing more than 4,500 g for the time period of January 2007 to December 2009 at the UHWI. The study also showed that women who delivered a macrosomic infant were more likely to be older, taller, multiparous, and heavier with a greater BMI at the start of the pregnancy. They tended to gain more weight during pregnancy, had a longer gestational period, an increased incidence of abnormalities of glucose control, and a history of previous macrosomia. LSCS was the preferred mode of delivery for macrosomic babies and a male preponderance was demonstrated. Genetic, racial, and ethnic factors influence birth weight and the risk of macrosomia. Thus the incidence varies according to the population that is being studied. Koyanagi et al looked at macrosomia (birth weight 4,000 g) in 23 developing countries within Africa, Asia, and Latin America. This study showed that the prevalence of macrosomia ranged from 0.5%, in India, to as high as 14.9%, in Algeria.10 Within the developed countries, the incidence varies from a low of 2.2% to a high of 31%.6,11–16 American Journal of Perinatology
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The incidence of macrosomia in this study is comparable to other published incidences in both developed and developing countries and is even lower in some instances. Within the Caribbean, in a study by Martin and Clarke, on a population from Antigua, the incidence of birth weight > 4,000 g was 5.7% and > 4,500 g was 1%.8 There appears to be an increasing incidence of fetal macrosomia worldwide apart from the United States.13,14,17 This has been attributed mostly to the increasing incidence of obesity and diabetes.12,18 The average height for women who delivered macrosomic babies in our study was 165.5 cm (which is above the normal average female height of 164 cm within the black population)19 and the average BMI was 29.36 kg/m2. This showed that many of the women were already overweight before becoming pregnant. Maternal prepregnancy weight has been shown to be an important factor in determining the fetal weight.4,15,20,21 Obesity has been associated with an increased risk of delivering a macrosomic baby and has been documented in previous studies to increase the risk by 2-fold.7 Our study showed that women who were obese were more likely to deliver macrosomic babies and gain more weight in the pregnancy. This finding has been reflected in several studies but the exact reason has not been fully elucidated.4 In a study by Bao et al, they showed that BMI had the greatest impact on macrosomia followed by height and then male gender.12 Khashan et al showed that there is an increase in the relative risk of macrosomia as the BMI increases; the highest risk being in the morbidly obese category.22 In a study by Asplund et al, they found that regardless of weight gain and initial prepregnancy BMI, an increase in maternal BMI of 25% or greater during pregnancy was associated with macrosomia.23 It has been postulated that there may be a link with abnormalities of glucose metabolism, but this was not seen in our study. Only 23% of the mothers who delivered a macrosomic baby were obese and also diabetic. Diabetes in pregnancy (gestational and pregestational) has been shown to be a significant risk factor for macrosomia.1 In our study, 15% of the cases within the macrosomic group had abnormalities of glucose control and these mothers had a > 2.5 chance of having a macrosomic baby. The average weight gain in our study was 12.6 kg among the women who delivered a macrosomic baby. Excessive
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are obese, for early screening and proper glucose monitoring and control throughout pregnancy.
Conclusion The maternal risk factors for fetal macrosomia identified in this study mirrors those of previous studies. Identification of modifiable risk factors for the delivery of macrosomic infants —nutritional status at the start of pregnancy, weight gain, and glucose control during pregnancy—will inform management protocols and guidelines to help decrease the incidence of macrosomia at our institution.
References 1 American College of Obstetricians and Gynaecologists (ACOG).
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9
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Fetal macrosomia. ACOG Practice Bulletin No. 22. Washington, DC: ACOG; 2000 Zhang X, Decker A, Platt RW, Kramer MS. How big is too big? The perinatal consequences of fetal macrosomia. Am J Obstet Gynecol 2008;198(5):e1–e6 Boulet SL, Salihu HM, Alexander GR. Mode of delivery and birth outcomes of macrosomic infants. J Obstet Gynaecol 2004;24(6): 622–629 Kamanu CI, Onwere S, Chigbu B, Aluka C, Okoro O, Obasi M. Fetal macrosomia in African women: a study of 249 cases. Arch Gynecol Obstet 2009;279(6):857–861 Lim JH, Tan BC, Jammal AE, Symonds EM. Delivery of macrosomic babies: management and outcomes of 330 cases. J Obstet Gynaecol 2002;22(4):370–374 Ju H, Chadha Y, Donovan T, O’Rourke P. Fetal macrosomia and pregnancy outcomes. Aust N Z J Obstet Gynaecol 2009;49(5): 504–509 Pundir J, Sinha P. Non-diabetic macrosomia: an obstetric dilemma. J Obstet Gynaecol 2009;29(3):200–205 Martin TC, Clarke A. A case control study of the prevalence of perinatal complications associated with fetal macrosomia in Antigua and Barbuda. West Indian Med J 2003;52(3):231–234 Gueri M, Jutsum P, Sorhaindo B. Anthropometric assessment of nutritional status in pregnant women: a reference table of weightfor-height by week of pregnancy. Am J Clin Nutr 1982;35(3): 609–616 Koyanagi A, Zhang J, Dagvadorj A, et al. Macrosomia in 23 developing countries: an analysis of a multicountry, facility-based, cross-sectional survey. Lancet 2013;381(9865):476–483 Sadeh-Mestechkin D, Walfisch A, Shachar R, Shoham-Vardi I, Vardi H, Hallak M. Suspected macrosomia? Better not tell. Arch Gynecol Obstet 2008;278(3):225–230 Bao C, Zhou Y, Jiang L, et al. Reasons for the increasing incidence of macrosomia in Harbin, China. BJOG 2011;118(1):93–98 Martin JA, Hamilton BE, Sutton PD, et al; Centers for Disease Control and Prevention National Center for Health Statistics National Vital Statistics System. Births: final data for 2005. Natl Vital Stat Rep 2007;56(6):1–103 Ventura SJ, Martin JA, Curtin SC, Mathews TJ, Park MM. Births: final data for 1998. Natl Vital Stat Rep 2000;48(3):1–100 Ørskou J, Henriksen TB, Kesmodel U, Secher NJ. Maternal characteristics and lifestyle factors and the risk of delivering high birth weight infants. Obstet Gynecol 2003;102(1):115–120 Luo ZC, Wilkins R, Heaman M, et al. Birth outcomes and infant mortality among First Nation Inuit and non – Indigenous Women by northern versus southern residence, Quebec. J Epidemiol Community Health 2012;66(4):328–333 Henriksen T. The macrosomic fetus: a challenge in current obstetrics. Acta Obstet Gynecol Scand 2008;87(2):134–145 American Journal of Perinatology
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weight gain has been implicated as one of the independent risk factors for macrosomia.24 In our study, women who gained in excess of 15 kg were more likely to deliver a macrosomic baby. The same was documented in a study of Japanese women by Morikawa et al.20 Tabatabaei showed that a gestational weight gain of 0.5 kg/wk was associated with a higher risk of fetal macrosomia.25 According to the guidelines from the U.S. Institute of Medicine (IOM) 2009, the recommended weight gain in pregnancy is 11.5 to 16 kg in a woman who has a normal BMI and 5 to 9 kg in obese women.26 Kac and Velásquez-Meléndez showed a 5.83 increase; and Hedderson et al a 3-fold increase in risk once there was weight gain higher than the IOM recommendations.27,28 Although these recommendations have been suggested, there still remains an issue of whether or not these restrictions can be followed. The finding of increased weight gain greater than the IOM recommendations predisposing to macrosomia is consistent with other studies in the literature.28–32 It has been found that a previous delivery of a macrosomic infant can increase the likelihood of a macrosomic infant in the next pregnancy by as much as 5 to 10 times.7 In our study, it did prove significant in keeping with earlier studies. It was shown to increase the likelihood by six times. Kamanu et al, in Nigeria, found that approximately 63% of the mothers had previous macrosomic infants4 and that this increased the risk of them having future macrosomic babies. Walsh et al showed that a history of delivery of more than one macrosomic infant further increased the risk of macrosomia in subsequent pregnancies.33 Studies by Ezegwui et al and Najafian et al have also proven the significance of previous delivery of a macrosomic infant.34,35 The preponderance of the male gender in macrosomic infants is a consistent finding that has yet to be explained.4–7,10,21,34 Being a retrospective study data collection was limited by what data were recorded, this was particularly evident in the recording of maternal height which limited the determination of BMI. In our study, there were a few cases where the mother did not book within the first trimester. However, factoring out the cases who booked outside of this trimester, weight gain still remained statistically significant. Obesity in the general population is concerning and its prevalence continues to increase. This has been shown to be a significant factor for macrosomia and so has long-term implications for perinatal care. We recommend that in our setting prepregnancy and pregnancy counselling on nutrition and diet needs to be strengthened. We need to ensure appropriate measurements are taken and BMI calculated for all women at their first antenatal visit. Excessive weight gain outside of the recommended guidelines increases the risk of macrosomia. We therefore need to identify women who are at high risk as early in the pregnancy as possible and institute ongoing dietary and nutritional advice and education on appropriate exercise. Abnormalities of glucose control can as much as double the risk of macrosomia we therefore recommend prepregnancy and pregnancy counselling to maintain appropriate glucose control before and during the pregnancy. Prompt identification of mothers who are at high risk, for example, those who
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18 Surkan PJ, Hsieh CC, Johansson AL, Dickman PW, Cnattingius S.
27 Kac G, Velásquez-Meléndez G. Gestational weight gain and macro-
Reasons for increasing trends in large for gestational age births. Obstet Gynecol 2004;104(4):720–726 Ogden CL, Fryar CD, Carroll MD, Flegal KM. Mean body weight, height, and body mass index, United States 1960–2002. Adv Data 2004;347:1–17 Sacks DA. Etiology, detection, and management of fetal macrosomia in pregnancies complicated by diabetes mellitus. Clin Obstet Gynecol 2007;50(4):980–989 Morikawa M, Cho K, Yamada T, Yamada T, Sato S, Minakami H. Fetal macrosomia in Japanese women. J Obstet Gynaecol Res 2013; 39(5):960–965 Khashan AS, Kenny LC. The effects of maternal body mass index on pregnancy outcome. Eur J Epidemiol 2009;24(11): 697–705 Asplund CA, Seehusen DA, Callahan TL, Olsen C. Percentage change in antenatal body mass index as a predictor of neonatal macrosomia. Ann Fam Med 2008;6(6):550–554 Stotland NE, Hopkins LM, Caughey AB. Gestational weight gain, macrosomia, and risk of cesarean birth in nondiabetic nulliparas. Obstet Gynecol 2004;104(4):671–677 Tabatabaei M. Gestational weight gain, prepregnancy body mass index related to pregnancy outcomes in KAZERUN, FARS, IRAN. J Prenat Med 2011;5(2):35–40 Rasmussen KM, Yaktine AL (eds). Weight gain during pregnancy: reexamining the guidelines. Washington, DC: National Academies Press; 2009. Available at: http://books.nap.edu/openbook.php? record_id¼12584. Accessed December 31, 2010
somia in a cohort of mothers and their children [in Portuguese]. J Pediatr (Rio J) 2005;81(1):47–53 Hedderson MM, Weiss NS, Sacks DA, et al. Pregnancy weight gain and risk of neonatal complications: macrosomia, hypoglycemia, and hyperbilirubinemia. Obstet Gynecol 2006;108(5):1153–1161 Flick AA, Brookfield KF, de la Torre L, Tudela CM, Duthely L, González-Quintero VH. Excessive weight gain among obese women and pregnancy outcomes. Am J Perinatol 2010;27(4):333–338 Siega-Riz AM, Viswanathan M, Moos MK, et al. A systematic review of outcomes of maternal weight gain according to the Institute of Medicine recommendations: birthweight, fetal growth, and postpartum weight retention. Am J Obstet Gynecol 2009;201(4):e1–e14 Halloran DR, Wall TC, Guild C, Caughey AB. Effect of revised IOM weight gain guidelines on perinatal outcomes. J Matern Fetal Neonatal Med 2011;24(3):397–401 Hinkle SN, Sharma AJ, Dietz PM. Gestational weight gain in obese mothers and associations with fetal growth. Am J Clin Nutr 2010; 92(3):644–651 Walsh CA, Mahony RT, Foley ME, Daly L, O’Herlihy C. Recurrence of fetal macrosomia in non-diabetic pregnancies. J Obstet Gynaecol 2007;27(4):374–378 Ezegwui HU, Ikeako LC, Egbuji C. Fetal macrosomia: obstetric outcome of 311 cases in UNTH, Enugu, Nigeria. Niger J Clin Pract 2011;14(3):322–326 Najafian M, Cheraghi M. Occurrence of fetal macrosomia rate and its maternal and neonatal complications: a 5-year cohort study. ISRN Obstet Gynecol 2012;2012:353791
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Risk Factors for the Delivery of Macrosomic Infants at the University Hospital of the West Indies H. Trotman, MBBS, DCH, DM (Paed), MPH1
1 Department of Child and Adolescent Health, University of the West
Indies, Mona, Kingston 7, Jamaica Am J Perinatol 2014;31:927–932.
Abstract
Keywords
► fetal macrosomia ► risk factors ► large for gestational age ► abnormal glucose control
Address for correspondence Helen Trotman, MBBS, DCH, DM (Paed), MPH, Department of Child and Adolescent Health, University of the West Indies, Mona, Kingston 7, Jamaica (e-mail: [email protected]).
Objective The aim of this study is to determine the risk factors for the delivery of macrosomic infants at the University Hospital of the West Indies over a 3-year period. Design and Methods A retrospective, descriptive, case-controlled study was performed. Data were extracted from the maternal medical records of 316 macrosomic infants (weighing 4,000 g) and 316 controls (weighing from 2,500–3,999 g) delivered at the University Hospital of the West Indies. Descriptive analyses were performed comparing maternal characteristics between the two groups. Risk factors were determined using multiple logistic regression models. Results The incidence of macrosomia for the study period was 4.3%. Women who delivered a macrosomic infant were older, taller, and heavier with a greater body mass index at the start of the pregnancy and gained more weight during pregnancy than their counterparts in the control group (p < 0.05). Maternal obesity, height > 164 cm, abnormalities of glucose control, weight gain > 15 kg, gestational age > 40 weeks, and male gender of the infant were found to increase the risk of delivering a macrosomic infant by over 2-fold (p < 0.05). The greatest risk factor was that of having had a previous macrosomic infant which increased the risk of delivering a macrosomic infant by as much as 6-fold (adjusted odds ratio, 6.0; 95% confidence interval, 1.9–18.7). Conclusion The maternal risk factors for fetal macrosomia identified in this study mirror those of previous studies.
There is no general consensus as to the definition of fetal macrosomia. It is defined as the birth weight 4,000 g or 4,500 g regardless of the gestational age.1 The prevalence of fetal macrosomia varies from 0.5 to 15% depending on the weight used.2 Macrosomia has been linked to both maternal and fetal complications. Maternal complications include prolonged labor, cesarean delivery, and postpartum hemorrhage.1,2 Neonatal complications include stillbirth, shoulder dystocia, birth injury, meconium aspiration syndrome, perinatal asphyxia, and neonatal mortality secondary to birth asphyxia.1,3,4
Studies have shown that with increased birth weight, the higher the neonatal and perinatal morbidity rates particularly when the birth weight is 5,000 g. The maternal risk factors that have been associated with fetal macrosomia are weight at first visit, previous macrosomic infant, excessive weight gain in pregnancy, obesity, gestational diabetes, multiparity, postdatism, male fetus, and advanced maternal age.4–7 Similar to international studies, a study in the Caribbean region found that advanced maternal age, multiparity, diabetes, hypertension, and postdatism were maternal risk factors for macrosomia.8
received July 9, 2013 accepted after revision November 21, 2013 published online May 2, 2014
Copyright © 2014 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA. Tel: +1(212) 584-4662.
DOI http://dx.doi.org/ 10.1055/s-0033-1363769. ISSN 0735-1631.
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C. Richardson, MBBS, DM (Paed)1
Fetal Macrosomia at UHWI
Richardson, Trotman
Table 1 Maternal demographics of women who delivered macrosomic infants at the UHWI between 2007 and 2009 versus their control group N
Macrosomic group (mean SD)
N
Control group (mean SD)
p-Value (t-test)
Age (y)
316
29.84 6.1
316
28.34 6.8
0.003
Height (cm)
194
165.5 5.6
228
163.2 6.1
< 0.001
Weight at first visit (kg)
289
81.2 17.7
305
71.6 15.4
< 0.001
Weight gain (kg)
281
12.6 5.6
295
11.1 5.1
< 0.001
Body mass index (kg/m )
193
29.36 5.76
224
26.85 5.67
< 0.001
Gestational age (wk)
316
39.3 1.1
316
39.1 1.1
0.001
2
Abbreviations: UHWI, University Hospital of the West Indies; wk, weeks; y, years.
With the ongoing concern of the increased morbidity and mortality of macrosomic infants, it is important to identify the associated risk factors so that interventions can be made to decrease the incidence of fetal macrosomia. There has been no study to date in Jamaica that has identified maternal risk factors for the delivery of a macrosomic infant. This study aimed to determine the risk factors for the delivery of macrosomic infants at the University Hospital of the West Indies (UHWI) over a 3-year period.
Methods This was a retrospective, descriptive, case-controlled study to determine the risk factors associated with the delivery of macrosomic infants at the UHWI. For the purpose of this study, a birth weight of 4,000 g was used to define macrosomia regardless of gestational age. All macrosomic infants, delivered at UHWI between January 1, 2007 and December 31, 2009 were entered into the study except those with chromosomal abnormalities or congenital anomalies. A normal birth weight infant (2,500 to 3,999 g) born closest in time to the index case was also included in the study and used as the control.
Abnormalities of glucose control: Women who have pregestational diabetes, gestational diabetes or impaired glucose tolerance. Weight gain in pregnancy: This was calculated as the difference in weight between the first and final antenatal clinic visit.
Statistical Analysis Descriptive analyses were performed. Maternal differences between normal birth weight infants and macrosomic infants were determined using Chi-square and the independentsample t-test. Factors found to be associated with the delivery of a macrosomic infant were offered into a multiple logistic regression model to determine risk factors for the delivery of a macrosomic infant. Data were analyzed using the Statistical Package for the Social Sciences (SPSS) version 17 (IBM Corporation, Armonk, NY). Statistical significance was taken at p < 0.05 The UHWI/UWI Ethics Committee granted permission for conducting this study.
Results
Data Collection
Maternal Demographics
The subject population was identified from the labor ward log books, newborn special care nursery log books, and the pathology stillbirth log book. Patients’ charts (both mother and neonate) were retrieved and data on maternal and neonatal demographics were recorded using a data extraction sheet. At the time of the study women attending the antenatal clinic at the UHWI were required to register by the time they had missed two menstrual cycles about 8 weeks gestation, therefore as previously shown9 their weight at entry into the clinic was used as a measure of their prepregnancy weight. All women attending the antenatal clinic at the UHWI received glucose screening between 24 and 28 weeks of gestation.
There were a total of 7,279 deliveries at the UHWI during the study period, January 1, 2007 to December 31, 2009. Out of these, 317 babies had a birth weight of 4,000 g, one case was excluded because of the presence of congenital anomalies giving a rate of 43.5 per 1,000 deliveries for macrosomic infants. There were 34 babies with a birth weight of 4,500 g giving a rate of 4.7 per 1,000 deliveries. The maternal age of women who delivered macrosomic infants ranged from 17 to 44 years with 75% of them being less than 35 years. While in the control group maternal age ranged from 15 to 46 years with 79% of the mothers being less than 35 years. Mothers who delivered macrosomic infants were significantly older than mothers who did not (p < 0.5) (►Table 1). The mean maternal height and body mass index (BMI) at first visit of women who gave birth to macrosomic infants was significantly higher than that of the women in the control group (p < 0.001) (►Table 1). Women who delivered macrosomic babies were older (p < 0.05), taller, and heavier with a
Definitions Hypertension in pregnancy: Women who have chronic hypertension as well as women with hypertensive disorders of pregnancy. American Journal of Perinatology
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Table 2 Maternal characteristics of women who delivered macrosomic infants at the UHWI between 2007 and 2009 versus their control group Macrosomic group n (%)
Control group n (%)
p-Value (Chi-square)
80 (25)
67 (21)
0.129
Multiparity
84 (27)
61 (19)
0.019
Weight gain > 15 kg
83 (30)
66 (22)
0.031
Abnormalities of glucose control
46 (15)
19 (6)
< 0.001
Hypertension in pregnancy
36 (12)
37 (12)
0.499
Maternal age > 35 y
greater BMI at the start of the pregnancy and gained more weight during pregnancy than their counterparts in the control group p < 0.001 (►Tables 1 and 2). There were also significantly more obese women who gave birth to macrosomic infants when compared with controls (p < 0.001) (►Table 3). BMI was not documented for 39% of cases and 29% of controls. Around 30% of women who delivered macrosomic infants had a duration of gestation greater than 40 weeks compared with only 22% of women who delivered normal birth weight infants (p ¼ 0.001). Significantly more women who delivered macrosomic infants had abnormalities of glucose control compared with their counterparts in the control group, (p < 0.001) (►Table 2). Mothers in the macrosomic group accounted for 68% of the women with gestational diabetes, 90% of those with pregestational diabetes, and 64% of those with impaired glucose tolerance. Overall 156 (49%) women who had a macrosomic infant were delivered by lower segment cesarean section (LSCS) compared with 93 (29%) women in the control group (p < 0.001) (►Table 4). The most common indication for elective LSCS in the macrosomic group was presumed macrosomia (estimated by ultrasound) 38% while in the control group it was the history of a previous LSCS 40%. There was no significant difference in the emergency LSCS rate between the two groups (48 vs. 45%). Of the women who delivered vaginally a significantly greater proportion of women who
Table 3 Body mass index of women who delivered macrosomic infants at the UHWI between 2007 and 2009 versus their control group Macrosomic group n (%)
Control group n (%)
Underweight
3 (2)
6 (3)
Normal
45 (23)
92 (41)a
Overweight
66 (34)
68 (30)
Obese
79 (41)
58(26)a
Abbreviation: UHWI, University Hospital of the West Indies. a p < 0.001.
delivered macrosomic infants experienced shoulder dystocia 15% compared with 2% in controls (p < 0.001) (►Table 4). Around 10% of mothers who delivered macrosomic infants had postpartum hemorrhage as compared with 6% of controls p < 0.05 (►Table 4).
Neonatal Demographics There was a male preponderance 201 (64%) in the macrosomic group as opposed to 161 (51%) in the control group (p ¼ 0.001). The birth weights of the macrosomic population ranged from 4,000 to 5,100 g with a mean standard deviation (SD) of 4,219 207 g. The majority, of the cases, (89%)
Table 4 Outcomes of women who delivered macrosomic infants at the UHWI between 2007 and 2009 versus their control group Macrosomic group n (%)
Control group n (%)
p-Value (Chi-square)
Prolonged second stage
4 (3)
9 (4)
0.36
Cesarean delivery
156 (49.4)
93 (29.4)
< 0.001
Emergency LSCS
75 (48)
42 (45)
0.66
2(0.7)
1(0.3)
0.478
24 (15)
5 (2)
< 0.001
Postpartum hemorrhage
32 (10.1)
18 (5.7)
0.015
Length of stay > 3 d
46 (15)
36 (11)
0.14
Instrumentation Shoulder dystocia
a
Abbreviations: d, days; LSCS, lower segment cesarean section; UHWI, University Hospital of the West Indies. a Percentages based on vaginal deliveries. American Journal of Perinatology
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Abbreviations: UHWI, University Hospital of the West Indies; y, years.
Fetal Macrosomia at UHWI
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Table 5 Risk Factors for the delivery of a macrosomic infant at the UHWI between 2007 and 2009 Variable
Odds ratio
95% Confidence interval for odds ratio
p-Value
Male gender
2.1
1.3–3.2
0.001
Multiparity
1.3
0.8–2.3
0.264
Maternal weight gain > 15 kg
2.1
1.27–3.4
0.004
Maternal height > 164 cm
1.99
1.3–3.0
0.002
Obesity
2.14
1.3–3.5
0.003
Abnormal glucose control
2.78
1.2–6.5
0.018
Previous macrosomia
6.10
1.9–19.1
0.002
Gestational age > 40 wk
2.28
1.4–3.7
0.001
Abbreviations: UHWI, University Hospital of the West Indies; wk, weeks.
fell within the range between 4,000 and 4,499 g. In the control group the birth weights ranged from 2,500 to 3,920 g with a mean SD of 3,206 334 g. There were three stillbirths and all were within the macrosomic group. Of these one mother was diagnosed with pregestational diabetes and chronic hypertension and another with gestational diabetes. There were no neonatal deaths in either group.
Risk Factors for Macrosomia When significant risk factors found to be associated with the delivery of a macrosomic infant were offered into a multiple logistic regression model, maternal obesity, maternal weight gain of > 15 kg, maternal height > 164 cm, abnormal glucose control in the mother, a previous history of having a macrosomic infant, gestational period > 40 weeks, and male gender of the infant remained independent risk factors for the delivery of a macrosomic infant (see ►Table 5).
Discussion This study showed that the incidence of macrosomia was 4.3% for babies weighing more than 4,000 g and 0.5% in babies weighing more than 4,500 g for the time period of January 2007 to December 2009 at the UHWI. The study also showed that women who delivered a macrosomic infant were more likely to be older, taller, multiparous, and heavier with a greater BMI at the start of the pregnancy. They tended to gain more weight during pregnancy, had a longer gestational period, an increased incidence of abnormalities of glucose control, and a history of previous macrosomia. LSCS was the preferred mode of delivery for macrosomic babies and a male preponderance was demonstrated. Genetic, racial, and ethnic factors influence birth weight and the risk of macrosomia. Thus the incidence varies according to the population that is being studied. Koyanagi et al looked at macrosomia (birth weight 4,000 g) in 23 developing countries within Africa, Asia, and Latin America. This study showed that the prevalence of macrosomia ranged from 0.5%, in India, to as high as 14.9%, in Algeria.10 Within the developed countries, the incidence varies from a low of 2.2% to a high of 31%.6,11–16 American Journal of Perinatology
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The incidence of macrosomia in this study is comparable to other published incidences in both developed and developing countries and is even lower in some instances. Within the Caribbean, in a study by Martin and Clarke, on a population from Antigua, the incidence of birth weight > 4,000 g was 5.7% and > 4,500 g was 1%.8 There appears to be an increasing incidence of fetal macrosomia worldwide apart from the United States.13,14,17 This has been attributed mostly to the increasing incidence of obesity and diabetes.12,18 The average height for women who delivered macrosomic babies in our study was 165.5 cm (which is above the normal average female height of 164 cm within the black population)19 and the average BMI was 29.36 kg/m2. This showed that many of the women were already overweight before becoming pregnant. Maternal prepregnancy weight has been shown to be an important factor in determining the fetal weight.4,15,20,21 Obesity has been associated with an increased risk of delivering a macrosomic baby and has been documented in previous studies to increase the risk by 2-fold.7 Our study showed that women who were obese were more likely to deliver macrosomic babies and gain more weight in the pregnancy. This finding has been reflected in several studies but the exact reason has not been fully elucidated.4 In a study by Bao et al, they showed that BMI had the greatest impact on macrosomia followed by height and then male gender.12 Khashan et al showed that there is an increase in the relative risk of macrosomia as the BMI increases; the highest risk being in the morbidly obese category.22 In a study by Asplund et al, they found that regardless of weight gain and initial prepregnancy BMI, an increase in maternal BMI of 25% or greater during pregnancy was associated with macrosomia.23 It has been postulated that there may be a link with abnormalities of glucose metabolism, but this was not seen in our study. Only 23% of the mothers who delivered a macrosomic baby were obese and also diabetic. Diabetes in pregnancy (gestational and pregestational) has been shown to be a significant risk factor for macrosomia.1 In our study, 15% of the cases within the macrosomic group had abnormalities of glucose control and these mothers had a > 2.5 chance of having a macrosomic baby. The average weight gain in our study was 12.6 kg among the women who delivered a macrosomic baby. Excessive
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are obese, for early screening and proper glucose monitoring and control throughout pregnancy.
Conclusion The maternal risk factors for fetal macrosomia identified in this study mirrors those of previous studies. Identification of modifiable risk factors for the delivery of macrosomic infants —nutritional status at the start of pregnancy, weight gain, and glucose control during pregnancy—will inform management protocols and guidelines to help decrease the incidence of macrosomia at our institution.
References 1 American College of Obstetricians and Gynaecologists (ACOG).
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3
4
5
6
7 8
9
10
11
12 13
14 15
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Fetal macrosomia. ACOG Practice Bulletin No. 22. Washington, DC: ACOG; 2000 Zhang X, Decker A, Platt RW, Kramer MS. How big is too big? The perinatal consequences of fetal macrosomia. Am J Obstet Gynecol 2008;198(5):e1–e6 Boulet SL, Salihu HM, Alexander GR. Mode of delivery and birth outcomes of macrosomic infants. J Obstet Gynaecol 2004;24(6): 622–629 Kamanu CI, Onwere S, Chigbu B, Aluka C, Okoro O, Obasi M. Fetal macrosomia in African women: a study of 249 cases. Arch Gynecol Obstet 2009;279(6):857–861 Lim JH, Tan BC, Jammal AE, Symonds EM. Delivery of macrosomic babies: management and outcomes of 330 cases. J Obstet Gynaecol 2002;22(4):370–374 Ju H, Chadha Y, Donovan T, O’Rourke P. Fetal macrosomia and pregnancy outcomes. Aust N Z J Obstet Gynaecol 2009;49(5): 504–509 Pundir J, Sinha P. Non-diabetic macrosomia: an obstetric dilemma. J Obstet Gynaecol 2009;29(3):200–205 Martin TC, Clarke A. A case control study of the prevalence of perinatal complications associated with fetal macrosomia in Antigua and Barbuda. West Indian Med J 2003;52(3):231–234 Gueri M, Jutsum P, Sorhaindo B. Anthropometric assessment of nutritional status in pregnant women: a reference table of weightfor-height by week of pregnancy. Am J Clin Nutr 1982;35(3): 609–616 Koyanagi A, Zhang J, Dagvadorj A, et al. Macrosomia in 23 developing countries: an analysis of a multicountry, facility-based, cross-sectional survey. Lancet 2013;381(9865):476–483 Sadeh-Mestechkin D, Walfisch A, Shachar R, Shoham-Vardi I, Vardi H, Hallak M. Suspected macrosomia? Better not tell. Arch Gynecol Obstet 2008;278(3):225–230 Bao C, Zhou Y, Jiang L, et al. Reasons for the increasing incidence of macrosomia in Harbin, China. BJOG 2011;118(1):93–98 Martin JA, Hamilton BE, Sutton PD, et al; Centers for Disease Control and Prevention National Center for Health Statistics National Vital Statistics System. Births: final data for 2005. Natl Vital Stat Rep 2007;56(6):1–103 Ventura SJ, Martin JA, Curtin SC, Mathews TJ, Park MM. Births: final data for 1998. Natl Vital Stat Rep 2000;48(3):1–100 Ørskou J, Henriksen TB, Kesmodel U, Secher NJ. Maternal characteristics and lifestyle factors and the risk of delivering high birth weight infants. Obstet Gynecol 2003;102(1):115–120 Luo ZC, Wilkins R, Heaman M, et al. Birth outcomes and infant mortality among First Nation Inuit and non – Indigenous Women by northern versus southern residence, Quebec. J Epidemiol Community Health 2012;66(4):328–333 Henriksen T. The macrosomic fetus: a challenge in current obstetrics. Acta Obstet Gynecol Scand 2008;87(2):134–145 American Journal of Perinatology
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weight gain has been implicated as one of the independent risk factors for macrosomia.24 In our study, women who gained in excess of 15 kg were more likely to deliver a macrosomic baby. The same was documented in a study of Japanese women by Morikawa et al.20 Tabatabaei showed that a gestational weight gain of 0.5 kg/wk was associated with a higher risk of fetal macrosomia.25 According to the guidelines from the U.S. Institute of Medicine (IOM) 2009, the recommended weight gain in pregnancy is 11.5 to 16 kg in a woman who has a normal BMI and 5 to 9 kg in obese women.26 Kac and Velásquez-Meléndez showed a 5.83 increase; and Hedderson et al a 3-fold increase in risk once there was weight gain higher than the IOM recommendations.27,28 Although these recommendations have been suggested, there still remains an issue of whether or not these restrictions can be followed. The finding of increased weight gain greater than the IOM recommendations predisposing to macrosomia is consistent with other studies in the literature.28–32 It has been found that a previous delivery of a macrosomic infant can increase the likelihood of a macrosomic infant in the next pregnancy by as much as 5 to 10 times.7 In our study, it did prove significant in keeping with earlier studies. It was shown to increase the likelihood by six times. Kamanu et al, in Nigeria, found that approximately 63% of the mothers had previous macrosomic infants4 and that this increased the risk of them having future macrosomic babies. Walsh et al showed that a history of delivery of more than one macrosomic infant further increased the risk of macrosomia in subsequent pregnancies.33 Studies by Ezegwui et al and Najafian et al have also proven the significance of previous delivery of a macrosomic infant.34,35 The preponderance of the male gender in macrosomic infants is a consistent finding that has yet to be explained.4–7,10,21,34 Being a retrospective study data collection was limited by what data were recorded, this was particularly evident in the recording of maternal height which limited the determination of BMI. In our study, there were a few cases where the mother did not book within the first trimester. However, factoring out the cases who booked outside of this trimester, weight gain still remained statistically significant. Obesity in the general population is concerning and its prevalence continues to increase. This has been shown to be a significant factor for macrosomia and so has long-term implications for perinatal care. We recommend that in our setting prepregnancy and pregnancy counselling on nutrition and diet needs to be strengthened. We need to ensure appropriate measurements are taken and BMI calculated for all women at their first antenatal visit. Excessive weight gain outside of the recommended guidelines increases the risk of macrosomia. We therefore need to identify women who are at high risk as early in the pregnancy as possible and institute ongoing dietary and nutritional advice and education on appropriate exercise. Abnormalities of glucose control can as much as double the risk of macrosomia we therefore recommend prepregnancy and pregnancy counselling to maintain appropriate glucose control before and during the pregnancy. Prompt identification of mothers who are at high risk, for example, those who
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18 Surkan PJ, Hsieh CC, Johansson AL, Dickman PW, Cnattingius S.
27 Kac G, Velásquez-Meléndez G. Gestational weight gain and macro-
Reasons for increasing trends in large for gestational age births. Obstet Gynecol 2004;104(4):720–726 Ogden CL, Fryar CD, Carroll MD, Flegal KM. Mean body weight, height, and body mass index, United States 1960–2002. Adv Data 2004;347:1–17 Sacks DA. Etiology, detection, and management of fetal macrosomia in pregnancies complicated by diabetes mellitus. Clin Obstet Gynecol 2007;50(4):980–989 Morikawa M, Cho K, Yamada T, Yamada T, Sato S, Minakami H. Fetal macrosomia in Japanese women. J Obstet Gynaecol Res 2013; 39(5):960–965 Khashan AS, Kenny LC. The effects of maternal body mass index on pregnancy outcome. Eur J Epidemiol 2009;24(11): 697–705 Asplund CA, Seehusen DA, Callahan TL, Olsen C. Percentage change in antenatal body mass index as a predictor of neonatal macrosomia. Ann Fam Med 2008;6(6):550–554 Stotland NE, Hopkins LM, Caughey AB. Gestational weight gain, macrosomia, and risk of cesarean birth in nondiabetic nulliparas. Obstet Gynecol 2004;104(4):671–677 Tabatabaei M. Gestational weight gain, prepregnancy body mass index related to pregnancy outcomes in KAZERUN, FARS, IRAN. J Prenat Med 2011;5(2):35–40 Rasmussen KM, Yaktine AL (eds). Weight gain during pregnancy: reexamining the guidelines. Washington, DC: National Academies Press; 2009. Available at: http://books.nap.edu/openbook.php? record_id¼12584. Accessed December 31, 2010
somia in a cohort of mothers and their children [in Portuguese]. J Pediatr (Rio J) 2005;81(1):47–53 Hedderson MM, Weiss NS, Sacks DA, et al. Pregnancy weight gain and risk of neonatal complications: macrosomia, hypoglycemia, and hyperbilirubinemia. Obstet Gynecol 2006;108(5):1153–1161 Flick AA, Brookfield KF, de la Torre L, Tudela CM, Duthely L, González-Quintero VH. Excessive weight gain among obese women and pregnancy outcomes. Am J Perinatol 2010;27(4):333–338 Siega-Riz AM, Viswanathan M, Moos MK, et al. A systematic review of outcomes of maternal weight gain according to the Institute of Medicine recommendations: birthweight, fetal growth, and postpartum weight retention. Am J Obstet Gynecol 2009;201(4):e1–e14 Halloran DR, Wall TC, Guild C, Caughey AB. Effect of revised IOM weight gain guidelines on perinatal outcomes. J Matern Fetal Neonatal Med 2011;24(3):397–401 Hinkle SN, Sharma AJ, Dietz PM. Gestational weight gain in obese mothers and associations with fetal growth. Am J Clin Nutr 2010; 92(3):644–651 Walsh CA, Mahony RT, Foley ME, Daly L, O’Herlihy C. Recurrence of fetal macrosomia in non-diabetic pregnancies. J Obstet Gynaecol 2007;27(4):374–378 Ezegwui HU, Ikeako LC, Egbuji C. Fetal macrosomia: obstetric outcome of 311 cases in UNTH, Enugu, Nigeria. Niger J Clin Pract 2011;14(3):322–326 Najafian M, Cheraghi M. Occurrence of fetal macrosomia rate and its maternal and neonatal complications: a 5-year cohort study. ISRN Obstet Gynecol 2012;2012:353791
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