Maternal Body Height Is a Stronger Predictor of Birth Weight Than Ethnicity

J. Perinat. Med. 2018; aop

Niels Rochow*, Malak AlSamnan, Hon Yiu So, Dirk Olbertz, Anna Pelc, Jan Däbritz, Roland Hentschel, Ursula Wittwer-Backofen and Manfred Voigt Maternal body height is a stronger predictor of birth weight than ethnicity: analysis of birth weight percentile charts https://doi.org/10.1515/jpm-2017-0349 Middle East and North Africa, and Asia excluding Middle Received November 9, 2017. Accepted April 27, 2018. East). Percentile charts were calculated for each maternal Abstract height group. Results: The average BW and maternal height differ sig- Background: Anthropometric parameters such as birth nificantly between ethnic groups. On current percentile weight (BW) and adult body height vary between ethnic charts, newborns of taller mothers (≥176 cm) have a low groups. Ethnic-specific percentile charts are currently rate of SGA and a high rate of LGA, whereas newborns of being used for the assessment of newborns. However, shorter mothers (≤157 cm) have a high rate of SGA and a due to globalization and interethnic families, it is unclear low rate of LGA. When the BW data are stratified based on which charts should be used. A correlation between a the maternal height, mothers of similar height from dif- mother’s height and her child’s BW (1 cm accounts for a ferent ethnic groups show similar average BWs, SGA and 17 g increase in BW) has been observed. The study aims LGA rates. to test differences in small for gestational age (SGA) and Conclusion: Maternal body height has a greater influence large for gestational age (LGA) rates, employing BW per- on BW than maternal ethnicity. The use of BW percentile centile charts based on maternal height between ethnic charts for maternal height should be considered. groups. Keywords: Birth weight percentiles; growth restriction; Methods: This retrospective study of 2.3 million mother/ large for gestational age; small for gestational age. newborn pairs analyzed BW, gestational age, sex, maternal height and ethnicity from the German perinatal survey (1995–2000). These data were stratified for maternal height (≤157, 158–163, 164–169, 170–175, ≥176 cm) and Introduction region of origin (Germany, Central and Northern Europe, North America, Mediterranean region, Eastern Europe, The assessment of intrauterine growth is a daily routine of perinatal care to identify fetuses and newborns that are intrauterine growth restricted, small for gestational *Corresponding author: Niels Rochow, MD, Department of Pediatrics, age (SGA) or large for gestational age (LGA) [1]. The SGA McMaster University, 1280 Main Street West, Room 4F, Hamilton, and LGA are often defined as birth weights (BWs) below ON L8S 4K1, Canada, E-mail: [email protected] th th Malak AlSamnan, Hon Yiu So and Anna Pelc: Department of the 10 and above the 90 percentile, respectively, for Pediatrics, McMaster University, Hamilton, ON, Canada sex and gestational age. Proper identification of SGA or Dirk Olbertz: Neonatology, Clinic Südstadt, Rostock, Germany LGA is imperative, as these fetuses and newborns exhibit Jan Däbritz: Department of Pediatrics, University Medicine Rostock, higher rates of mortality and morbidity. Consequently, Rostock, Germany; and Centre for Immunobiology, Blizard Institute, diagnostics, treatment and admission are often sug- Barts Cancer Institute the Barts and The London School of Medicine gested [2–5]. and Dentistry, Queen Mary University of London, London, UK Roland Hentschel: Department of General Pediatrics, Division of To assess intrauterine growth, BW charts for sex and Neonatology/Intensive Care Medicine, Medical Center – Faculty of gestational age were developed from perinatal surveys Medicine, University of Freiburg, Freiburg, Germany based on millions of datasets. It has been shown that BW Ursula Wittwer-Backofen: Centre for Medicine and Society, cutoffs for SGA and LGA differ between populations and University of Freiburg, Freiburg, Germany ethnic groups. The general perception is that ethnic-spe- Manfred Voigt: Department of General Pediatrics, Division of Neonatology/Intensive Care Medicine, Medical Center – Faculty of cific characteristics, such as differences in body height, Medicine, University of Freiburg, Freiburg, Germany; and Centre for are related to differences in BWs. This led to the adoption Medicine and Society, University of Freiburg, Freiburg, Germany and use of ethnic-specific growth charts [6–8].

Brought to you by | Washington University in St. Louis Authenticated Download Date | 6/6/18 2:15 PM 2 Rochow et al., Birth weight percentiles based on maternal height

However, due to globalization and migration, there Northern Europe (excluding Germany) and North America, 4.6% from is an increasing number of interethnic families. Based Mediterranean countries, 3.6% from Eastern Europe, 6.9% from Mid- dle East and North Africa, 1.1% from Asia (excluding Middle East) and on this observation, it could be hypothesized that ethnic- 1.5% from other regions. Data from all neonates were included in our specific cutoffs for SGA and LGA may not apply. analysis irrespective of the presence or absence of neonatal disorders Findings in the literature support the hypothesis that and irrespective of the length of gestation. The gestational age was maternal body height is a predictor of BW. For instance, estimated according to Naegele’s rule and was corrected by sono- in animal experiments, it has been demonstrated that graphic assessment in weeks 8–14 when there was a discrepancy of a fetus was smaller at birth than another fetus with the ≥14 days. BW percentiles were calculated for gestational age and sex. The empirical percentile values were determined using a weighted same genetics if the former was gestated in the uterus of means method, as expressed by the following formula: a smaller breed mare [9]. In humans, it has been shown that BW is related to the maternal height [10–15]. The rela- pp kn≤⋅ <+kd1, ,=⋅nk−= (xgpk+⋅dgkk+1 − g ) tion between maternal height and BW has been attributed 100100 to the fact that mothers of shorter stature have a smaller where n is the number of births for a specific gestational day, uterine environment, which ultimately limits the space g1 ≤ … ≤ gn are the sorted BWs for that gestational day, p is the percen- th available for intrauterine growth [11]. This concept is tile, xp is the weight representing the p percentile and k is the floor of further supported by the observation that the BWs of half- p n⋅ . For k < 1, xp was set to the smallest weight, g1 [18]. siblings are more strongly correlated when the common 100 Cutoffs for SGA, AGA (appropriate for gestational age) and parent is the mother [16]. Furthermore, in cases of ovum LGA were calculated for the complete dataset and selected cohorts donation, it has been shown that the maternal anthro- for five maternal height groups ≤( 157 cm, 158–163 cm, 164–169 cm, pometry was related to the BW. The BWs of the infants 170–175 cm and ≥176 cm). Neonates with BW less than the 10th per- were closely associated with the body anthropometry of centile were classified as SGA, while those with BW above the 90th the recipient mother but unrelated to the BW of the ovum percentile were classified as LGA. All newborns between the 10th and donor’s own child [17]. 90th BW percentiles were considered AGA. For this analysis, we also Recently, we found a linear relationship between classified the data based on the mother’s region of origin: Germany, Central and Northern Europe, North America, Mediterranean region, the maternal height and the infant’s BW over a wide Eastern Europe, Middle East and North Africa and Asia excluding the range. For each 1 cm increase in the maternal height, Middle East. the average BW increased by 17 g [15]. We have also Multivariate linear regression models were carried out to study shown that cutoffs for LGA, as well as SGA, differ by up the effects on BW using the “lm” function of R software package. to 600 g [12]. This was demonstrated by comparing term Model 1 tests the effect of either the region of origin or maternal height on BW. A variance analysis for the full and reduced models newborns of short and light-weight mothers (≤161 cm was performed. The F statistic was used to indicate the effect of either and ≤57 kg) with those of tall and heavy-weight mothers the region of origin or maternal height on BW. (≥172 cm and ≥106 kg) [12]. Equation model 1a: As evidence shows that there is a correlation between maternal height and BW, this study aims to test whether BW ~region of origin + maternal height group (full model) SGA and LGA rates differ between ethnic groups when BW ~region of origin (reduced model) reference values for BW percentiles based on maternal height groups are used. It is hypothesized that BW is more Equation model 1b: strongly affected by sex, gestational age and maternal BW ~region of origin + maternal height group (full model) height than by the newborn’s ethnicity. BW ~maternal height group (reduced model)

Model 2 analyzes the effects of the region of origin, maternal Methods height, gestational age and sex on BW. Boys born of German origin and a maternal height of 164–169 cm were the comparator. The data for this observational cohort study were taken from the Equation model 2: routine data collection of the German perinatal survey performed between 1995 and 2000. Between 1995 and 1997, all German federal BeWs~region of origin ++maternal height group gestational age + x states except Baden-Württemberg contributed to our dataset, while between 1998 and 2000, only Bavaria, Brandenburg, Hamburg, Meck- The analysis was assisted by IBM SPSS Statistics for Windows, lenburg-Western Pomerania, Lower Saxony, Saxony, Saxony-Anhalt Version 21.0. Armonk, NY, USA, Microsoft Excel®, Microsoft Corp., and Thuringia contributed data. Our dataset contains 2.3 million sam- Redmond, WA, USA and R software package for statistical analysis, ples from singleton pregnancies. The maternal regions of origin in this R Foundation for Statistical Computing, version 3.3.1 (2017-11-30), dataset were as follows: 80.8% from Germany, 1.7% from Central and Vienna, Austria.

Brought to you by | Washington University in St. Louis Authenticated Download Date | 6/6/18 2:15 PM Rochow et al., Birth weight percentiles based on maternal height 3

Results The average BW differs significantly based on the region of origin. Within a region of origin, the average This study comprises 2.3 million datasets from sin- BW differs significantly for different maternal heights. gleton pregnancies. The average maternal height in However, the average BW is not significantly different this population is 166.5 ± 6.3 cm (minimum = 141.0 cm, between mothers of different regions of origin within the maximum = 199.0 cm). There are significant differences same body height group (Figure 2). between the average maternal body heights for differ- BW percentile values calculated from the complete ent regions of origin. In the analyzed population, Asian population were applied to BWs stratified by the region of mothers have the shortest average body height (159 cm), origin and maternal body height. The resulting SGA rates whereas German mothers are the tallest (167 cm), with the were low and LGA rates were high for newborns of taller largest proportion of tall mothers (≥170 cm) (Figure 1). mothers, while the SGA rates were high and LGA rates Table 1 shows the rates of SGA, AGA and LGA, as well were low for newborns of shorter mothers. In the maternal as the duration of pregnancies for newborns from mothers height group of 164–169 cm, SGA and LGA rates were close with different body heights when the classification is to the 10% cutoff (Table 2). done with percentiles based on the complete population. Separate BW percentiles were calculated for different SGA rates are low (5%) and LGA rates are high (18%) for maternal height groups (Table 3 and Supplemental mate- newborns of taller mothers (≥176 cm), while SGA rates are rial Figures S1 and S2). When these percentiles were used high (17%) and LGA rates are low (5%) for newborns of to classify newborns from different ethnicities, the SGA shorter mothers (≤157 cm). The duration of pregnancies and LGA rates were close to the 10% cutoff, and differ- is on average 3 days longer in taller mothers compared to ences in SGA and LGA rates between ethnic groups were shorter mothers. minimized (Table 2).

Figure 1: Maternal body height for the region of origin.

Table 1: Rates of small (SGA), appropriate (AGA) and large (LGA) for gestational age as well as the duration of pregnancies by maternal body height based on birth weight percentile calculated for the complete population.

All Maternal body height

≤157 cm 158–163 cm 164–169 cm 170–175 cm ≥176 cm

Duration of pregnancy (days) 276 ± 14 275 ± 15 276 ± 14 276 ± 14 277 ± 13 278 ± 13 LGA (%) 9.8 5.0 6.6 9.2 12.5 17.9 AGA (%) 80.6 78.2 81.0 81.5 80.8 77.2 SGA (%) 9.6 16.8 12.4 9.3 6.7 4.9 n 2,303,353 158,882 538,451 823,300 576,928 172,946

Brought to you by | Washington University in St. Louis Authenticated Download Date | 6/6/18 2:15 PM 4 Rochow et al., Birth weight percentiles based on maternal height

Figure 2: Mean birth weight for the region of origin and maternal height.

Figure 3 shows the relationship between the BW and on median BW (Table 4 and Supplemental material maternal height for term newborns (37 + 0 to 41 + 6/7 weeks Figure S3). of gestation). The BW percentiles increase linearly with maternal height. The variance analysis comparing the regression model 1 (BW ~ region of origin + maternal height group) Discussion with model 1a (BW ~ region of origin) showed an F statistic The current study shows that BW percentile charts of 19,741 (P < 0.001). Comparing model 1 vs. model 1b developed for maternal height groups might be uni- (BW ~ maternal height group) showed an F statistic of 466 versally applicable for different ethnicities, which sim- (P < 0.001). The maternal height group had a more than plifies the assessment of newborns from interethnic 40 times stronger effect on BW compared to the region of families. This is a particularly important finding for origin in terms of the F statistic. health systems that need to account for ethnically spe- The effects on median BW by the maternal height, cific characteristics due to globalization and migration. sex, gestational age and region of origin are outlined Moreover, this study adds further evidence that mater- in Table 4. The multivariate regression analysis con- nal height is a strong determinant of the BW, and sup- firmed a significant effect of the maternal height group ports the recommendation to adopt BW charts based on maternal height as a standard [7, 8, 10, 12, 15, 17]. Further, the findings from the current study might also have some implications for the prenatal ultrasound. Including the maternal height in the assessment could aid in the determination of the fetal size, particularly for shorter or taller mothers. The schedule for prenatal fol- low-up ultrasounds might be altered, for example, when the smaller size of a fetus could be justified by the short stature of the mother. Differences in cutoff levels for SGA and LGA between ethnic-specific BW charts could be explained by significant differences in the maternal height. Interna- tional data show that average body height differs by up to 30 cm between different populations [19–22]. Also, Figure 3: Birth weight for maternal height for term newborns (37 + 0/7 to 41 + 6/7 weeks of gestation). it was shown that the average BW, as well as SGA and The lines represent percentile values calculated using the lambda- LGA BW cutoffs, are related to the maternal height. The mu-sigma method. increase in maternal body height by 1 cm accounts for a

Brought to you by | Washington University in St. Louis Authenticated Download Date | 6/6/18 2:15 PM Rochow et al., Birth weight percentiles based on maternal height 5 9.4 8.4 7.4 9.7 9.1 7.8 PAH Asia 10.4 79.4 10.2 80.2 10.4 80.9 10.6 82.9 83.1 154 1197 3743 8286 9006

7.2 8.9 9.6 7.3 4.9 5.2 PCP 80.1 12.7 81.4 10.9 81.8 14.8 80.3 78.6 16.2

9.7 9.3 8.4 7.6 8.9 PAH 11.1 79.3 79.9 10.7 79.9 11.8 80.3 12.1 13.1 78.0 Middle East Middle 799 9722 34,485 50,154 27,556

7.5 8.9 8.2 6.3 6.8 PCP 80.3 12.1 81.1 10.0 10.6 81.1 13.8 79.9 75.8 17.4

8.1 7.3 6.9 7.0 8.7 PAH 79.4 12.5 79.9 12.7 79.8 13.4 79.6 13.4 79.3 12.0 6288 1738 10,668 22,792 17,335

Europe Eastern 5.4 7.0 8.9 9.0 7.0 4.3 PCP 79.1 15.5 81.3 11.7 82.1 12.4 80.6 73.8 21.9

9.2 8.8 8.9 9.0 9.5 PAH 80.0 10.9 80.7 10.5 80.5 10.6 80.8 10.3 10.3 80.3 1869 12,220 26,068 27,426 12,683 Mediterranean

5.9 8.4 9.8 7.3 5.4 5.2 PCP 80.1 13.9 81.9 11.5 81.2 16.0 78.7 77.2 17.6

9.3 8.5 8.6 7.2 9.7 9.7 PAH 80.2 10.5 81.3 10.2 80.5 10.8 82.8 10.0 80.5 Central andCentral 6240 9045 6679 2550 1478 North America

Northern Europe, Northern Europe, 6.4 8.1 9.2 7.6 4.7 5.2 PCP 80.4 13.1 82.7 10.9 81.6 13.3 81.9 76.4 18.4

9.8 9.8 9.9 9.7 9.3 8.8 9.8 9.7 PAH 80.4 80.4 10.1 80.6 11.0 80.3 80.5 Germany 91,669 516,924 695,310 404,273 162,026

6.8 9.4 9.0 6.3 4.4 4.9 80.7 12.5 81.6 12.8 80.9 18.5 77.1 77.2 17.9 PCP

n Maternal body height ≥ 176 cm height body Maternal (%) LGA SGA (%) n (%) AGA Maternal body height 170–175 cm height body Maternal (%) LGA SGA (%) AGA (%) AGA n Maternal body height 164–169 cm height body Maternal (%) LGA SGA (%) AGA (%) AGA n Maternal body height 158–163 cm height body Maternal (%) LGA SGA (%) AGA (%) AGA n Maternal body height ≤ 157 cm height body Maternal (%) LGA SGA (%) AGA (%) AGA 157 cm, 158–163 cm, 164–169 cm, 164–169 cm, cm, 158–163 ≤ 157 cm, [ groups height on maternal based percentiles to compared population the complete from percentiles by classified newborns LGA SGA and of 2: Rate Table (PAH)]. group height for adjusted percentiles (PCP), population the complete for percentiles ≥ 176 cm, 170–175 cm,

Brought to you by | Washington University in St. Louis Authenticated Download Date | 6/6/18 2:15 PM 6 Rochow et al., Birth weight percentiles based on maternal height 3865 3670 3460 3200 2925 2638 2359 4600 4505 4363 4200 4025 ≥ 176 3820 3591 3320 4430 3030 4320 2720 4185 2437 4033

3765 3578 3362 3120 2840 2560 2292 4464 4400 4250 4090 3915 3710 3490 3225 4299 2932 4220 2646 4070 2378 3930 170–175

3843 3680 3500 3310 3070 2810 2530 2265 4350 4290 4150 4000 3830 3635 3410 3160 4180 2880 4110 2605 3983 2348 164–169

Percentile of birth weight (g) – maternal height (cm) height (g) – maternal birth of weight Percentile th 90 3760 3610 3435 3240 3000 2753 2488 2240 4300 4200 4065 3915 3750 3560 3350 3107 4100 2850 4030 2570 3900 2310 158–163

3690 3540 3370 3183 2970 2720 2459 2220 4183 4110 3985 3840 ≤ 157 3680 3500 3300 3074 4002 2820 3945 2563 3820 2318

2950 2772 2572 2350 2090 1830 1577 1353 3404 3350 3228 3077 ≥ 176 2900 2690 2459 2200 3230 1945 3210 1688 3085 1450

2875 2710 2518 2293 2043 1785 1530 1318 3320 3278 3150 3000 2830 2630 2403 2150 3150 1895 3130 1640 3015 1417 170–175

2805 2646 2455 2238 2000 1750 1516 1310 3230 3195 3070 2930 2760 2566 2347 2100 3070 1848 3060 1600 2950 1382 164–169

Percentile of birth weight (g) – maternal height (cm) height (g) – maternal birth of weight Percentile th 10 2743 2587 2400 2193 1970 1730 1498 1290 3150 3120 3000 2855 2695 2503 2295 2063 3035 1820 2997 1583 2880 1370 158–163

≤ 157 2665 2510 2340 2140 1932 1700 1480 1280 3037 3015 2910 2773 2616 2433 2230 2003 2920 1774 2900 1550 2796 1360

39 38 37 36 35 34 33 Girls 32 42 41 40 39 38 37 36 35 42 34 41 33 40 Boys 32 GA (weeks) Birth weight percentiles for maternal height, sex and gestational age (GA). age gestational and height, sex maternal for 3: Birthpercentiles weight Table

Brought to you by | Washington University in St. Louis Authenticated Download Date | 6/6/18 2:15 PM Rochow et al., Birth weight percentiles based on maternal height 7

Table 4: Effect of sex, gestational age, maternal height and region BW [12]. However, it would be of interest to study the of origin on the median birth weight. effects of the height difference between the mother and father on BW and perinatal risk. In light of the well-known Coefficient Estimate (g) Standard error (g) crossbreeding experiments in horses, it could be specu- Intercept −2181 10.4 lated that a baby who is born to a shorter mother and a Height group: ≤157 cm −165 1.3 taller father can have signs of intrauterine growth restric- Height group: 158–163 cm −79 0.8 tion [9]. Moreover, further studies can evaluate the perina- Height group: 170–175 cm 82 0.8 Height group: ≥176 cm 176 1.2 tal risk of infants from different maternal height groups, th th Girl −145 0.6 which are born below the 10 or above the 90 BW percen- Gestational age (weeks) 145 0.3 tile cutoffs based on the maternal height. Central and Northern Europe, 22 2.8 A potential limitation of the study is the observed North America difference in pregnancy duration of 3 days between the Mediterranean 22 1.6 maternal height groups. However, in this analysis we con- Eastern Europe 74 1.9 Middle East and North Africa 38 1.3 trolled for the gestational age. Infants born at the same Asia 25 3.0 gestational age were compared, which minimized the effect of pregnancy duration on BW. Multivariate regression model using boys born of German origin and a maternal height of 164–169 cm as a comparator. Another limitation of our study is that the number of newborns from different ethnic groups abstracted from the German perinatal survey is not equal. In this 17 g higher BW in term newborns [12, 15]. This aforemen- dataset, most newborns are of German origin. Therefore, tioned finding is clinically significant, as it could explain our approach should be applied to more diverse inter- differences in average BW by up to 510 g (30 cm · 17 g/ national data. To enable this, the collection of parental cm = 510 g). The magnitude of this variation in average heights should be a standard for international perinatal BW has been found when comparing perinatal surveys surveys. [8, 12, 15, 23, 24]. Also, the ethnic allocation might be blurred by the Furthermore, when one specific ethnic group is ana- fact that some larger groups are comprised of different lyzed, the average BW, as well as the SGA and LGA cutoffs, subgroups. For instance, the “Asian” ethnicity consists of vary significantly between different maternal height groups India, China and the Philippines, among others. Combin- within this ethnic group. There is no “standard human” ing these subgroups may conceal regional disparities in for each ethnic group; each of the groups is characterized body proportions, which are due to different population by variations in the maternal height. This study deter- history and evolution. mined that this variation in the maternal height within an In conclusion, this study suggests that maternal body ethnic group is around 25 cm (±2 standard deviation) [12, height has a greater influence on BW than maternal eth- 14, 15]. Considering this 25 cm difference and the observed nicity. BW percentile charts based on the maternal height increase in average BW based on the maternal height (17 g instead of ethnicity should be developed for growth for every 1 cm), the average BW of term newborns varies up assessment of the newborn. This finding should be further to 425 g (25 cm · 17 g/cm = 425 g) [12, 14, 15]. In this study, investigated using genetic traits, biomarkers and life-long these findings have been confirmed for the average BW health outcomes. within different ethnic groups (Figure 2). Also, SGA and LGA cutoffs were found to differ significantly with maternal Acknowledgment: The authors would like to thank Chris- height (Figure S3) [14]. This demonstrates that the current tel Fernow for the preparation of figures and tables. practice of using only one standard BW chart for one specific ethnic group introduces a systematic error in clinical Funding source: No funding was secured for this study. routine. These findings fundamentally suggest the need for Author contributions: Dr. Niels Rochow conceptualized BW charts based on the maternal height to assess the size and designed the study and wrote the initial manuscript. of newborns. Dr. Malak AlSamnan drafted parts of the manuscript and A limitation of our study is that the body height of contributed to the study design. Dr. Hon Yiu So carried out the father is not included in the German perinatal survey. the statistical analysis. Dr. Dirk Olbertz assisted with the Although it is sensible to assume that the body heights of data analysis and was involved in the interpretation of the both the mother and the father affect the BW, the mater- data. Anna Pelc drafted parts of the manuscript and con- nal body height has a more significant influence on the tributed to the study design. Dr. Jan Däbritz drafted parts

Brought to you by | Washington University in St. Louis Authenticated Download Date | 6/6/18 2:15 PM 8 Rochow et al., Birth weight percentiles based on maternal height of the manuscript. Dr. Roland Hentschel was involved in countries affects the prevalence of small for gestational age the interpretation of the data. Dr. Ursula Wittwer-Back- among very preterm infants. Acta Paediatr. 2017;106:1447–55. [9] Allen WR, Wilsher S, Turnbull C, Stewart F, Ousey J, Rossdale ofen drafted parts of the manuscript and contributed to PD, et al. Influence of maternal size on placental, fetal and the data analysis. Dr. Manfred Voigt collected the data and postnatal growth in the horse. I. Development in utero. Repro- carried out the statistical analysis. All authors approved duction. 2002;123:445–53. the final manuscript as submitted and agree to be account- [10] Britto RP, Florencio TM, Benedito Silva AA, Sesso R, Cavalcante able for all aspects of the work. JC, Sawaya AL. Influence of maternal height and weight on low birth weight: a cross-sectional study in poor communities of northeastern Brazil. PLoS One. 2013;8:e80159. Author’s statement [11] Miletic T, Stoini E, Mikulandra F, Tadin I, Roje D, Milic N. Effect Conflict of interest: The authors have no conflicts of inter- of parental anthropometric parameters on neonatal birth est to disclose. weight and birth length. Coll Antropol. 2007;31:993–7. Financial disclosure: The authors have no financial rela- [12] Rochow N, Voigt M, Olbertz DM, Straube S. Birth weight tionships relevant to this article to disclose. percentiles: an international comparison. In: Zabransky S, editor. Caring for children born small for gestational age. Material and methods: Informed consent: Informed London: Springer; 2013. consent has been obtained from all individuals included [13] Witter FR, Luke B. The effect of maternal height on birth weight in this study. and birth length. Early Hum Dev. 1991;25:181–6. Ethical approval: The research related to human subject use [14] Voigt M, Rochow N, Jahrig K, Straube S, Hufnagel S, Jorch G. has complied with all the relevant national regulations, and Dependence of neonatal small and large for gestational age institutional policies, and is in accordance with the tenets rates on maternal height and weight – an analysis of the German Perinatal Survey. J Perinat Med. 2010;38:425–30. of the Helsinki Declaration, and has been approved by the [15] Voigt M, Rochow N, Guthmann F, Hesse V, Schneider KT, authors’ institutional review board or equivalent committee. Schnabel D. Birth weight percentile values for girls and boys under consideration of maternal height. Z Geburtshilfe Neona- tol. 2012;216:212–9. [16] Morton NE. The inheritance of human birth weight. Ann Hum References Genet. 1955;20:125–34. [17] Brooks AA, Johnson MR, Steer PJ, Pawson ME, Abdalla HI. Birth [1] WHO Child Growth Standards. Length/height-for-age, weight- weight: nature or nurture? Early Hum Dev. 1995;42:29–35. for-age, weight-for-length, weight-for-height and body mass [18] Voigt M, Rochow N, Straube S, Briese V, Olbertz D, Jorch index-for-age: methods and development. Geneva, Switzer- G. Birth weight percentile charts based on daily measure- land: World Health Organization; 2006. ments for very preterm male and female infants at the age of [2] Nardozza LM, Caetano AC, Zamarian AC, Mazzola JB, Silva CP, 154–223 days. J Perinat Med. 2010;38:289–95. Marcal VM, et al. Fetal growth restriction: current knowledge. [19] Bjelica D, Popovic S, Kezunovic M, Petkovic J, Jurak G, Gras- Arch Gynecol Obstet. 2017;295:1061–77. gruber P. Body height and its estimation utilising arm span [3] Figueras F, Gratacos E. An integrated approach to fetal growth measurements in Montenegrin adults. Anthropol Noteb. restriction. Best Pract Res Clin Obstet Gynaecol. 2017;38: 2012;18:69–83. 48–58. [20] Bogin B, Varela-Silva MI. Leg length, body proportion, and [4] Schaefer-Graf UM, Rossi R, Bührer C, Siebert G, Kjos SL, health: a review with a note on beauty. Int J Environ Res Public Dudenhausen JW, et al. Rate and risk factors of hypoglycemia Health. 2010;7:1047–75. in large-for-gestational-age newborn infants of nondiabetic [21] Dietz WH, Marino B, Peacock NR, Bailey RC. Nutritional status mothers. Am J Obstet Gynecol. 2002;187:913–7. of Efe pygmies and Lese horticulturists. Am J Phys Anthropol. [5] Rozance PJ, Hay WW Jr. New approaches to management of 1989;78:509–18. neonatal hypoglycemia. Matern Health Neonatol Perinatol. [22] Roser M. Human height. https://ourworldindata.org/human- 2016;2:3. height/. Published 2016. [6] Chiossi G, Pedroza C, Costantine MM, Truong VT, Gargano G, [23] Alshimmiri MM, Hammoud MS, Al-Saleh EA, Alsaeid KM. Ethnic Saade GR. Customized versus population-based growth charts variations in birthweight percentiles in Kuwait. Paediatr Perinat to identify neonates at risk of adverse outcomes: a systematic Epidemiol. 2003;17:355–62. review and Bayesian meta-analysis of observational studies. [24] Seaton SE, Yadav KD, Field DJ, Khunti K, Manktelow BN. Birth- Ultrasound Obstet Gynecol. 2017;50:156–66. weight centile charts for South Asian infants born in the UK. [7] Kierans WJ, Joseph KS, Luo ZC, Platt R, Wilkins R, Kramer MS. Neonatology. 2011;100:398–403. Does one size fit all? The case for ethnic-specific standards of fetal growth. BMC Pregnancy Childbirth. 2008;8:1. [8] Zeitlin J, Bonamy AE, Piedvache A, Cuttini M, Barros H, Van Supplemental Material: The online version of this article offers Reempts P, et al. Variation in term birthweight across European supplementary material (https://doi.org/10.1515/jpm-2017-0349).

Brought to you by | Washington University in St. Louis Authenticated Download Date | 6/6/18 2:15 PM