Growth pattern of the Indian fetus

Birth-weight differences at term are explained by placental dysfunction and not by maternal ethnicity. Study in newborns of first generation immigrants

Objective: The aim of the study was to investigate the influence of ethnicity and cerebroplacental ratio (CPR) on the birth weight (BW) of first generation Indo-Pakistan immigrants' newborns.Methods: This was a retrospective study in a mixed population of 620 term Caucasian and Indo-Pakistan pregnancies, evaluated in two reference hospitals of Spain and Italy. All fetuses underwent a scan and Doppler examination within two weeks of delivery. The influence of fetal gender, ethnicity, GA at delivery, CPR, maternal age, height, weight and parity on BW was evaluated by multivariable regression analysis.Results: Newborns of first generation Indo-Pakistan immigrants were smaller than local Caucasian newborns (mean BW mean= 3048 ± 435 g versus 3269 ± 437 g, p < .001). Multivariable regression analysis demonstrated that all studied parameters, but maternal age and ethnicity, were significantly associated with BW. The most important were GA at delivery (partial R² = 0.175, p < .001), CPR (partial R² = 0.032, p < .001), and fetal gender (partial R² = 0,029, p < .001).Conclusions: The propensity to a lower BW, explained by placental dysfunction but not by maternal ethnicity is transmitted to newborns of first generation immigrants. Whatever are the factors implied they persist in the new residential setting.

Birth-weight differences at term are explained by placental dysfunction and not by maternal ethnicity

OBJECTIVE

To investigate the influence of ethnicity, fetal gender and placental dysfunction on birth weight (BW) in term fetuses of South Asian and Caucasian origin.

METHODS

This was a retrospective study of 627 term pregnancies assessed at two public tertiary hospitals in Spain and Sri Lanka. All fetuses underwent biometry and Doppler examinations within 2 weeks of delivery. The influences of fetal gender and ethnicity, gestational age (GA) at delivery, cerebroplacental ratio (CPR) and maternal age, height, weight and parity on BW were evaluated by multivariable regression analysis.

RESULTS

Fetuses born in Sri Lanka were smaller than those born in Spain (mean BW = 3026 ± 449 g vs 3295 ± 444 g; P < 0.001). Multivariable regression analysis demonstrated that GA at delivery, maternal weight, CPR, maternal height and fetal gender (estimates = 0.168, P < 0.001; 0.006, P < 0.001; 0.092, P = 0.003; 0.009, P = 0.002; 0.081, P = 0.01, respectively) were associated significantly with BW. Conversely, no significant association was noted for maternal ethnicity, age or parity (estimates = -0.010, P = 0.831; 0.005, P = 0.127; 0.035, P = 0.086, respectively). The findings were unchanged when the analysis was repeated using INTERGROWTH-21^st fetal weight centiles instead of BW (log odds, -0.175, P = 0.170 and 0.321, P < 0.001, respectively for ethnicity and CPR).

CONCLUSION

Fetal BW variation at term is less dependent on ethnic origin and better explained by placental dysfunction. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Fetal weight estimation by ultrasound: development of Indian population-based models

Purpose

Existing ultrasound-based fetal weight estimation models have been shown to have high errors when used in the Indian population. Therefore, the primary objective of this study was to develop Indian population-based models for fetal weight estimation, and the secondary objective was to compare their performance against established models.

Methods

Retrospectively collected data from 173 cases were used in this study. The inclusion criteria were a live singleton pregnancy and an interval from the ultrasound scan to delivery of ≤7 days. Multiple stepwise regression (MSR) and lasso regression methods were used to derive fetal weight estimation models using a randomly selected training group (n=137) with cross-products of abdominal circumference (AC), biparietal diameter (BPD), head circumference (HC), and femur length (FL) as independent variables. In the validation group (n=36), the bootstrap method was used to compare the performance of the new models against 12 existing models.

Results

The equations for the best-fit models obtained using the MSR and lasso methods were as follows: log₁₀(EFW)=2.7843700+0.0004197(HC×AC)+0.0008545(AC×FL) and log₁₀(EFW)=2.38 70211110+0.0074323216(HC)+0.0186555940(AC)+0.0013463735(BPD×FL)+0.0004519715 (HC×FL), respectively. In the training group, both models had very low systematic errors of 0.01% (±7.74%) and -0.03% (±7.70%), respectively. In the validation group, the performance of these models was found to be significantly better than that of the existing models.

Conclusion

The models presented in this study were found to be superior to existing models of ultrasound-based fetal weight estimation in the Indian population. We recommend a thorough evaluation of these models in independent studies.

Postnatal Weight Gain Patterns in Preterm Very-Low-Birth-Weight Infants Born in a Tertiary Care Center in South India

BACKGROUND

Extrauterine growth retardation is a common problem in preterm, very-low-birth-weight (VLBW) babies, as well as paucity of growth charts that follow their postnatal growth.

AIM

To evaluate and plot postnatal weight gain patterns of preterm VLBW babies of <34 weeks' gestation born at a tertiary care neonatal unit in South India.

METHODS

Weight gain patterns of all preterm (27 to < 34 weeks' gestation) and VLBW (<1500 g) neonates were used for plotting the centile curves by retrospective review of electronic medical records. The growth velocity was calculated from birth and from the time baby regained their birth weight.

RESULTS

Mean growth rate (±SD) of these babies was 16.2 ± 2.4 g/kg/day and average time to regain birth weight was 14.2 days (range 12.0-17.6).

CONCLUSION

The recommended growth velocity of 10-15 g/kg/day can be achieved using unfortified expressed breast milk, though at higher feeding volumes of 200 ml/kg/day. These centile curves can be useful for monitoring postnatal growth.

Ultrasound measurement of fetal size in rural Guatemala

OBJECTIVES

To describe the fetal growth pattern of a population from rural Guatemala and determine when during gestation growth faltering becomes evident.

METHODS

Ultrasound examinations were conducted for 319 women. Femur length (FL), biparietal diameter (BPD), abdominal (AC) and head circumference (HC) were compared with reference values.

RESULTS

FL and AC were similar to reference values throughout gestation. BPD and HC were below the 50th percentile by 30 weeks' gestation and below the 10th percentile later in gestation. We expected all four dimensions to show marked growth restriction during gestation. Measurement differences may explain the results but would call into question the value of cross-study comparisons. Infants born small for gestational age were small in all measures as early as 15 weeks.

CONCLUSIONS

Fetal growth faltering begins in early gestation among infants who were born small. The lack of deviation from reference data for FL and AC requires further clarification.

Between Scylla and Charybdis: renegotiating resolution of the 'obstetric dilemma' in response to ecological change

Hominin evolution saw the emergence of two traits-bipedality and encephalization-that are fundamentally linked because the fetal head must pass through the maternal pelvis at birth, a scenario termed the 'obstetric dilemma'. While adaptive explanations for bipedality and large brains address adult phenotype, it is brain and pelvic growth that are subject to the obstetric dilemma. Many contemporary populations experience substantial maternal and perinatal morbidity/mortality from obstructed labour, yet there is increasing recognition that the obstetric dilemma is not fixed and is affected by ecological change. Ecological trends may affect growth of the pelvis and offspring brain to different extents, while the two traits also differ by a generation in the timing of their exposure. Two key questions arise: how can the fit between the maternal pelvis and the offspring brain be 'renegotiated' as the environment changes, and what nutritional signals regulate this process? I argue that the potential for maternal size to change across generations precludes birthweight being under strong genetic influence. Instead, fetal growth tracks maternal phenotype, which buffers short-term ecological perturbations. Nevertheless, rapid changes in nutritional supply between generations can generate antagonistic influences on maternal and offspring traits, increasing the risk of obstructed labour.

Patterns of fetal growth in an Asian Indian cohort in the USA

OBJECTIVE

To determine whether a greater proportion of fetuses in an Asian Indian cohort are classified as small for gestational age than would be expected from a normally distributed population.

METHODS

A retrospective analysis of fetal growth pattern and neonatal outcome was conducted among Asian Indian women who were referred to a maternal-fetal medicine center in Park Ridge, IL, USA, for evaluation of fetal growth between January 1, 2012, and December 31, 2013. The primary outcome was an abdominal circumference or estimated weight of lower than the 10th percentile for gestational age according to the Hadlock formula.

RESULTS

Overall, 207 women and 210 fetuses were included. Forty-eight (22.9%) fetuses had an abdominal circumference lower than the 10th percentile. The total number of neonates classified as small for gestational age at delivery was 22 (10.5%), a value indicative of a normally distributed population.

CONCLUSION

Fetal size was smaller than expected among the present Asian Indian cohort, but most neonates were classified as appropriate for gestational age at birth. Population specific growth curves are needed to improve assessment of fetal growth.

Postnatal percentile growth charts for Indian appropriate for gestational age (AGA) very low birth weight babies

AIMS

To develop postnatal percentile growth charts for Indian very low birth weight (VLBW) appropriate for gestational age (AGA) babies till 37 weeks post conceptional age (PCA).

METHODS

Prospective, mixed longitudinal study in 105 VLBW AGA (male 73 and female 32) babies weighing <1500 g and <34 weeks gestation born over 1 year. All were weighed daily until discharge and then weekly till 37 weeks of PCA. The percentile weight curves were computed in four categories : ≤28 weeks, 29-30, 31-32 and 33 weeks, and a total of seven percentile distributions (3rd, 10th, 25th, 50th, 75th, 90th& 97th) were generated. Entire data were subjected to Tanner's 1951 method to compute mean and standard deviation for body weight. The arithmetic mean served the 50(th) percentile.

RESULTS

All babies at birth were <50th centile as per Lubchenco's intrauterine growth chart. This pattern was more evident in higher gestation (31-32 and 33 weeks) than lower gestation (≤28 and 29-30 weeks). At 37 weeks PCA, all were <10th centile and the lowest was in ≤28 weeks gestation.

CONCLUSIONS

Our babies are born smaller, and growth rate is slower than their western counterparts. Babies at lowest gestation had slowest postnatal growth. Hence, we need a separate growth chart for our babies.

Systematic review of methodology used in ultrasound studies aimed at creating charts of fetal size

BACKGROUND

Reliable ultrasound charts are necessary for the prenatal assessment of fetal size, yet there is a wide variation of methodologies for the creation of such charts.

OBJECTIVE

To evaluate the methodological quality of studies of fetal biometry using a set of predefined quality criteria of study design, statistical analysis and reporting methods.

SEARCH STRATEGY

Electronic searches in MEDLINE, EMBASE and CINAHL, and references of retrieved articles.

SELECTION CRITERIA

Observational studies whose primary aim was to create ultrasound size charts for bi-parietal diameter, head circumference, abdominal circumference and femur length in fetuses from singleton pregnancies.

DATA COLLECTION AND ANALYSIS

Studies were scored against a predefined set of independently agreed methodological criteria and an overall quality score was given to each study. Multiple regression analysis between quality scores and study characteristics was performed.

MAIN RESULTS

Eighty-three studies met the inclusion criteria. The highest potential for bias was noted in the following fields: 'Inclusion/exclusion criteria', as none of the studies defined a rigorous set of antenatal or fetal conditions which should be excluded from analysis; 'Ultrasound quality control measures', as no study demonstrated a comprehensive quality assurance strategy; and 'Sample size calculation', which was apparent in six studies only. On multiple regression analysis, there was a positive correlation between quality scores and year of publication: quality has improved with time, yet considerable heterogeneity in study methodology is still observed today.

CONCLUSIONS

There is considerable methodological heterogeneity in studies of fetal biometry. Standardisation of methodologies is necessary in order to make correct interpretations and comparisons between different charts. A checklist of recommended methodologies is proposed.

Patterns of fetal growth in a rural Indian cohort and comparison with a Western European population: data from the Pune maternal nutrition study

OBJECTIVE

The purpose of this study was to describe fetal size on sonography in a rural Indian population and compare it with those in European and urban Indian populations. Methods. Participants were from the Pune Maternal Nutrition Study of India. Fetal growth curves were constructed from serial ultrasound scans at approximately 18, 30, and 36 weeks' gestation in 653 singleton pregnancies. Measurements included femur length (FL), abdominal circumference (AC), biparietal diameter (BPD), and occipitofrontal diameter, from which head circumference (HC) was estimated. Measurements were compared with data from a large population-based study in France and a study of urban mothers in Vellore, south India.

RESULTS

Fetal AC and BPD were smaller than the French reference at 18 weeks' gestation (-1.38 and -1.30 SD, respectively), whereas FL and HC were more comparable (-0.77 and -0.59 SD). The deficit remained similar at 36 weeks for AC (-0.97 SD), FL (-0.43 SD), and HC (-0.52 SD) and increased for BPD (-2.3 SD). Sonography at 18 weeks underestimated gestational age compared with the last menstrual period date by a median of -1.4 (interquartile range, -4.6, 1.8) days. The Pune fetuses were smaller, even at the first scan, than the urban Vellore sample.

CONCLUSIONS

Fetal size was smaller in a rural Indian population than in European and urban Indian populations, even in mid pregnancy. The deficit varied for different fetal measurements; it was greatest for AC and BPD and least for FL and HC.

A principal components approach to parent-to-newborn body composition associations in South India

Background

Size at birth is influenced by environmental factors, like maternal nutrition and parity, and by genes. Birth weight is a composite measure, encompassing bone, fat and lean mass. These may have different determinants. The main purpose of this paper was to use anthropometry and principal components analysis (PCA) to describe maternal and newborn body composition, and associations between them, in an Indian population. We also compared maternal and paternal measurements (body mass index (BMI) and height) as predictors of newborn body composition.

Methods

Weight, height, head and mid-arm circumferences, skinfold thicknesses and external pelvic diameters were measured at 30 ± 2 weeks gestation in 571 pregnant women attending the antenatal clinic of the Holdsworth Memorial Hospital, Mysore, India. Paternal height and weight were also measured. At birth, detailed neonatal anthropometry was performed. Unrotated and varimax rotated PCA was applied to the maternal and neonatal measurements.

Results

Rotated PCA reduced maternal measurements to 4 independent components (fat, pelvis, height and muscle) and neonatal measurements to 3 components (trunk+head, fat, and leg length). An SD increase in maternal fat was associated with a 0.16 SD increase (β) in neonatal fat (p < 0.001, adjusted for gestation, maternal parity, newborn sex and socio-economic status). Maternal pelvis, height and (for male babies) muscle predicted neonatal trunk+head (β = 0. 09 SD; p = 0.017, β = 0.12 SD; p = 0.006 and β = 0.27 SD; p < 0.001). In the mother-baby and father-baby comparison, maternal BMI predicted neonatal fat (β = 0.20 SD; p < 0.001) and neonatal trunk+head (β = 0.15 SD; p = 0.001). Both maternal (β = 0.12 SD; p = 0.002) and paternal height (β = 0.09 SD; p = 0.030) predicted neonatal trunk+head but the associations became weak and statistically non-significant in multivariate analysis. Only paternal height predicted neonatal leg length (β = 0.15 SD; p = 0.003).

Conclusion

Principal components analysis is a useful method to describe neonatal body composition and its determinants. Newborn adiposity is related to maternal nutritional status and parity, while newborn length is genetically determined. Further research is needed to understand mechanisms linking maternal pelvic size to fetal growth and the determinants and implications of the components (trunk v leg length) of fetal skeletal growth.

Birth outcomes of Asian-Indian-Americans

OBJECTIVE

This study examines the maternal characteristics and birth outcomes of infants of U.S. resident Asian-Indian-American (AIA) mothers and compares those to infants of U.S. resident Whites and African-American (AA) mothers.

METHODS

Single live births to U.S. resident mothers with race/ethnicity coded on birth certificate as AIA, non-Hispanic White, or non-Hispanic AA were drawn from NCHS 1995 to 2000 U.S. Linked Live Birth/Infant Death files.

RESULTS

Compared to AAs or Whites, AIAs have the lowest percentage of births to teen or unmarried mothers and mothers with high parity for age or with low educational attainment. After taking these factors into account, AIA had the highest risk of LBW, small-for-gestational age and term SGA births but a risk of infant death only slightly higher than Whites and far less than AAs.

CONCLUSIONS

The birth outcomes of AIAs do not follow the paradigm that more impoverished minority populations should have greater proportions of low birth weight and preterm births and accordingly greater infant mortality rates.

Fetal growth in Peru: comparisons with international fetal size charts and implications for fetal growth assessment

OBJECTIVES

To compare fetal biometry measurements obtained in a Peruvian population with reference fetal size charts obtained in Peruvian and non-Peruvian populations.

METHODS

Fetal biometry measurements collected prospectively in 195 uncomplicated pregnancies were included in the presented analysis. At 20, 24, 28, 32, 36 and 38 weeks' gestation, fetal head circumference, abdominal circumference and femur diaphysis length were measured. Fetal biometry measurements were compared with fetal size charts obtained from another Peruvian and two non-Peruvian populations from North America and Europe.

RESULTS

When compared with ultrasound-based reference fetal size charts obtained from North American and European populations, fetuses from the studied population appeared to grow more slowly with advancing gestational age. This trend was not observed when a Peruvian population, similar to the one studied here, was used as a reference.

CONCLUSIONS

The results suggest that fetal growth in this Peruvian population may not be adequately assessed by using reference charts obtained from other populations and have implications for the use of growth standards in antenatal management.

Ethnicity and fetal growth in Fiji

BACKGROUND

Indigenous Fijians and the descendants of Asian Indians constitute the two major ethnic groups in Fiji. There are differences between the two groups in perinatal outcomes.

AIMS

To study fetal growth patterns in the two ethnic groups and to ascertain the influence, if any, of ethnicity on fetal growth.

METHODS

A longitudinal study was carried out on women with sure dates, regular cycles, no known risk factor complicating pregnancy and having their first antenatal examination before 20 weeks. Symphysis-fundal height, biparietal diameter, abdominal circumference and femur length were measured by the same observer at recruitment and at follow-up visits until delivery. Infant measurements were recorded soon after birth.

RESULTS

Indian babies were on average 795 g lighter, had 5.5 days shorter mean length of gestation and slower growth of biparietal diameter and abdominal circumference when compared to Fijian babies. Ethnicity of the mother was significantly associated with the difference in growth even after adjusting for other factors known to influence fetal growth.

CONCLUSION

Given the ethnic differences in fetal growth and maturation, it would be appropriate to use ethnicity-specific standards for perinatal care in Fiji.

Changes in maternal weight from the first to second trimester of pregnancy are associated with fetal growth and infant length at birth

BACKGROUND

Despite our knowledge of the negative consequences of stunting during early childhood and the important role that maternal nutritional status plays in the development of intrauterine growth retardation, we do not know the extent to which maternal nutritional status influences the growth in length of the fetus or whether a sensitive period for fetal linear growth exists during gestation.

OBJECTIVE

Our objective was to explore the relation between maternal weight gain during different stages of pregnancy and linear growth of the fetus.

DESIGN

Ultrasound examinations were conducted at 15-24 (x: 17.5) and 28-32 (x: 29.9) wk of gestation in 200 women from 4 rural Guatemalan villages. The associations between maternal weight gain from approximately 10 to 20 and 20 to 30 wk of pregnancy (from the first to the second and from the second to the third trimester, respectively) and fetal linear growth were tested with the use of ordinary least-squares regression.

RESULTS

Maternal weight gain from the first to the second trimester was associated with fetal femur and tibia lengths measured at both means of 17 and 30 wk (P < 0.05) and infant length at birth (P < 0.001). Weight gain from the second to the third trimester of pregnancy did not predict fetal linear growth or infant length at birth.

CONCLUSIONS

Maternal weight change from the first to the second trimester of pregnancy is strongly associated with fetal growth. Mid-gestation may be a sensitive period for fetal linear growth.

Why do aboriginal newborns weigh less? Determinants of birthweight for gestation

OBJECTIVE

To compare birthweight for gestational age of Aboriginal with Caucasian infants and investigate the origins of their differences.

METHODOLOGY

Data pertaining to birthweight, gestational age at delivery and pathological factors were abstracted from birth records of 1301 Western Australian singleton Aboriginal pregnancies dated before 24 weeks by ultrasound fetometry and compared with routinely collected data pertaining to Caucasian births of the same period.

RESULTS

Median birthweight for gestation was lower in Aboriginal than in Caucasian infants for deliveries after 35 weeks of gestation, and that of pure-descent lower than that of mixed-descent Aboriginal infants at all gestations. Pathological factors (e.g. diabetes, urogenital infections, alcoholism and leprosy) occurring more commonly in Aboriginal than in Caucasian pregnancies accounted for most of the differences in birthweight for gestation between mixed-descent Aboriginal and Caucasian infants but a discrepancy of almost 180 g remained between pure-descent Aboriginal and Caucasian infants.

CONCLUSIONS

Identified pathological factors contribute but do not entirely explain the lower birthweights for gestation observed in Aboriginal infants.