Performance of different fetal growth charts in prediction of large-for-gestational age and associated neonatal morbidity in multiethnic obese population

OBJECTIVES

To examine the performance of different fetal growth charts in the prediction of large-for-gestational age (LGA) and associated neonatal morbidity at term in a multiethnic, obese population.

METHODS

This was a retrospective cohort study of 253 non-anomalous, singleton, term pregnancies that underwent serial third-trimester ultrasound scans due to maternal body mass index ≥ 35 kg/m² . We compared the performance of the Hadlock, Gestation Related Optimal Weight (GROW), INTERGROWTH-21^st (IG-21), World Health Organization (WHO) and Fetal Medicine Foundation (FMF) fetal growth reference charts in the prediction of LGA at birth, defined as birth weight > 90^th percentile, and neonatal morbidity, defined as a composite of neonatal intensive care unit admission or 5-min Apgar score < 7.

RESULTS

In the study population, 53 (20.9%) infants were born LGA, 27 (10.7%) experienced neonatal morbidity and nine (3.6%) were LGA with associated neonatal morbidity. The Hadlock and GROW charts showed similar performance in predicting LGA, with sensitivity of 66.0% for both and specificity of 82.5% and 83.5%, respectively. The positive likelihood ratios (LR+) were 3.77 (95% CI, 2.64-5.40) and 4.00 (95% CI, 2.77-5.78), respectively. The IG-21, WHO and FMF charts performed similarly and had higher sensitivity of about 85%, with specificity between 66% and 72%. LR+ was 2.74 (95% CI, 2.16-3.47), 2.50 (95% CI, 2.00-3.12) and 3.03 (95% CI, 2.36-3.89), respectively. All charts had high sensitivity for predicting neonatal morbidity associated with LGA, with LR+ ranging between 2.35 and 3.61.

CONCLUSIONS

In our multiethnic, obese population, all fetal growth charts performed well in predicting LGA and associated neonatal morbidity. However, the choice of fetal reference chart is likely to affect intervention rates. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Racial and Ethnic Patterning of Low Birth Weight, Normal Birth Weight, and Macrosomia

Both low birthweight (<2500 g; LBW) and macrosomia (>4000 g) are considered adverse birth outcomes and are associated with later poor health conditions, yet the social determinants of macrosomia are understudied. In this study, we explore patterning of LBW, normal birthweight, and macrosomia by race/ethnicity and nativity. We examined data from all live births between 1999 and 2014 in New Jersey with a non-missing, plausible value of birthweight (n = 1,609,516). We compared the risk for LBW and macrosomia among non-Hispanic White, non-Hispanic Black, Hispanic, and non-Hispanic Asian mothers, and between the US- and native-born. For Hispanics and Asians, we also examined differences by country of origin. The racial/ethnic patterns for macrosomia mirrored those of LBW, suggesting that the factors underlying LBW shift birthweight distributions. For example, non-Hispanic White mothers had the lowest risk for LBW and the highest risk for macrosomia. Nativity patterns differed by subgroup, however, with unique risks for macrosomia among some origin groups, such as foreign-born Cubans. The racial/ethnic and nativity patterns of macrosomia do not completely mirror those of LBW, suggesting some distinct social risk factors for macrosomia. Our findings raise questions about whether and how racial/ethnic and nativity patterning in both low and excess birthweight is retained in later conditions, such as childhood obesity.

Ethnic differences in antepartum glucose values that predict postpartum dysglycemia and neonatal macrosomia

BACKGROUND AND OBJECTIVE

Gestational diabetes (GDM) occurs more often in women from certain ethnic groups and is also associated with fetal macrosomia. In this study, we investigated the ability of a gestational diabetes screening test (GDS), the 2 h 75 g-Oral Glucose Tolerance Test (OGTT), and glycated hemoglobin (HbA1c) in predicting postpartum dysglycemia and fetal macrosomia in women of Caucasian, Filipino, Chinese and South-Asian descent.

METHODS

848 women diagnosed with carbohydrate intolerance in pregnancy who completed a 2 h 75 g- OGTT within 6 months postpartum, were included in the study. Receiver Operating Characteristic curve analysis was used to test the ability of antepartum GDS, HbA1c and OGTT in predicting postpartum hyperglycemia, type 2 diabetes (T2D) and neonatal macrosomia (birth weight >4000 g).

RESULTS

20.2% had postpartum hyperglycemia while 3.8% had T2D. Those with postpartum dysglycemia were more likely to be non-Caucasian (South-Asian > Filipino > Chinese), have higher antepartum glucose values, require insulin during pregnancy and have cesarean births. Of HbA1c and the antepartum glucose values, a fasting glucose of ≥5.25 mmol/L was predictive of fetal macrosomia in Caucasians. 1 h glucose of ≥11.05 mmol/L was predictive of postpartum hyperglycemia, while 2 h glucose of ≥9.75 mmol/L was predictive of T2D; ethnicity influenced the predictive ability of these tests.

CONCLUSIONS

Ethnicity influences the ability of antepartum glucose and HbA1c to predict the risk of macrosomia and postpartum dysglycemia. This information will help detect those most at risk of T2D.

Does the impact of a plant-based diet during pregnancy on birth weight differ by ethnicity? A dietary pattern analysis from a prospective Canadian birth cohort alliance

OBJECTIVE

Birth weight is an indicator of newborn health and a strong predictor of health outcomes in later life. Significant variation in diet during pregnancy between ethnic groups in high-income countries provides an ideal opportunity to investigate the influence of maternal diet on birth weight.

SETTING

Four multiethnic birth cohorts based in Canada (the NutriGen Alliance).

PARTICIPANTS

3997 full-term mother-infant pairs of diverse ethnic groups who had principal component analysis-derived diet pattern scores-plant-based, Western and health-conscious-and birth weight data.

RESULTS

No associations were identified between the Western and health-conscious diet patterns and birth weight; however, the plant-based dietary pattern was inversely associated with birth weight (β=-67.6 g per 1-unit increase; P<0.001), and an interaction with non-white ethnicity and birth weight was observed. Ethnically stratified analyses demonstrated that among white Europeans, maternal consumption of a plant-based diet associated with lower birth weight (β=-65.9 g per 1-unit increase; P<0.001), increased risk of small-for-gestational age (SGA; OR=1.46; 95% CI 1.08 to 1.54;P=0.005) and reduced risk of large-for-gestational age (LGA; OR=0.71; 95% CI 0.53 to 0.95;P=0.02). Among South Asians, maternal consumption of a plant-based diet associated with a higher birth weight (β=+40.5 g per 1-unit increase; P=0.01), partially explained by cooked vegetable consumption.

CONCLUSIONS

Maternal consumption of a plant-based diet during pregnancy is associated with birth weight. Among white Europeans, a plant-based diet is associated with lower birth weight, reduced odds of an infant born LGA and increased odds of SGA, whereas among South Asians living in Canada, a plant-based diet is associated with increased birth weight.

Birth outcomes of immigrant women married to native men in the Republic of Korea: a population register-based study

OBJECTIVES

The Republic of Korea (Korea) has experienced a steady increase in the number of births from immigrant women over the last 20 years. However, little is known about the birth outcomes of immigrant women in Korea. This study compared Korean birth data from immigrant and native women who married native men, and explored the factors that affected birth outcomes among immigrant women.

DESIGN

Observational cross-sectional study.

SETTING

Nationwide registry-based study in Korea.

PARTICIPANTS

A total of 70 258 records from immigrant women and 1700 976 records from native women were examined using the National Birth Registration Database, from 2010 to 2013.

INDEPENDENT VARIABLE

Native Korean women and immigrant women who married native men.

OUTCOMES

Proportion of preterm births, post-term births, low birth weights and macrosomia.

RESULTS

Adjusted ORs (aOR) were calculated for the adverse birth outcomes, and subgroup analyses were performed according to parity and mothers from three Asian countries (China, Vietnam, the Philippines). Multivariate logistic regression analyses were also conducted to evaluate the association of these factors with birth outcomes among immigrant women. Immigrant women had higher OR of post-term births (aOR 1.62; 95% CI 1.44 to 1.83) and low birth weights (aOR 1.17; CI 1.12 to 1.22). Mothers from the Philippines had higher OR of preterm births (aOR 1.26; CI 1.12 to 1.52) and Chinese mothers had higher OR of macrosomia (aOR 1.55; CI 1.44 to 1.66). The OR of post-term births and low birth weights was significantly higher in the first pregnancies of immigrant women.

CONCLUSIONS

This study has demonstrated higher proportions of adverse birth outcomes among immigrant women who married Korean men, compared with native women in Korea. Policies reducing the gap in birth outcomes between native and immigrant women are needed.

Association between Native American-owned casinos and the prevalence of large-for-gestational-age births

Background

A small number of studies have used a natural experiment approach to examine the health impacts of increased economic resources stemming from Native American-owned casinos. We build on this work by examining whether casinos are associated with obesity-related health in utero.

Methods

We examined whether casino openings or expansion (as proxy for increased economic resources) are associated with a decreased likelihood of infants being born large-for-gestational-age (LGA), an important risk factor for childhood overweight/obesity. We used repeated cross-sectional data from California birth records (1987-2011) to assess the prevalence of LGA births among Native Americans (n = 21 011). Using zip code fixed-effect regression models, we compared how prevalence of LGA births changed in association with casino openings or expansions, while controlling for secular trends through the inclusion of a comparison group of Native American newborns in zip codes that were eligible to open or expand casinos, but did not do so. In sensitivity analyses, we evaluated whether there was any change in small-for-gestational-age births (SGA).

Results

Average prevalence of LGA births over the period was 11%. Every one slot machine per capita increase was associated with a 0.13 percentage point decrease (95% confidence interval: -0.25, -0.01) in the prevalence of LGA births but was not associated with SGA prevalence.

Conclusions

Casino expansion in California is associated with a lower prevalence of LGA births. Interpreted in combination with previous work showing that California casino expansions were associated with a lower body mass index (BMI) among schoolchildren, these results suggest that casinos are associated with improvement in a surrogate marker of excess adiposity. Further studies are needed to elucidate the mechanisms by which casinos might be associated with obesity-related health outcomes among Native Americans.

Role of First-Trimester HbA1c as a Predictor of Adverse Obstetric Outcomes in a Multiethnic Cohort

CONTEXT

Risk of obstetric complications increases linearly with rising maternal glycemia. Testing hemoglobin A1c (HbA1c) is an effective option to detect hyperglycemia, but its association with adverse pregnancy outcomes remains unclear. Emerging data sustain that an early HbA1c ≥5.9% could act as a pregnancy risk marker.

OBJECTIVE

To determine, in a multiethnic cohort, whether an early ≥5.9% HbA1c could be useful to identify women without diabetes mellitus at increased pregnancy risk.

DESIGN AND SETTING

A prospective study was conducted at Hospital del Mar, Barcelona, between April 2013 and September 2015.

PATIENTS AND INTERVENTION

A total of 1631 pregnant women had an HbA1c measurement added to their first antenatal blood tests and were screened for gestational diabetes mellitus at 24 to 28 weeks' gestation.

OUTCOME MEASURES

Primary outcome was macrosomia. Secondary outcomes were preeclampsia, preterm birth, and cesarean section rate.

RESULTS

A total of 1228 pregnancies were included for outcome analysis. Women with HbA1c ≥5.9% (n = 48) showed a higher rate of macrosomia (16.7% vs 5.9%, P = 0.008) and a tendency toward a higher rate of preeclampsia (9.32% vs 3.9%, P = 0.092). There were no statistically significant differences in other pregnancy outcomes. After adjusting for potential confounders, an HbA1c ≥5.9% was independently associated with a 3-fold increased risk of macrosomia (95% confidence interval, 1.127 to 8.603, P = 0.028) and preeclampsia (95% confidence interval, 1.086 to 11.532, P = 0.036).

CONCLUSIONS

In a multiethnic population, an early HbA1c ≥5.9% measurement identifies women at high risk for poorer pregnancy outcomes independently of gestational diabetes mellitus diagnosis later in pregnancy. Further studies are required to establish cutoff points adapted to each ethnic group and to assess whether early detection and treatment are of benefit.

Obesity, Diabetes, and Birth Outcomes Among American Indians and Alaska Natives

Objectives To examine the relationships between prepregnancy diabetes mellitus (DM), gestational diabetes mellitus (GDM), and prepregnancy body mass index, with several adverse birth outcomes: preterm delivery (PTB), low birthweight (LBW), and macrosomia, comparing American Indians and Alaska Natives (AI/AN) with other race/ethnic groups. Methods The sample includes 5,193,386 singleton US first births from 2009-2013. Logistic regression is used to calculate adjusted odds ratios controlling for calendar year, maternal age, education, marital status, Kotelchuck prenatal care index, and child's sex. Results AI/AN have higher rates of diabetes than all other groups, and higher rates of overweight and obesity than whites or Hispanics. Neither overweight nor obesity predict PTB for AI/AN, in contrast to other groups, while diabetes predicts increased odds of PTB for all groups. Being overweight predicts reduced odds of LBW for all groups, but obesity is not predictive of LBW for AI/AN. Diabetes status also does not predict LBW for AI/AN; for other groups, LBW is more likely for women with DM or GDM. Overweight, obesity, DM, and GDM all predict higher odds of macrosomia for all race/ethnic groups. Conclusions for Practice Controlling diabetes in pregnancy, as well as prepregnancy weight gain, may help decrease preterm birth and macrosomia among AI/AN.

Macrosomia, Perinatal and Infant Mortality in Cree Communities in Quebec, 1996-2010

BACKGROUND

Cree births in Quebec are characterized by the highest reported prevalence of macrosomia (~35%) in the world. It is unclear whether Cree births are at greater elevated risk of perinatal and infant mortality than other First Nations relative to non-Aboriginal births in Quebec, and if macrosomia may be related.

METHODS

This was a population-based retrospective birth cohort study using the linked birth-infant death database for singleton births to mothers from Cree (n = 5,340), other First Nations (n = 10,810) and non-Aboriginal (n = 229,960) communities in Quebec, 1996-2010. Community type was ascertained by residential postal code and municipality name. The primary outcomes were perinatal and infant mortality.

RESULTS

Macrosomia (birth weight for gestational age >90th percentile) was substantially more frequent in Cree (38.0%) and other First Nations (21.9%) vs non-Aboriginal (9.4%) communities. Comparing Cree and other First Nations vs non-Aboriginal communities, perinatal mortality rates were 1.52 (95% confidence intervals 1.17, 1.98) and 1.34 (1.10, 1.64) times higher, and infant mortality rates 2.27 (1.71, 3.02) and 1.49 (1.16, 1.91) times higher, respectively. The risk elevations in perinatal and infant death in Cree communities attenuated after adjusting for maternal characteristics (age, education, marital status, parity), but became greater after further adjustment for birth weight (small, appropriate, or large for gestational age).

CONCLUSIONS

Cree communities had greater risk elevations in perinatal and infant mortality than other First Nations relative to non-Aboriginal communities in Quebec. High prevalence of macrosomia did not explain the elevated risk of perinatal and infant mortality in Cree communities.

Indigenous and tribal peoples' health (The Lancet-Lowitja Institute Global Collaboration): a population study

BACKGROUND

International studies of the health of Indigenous and tribal peoples provide important public health insights. Reliable data are required for the development of policy and health services. Previous studies document poorer outcomes for Indigenous peoples compared with benchmark populations, but have been restricted in their coverage of countries or the range of health indicators. Our objective is to describe the health and social status of Indigenous and tribal peoples relative to benchmark populations from a sample of countries.

METHODS

Collaborators with expertise in Indigenous health data systems were identified for each country. Data were obtained for population, life expectancy at birth, infant mortality, low and high birthweight, maternal mortality, nutritional status, educational attainment, and economic status. Data sources consisted of governmental data, data from non-governmental organisations such as UNICEF, and other research. Absolute and relative differences were calculated.

FINDINGS

Our data (23 countries, 28 populations) provide evidence of poorer health and social outcomes for Indigenous peoples than for non-Indigenous populations. However, this is not uniformly the case, and the size of the rate difference varies. We document poorer outcomes for Indigenous populations for: life expectancy at birth for 16 of 18 populations with a difference greater than 1 year in 15 populations; infant mortality rate for 18 of 19 populations with a rate difference greater than one per 1000 livebirths in 16 populations; maternal mortality in ten populations; low birthweight with the rate difference greater than 2% in three populations; high birthweight with the rate difference greater than 2% in one population; child malnutrition for ten of 16 populations with a difference greater than 10% in five populations; child obesity for eight of 12 populations with a difference greater than 5% in four populations; adult obesity for seven of 13 populations with a difference greater than 10% in four populations; educational attainment for 26 of 27 populations with a difference greater than 1% in 24 populations; and economic status for 15 of 18 populations with a difference greater than 1% in 14 populations.

INTERPRETATION

We systematically collated data across a broader sample of countries and indicators than done in previous studies. Taking into account the UN Sustainable Development Goals, we recommend that national governments develop targeted policy responses to Indigenous health, improving access to health services, and Indigenous data within national surveillance systems.

FUNDING

The Lowitja Institute.

Indigenous and tribal peoples' health (The Lancet-Lowitja Institute Global Collaboration): a population study

BACKGROUND

International studies of the health of Indigenous and tribal peoples provide important public health insights. Reliable data are required for the development of policy and health services. Previous studies document poorer outcomes for Indigenous peoples compared with benchmark populations, but have been restricted in their coverage of countries or the range of health indicators. Our objective is to describe the health and social status of Indigenous and tribal peoples relative to benchmark populations from a sample of countries.

METHODS

Collaborators with expertise in Indigenous health data systems were identified for each country. Data were obtained for population, life expectancy at birth, infant mortality, low and high birthweight, maternal mortality, nutritional status, educational attainment, and economic status. Data sources consisted of governmental data, data from non-governmental organisations such as UNICEF, and other research. Absolute and relative differences were calculated.

FINDINGS

Our data (23 countries, 28 populations) provide evidence of poorer health and social outcomes for Indigenous peoples than for non-Indigenous populations. However, this is not uniformly the case, and the size of the rate difference varies. We document poorer outcomes for Indigenous populations for: life expectancy at birth for 16 of 18 populations with a difference greater than 1 year in 15 populations; infant mortality rate for 18 of 19 populations with a rate difference greater than one per 1000 livebirths in 16 populations; maternal mortality in ten populations; low birthweight with the rate difference greater than 2% in three populations; high birthweight with the rate difference greater than 2% in one population; child malnutrition for ten of 16 populations with a difference greater than 10% in five populations; child obesity for eight of 12 populations with a difference greater than 5% in four populations; adult obesity for seven of 13 populations with a difference greater than 10% in four populations; educational attainment for 26 of 27 populations with a difference greater than 1% in 24 populations; and economic status for 15 of 18 populations with a difference greater than 1% in 14 populations.

INTERPRETATION

We systematically collated data across a broader sample of countries and indicators than done in previous studies. Taking into account the UN Sustainable Development Goals, we recommend that national governments develop targeted policy responses to Indigenous health, improving access to health services, and Indigenous data within national surveillance systems.

FUNDING

The Lowitja Institute.

Associations between body mass index and maternal weight gain on the delivery of LGA infants in Chinese women with gestational diabetes mellitus

BACKGROUND

Women with gestational diabetes mellitus (GDM) are at increased risk for maternal and fetal complications including delivery of large for gestational age (LGA) infants. Maternal body mass index (BMI) and excessive weight gain during pregnancy are associated with delivery of LGA infants. However, whether maternal BMI and weight gain are associated with LGA infants in women with GDM is unclear.

BASIC PROCEDURES

Data on 1049 pregnant women who developed GDM were collected from a university teaching hospital in China and retrospectively analyzed. Data included maternal BMI, weight gain, incidence of LGA and gestational week at diagnosis.

MAIN FINDINGS

The incidence of LGA infants was significantly associated with maternal BMI (p=0.0002) in women with GDM. The odds of delivery of LGA for obese or overweight pregnant women are 3.8 or 2 times more than normal weight pregnant women. The incidence of LGA infants was also significantly associated with maternal weight gain in women with GDM. The odds ratio of delivery of LGA for pregnant women with excessive weight gain was 3.3 times more than pregnant women with normal weight gain. The effect of weight gain was not significantly different between different maternal BMI.

PRINCIPAL CONCLUSION

The incidence of delivery of LGA infants in Chinese women with GDM who were overweight or obese is higher than Caucasians, Hispanic, and Asian-Americans. The effects of maternal BMI and weight gain on the delivery of LGA infants by women with GDM are additive.

Association between hyperglycaemia and adverse perinatal outcomes in south Asian and white British women: analysis of data from the Born in Bradford cohort

BACKGROUND

Diagnosis of gestational diabetes predicts risk of infants who are large for gestational age (LGA) and with high adiposity, which in turn aims to predict a future risk of obesity in the offspring. South Asian women have higher risk of gestational diabetes, lower risk of LGA, and on average give birth to infants with greater adiposity than do white European women. Whether the same diagnostic criteria for gestational diabetes should apply to both groups of women is unclear. We aimed to assess the association between maternal glucose and adverse perinatal outcomes to ascertain whether thresholds used to diagnose gestational diabetes should differ between south Asian and white British women. We also aimed to assess whether ethnic origin affected prevalence of gestational diabetes irrespective of criteria used.

METHODS

We used data (including results of a 26-28 week gestation oral glucose tolerance test) of women from the Born in Bradford study, a prospective study that recruited women attending the antenatal clinic at the Bradford Royal Infirmary, UK, between 2007 and 2011 and who intended to give birth to their infant in that hospital. We studied the association between fasting and 2 h post-load glucose and three primary outcomes (LGA [defined as birthweight >90th percentile for gestational age], high infant adiposity [sum of skinfolds >90th percentile for gestational age], and caesarean section). We calculated adjusted odds ratios (ORs) and their 95% confidence intervals (CIs) for a 1 SD increase in fasting and post-load glucose. We established fasting and post-load glucose thresholds that equated to an OR of 1·75 for LGA and high infant adiposity in each group of women to identify ethnic-specific criteria for diagnosis of gestational diabetes.

FINDINGS

Of 13,773 pregnancies, 3420 were excluded from analyses. Of 10,353 eligible pregnancies, 4088 women were white British, 5408 were south Asian, and 857 were of other ethnic origin. The adjusted ORs of LGA per 1 SD fasting glucose were 1·22 (95% CI 1·08-1·38) in white British women and 1·43 (1·23-1·67) in south Asian women (pinteraction with ethnicity = 0·39). Results for high infant adiposity were 1·35 (1·23-1·49) and 1·35 (1·18-1·54; pinteraction with ethnicity=0·98), and for caesarean section they were 1·06 (0·97-1·16) and 1·11 (1·02-1·20; pinteraction with ethnicity=0·47). Associations between post-load glucose and the three primary outcomes were weaker than for fasting glucose. A fasting glucose concentration of 5·4 mmol/L or a 2 h post-load level of 7·5 mmol/L identified white British women with 75% or higher relative risk of LGA or high infant adiposity; in south Asian women, the cutoffs were 5·2 mmol/L or 7·2 mml/L; in the whole cohort, the cutoffs were 5·3 mmol/L or 7·5 mml/L. The prevalence of gestational diabetes in our cohort ranged from 1·2% to 8·7% in white British women and 4% to 24% in south Asian women using six different criteria. Compared with the application of our whole-cohort criteria, use of our ethnic-specific criteria increased the prevalence of gestational diabetes in south Asian women from 17·4% (95% CI 16·4-18·4) to 24·2% (23·1-25·3).

INTERPRETATION

Our data support the use of lower fasting and post-load glucose thresholds to diagnose gestational diabetes in south Asian than white British women. They also suggest that diagnostic criteria for gestational diabetes recommended by UK NICE might underestimate the prevalence of gestational diabetes compared with our criteria or those recommended by the International Association of Diabetes and Pregnancy Study Groups and WHO, especially in south Asian women.

FUNDING

The National Institute for Health Research.

Searching for the definition of macrosomia through an outcome-based approach

Background

Macrosomia has been defined in various ways by obstetricians and researchers. The purpose of the present study was to search for a definition of macrosomia through an outcome-based approach.

Methods

In a study of 30,831,694 singleton term live births and 38,053 stillbirths in the U.S. Linked Birth-Infant Death Cohort datasets (1995–2004), we compared the occurrence of stillbirth, neonatal death, and 5-min Apgar score less than four in subgroups of birthweight (4000–4099 g, 4100–4199 g, 4200–4299 g, 4300–4399 g, 4400–4499 g, 4500–4999 g vs. reference group 3500–4000 g) and birthweight percentile for gestational age (90^th–94^th percentile, 95^th-96^th, and ≥97^th percentile, vs. reference group 75^th–90^th percentile).

Results

There was no significant increase in adverse perinatal outcomes until birthweight exceeded the 97^th percentile. Weight-specific odds ratios (ORs) elevated substantially to 2 when birthweight exceeded 4500 g in Whites. In Blacks and Hispanics, the aORs exceeded 2 for 5-min Apgar less than four when birthweight exceeded 4300 g. For vaginal deliveries, the aORs of perinatal morbidity and mortality were larger for most of the subgroups, but the patterns remained the same.

Conclusions

A birthweight greater than 4500 g in Whites, or 4300 g in Blacks and Hispanics regardless of gestational age is the optimal threshold to define macrosomia. A birthweight greater than the 97^th percentile for a given gestational age, irrespective of race is also reasonable to define macrosomia. The former may be more clinically useful and simpler to apply.

Central adiposity and other anthropometric factors in relation to risk of macrosomia in an African American population

OBJECTIVE

Previous studies have consistently identified maternal obesity and gestational weight gain (GWG) as risk factors for macrosomia, but little is known about the effects of central adiposity and body fat distribution. Using self-reported data from the Black Women's Health Study (BWHS), a large follow-up study of US black women, we examined the risk of macrosomia in relation to prepregnancy waist circumference, prepregnancy waist-to-hip ratio (WHR), prepregnancy BMI, and GWG.

DESIGN AND METHODS

During 1995-2003, BWHS participants ages 21-44 years delivered 6,687 full-term singleton births (gestational age >37 weeks). We compared mothers of 691 infants weighing ≥ 4,000 g with mothers of 5,996 infants weighing <4,000 g. Generalized estimating equation models (GEE) that accounted for more than one birth per mother were used to estimate multivariable odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Independent of prepregnancy BMI, prepregnancy waist circumference was positively associated with risk of macrosomia (OR = 1.58, 95% CI: 1.07-2.32, for ≥ 35.0 vs. <27.0 inches (≥ 88.9 vs. <68.6 cm); P trend = 0.04). As expected, prepregnancy BMI was also positively associated with macrosomia (OR = 1.74, 95% CI: 1.25-2.41 for BMI ≥ 35.0 vs. 18.5-24.9 kg m(-2)). GWG above the amount recommended by the 2009 Institute of Medicine report was associated with an increased risk of macrosomia and the association was present in each category of prepregnancy BMI (18.5-24.9, 25.0-29.9, and ≥ 30.0 kg m(-2); P trend <0.001).

CONCLUSIONS

Our data suggest that overall obesity, high GWG, and high waist circumference are independent risk factors for macrosomia among US black women.

A prospective evaluation of neonatal hypoglycaemia in infants of women with gestational diabetes mellitus

OBJECTIVE

To analyse first-day-of-life glucose levels in infants of women with gestational diabetes (GDM) and the influence of maternal, gestational and peripartum factors on the development of neonatal hypoglycaemia.

STUDY DESIGN

Prospective cohort study including newborns of GDM mothers. Capillary blood glucose (CBG) was measured serially on the first day of life. CBG values were defined as normal (≥ 2.5 mmol/l), mild hypoglycaemia (2.2-2.4 mmol/l), moderate hypoglycaemia (1.6-2.1 mmol/l) and severe hypoglycaemia (<1.6 mmol/l).

RESULTS

One hundred and ninety infants were included: 23 (12.1%) presented mild, 20 (10.5%) moderate and only 5 (2.6%) severe hypoglycaemia. Hypoglycaemic infants were more frequently large-for-gestational-age (29.3% vs 11.3%, p=0.003), had lower umbilical cord pH (7.28 vs 7.31, p=0.03) and their mothers had more frequently been hyperglycaemic during labour (18.8% vs 8.5%, p=0.04). In multivariate analysis Pakistani origin (OR: 2.94; 95% CI: 1.14-7.55) and umbilical cord venous pH (OR: 0.04, 95% CI: 0.261-0.99) were significantly and independently associated with hypoglycaemia.

CONCLUSIONS

Mild and moderate neonatal hypoglycaemias were common although severe episodes were unusual in infants of women with GDM. Hypoglycaemia is mainly influenced by ethnicity and cord blood pH, although maternal peripartum glycaemic control and large-for-gestational-age condition may also play a role.

Gestational diabetes mellitus in five ethnic groups: a comparison of their clinical characteristics

AIMS

The prevalence of gestational diabetes mellitus has been shown to vary between ethnic groups. The differences in the clinical characteristics and outcomes of women with gestational diabetes mellitus from various ethnic groups have not been clearly defined.

METHODS

A retrospective review of women with gestational diabetes mellitus from a single institution between 2007 and 2010 was conducted. The clinical profiles of women from five ethnic groups (South-East Asian, South Asian, Middle Eastern, Anglo-European and Pacific Islander) were documented, including the outcomes of their pregnancy.

RESULTS

In this cohort of 827 women from these five ethnic groups, South-East Asians had the lowest BMI, lowest fasting (yet highest 2-h) glucose level on 75-g glucose tolerance test, lowest need for insulin therapy and lowest rate of macrosomia. South Asians had the lowest parity but strongest family history of diabetes. Their offspring also had the lowest birthweight. Women from Pacific Islands had the highest parity, BMI, fasting glucose levels on 75-g glucose tolerance test, HbA(1c) (at diagnosis of gestational diabetes mellitus as well as at 36 weeks' gestation) and greatest need for insulin therapy. Their offspring also had the highest birthweights.

CONCLUSION

This study highlighted the significant differences in clinical characteristics of women with gestational diabetes mellitus among five ethnic groups. These differences may need to be considered in the management of gestational diabetes mellitus, especially in the interpretation of normality for pregnancy.

Low gestational weight gain improves infant and maternal pregnancy outcomes in overweight and obese Korean women with gestational diabetes mellitus

OBJECTIVE

The aim of the study was to retrospectively assess what was the optimal gestational weight gain to have better maternal and neonatal outcomes in overweight and obese Korean women with gestational diabetes mellitus (GDM) who maintained normoglycemia throughout pregnancy by dietary modification, exercise, and/or insulin treatment.

STUDY DESIGN

We performed a hospital-based study of 215 GDM women with prepregnancy BMI ≥ 25 kg/m(2). Body weight, glucose homeostasis, lipid profiles, insulin treatment, and maternal outcomes were collected as predictors of neonatal birth weight. We divided the subjects into three groups according to modified Institute of Medicine (IOM) guidelines for weight gain during pregnancy: inadequate (n = 42), normal (n = 96), and excessive (n = 77) groups.

RESULTS

Excessive weight gain resulted in increased macrosomia, HbA(1c) at delivery, and postprandial blood glucose levels, but fasting blood glucose levels were not significantly different among the groups. The inadequate weight gain group (2.4 kg weight gain during pregnancy) had better neonatal outcomes and better maternal glycemic control with fewer requiring insulin treatment.

CONCLUSION

Minimal weight gain, well below IOM recommendations, and tight control of blood glucose levels during pregnancy with proper medical management and dietary modification may eliminate most of the adverse pregnancy outcomes experienced by obese GDM Asian women.

Pregnancy outcome in immigrant women with gestational diabetes mellitus

Recent studies show adverse outcomes of pregnancy among immigrant women from countries with high diabetes rates. We compared maternal and fetal outcomes in immigrant and Italian women with gestational diabetes mellitus (GDM) followed up at our center. Maternal characteristics considered were age, pre-pregnancy body mass index (BMI), HbA1c, frequency of insulin treatment, timing and mode of delivery, and hypertensive disorders; and, for fetal outcome, infants large or small for gestational age, and fetal complications. Pre-pregnancy BMI and HbA1c were higher in immigrant GDM women than in Italians, and more of them were on insulin. No differences in maternal outcome emerged between the two groups. More large for gestational age (LGA) babies were born to immigrant women than to Italians, but no other differences emerged. Apart from newborn LGA, maternal and fetal outcomes were comparable in our immigrant and Italian GDM women. Immigrant GDM women have favourable outcomes if given access to health care and language and cultural barriers are removed.

Being too large for gestational age precedes childhood obesity in African Americans

OBJECTIVE

The purpose of this study was to investigate the association between large-for-gestational-age (LGA) infants and the development of childhood obesity in an inner-city primarily African American population.

STUDY DESIGN

Maternal, neonatal, socioeconomic, and nutritional histories were collected for mothers with children who were 2-5 years old. Associations between Alexander and customized birthweight percentiles and body mass index for the age of the child were examined.

RESULTS

One hundred ninety-five mother-child pairs were enrolled; the childhood obesity rate was 18%. Increasing Alexander and customized birthweight percentiles were related to increasing obesity. LGA newborn infants were 2.5 times more likely to be obese in childhood than average size newborn infants. Maternal smoking was also associated with childhood obesity.

CONCLUSION

LGA infants have the highest likelihood of childhood obesity in this inner-city predominantly African American population. Customized growth percentiles perform best in the identification of the highest risk population.

Maternal immigrant status and high birth weight: implications for childhood obesity

OBJECTIVES

Childhood obesity, a growing epidemic, is associated with greater risk of several chronic diseases in adulthood. Children of immigrant mothers are at higher risk for obesity than children of non-immigrant mothers. High birth weight is the most important neonatal predictor of childhood obesity in the general population. To understand the etiology of obesity in children of immigrant mothers, we assessed the relation between maternal immigrant status and risk for high birth weight.

METHODS

Data about all births in Michigan (N = 786,868) between 2000-2005 were collected. We used bivariate chi-square tests and multivariate logistic regression models to assess the relation between maternal immigrant status and risk for neonatal high birth weight.

RESULTS

The prevalence of high birth weight among non-immigrant mothers was 10.6%; the prevalence among immigrant mothers was 8.0% (P < .01). In multivariate regression models adjusted for maternal age, education, marital status, parity, and tobacco use, children of immigrant mothers had lower odds (odds ratio = 0.69, 95% confidence interval = 0.67-0.70) of high birth weight compared to those of non-immigrant mothers.

DISCUSSION

Although maternal immigrant status has been shown to be associated with greater childhood obesity, surprisingly, children of immigrant mothers have lower risk of high birth weight than children of non-immigrant mothers. This suggests that factors in early childhood, potentially cultural or behavioral factors, may play a disproportionately important role in the etiology of childhood obesity in children of immigrant vs non-immigrant mothers.

[Factors related to birth weight: a comparison of related factors between newborns of Spanish and Colombian immigrant women in Spain]

The objective of this study is to establish differentials in birth weight (BW) and related factors, in term newborns (NB) of Spanish (SP) and Colombian (CO) immigrant mothers living in Spain, between 2001-2005. Data on the NB population of SP and CO mothers was retrieved from the National Statistical Bulletin of Birth in Spain. We analysed the association with BW (Low birth weight -LBW- insufficient weight -IW- macrosomia), by the nationality of the mother; taking into account variables such as the intergenesic interval, maternal age, number of live children, maternal occupation and sex of NB. The analysis was based on frequencies and the estimation of simple and adjusted odds ratios (OR) by means of logistic regression with 95% confidence intervals (95% CI). A higher prevalence of LBW was found in SP mothers (3.4%) than in their CO counterparts (2.1%). In SP mothers a higher risk of LBW (aOR 1.89, 950% CI 1.65- 2.16) and IW (aOR 1.49, 95% CI 1.51- 1.57) was observed. In CO mothers a higher percentage of macrosomia was found (8.0%). Also, a higher percentage of LBW was observed in female new borns (SP4.1%; CO 2.7%) as well as IW (PI (SP 25.6%; CO 19.6%) (p < 0.001). Mothers aged > 40 years and having 4 or more children were associated with LBW in both nationalities. As a conclusion, NB of Colombian mothers presented a lower prevalence of LBW and IW, which could be explained by the healthy migrant effect.

Insulin resistance in Hispanic large-for-gestational-age neonates at birth

CONTENT

Intrauterine exposure to maternal diabetes and large size at birth are known risk factors for the subsequent development of insulin resistance and metabolic syndrome. Although Hispanic youth have been shown to have a high prevalence of metabolic syndrome, it is unknown whether metabolic abnormalities and a predisposition for glucose intolerance are present at birth.

OBJECTIVE

The objective of the study was to determine whether abnormalities in insulin sensitivity exist at or soon after birth in large-for-gestational-age neonates born to Hispanic women with and without gestational diabetes. DESIGN/PATIENTS/SETTING: Forty-two term Hispanic neonates were enrolled for cross-sectional studies at 24-48 h after birth and included nine large-for-gestational-age neonates delivered of women with gestational diabetes (large-for-gestational-age-IDM), 12 large-for-gestational-age but not IDM neonates, 11 poorly grown (at the fifth to 10th percentile), and 10 appropriate-for-gestational-age neonates. Insulin sensitivity and secretion were measured by shortened fasting iv glucose tolerance test.

MAIN OUTCOME MEASURE

Insulin sensitivity index was measured within 48 h of birth.

RESULTS

Neonates were studied at 36 +/- 11 h postnatally, and all groups were euglycemic at the time of study. However, insulin sensitivity was significantly lower (P < 0.05, ANOVA) in large-for-gestational-age-IDM [3.0 +/- 0.7 (sem) mU/liter.min] and large-for-gestational-age-non-IDM (2.2 +/- 0.4 mU/liter.min) cohorts in comparison with poorly grown (5.0 +/- 0.7 mU/liter.min) and appropriate-for-gestational-age controls (5.4 +/- 0.8 mU/liter.min). Insulin secretion did not differ between groups.

CONCLUSIONS

Reduced insulin sensitivity is present soon after birth in Hispanic large-for-gestational-age neonates born to mothers with and without gestational diabetes, demonstrating the onset of insulin resistance before birth and evidence of altered fetal programming.

Macrosomic infants are not all equal

AIMS

To see whether macrosomic infants have different morbidity according to maternal screening results for gestational diabetes mellitus (GDM) and ethnicity.

METHODS

After excluding infants of women with diabetes, the National Women's Hospital database identified 134 infants who were delivered in 2003 and weighed >or= 4500 g. Case notes were reviewed to record risk factors for macrosomia, delivery details and neonatal morbidity. Outcomes were analysed according to screening results for GDM and compared between Polynesian and Asian women.

RESULTS

Body mass index (BMI) was calculated in 29% of women, and GDM screening was undertaken in 51%. Infants of women who had a screening glucose < 7.2 mmol/L compared to >or= 7.8 mmol/L had lower rates of admission to the neonatal intensive care unit (NICU) (6.4 vs 28.6%, P=0.049), had less respiratory distress (3.2 vs 23.8%P=0.033) and display a trend to less require intravenous dextrose (6.4 vs 23.8%P=0.10). Maternal BMI was lower in Asian (26.5 +/- 4.4 kg/m(2)) compared to Polynesian women (35.2 +/- 8.1 kg/m(2), P=0.008). More Asian women had a Caesarean delivery (73.3 vs 25%P<0.001) and their infants were more likely to be admitted to NICU (33.3 vs 7.7%P=0.02), require intravenous dextrose (20 vs 1.9%P=0.03) and have respiratory distress (26.7 vs 3.8%P=0.02).

CONCLUSION

Risk factors for macrosomia are not assessed adequately, which may contribute to morbidity. Using a birthweight >or= 4500 g to define macrosomia is associated with disparate morbidity between ethnicities that have different body compositions.

Development and internal validation of a nomogram to predict macrosomia

OBJECTIVE

To develop a nomogram to predict macrosomia with a combination of clinical and ultrasound variables.

METHODS

Data from 194 women who underwent sonographic fetal weight estimation were used to develop and calibrate a nomogram to predict fetal macrosomia. The nomogram was subjected to 200 bootstrap resamples for internal validation and to reduce overfit bias. An Internet-based tool was developed to facilitate use of the nomogram.

RESULTS

The macrosomia prediction nomogram, based on parity, ethnicity, body mass index and fetal weight estimated macrosomia, had good discrimination and calibration before and after bootstrapping (area under curve (AUC), 0.860 and 0.850, respectively). The predictive accuracy of our nomogram was significantly better than was sonographically estimated fetal weight using Hadlock's formula (AUC, 0.740; P<0.001). We have provided a web-based interface to predict the individual probability of macrosomia.

CONCLUSION

We have developed a nomogram to predict the individual probability of macrosomia based on clinical and ultrasound findings. Our web-based interface should help to guide patients and physicians in decision-making.

Perinatal outcomes and macrosomia in a multi-ethnic population of women with type 2 diabetes

We reviewed pregnancy outcomes of women with type 2 diabetes giving birth over a six-year period, comparing the main ethnic groups. Asian women had significantly smaller babies and lower rates of macrosomia as defined by standard growth charts. Other outcomes were similar between the Asian, European and Polynesian women.

Ethnic differences in perinatal outcome of gestational diabetes mellitus

OBJECTIVE

Despite the high rates of gestational diabetes mellitus (GDM) among certain Pacific Islander and Asian ethnic groups in the U.S., little is known about the risk for adverse perinatal outcomes in these populations. We sought to examine ethnic differences in perinatal outcome among Asian and Pacific-Islander women with GDM.

RESEARCH DESIGN AND METHODS

A retrospective review of all women referred to the largest outpatient GDM program in the state of Hawai'i from 1995 to 2005 was conducted. Patients of Native-Hawaiian/Pacific-Islander, Japanese, Chinese, Filipino, and Caucasian ethnicity were included (n = 2,155). Treatment of all patients consisted of an outpatient education class, dietary management, self-monitoring of blood glucose, and insulin instruction (if indicated). Demographics, maternal and neonatal characteristics, and delivery information were evaluated.

RESULTS

Neonates born to Native-Hawaiian/Pacific-Islander mothers and Filipino mothers had 4 and 2 times the prevalence of macrosomia, respectively, compared with neonates born to Japanese, Chinese, and Caucasian mothers. These differences persisted after adjustment for other statistically significant maternal and fetal characteristics. Ethnic differences were not observed for other neonatal or maternal complications associated with GDM, with the exception of neonatal hypoglycemia and hyperbilirubinemia.

CONCLUSIONS

Significant ethnic differences in perinatal outcomes exist across Asian and Pacific-Islander women with GDM. This finding emphasizes the need to better understand ethnic-specific factors in GDM management and the importance of developing ethnic-tailored GDM interventions to address these disparities.

Fetal growth curves for an ethnically diverse military population: the American Institute of Ultrasound in Medicine-accredited platform experience

OBJECTIVE

To determine which fetal growth curve provided the best estimates of fetal weight for a cohort of ethnically diverse patients at sea level.

METHODS

The study consisted of a population of 1,729 fetuses examined at sea level between January 1, 1997, and June 30, 2000, at 18 weeks, 28 weeks, and term. Gestational age (GA) based on menstrual dates was confirmed or adjusted by crown-rump length or early second-trimester biometry. Fetal weight was estimated by using biparietal diameter, head circumference, abdominal circumference, and femur length. Our fetal growth curves were analyzed with fourth-order polynomial regression analysis, applying four previously defined formulae for fetal growth.

RESULTS

Fetal growth curves for estimated fetal weight demonstrated the expected parabolic shape, which varied according to the formulae used. Our curve best fit the following equation: estimated fetal weight = 4.522 - 0.22 x GA age + 0.25 x GA(2) - 0.001 x GA(3) + 5.248 x 10(-6) x GA(4) (R2 = 0.976). SD increased in concordance with GA.

CONCLUSION

Madigan Army Medical Center serves a racially mixed, culturally diverse, military community with unrestricted access to prenatal care. Determination of the optimal population-appropriate growth curve at the correct GA assists clinicians in identifying fetuses at risk for growth restriction or macrosomia and therefore at risk for increased perinatal morbidity and death.

A prospective cohort study of pregnancy risk factors and birth outcomes in Aboriginal women

BACKGROUND

Aboriginal women have been identified as having poorer pregnancy outcomes than other Canadian women, but information on risk factors and outcomes has been acquired mostly from retrospective databases. We compared prenatal risk factors and birth outcomes of First Nations and Métis women with those of other participants in a prospective study.

METHODS

During the 12-month period from July 1994 to June 1995, we invited expectant mothers in all obstetric practices affiliated with a single teaching hospital in Edmonton to participate. Women were recruited at their first prenatal visit and followed through delivery. Sociodemographic and clinical data were obtained by means of a patient questionnaire, and microbiological data were collected at 3 points during gestation: in the first and second trimesters and during labour. Our primary outcomes of interest were low birth weight (birth weight less than 2500 g), prematurity (birth at less than 37 weeks' gestation) and macrosomia (birth weight greater than 4000 g).

RESULTS

Of the 2047 women consecutively enrolled, 1811 completed the study through delivery. Aboriginal women accounted for 70 (3.9%) of the subjects who completed the study (45 First Nations women and 25 Métis women). Known risk factors for adverse pregnancy outcome were more common among Aboriginal than among non-Aboriginal women, including previous premature infant (21% v. 11%), smoking during the current pregnancy (41% v. 13%), presence of bacterial vaginosis in midgestation (33% v. 13%) and poor nutrition as measured by meal consumption. Although Aboriginal women were less likely than non-Aboriginal women to have babies of low birth weight (odds ratio [OR] 1.46, 95% confidence interval [CI] 0.52-4.15) or who were born prematurely (OR 1.45, 95% CI 0.57-3.72) and more likely to have babies with macrosomia (OR 2.04, 95% CI 1.03-4.03), these differences were lower and statistically nonsignificant after adjustment for smoking, cervicovaginal infection and income (adjusted OR for low birth weight 0.85, 95% CI 0.19-3.78; for prematurity 0.90, 95% CI 0.21-3.89; and for macrosomia 2.12, 95% CI 0.84-5.36).

INTERPRETATION

After adjustment for potential confounding factors, we found no statistically significant relation between Aboriginal status and birth outcome.

Incidence of fetal macrosomia and birth complications in Chinese immigrant women

OBJECTIVE

To compare rates of fetal macrosomia (birthweight > 4000 g) and birth complications in both Chinese women immigrants and Caucasian women for two time periods: 1992 and 1999-2000.

POPULATION

Chinese women immigrants and Caucasian women attending the Royal North Shore Hospital and Hornsby Ku-Ring-Gai Hospital in Sydney's northern health region.

METHODS

Data used were extracted from the Northern Suburbs Area Health Service OBSTET database. Significance of trends were assessed using chi2 test.

RESULTS

The results show a rise in macrosomic babies born to Chinese immigrants from 4% of total Chinese births in 1992 to 9.8% in 1999-2000 (P = 0.02). There was no significant difference in the rate of macrosomia among Caucasian women with respective rates of 11 and 14% for the same periods. The incidence of post-partum haemorrhage increased significantly in both Chinese immigrants and Caucasian women (P < 0.001).

CONCLUSION

Australia has a multicultural population and yet the normal ranges defined for many obstetric investigations do not adjust for ethnicity. The application of values derived from a Caucasian population to other ethnic populations may be inappropriate and conceal important pathologies.

High rates of infant macrosomia: a comparison of a Canadian native and a non-native population

The Cree of James Bay have the highest ever reported mean birth weight and a high prevalence of infant macrosomia. This study was designed to examine independent risk factors for infant macrosomia among the Cree, to compare these to risk factors among non-Native Canadians and to determine if ethnic differences persist after adjusting for differences in the distribution of other risk factors. Macrosomia was defined as birth weight >90(th) percentile for gestational age of a reference population. Independent determinants of macrosomia were examined in 385 Cree and 5644 non-Native women. The potential effect of ethnicity (Cree vs. non-Native) was determined after statistically adjusting for age, parity, pregravid weight, height, net rate of weight gain, gestational diabetes mellitus (GDM) and smoking status. The prevalence of macrosomia among the Cree was 34.3% vs. 11.1% among non-Natives. Although GDM significantly increased the risk for macrosomia among the Cree (odds ratio: 4.46, 95% CI: 2.24-9.26), it was not a significant risk factor among non-Natives (odds ratio: 1.15, 95% CI: 0.79-1.65). The risk for infant macrosomia remained elevated among the Cree compared with non-Natives after adjusting for other risk factors (odds ratio: 3.64, 95% CI: 2.69-4.90). In conclusion, the Cree have a high prevalence of macrosomia despite controlling for important differences in pregravid weight and GDM. Some of this variation may be due to genetic differences in fetal growth. The differential impact of GDM on macrosomia in the two ethnic groups may be due to differences in treatment strategies for GDM.

A multiethnic study of the predictors of macrosomia

PURPOSE

This study examined predictors of macrosomia in a multiethnic sample of 213 low-income women diagnosed with gestational diabetes mellitus (GDM) after week 24 of their pregnancy.

METHODS

Medical records were reviewed retrospectively. Variables examined were mother's height, weight history, educational level, age at diagnosis, weeks at diagnosis and delivery, type of diabetes, mean fasting blood glucose (FBG), and infant's weight, sex, and Apgar scores.

RESULTS

Fifty-one percent of babies were macrosomic. Weight gain, nonpregnant weight, weight at delivery, FBG, and Apgar scores at 1 minute were associated with macrosomia, especially in Hispanic women. Logistic regression revealed that nonpregnant weight was the strongest predictor of macrosomia.

CONCLUSIONS

Nonobese GDM mothers with optimal weight gain but with high FBG levels > 90 mg/dL may be at risk for macrosomia. The major concerns with obese GDM mothers are nonpregnant weight and high blood glucose levels, in this order. Education for women with GDM should target these risk factors to decrease macrosomia.

Influence of diabetes during pregnancy on gestational age-specific newborn weight among US black and US white infants

This study examined the impact of maternal diabetes on birth weight for gestational age patterns of all term black infants and white infants in the United States using data derived from the 1990-1991 US Live Birth File of the National Center for Health Statistics. Infants of both black mothers and white mothers exhibited the expected fetal overgrowth associated with maternal diabetes. However, the increase in birth weight was much greater in infants of black than white diabetic mothers in comparison with their nondiabetic counterparts, as measured by the discrepancy in birth weight between infants of diabetic and nondiabetic mothers at each gestational week, the incidence of large for gestational age, high birth weight, small for gestational age, and low birth weight. After adjustment for maternal hypertension, prenatal care use, and sociodemographic factors, the disparity in mean birth weight associated with diabetes was 211.67 g in black infants and 115.74 g in white infants. The adjusted odds ratios of birth weight > or = 4,000 g were 2.98 (95% confidence interval 2.89-3.12) for black infants and 1.83 (95% confidence interval 1.78-1.89) for white infants. Given the potential risks for mothers and infants consequent to maternal diabetes and fetal hyperinsulinemia, further investigation of the prevalence, characteristics, and outcomes of diabetes during pregnancy among black mothers and infants is warranted.

A comparison of the 3 H glucose tolerance test and the 2 H value in identifying risk for excessive fetal growth

The objective of this study was to determine if the 2 h value of the glucose tolerance test (GTT) is as reliable as the complete GTT in identifying risk for excessive fetal growth. Five hundred eighty-eight patients underwent a 3 h oral GTT at 26-28 weeks' gestation. The 2 h value of the test was compared to the results of the GTT. The incidence of large for gestational age (LGA) infants was compared for patients who had an abnormal GTT or an abnormal 2 h value only. A normal 2 h value was associated with a normal GTT in 98.5% of cases, while an abnormal 2 h value was associated with an abnormal GTT in 70% of cases. An abnormal GTT was associated with a 22% incidence of LGA, while a 2 h value > or = 165 mgm/dl was associated with a 20% incidence of LGA. This difference was not statistically significant. A single 2 h value GTT is more cost-effective and as predictive as a complete 3 h GTT in identifying risk for excessive fetal growth.

Determinants of birth-weight in women with established and gestational diabetes

Increased birth-weight (macrosomia) can complicate the diabetic pregnancy, but many factors other than hyperglycaemia can influence birth-weight, in particular maternal obesity. In a mixed population (European, Maori and Pacific Islander) with a high prevalence of glucose intolerance and obesity we have examined the relative impact of various maternal factors on birth-weight in women with both established and gestational diabetes. Mean birth-weight was significantly greater in women with established or gestational diabetes than in controls (p < 0.0001), but was similar in women with gestational and established diabetes, despite glycaemic control being significantly poorer (p < 0.0001) in the latter. Birth-weight closely paralleled prepregnancy body mass index rather than glycaemic control, but in Maori women it was lower than expected, probably because of their high prevalence of smoking. Daily cigarette consumption was negatively correlated with birth-weight (p < 0.01) despite the smokers having significantly poorer glycaemic control (p < 0.001). The most significant variables influencing birth-weight in the diabetic pregnancy were gestational age at delivery, prepregnancy body mass index, maternal height, estimated weight gain during pregnancy, the presence of hypertension and cigarette smoking (the latter 2 having negative effects on birth-weight). Glycaemic control in the last half of pregnancy was not significant in this analysis. We conclude that within the limits of glycaemic control which we obtained, birth-weight was largely determined by maternal factors other than hyperglycaemia. Birth-weight thus has severe limitations as an outcome measure of the diabetic pregnancy.

Mexican-Americans' use of prenatal care and its relationship to maternal risk factors and pregnancy outcome

We evaluate the adequacy of prenatal care use and the association of use to a series of maternal risk factors and pregnancy outcomes, such as low birthweight, preterm delivery, and macrosomia in both Mexican-Americans and non-Hispanic whites in Arizona. The data came from all live-birth certificates from 1986 and 1987 for a total of 101,202 (26,826 Mexican-Americans). We evaluated the adequacy of prenatal care using a redesigned index that accounts for three factors: the month when prenatal care began, the number of prenatal care visits, and the duration of pregnancy. From this index we identified six prenatal care groups: intensive, adequate, intermediate, inadequate, no-care, and missing/unknown. Overall, we observed ethnic differences in patterns of prenatal care use, social profiles, and medical risk factors. Non-Hispanic whites, compared to Mexican-Americans, showed a greater risk for low birthweight and preterm delivery in those groups receiving poor prenatal care versus those who received adequate care. Within Mexican-Americans the risk of low birthweight was not the same for all subgroups. A higher overall prevalence of preterm delivery and macrosomia in comparison to low birthweight occurred in Mexican-Americans. We discuss the implications of the results for the identification, interpretation, evaluation, and public health significance of perinatal health problems of Mexican-Americans.

Influence of maternal body habitus and glucose tolerance on birth weight

Many physicians believe that macrosomia is a hallmark of a pregnancy complicated by glucose intolerance. Because the prevalence of obesity is increased among women with gestational diabetes, fetal overgrowth may be attributable at least in part to maternal obesity. We studied 2069 black, Latina, Chinese, and white mother-infant pairs to determine the interaction between maternal body habitus, maternal glucose homeostasis, and certain indices of fetal growth. Chinese women had a significantly higher serum glucose 1 hour after administration of 50 g glucose (136.6 +/- 32.7 mg/dL) than any of the other three ethnic groups. Black women had a significantly lower value for glucose (114.8 +/- 28.2 mg/dL) than either Chinese or Latina women (124.9 +/- 31.4 mg/dL). Results for Latina and white women (121.5 +/- 26.2 mg/dL) were not significantly different. Body mass index (BMI) was used to classify the subjects. The regression coefficient for the entire sample indicated a modest association of glucose with increased birth weight when maternal BMI was controlled. The BMI of the Chinese infants had a significant association with higher concentrations of glucose after administration of 50 g glucose. Maternal body habitus should be considered a major confounder in studies of the relationship of maternal glucose tolerance and infant birth weight.

Obstetric complications of macrosomic babies in African women

A prospective analysis has been made on 145 consecutive deliveries resulting in babies weighing 4.5 kg and above delivered at the University of Nigeria Teaching Hospital (U.N.T.H.), Enugu, over a 1-year period (1985). Babies weighing 4.5 kg and over are regarded as macrosomic babies. The incidence of macrosomic babies in this study is 11 per thousand deliveries or 1 in 90. Factors that predisposed to the birth of macrosomic babies include: excessive weight gain during the course of pregnancy, tall height of the woman, multiparity and prolonged gestation. Diabetes mellitus was not a significant factor. Complications include prolonged labor, post-partum hemorrhage, ruptured uterus, shoulder dystocia and an increased perinatal mortality rate. Maternal mortality was also increased. Ninety percent of the multiparous women achieved spontaneous vaginal delivery while only 42% of the primigravidae achieved vaginal delivery. The implications are discussed.