Paternal and maternal birthweight and offspring risk of macrosomia at term gestations: A nationwide population study

BACKGROUND

There is a paucity of data on whether parents' macrosomia (birthweight ≥4500 g) status influences the risk of macrosomia in the offspring. The role of maternal overweight in the generational effect of macrosomia is not known.

OBJECTIVE

To estimate the risk of macrosomia by parental birthweight at term and evaluate if this risk varied with maternal body mass index (BMI, kg/m2) early in pregnancy.

METHODS

We used data from the Medical Birth Registry of Norway on all singleton term births (37-42 gestational weeks) during 1967-2017. The primary exposure was parental macrosomia, and the outcome was macrosomia in the second generation. The secondary exposure was maternal BMI. We used binomial regression to calculate relative risk (RR) with a 95% confidence interval. We assessed potential unmeasured confounding and selection bias using a probabilistic bias analysis and performed analyses with and without imputation for variables with missing values.

RESULTS

The data included 647,957 singleton parent-offspring trios born at term. The prevalence of macrosomia was 3.2% (n = 41,396) in the parental generation and 4.0% (n = 25,673) in the offspring generation. Macrosomia in parents was associated with an increased risk of macrosomia in offspring, with the RR for both parents were born macrosomic being 6.53 (95% confidence interval [CI] 5.31, 8.05), only mother macrosomic 3.37 (95% CI 3.17, 3.57) and only father macrosomic RR 2.22 (95% CI 2.12, 2.33). These risks increased by maternal BMI in early pregnancy: if both parents were born macrosomic, 17% of infants were macrosomic among mothers with normal BMI. If both parents were macrosomic and the mothers were obese, 31% of offspring were macrosomic. Macrosomia-related adverse outcomes did not differ with parental macrosomia status.

CONCLUSIONS

Parents' weight at birth and maternal BMI appear to be strongly associated with macrosomia in the offspring delivered at term gestations.

Validity of two-dimensional ultrasound for determining extreme foetal weights to term

The aim of this study was to assess the validity of ultrasound carried out within seven days prior to birth at term for the calculation of full term estimated foetal weight (EFW) in order to diagnose extreme foetal weight, performed using a single-center retrospective cohort study of 2500 pregnant women. Ultrasound calculations of EFW with a standard error of less than 10% showed an accuracy ratio of 75.1% for the total sample. This percentage was similar for appropriate for gestational age (78.6%) and normal foetal weights (77.5%) but decreased significantly (p < .01) in the case of extreme foetal weights. The simple error increased in both the high and low EFWs, taking on positive values for the low weights and negative values for the high weights. As for the percentage error values, there was a tendency for positive errors for low weights and negative errors for high weights; this led to a tendency to overestimate low foetal weights and underestimate high foetal weights.IMPACT STATEMENTWhat is already known on this subject? Two-dimensional ultrasound is currently the principal tool used in obstetrics to evaluate foetal growth, mainly through the calculation of EFW. Foetal weight represents an important prognostic factor in perinatal results, with a greater risk of adverse effects in cases of extreme foetal weights. In this sense, there are few studies that assess the validity of EFW calculations focussing on extreme foetal weights to term.What do the results of this study add? The ultrasound estimates of EFW with an error lower than 10% in the seven days prior to birth showed an accuracy ratio of 75.1% for the total sample. This percentage was similar to appropriate for gestational age weights (78.6%) and of normal weights (77.5%), but decreased significantly (p < .01) in the case of extreme foetal weights: small for gestational age (52.1%), large for gestational age (68.2%), microsomia (49.1%), and macrosomia (61%). Likewise, we found high specificity and low sensitivity for ultrasound diagnosis of extreme foetal weights.What are the implications of these findings for clinical practice and/or future research? The validity of ultrasound EFW is influenced by extreme foetal weights, with a tendency to overestimate low weights and underestimate high weights, which represents a clinically important finding.

Differential Expression of Glucose Transporter Proteins GLUT-1, GLUT-3, GLUT-8 and GLUT-12 in the Placenta of Macrosomic, Small-for-Gestational-Age and Growth-Restricted Foetuses

Placental transfer of glucose constitutes one of the major determinants of the intrauterine foetal growth. The objective of the present study was to evaluate the expression of glucose transporter proteins GLUT-1, GLUT-3, GLUT-8 and GLUT-12 in the placenta of macrosomic, small-for-gestational-age (SGA) and growth-restricted foetuses (FGR). A total of 70 placental tissue samples were collected from women who delivered macrosomic ≥4000 g (n = 26), SGA (n = 11), growth-restricted (n = 13) and healthy control neonates (n = 20). Computer-assisted quantitative morphometry of stained placental sections was performed to determine the expression of selected GLUT proteins. Immunohistochemical staining identified the presence of all glucose transporters in the placental tissue. Quantitative morphometric analysis performed for the vascular density-matched placental samples revealed a significant decrease in GLUT-1 and increase in GLUT-3 protein expression in pregnancies complicated by FGR as compared to other groups (p < 0.05). In addition, expression of GLUT-8 was significantly decreased among SGA foetuses (p < 0.05). No significant differences in GLUTs expression were observed in women delivering macrosomic neonates. In the SGA group foetal birth weight (FBW) was negatively correlated with GLUT-3 (rho = −0.59, p < 0.05) and positively with GLUT-12 (rho = 0.616, p < 0.05) placental expression. In addition, a positive correlation between FBW and GLUT-12 expression in the control group (rho = 0.536, p < 0.05) was noted. In placentas derived from FGR-complicated pregnancies the expression of two major glucose transporters GLUT-1 and GLUT-3 is altered. On the contrary, idiopathic foetal macrosomia is not associated with changes in the placental expression of GLUT-1, GLUT-3, GLUT-8 and GLUT-12 proteins.

Are body roundness index and a body shape index in the first trimester related to foetal macrosomia?

This study investigated the effectiveness of maternal Body Roundness Index (BRI), Body Shape Index (ASBI), and Visceral Adiposity Index (VAI) in predicting foetal macrosomia and small for gestational age (SFGA) babies in obese and non-obese pregnant women. This prospective trial included 168 pregnant women (99 obese and 69 non-obese). A logistic regression model was used to identify the independent risk factors of foetal macrosomia and SFGA. BRI, waist/hip ratio, HbA1c and HOMA-IR were found to be significantly associated with increased macrosomia risk in obese women (OR = 1.469, % CI: 1.126-1.917, p = .005; OR = 4.289, % CI: 0.178-1.030, p = .012, OR = 6.277, %Cl: 1.233-31.948, p = .027, and OR = 1.393, %Cl: 1.060-1.832, p = .017). The present study indicates that first-trimester BRI and waist/hip ratio may be powerful determinants in predicting foetal macrosomia in obese pregnant women.Impact statementWhat is already known on this subject? Obesity is a major risk factor for maternal and foetal morbidity and mortality. The rate of obesity continues to increase rapidly around the world. The accuracy of ultrasound in estimated foetal weight is reduced in obese pregnant women. The Body Roundness Index (BRI) is a new anthropometric index that shows body fat distribution.What do the results of this study add? Our results show that the BRI was an independent risk factor associated with foetal macrosomia in obese pregnant women.What are the implications of these findings for future clinical practice and/or further research? BRI measurements should be taken before pregnancy to help predict shoulder dystocia, GDM, FGR and foetal macrosomia in obese women.

Influence of Foetal Macrosomia on the Neonatal and Maternal Birth Outcome

Introduction Foetal macrosomia is associated with various obstetrical complications and is a common reason for inductions and primary or secondary Caesarean sections. The objective of this study is the generation of descriptive data on the mode of delivery and on maternal and foetal complications in the case of foetal macrosomia. The causes and consequences of foetal macrosomia as well as the rate of shoulder dystocia are examined in relation to the severity of the macrosomia.

Patients The study investigated all singleton births ≥ 37 + 0 weeks of pregnancy with a birth weight ≥ 4000 g at the Charité University Medicine Berlin (Campus Mitte 2001 – 2017, Campus Virchow Klinikum 2014 – 2017).

Results 2277 consecutive newborns (birth weight 4000 – 4499 g [88%], 4500 – 4999 g [11%], ≥ 5000 g [1%]) were included. Maternal obesity and gestational diabetes were more common in the case of newborns weighing ≥ 4500 g than newborns weighing 4000 – 4499 g (p = 0.001 and p < 0.001). Women with newborns ≥ 5000 g were more often ≥ 40 years of age (p = 0.020) and multipara (p = 0.025). The mode of delivery was spontaneous in 60% of cases, vaginal-surgical in 9%, per primary section in 14% and per secondary section in 17%. With a birth weight ≥ 4500 g, a vaginal delivery was more rare (p < 0.001) and the rate of secondary sections was increased (p = 0.011). Women with newborns ≥ 4500 g suffered increased blood loss more frequently (p = 0.029). There was no significant difference with regard to the rate of episiotomies or serious birth injuries. Shoulder dystocia occurred more frequently at a birth weight of ≥ 4500 g (5 vs. 0.9%, p = 0.000). Perinatal acidosis occurred in 2% of newborns without significant differences between the groups. Newborns ≥ 4500 g were transferred to neonatology more frequently (p < 0.001).

Conclusion An increased birth weight is associated with an increased maternal risk and an increased rate of primary and secondary sections as well as shoulder dystocia; no differences in the perinatal outcome between newborns with a birth weight of 4000 – 4499 g and ≥ 4500 g were seen. In our collective, a comparably low incidence of shoulder dystocia was seen. In the literature, the frequency is indicated with a large range (1.9 – 10% at 4000 – 4499 g, 2.5 – 20% at 4500 – 5000 g and 10 – 20% at ≥ 5000 g). One possible cause for the low rate could be the equally low prevalence of gestational diabetes in our collective. A risk stratification of the pregnant women (e.g. avoidance of vacuum extraction, taking gestational diabetes into account during delivery planning) is crucial. If macrosomia is presumed, it is recommended that delivery take place at a perinatal centre in the presence of a specialist physician, due to the increased incidence of foetal and maternal complications.

Weight gain in pregnancy and child weight status from birth to adulthood in the United States

BACKGROUND

High weight gain in pregnancy has been associated with child adiposity, but few studies have assessed the relationship across childhood or in racially/ethnically diverse populations.

OBJECTIVES

The objectives of the study are to test if weight gain in pregnancy is associated with high birthweight and overweight/obesity in early, middle and late childhood and whether these associations differ by maternal race/ethnicity.

METHODS

Mother-child dyads (n = 7539) were included from the National Longitudinal Survey of Youth 1979, a nationally representative cohort study in the USA (1979-2012). Log-binomial regression models were used to analyse associations between weight gain and the outcomes: high birthweight (>4000 g) and overweight/obesity at ages 2-5, 6-11 and 12-19 years.

RESULTS

Excessive weight gain was positively associated, and inadequate weight gain was negatively associated with high birthweight after confounder adjustment (P < 0.05). Only excessive weight gain was associated with overweight in early, middle and late childhood. These associations were not significant in Hispanics or Blacks although racial/ethnic interaction was only significant ages 12-19 years (P = 0.03).

CONCLUSIONS

Helping pregnant women gain weight within national recommendations may aid in preventing overweight and obesity across childhood, particularly for non-Hispanic White mothers.

Percentage change in body mass index or gestational weight gain: Which is a better predictor of foetal macrosomia?

The aim of the study was to evaluate gestational weight gain (GWG) and percentage change in body mass index (BMI) for prediction of foetal macrosomia. A total of 409 term pregnant women, of whom 86 delivered macrosomic infants (> 4000 g) and 323 delivered non-macrosomic infants were recruited for the study. GWG and body mass index at delivery were significantly higher in the macrosomic than non-macrosomic group (15.8 ± 5.6 vs 13.9 ± 5.6, and 31.4 ± 4.3 vs 29.5 ± 4.3, respectively) (p < 0.05). The receiver operating characteristic curve analysis for testing the significance of weight gain in prediction of macrosomia showed an area under curve of 0.58 (p = 0.012, 95% confidence interval [CI] = 0.52-0.65), and significance of percentage change in BMI in prediction of macrosomia revealed an area under curve of 0.52 (p = 0.51, 95% CI = 0.46-0.59). BMI percentage changes both in obese (BMI ≥ 25) and non-obese (BMI < 25) groups were not statistically significant (p > 0.05). BMI percentage change does not seem to be a strong predictor of foetal macrosomia, and GWG was not found to be an independent risk factor after multivariate regression analysis was performed.