Identifying Fetal Growth Disorders Using Ultrasonography in Women With Diabetes

The influence of insulin-related genetic variants on fetal growth, fetal blood flow, and placental weight in a prospective pregnancy cohort

The fetal insulin hypothesis proposes that low birthweight and type 2 diabetes (T2D) in adulthood may be two phenotypes of the same genotype. In this study we aimed to explore this theory further by testing the effects of GWAS-identified genetic variants related to insulin release and sensitivity on fetal growth and blood flow from week 20 of gestation to birth and on placental weight at birth. We calculated genetic risk scores (GRS) of first phase insulin release (FPIR), fasting insulin (FI), combined insulin resistance and dyslipidaemia (IR + DLD) and insulin sensitivity (IS) in a study population of 665 genotyped newborns. Two-dimensional ultrasound measurements with estimation of fetal weight and blood flow were carried out at week 20, 25, and 32 of gestation in all 665 pregnancies. Birthweight and placental weight were registered at birth. Associations between the GRSs and fetal growth, blood flow and placental weight were investigated using linear mixed models. The FPIR GRS was directly associated with fetal growth from week 20 to birth, and both the FI GRS, IR + DLD GRS, and IS GRS were associated with placental weight at birth. Our findings indicate that insulin-related genetic variants might primarily affect fetal growth via the placenta.

Risk of Stillbirth in Pregnancies Complicated by Diabetes, Stratified by Fetal Growth

OBJECTIVE

To compare stillbirth rates per week of expectant management stratified by birth weight in pregnancies complicated by gestational diabetes mellitus (GDM) or pregestational diabetes mellitus.

METHODS

A national population-based retrospective cohort study of singleton, nonanomalous pregnancies complicated by pregestational diabetes or GDM was performed using national birth and death certificate data from 2014 to 2017. Stillbirth rates per 10,000 patients (stillbirth incidence at gestational age week/ongoing pregnancies-[0.5×live births at gestational age week]) were determined for each week of pregnancy from 34 to 39 completed weeks of gestation. Pregnancies were stratified by birth weight, categorized as having small-for-gestational-age (SGA), appropriate-for-gestational-age (AGA), or large-for-gestational-age (LGA) fetuses, assigned by sex-based Fenton criteria. Relative risk (RR) and 95% CI for stillbirth were calculated for each gestational age week compared with the GDM-related AGA group.

RESULTS

We included 834,631 pregnancies complicated by either GDM (86.9%) or pregestational diabetes (13.1%) in the analysis, with a total of 3,033 stillbirths. Stillbirth rates increased with advancing gestational age for pregnancies complicated by both GDM and pregestational diabetes regardless of birth weight. Compared with pregnancies with AGA fetuses, those with both SGA and LGA fetuses were significantly associated with an increased risk of stillbirth at all gestational ages. Ongoing pregnancies at 37 weeks of gestation complicated by pregestational diabetes with LGA or SGA fetuses had respective stillbirth rates of 64.9 and 40.1 per 10,000 patients. Pregnancies complicated by pregestational diabetes had an RR of stillbirth of 21.8 (95% CI 17.4-27.2) for LGA fetuses and 13.5 (95% CI 8.5-21.2) for SGA fetuses compared with GDM-related AGA at 37 weeks of gestation. The greatest absolute risk of stillbirth was in pregnancies complicated by pregestational diabetes at 39 weeks of gestation with LGA fetuses (97/10,000).

CONCLUSION

Pregnancies complicated by both GDM and pregestational diabetes affected by pathologic fetal growth have an increased risk of stillbirth with advancing gestational age. This risk is significantly higher with pregestational diabetes, especially pregestational diabetes with LGA fetuses.

Rethinking third trimester ultrasound measurements and risk of adverse neonatal outcomes in pregnancies complicated by hyperglycaemia: A retrospective study

BACKGROUND

Antenatal ultrasound is used frequently in pregnancies complicated by hyperglycaemia; however, it is unclear which measurements have the greatest association with adverse neonatal outcomes.

AIM

To assess the association between third trimester ultrasound parameters with adverse neonatal outcomes in pregnancies complicated by hyperglycaemia.

METHOD

All pregnant women with gestational or type 2 diabetes who birthed in a regional hospital over 12 months were included. A composite adverse neonatal outcome was defined by one or more: admission to special care nursery, acidosis, hypoglycaemia, jaundice, shoulder dystocia, respiratory distress syndrome or 5-minute Apgar score < 5. Logistic regression was used to determine odds ratios (OR) for an adverse neonatal outcome, according to pre-specified cut points in both lower and upper percentiles of abdominal circumference (AC) and estimated fetal weight (EFW).

RESULTS

Of 275 births an adverse outcome occurred in 122 (44%). Unadjusted OR (95% CI) for AC ≤30^th was 3.2 (1.1-8.8) and >95^th percentile was 3.1 (1.5-6.0) compared with the reference group of 31-70^th percentile. Unadjusted OR for EFW ≤30^th was 1.5 (0.7-3.1) and >95^th percentile was 3.0 (1.4-6.3). After adjusting for maternal age, body mass index, diabetes type, ethnicity, gravidity, mode of delivery and gestation at birth the OR (95% CI) were as follows: AC ≤30^th percentile, 3.7 (1.1-12.4); AC >95^th , 2.2 (1.1-4.8); EFW ≤30^th , 2.6 (1.1-6.1); EFW >95^th , 2.5 (1.1-6.1).

CONCLUSION

An AC and EFW up to the 30^th percentile may pose just as great a risk to the fetus as an AC or EFW >95^th percentile in pregnancies complicated by hyperglycaemia.

Agreement Analysis between Sonographic Estimates and Birth Weight, by the WHO and Intergrowth-21st Tables, in Newborns of Diabetic Mothers

OBJECTIVE

 To analyze the agreement, in relation to the 90th percentile, of ultrasound measurements of abdominal circumference (AC) and estimated fetal weight (EFW), between the World Health Organization (WHO) and the International Fetal and Newborn Growth Consortium for the 21st Century (intergrowth-21st) tables, as well as regarding birth weight in fetuses/newborns of diabetic mothers.

METHODS

 Retrospective study with data from medical records of 171 diabetic pregnant women, single pregnancies, followed between January 2017 and June 2018. Abdominal circumference and EFW data at admission (from 22 weeks) and predelivery (up to 3 weeks) were analyzed. These measures were classified in relation to the 90th percentile. The Kappa coefficient was used to analyze the agreement of these ultrasound variables between the WHO and intergrowth-21st tables, as well as, by reference table, these measurements and birth weight.

RESULTS

 The WHO study reported 21.6% large-for-gestational-age (LGA) newborns while the intergrowth-21st reported 32.2%. Both tables had strong concordances in the assessment of initial AC, final AC, and initial EFW (Kappa = 0.66, 0.72 and 0.63, respectively) and almost perfect concordance in relation to final EFW (Kappa = 0.91). Regarding birth weight, the best concordances were found for initial AC (WHO: Kappa = 0.35; intergrowth-21st: Kappa = 0.42) and with the final EFW (WHO: Kappa = 0.33; intergrowth- 21st: Kappa = 0.35).

CONCLUSION

 The initial AC and final EFW were the parameters of best agreement regarding birth weight classification. The WHO and intergrowth-21st tables showed high agreement in the classification of ultrasound measurements in relation to the 90th percentile. Studies are needed to confirm whether any of these tables are superior in predicting short- and long-term negative outcomes in the LGA group.

Ultrasound fetal anthropometry to identify large-for-gestational-age: a meta-analysis

INTRODUCTION

Large-for-gestational-age (LGA) has been suggested to show high rates of mortality and morbidity in pregnant women and their neonates. This study was based on data from 2015 or later to determine whether ultrasound fetal anthropometry is helpful for identifying LGA.

EVIDENCE ACQUISITION

Sensitivity, specificity, positive and negative likelihood ratios (LRs), and diagnostic odds ratio (DOR) of studies published in English were summarized using bivariate diagnostic meta-analysis. Study quality was assessed using the revised Quality Assessment of Diagnostic Accuracy Studies tool. Deeks' funnel plot asymmetry test was assessed to identify publication bias.

EVIDENCE SYNTHESIS

The findings of abdominal circumference were based on a single article. Despite high specificity (0.92), anthropometric formulas showed moderate sensitivity (0.71) and DOR (26) and were categorized as providing "neither exclusion (positive LR<10) nor confirmation (negative LR>0.1)" strategy based on 28 good-quality studies in five articles. However, they were more promising than previous meta-analytic findings not limited to 2015 or later. No publication bias was identified with respect to assessment of anthropometric formulas (P=0.286).

CONCLUSIONS

Current ultrasound fetal anthropometry is not strongly helpful, but the values of anthropometric formulas provided by future ultrasound are expected especially as the secondary screening of LGA.

Comparative analyses of umbilical cord lead concentration in term and IUGR complicated neonates

BACKGROUND

Lead as a toxic heavy metal can readily transfer through the placenta; this condition may increase the risk of lead toxicity for a developing fetus. Therefore, we undertook this study to evaluate the association between umbilical cord blood lead levels and the risk of intrauterine growth restriction (IUGR) occurrence.

METHODS

A cross-sectional study was done at an academic hospital (Tehran, Iran, 2017). The population study was term and IUGR complicated neonates. Immediately after birth, 3-ml umbilical cord blood was collected in some tubes and sent to a laboratory to assay plasma lead levels. Demographic data related neonates and their mothers were gathered from the medical record. All recorded data were analyzed to compare the cord blood lead levels among normal term and IUGR neonates as the primary outcome.

RESULTS

Totally 152 neonates, 76 in each group with inclusion criteria entered the study. Of all neonates, 71 subjects (47%) were male. The mean (±SD) cord blood lead levels was 6.5 ± 4.2 µg/l. Of all neonates, 102 (67.1%) had high cord blood lead levels (≥5 µg/dl) and 50 subjects (32.8%) had low cord blood lead levels (<5 µg/dl). The mean gestational age, birth weight and head circumference of term neonates were significantly higher than IUGR complicated neonates (p-value = .0001). On the other hand, no significant difference was observed between two groups regarding the mean cord blood lead concentrations (6.2 ± 2.2 and 6.8 ± 5.6 µg/dl; p-value = .855). ANOVA analyses showed no relationships between cord blood lead levels and all assessed qualitative variables except from mother's educational status (in IUGR group; p-value = .048 and in term group; p-value = .010).

CONCLUSION

Our results highlighted that IUGR occurrence was not associated with fetal blood lead levels alone. Moreover, highly educated mothers had neonates with low blood lead levels, showing that maternal education may be a potentially protective factor against this toxin exposure in newborns. The majority of neonates in the present study had high blood lead concentrations that show a necessity for more efforts and strategies regarding protection against potential deleterious effects of lead toxicity.