The effectiveness and costs of elective cesarean delivery for fetal macrosomia diagnosed by ultrasound

The Impact on Birth Outcomes of Sonographic Fetal Weight Estimation in Neonatal Macrosomia

OBJECTIVE

 Our objective was to examine the association between sonographic estimated fetal weight (EFW) and obstetrical and neonatal outcomes in women with neonatal macrosomia.

STUDY DESIGN

 This study, conducted at a tertiary university-affiliated hospital from 2017 to 2021, compared obstetrical and neonatal outcomes between two groups of women who delivered macrosomic newborns (actual birthweight ≥ 4,000 g): (1) those with EFW ≥ 3,800 g (suspected impending macrosomia) and (2) those with EFW < 3,800 g (unsuspected impending macrosomia).

RESULTS

 During the study period, 854 women with neonatal macrosomia attempted vaginal delivery. Only 9.2% had a sonographic EFW ≥ 4,000 g. Among women with EFW ≥ 3,800 g (n = 317) compared with EFW < 3,800 g (n = 537), the cesarean delivery (CD) rate was higher (17.0 vs. 10.5%, p = 0.004) and the operative delivery rate was lower (3.2 vs. 0.6%, p = 0.015). Among primiparous women, the CD rate was higher among those with EFW ≥ 3,800 versus <3,800 g (37.3 vs. 23.2%, p = 0.033). EFW ≥3,800 g was associated with CD, regardless of predelivery body mass index, parity, diabetes mellitus, maximal fetal weight at previous deliveries, actual birthweight, and labor induction (p = 0.014). EFW ≥ 3,800 g and diabetes mellitus were independent predictors of CD. Among women with EFW ≥3,800 g and diabetes mellitus, the risk of CD was double that of those without diabetes and with EFW ≥ 3,800 g (31.4% vs. 15.2%, p = 0.02), although their actual birthweights were similar. Obstetrical and neonatal outcomes were similar between those with sonographic EFW ≥ 3,800 and < 3,800 g.

CONCLUSION

 Larger EFW increased CD risk among pregnancies with actual neonatal macrosomia. Antenatally suspected macrosomia might alter labor management due to concerns for potential complications, especially when associated with primiparity, diabetes mellitus, or maternal obesity. The increase in the CD rate did not show an association with improved maternal and neonatal outcomes.

KEY POINTS

· Antenatally suspected macrosomia might alter labor management due to concerns about complications.. · Larger EFW increased cesarean delivery risk among pregnancies with actual neonatal macrosomia.. · The increase in the cesarean delivery rate was not associated with improved outcomes..

Fetal Growth Biometry as Predictors of Shoulder Dystocia in a Low-Risk Obstetrical Population

OBJECTIVE

 This study aimed to evaluate fetal biometrics as predictors of shoulder dystocia (SD) in a low-risk obstetrical population.

STUDY DESIGN

 Participants were enrolled as part of a U.S.-based prospective cohort study of fetal growth in low-risk singleton gestations (n = 2,802). Eligible women had liveborn singletons ≥2,500 g delivered vaginally. Sociodemographic, anthropometric, and pregnancy outcome data were abstracted by research staff. The diagnosis of SD was based on the recorded clinical impression of the delivering physician. Simple logistic regression models were used to examine associations between fetal biometrics and SD. Fetal biometric cut points, selected by Youden's J and clinical determination, were identified to optimize predictive capability. A final model for SD prediction was constructed using backward selection. Our dataset was randomly divided into training (60%) and test (40%) datasets for model building and internal validation.

RESULTS

 A total of 1,691 women (98.7%) had an uncomplicated vaginal delivery, while 23 (1.3%) experienced SD. There were no differences in sociodemographic or maternal anthropometrics between groups. Epidural anesthesia use was significantly more common (100 vs. 82.4%; p = 0.03) among women who experienced SD compared with those who did not. Amniotic fluid maximal vertical pocket was also significantly greater among SD cases (5.8 ± 1.7 vs. 5.1 ± 1.5 cm; odds ratio = 1.32 [95% confidence interval: 1.03,1.69]). Several fetal biometric measures were significantly associated with SD when dichotomized based on clinically selected cut-off points. A final prediction model was internally valid with an area under the curve of 0.90 (95% confidence interval: 0.81, 0.99). At a model probability of 1%, sensitivity (71.4%), specificity (77.5%), positive (3.5%), and negative predictive values (99.6%) did not indicate the ability of the model to predict SD in a clinically meaningful way.

CONCLUSION

 Other than epidural anesthesia use, neither sociodemographic nor maternal anthropometrics were significantly associated with SD in this low-risk population. Both individually and in combination, fetal biometrics had limited ability to predict SD and lack clinical usefulness.

KEY POINTS

· SD unpredictable in low-risk women.. · Fetal biometry does not reliably predict SD.. · Epidural use associated with increased SD risk.. · SD prediction models clinically inefficient..

Maternal serum dioxin-like activity and gestational age at birth and indices of foetal growth: The Aarhus birth cohort

Human exposure to lipophilic persistent organic pollutants (lipPOP) is ubiquitous and life-long, beginning during foetal development. Exposure to lipPOP elicits a number of species and tissue specific responses including dioxin-like activity which involve the activation of aryl hydrocarbon receptor (AhR). This study aims i) to describe the combined dioxin-like activity in serum from Danish pregnant women collected during 2011-2013; ii) to assess the association between maternal serum dioxin-like activity, gestational age at birth and foetal growth indices. The serum lipPOP fraction was extracted using Solid Phase Extraction and cleaned-up on Supelco multi-layer silica and florisil columns. The combined dioxin-like activity of the extract was determined using the AhR reporter gene bioassay, expressed as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxic equivalent (TEQ) [AhR-TEQ (pg/g lipid)]. The associations of AhR-TEQ and foetal growth indices (birth weight, birth length and head circumference) and gestational age were assessed by linear regression models. We detected AhR-TEQ in 93.9 % of maternal first trimester serum samples, with a median level of 185 pg/g lipid. Each ln-unit increase in AhR-TEQ was associated with an increase in birth weight of 36 g (95 % CI: 5; 68), birth length of 0.2 cm (95 % CI: 0.01; 0.3) and pregnancy duration of 1 day (95 % CI: 0; 1.5). In women who never smoked, higher AhR-TEQ values were associated with higher birth weight and longer duration of gestation, while in smokers the association was the opposite. Mediation analyses suggested that gestational age may mediate the association of AhR-TEQ with foetal growth indices. We conclude that AhR activating substances are present in the bloodstream of almost all pregnant women in Denmark and the AhR-TEQ level was around four times higher than previously reported. The AhR-TEQ was associated with slightly longer gestational duration and thereby higher birth weight and birth length.

The impact of different growth charts on birthweight prediction: obstetrical ultrasound vs magnetic resonance imaging

BACKGROUND

The estimation of fetal weight by fetal magnetic resonance imaging is a simple and rapid method with a high sensitivity in predicting birthweight in comparison with ultrasound. Several national and international growth charts are currently in use, but there is substantial heterogeneity among these charts due to variations in the selected populations from which they were derived, in methodologies, and in statistical analysis of data.

OBJECTIVE

This study aimed to compare the performance of magnetic resonance imaging and ultrasound for the prediction of birthweight using 3 commonly used fetal growth charts: the INTERGROWTH-21st Project, World Health Organization, and Fetal Medicine Foundation charts.

STUDY DESIGN

Data derived from a prospective, single-center, blinded cohort study that compared the performance of magnetic resonance imaging and ultrasound between 36+0/7 and 36+6/7 weeks of gestation for the prediction of birthweight ≥95th percentile were reanalyzed. Estimated fetal weight was categorized as above or below the 5th, 10th, 90th, and 95th percentile according to the 3 growth charts. Birthweight was similarly categorized according to the birthweight standards of each chart. The performances of ultrasound and magnetic resonance imaging for the prediction of birthweight <5th, <10th, >90th, and >95th percentile using the different growth charts were compared. Data were analyzed with R software, version 4.1.2. The comparison of sensitivity and specificity was done using McNemar and exact binomial tests. P values <.05 were considered statistically significant.

RESULTS

A total of 2378 women were eligible for final analysis. Ultrasound and magnetic resonance imaging were performed at a median gestational age of 36+3/7 weeks, delivery occurred at a median gestational age of 39+3/7 weeks, and median birthweight was 3380 g. The incidences of birthweight <5th and <10th percentiles were highest with the Fetal Medicine Foundation chart and lowest with the INTERGROWTH-21st chart, whereas the incidences of birthweight >90th and >95th percentiles were lowest with the Fetal Medicine Foundation chart and highest with the INTERGROWTH-21st chart. The sensitivity of magnetic resonance imaging with an estimated fetal weight >95th percentile in the prediction of birthweight >95th percentile was significantly higher than that of ultrasound across the 3 growth charts; however, its specificity was slightly lower than that of ultrasound. In contrast, the sensitivity of magnetic resonance imaging with an estimated fetal weight <10th percentile for predicting birthweight <10th percentile was significantly lower than that of ultrasound in the INTERGROWTH-21st and Fetal Medicine Foundation charts, whereas the specificity and positive predictive value of magnetic resonance imaging were significantly higher than those of ultrasound for all 3 charts. Findings for the prediction of birthweight >90th percentile were close to those of birthweight >95th percentile, and findings for the prediction of birthweight <5th percentile were close to those of birthweight <10th percentile.

CONCLUSION

The sensitivity of magnetic resonance imaging is superior to that of ultrasound for the prediction of large for gestational age fetuses and inferior to that of ultrasound for the prediction of small for gestational age fetuses across the 3 different growth charts. The reverse is true for the specificity of magnetic resonance imaging in comparison with that of ultrasound.

Prediction of birthweight and risk of macrosomia in pregnancies complicated by diabetes

BACKGROUND

Antenatal detection of accelerated fetal growth and macrosomia in pregnancies complicated by diabetes mellitus is important for patient counseling and management. Sonographic fetal weight estimation is the most commonly used tool to predict birthweight and macrosomia. However, the predictive accuracy of sonographic fetal weight estimation for these outcomes is limited. In addition, an up-to-date sonographic fetal weight estimation is often unavailable before birth. This may result in a failure to identify macrosomia, especially in pregnancies complicated by diabetes mellitus where care providers might underestimate fetal growth rate. Therefore, there is a need for better tools to detect and alert care providers to the potential risk of accelerated fetal growth and macrosomia.

OBJECTIVE

This study aimed to develop and validate prediction models for birthweight and macrosomia in pregnancies complicated by diabetes mellitus.

STUDY DESIGN

This was a completed retrospective cohort study of all patients with a singleton live birth at ≥36 weeks of gestation complicated by preexisting or gestational diabetes mellitus observed at a single tertiary center between January 2011 and May 2022. Candidate predictors included maternal age, parity, type of diabetes mellitus, information from the most recent sonographic fetal weight estimation (including estimated fetal weight, abdominal circumference z score, head circumference-to-abdomen circumference z score ratio, and amniotic fluid), fetal sex, and the interval between ultrasound examination and birth. The study outcomes were macrosomia (defined as birthweights >4000 and >4500 g), large for gestational age (defined as a birthweight >90th percentile for gestational age), and birthweight (in grams). Multivariable logistic regression models were used to estimate the probability of dichotomous outcomes, and multivariable linear regression models were used to estimate birthweight. Model discrimination and predictive accuracy were calculated. Internal validation was performed using the bootstrap resampling technique.

RESULTS

A total of 2465 patients met the study criteria. Most patients had gestational diabetes mellitus (90%), 6% of patients had type 2 diabetes mellitus, and 4% of patients had type 1 diabetes mellitus. The overall proportions of infants with birthweights >4000 g, >4500 g, and >90th percentile for gestational age were 8%, 1%, and 12%, respectively. The most contributory predictor variables were estimated fetal weight, abdominal circumference z score, ultrasound examination to birth interval, and type of diabetes mellitus. The models for the 3 dichotomous outcomes had high discriminative accuracy (area under the curve receiver operating characteristic curve, 0.929-0.979), which was higher than that achieved with estimated fetal weight alone (area under the curve receiver operating characteristic curve, 0.880-0.931). The predictive accuracy of the models had high sensitivity (87%-100%), specificity (84%-92%), and negative predictive values (84%-92%). The predictive accuracy of the model for birthweight had low systematic and random errors (0.6% and 7.5%, respectively), which were considerably smaller than the corresponding errors achieved with estimated fetal weight alone (-5.9% and 10.8%, respectively). The proportions of estimates within 5%, 10%, and 15% of the actual birthweight were high (52.3%, 82.9%, and 94.9%, respectively).

CONCLUSION

The prediction models developed in the current study were associated with greater predictive accuracy for macrosomia, large for gestational age, and birthweight than the current standard of care that includes estimated fetal weight alone. These models may assist care providers in counseling patients regarding the optimal timing and mode of delivery.

Efficacy of Kinesio® tapes in obstetrical brachial plexus injury: a randomized controlled trial

OBJECTIVES

The purpose of this study was to investigate the effectiveness of Kinesio® tape application associated to exercise in patients with obstetric brachial plexus injury (OBPI).

MATERIALS AND METHODS

Ninety patients with Erb-Duchenne palsy secondary to OBPI participated in a 3-month study, in 2 groups; study group (n = 50) and control group (n = 40). Both followed the same physical therapy program, while the study group also received Kinesio® taping over the scapula and forearm. The patients were evaluated, pre- and post-treatment, using the Modified Mallet Classification (MMC), Active Movement Scale (AMS), and active range of motion (ROM) of the plegic side.

RESULTS

There were no statistically significant intergroup differences in age, gender, birth weight or plegic side (p > 0.05), or in pre-treatment MMC and AMS scores (p > 0.05). There were significant differences in favor of the study group for Mallet 2 (external rotation) (p = 0.012), Mallet 3 (hand on the back of the neck) (p < 0.001), Mallet 4 (hand on the back) (p = 0.001) and total Mallet score (p = 0.025), and for AMS shoulder flexion (p = 0.004) and elbow flexion (p < 0.001). ROM results before and after treatment (within groups) showed significant improvement in both groups (p < 0.001).

CONCLUSION

Since this a was a preliminary study, the results should be interpreted with caution in terms of clinical efficacy. The results suggest that associating Kinesio® taping to conventional treatment helps functional development in patients with OBPI.'

Association between Diabetes in Pregnancy and Shoulder Dystocia by Infant Birth Weight in an Era of Cesarean Delivery for Suspected Macrosomia

OBJECTIVE

 We estimated the association between diabetes and shoulder dystocia by infant birth weight subgroups (<4,000, 4,000-4,500, and >4,500 g) in an era of prophylactic cesarean delivery for suspected macrosomia.

STUDY DESIGN

 A secondary analysis from the National Institute of Child Health and Human Development U.S. Consortium for Safe Labor of deliveries at ≥24 weeks with a nonanomalous, singleton fetus with vertex presentation undergoing a trial of labor. The exposure was either pregestational or gestational diabetes compared with no diabetes. The primary outcome was shoulder dystocia and secondarily, birth trauma with a shoulder dystocia. We calculated adjusted risk ratios (aRRs) with modified Poison's regression between diabetes and shoulder dystocia and the number needed to treat (NNT) to prevent a shoulder dystocia with cesarean delivery.

RESULTS

 Among 167,589 assessed deliveries (6% with diabetes), pregnant individuals with diabetes had a higher risk of shoulder dystocia at birth weight <4,000 g (aRR: 1.95; 95% confidence interval [CI]: 1.66-2.31) and 4,000 to 4,500 g (aRR: 1.57; 95% CI: 1.24-1.99), albeit not significantly at birth weight >4,500 g (aRR: 1.26; 95% CI: 0.87-1.82) versus those without diabetes. The risk of birth trauma with shoulder dystocia was higher with diabetes (aRR: 2.29; 95% CI: 1.54-3.45). The NNT to prevent a shoulder dystocia with diabetes was 11 and 6 at ≥4,000 and >4,500 g, versus without diabetes, 17 and 8 at ≥4,000 and >4,500 g, respectively.

CONCLUSION

 Diabetes increased the risk of shoulder dystocia, even at lower birth weight thresholds than at which cesarean delivery is currently offered. Guidelines providing the option of cesarean delivery for suspected macrosomia may have decreased the risk of shoulder dystocia at higher birth weights.

KEY POINTS

· >Diabetes increased the risk of shoulder dystocia, even at lower birth weight thresholds than at which cesarean delivery is currently offered.. · Cesarean delivery for suspected macrosomia may have decreased the risk of shoulder dystocia at higher birth weights.. · These findings can inform delivery planning for providers and pregnant individuals with diabetes..

Shoulder Dystocia: Challenging Basic Assumptions

Most of our knowledge pertaining to this obstetric emergency has emanated from case reports and retrospective studies that have subsequently resulted in empirical management protocols. This article has identified the existence of large gaps in our clinical knowledge base regarding the prevention and resolution of shoulder dystocia, as well as its long-term sequelae. We have attempted to challenge current recommendations regarding whether prophylactic cesarean delivery should be performed based on estimated fetal weight alone or a prior history of shoulder dystocia, shoulder dystocia management techniques, what defines "excessive" traction, and the role of simulation training for all clinicians.

A Maternal Serum Metabolite Ratio Predicts Large for Gestational Age Infants at Term: A Prospective Cohort Study

CONTEXT

Excessive birth weight is associated with maternal and neonatal complications. However, ultrasonically estimated large for gestational age (LGA; >90th percentile) predicts these complications poorly.

OBJECTIVE

To determine whether a maternal serum metabolite ratio developed for fetal growth restriction (FGR) is predictive of birth weight across the whole range, including LGA at birth.

METHODS

Metabolites were measured using ultrahigh performance liquid chromatography-tandem mass spectroscopy. The 4-metabolite ratio was previously derived from an analysis of FGR cases and a random subcohort from the Pregnancy Outcome Prediction study. Here, we evaluated its relationship at 36 weeks of gestational age (wkGA) with birth weight in the subcohort (n = 281). External validation in the Born in Bradford (BiB) study (n = 2366) used the metabolite ratio at 24 to 28 wkGA.

RESULTS

The inverse of the metabolite ratio at 36 wkGA predicted LGA at term [the area under the receiver operating characteristic curve (AUROCC) = 0.82, 95% CI 0.73 to 0.91, P = 6.7 × 10-5]. The ratio was also inversely associated with birth weight z score (linear regression, beta = -0.29 SD, P = 2.1 × 10-8). Analysis in the BiB cohort confirmed that the ratio at 24 to 28 wkGA predicted LGA (AUROCC = 0.60, 95% CI 0.54 to 0.67, P = 8.6 × 10-5) and was inversely associated with birth weight z score (beta = -0.12 SD, P = 1.3 × 10-9).

CONCLUSIONS

A metabolite ratio which is strongly predictive of FGR is equally predictive of LGA birth weight and is inversely associated with birth weight across the whole range.

Fetal magnetic resonance imaging at 36 weeks predicts neonatal macrosomia: the PREMACRO study

BACKGROUND

Large-for-gestational-age fetuses are at increased risk of perinatal morbidity and mortality. Magnetic resonance imaging seems to be more accurate than ultrasound in the prediction of macrosomia; however, there is no well-powered study comparing magnetic resonance imaging with ultrasound in routine pregnancies.

OBJECTIVE

This study aimed to prospectively compare estimates of fetal weight based on 2-dimensional ultrasound and magnetic resonance imaging with actual birthweights in routine pregnancies.

STUDY DESIGN

From May 2016 to February 2019, women received counseling at the 36-week clinic. Written informed consent was obtained for this Ethics Committee-approved study. In this prospective, single-center, blinded study, pregnant women with singleton pregnancies between 36 0/7 and 36 6/7 weeks' gestation underwent both standard evaluation of estimated fetal weight with ultrasound according to Hadlock et al and magnetic resonance imaging according to the formula developed by Baker et al, based on the measurement of the fetal body volume. Participants and clinicians were aware of the results of the ultrasound but blinded to the magnetic resonance imaging estimates. Birthweight percentile was considered as the gold standard for the ultrasound and magnetic resonance imaging-derived percentiles. The primary outcome was the area under the receiver operating characteristic curve for the prediction of large-for-gestation-age neonates with birthweights of ≥95th percentile. Secondary outcomes included the comparative prediction of large-for-gestation-age neonates with birthweights of ≥90th, 97th, and 99th percentiles and small-for-gestational-age neonates with birthweights of ≤10th, 5th, and 3rd percentiles for gestational age and maternal and perinatal complications.

RESULTS

Of 2914 women who were initially approached, results from 2378 were available for analysis. Total fetal body volume measurements were possible for all fetuses, and the time required to perform the planimetric measurements by magnetic resonance imaging was 3.0 minutes (range, 1.3-5.6). The area under the receiver operating characteristic curve for the prediction of a birthweight of ≥95th percentile was 0.985 using prenatal magnetic resonance imaging and 0.900 using ultrasound (difference=0.085, P<.001; standard error, 0.020). For a fixed false-positive rate of 5%, magnetic resonance imaging for the estimation of fetal weight detected 80.0% (71.1-87.2) of birthweight of ≥95th percentile, whereas ultrasound for the estimation of fetal weight detected 59.1% (49.0-68.5) of birthweight of ≥95th percentile. The positive predictive value was 42.6% (37.8-47.7) for the estimation of fetal weight using magnetic resonance imaging and 35.4% (30.1-41.1) for the estimation of fetal weight using ultrasound, and the negative predictive value was 99.0% (98.6-99.3) for the estimation of fetal weight using magnetic resonance imaging and 98.0% (97.6-98.4) for the estimation of fetal weight using ultrasound. For a fixed false-positive rate of 10%, magnetic resonance imaging for the estimation of fetal weight detected 92.4% (85.5-96.7) of birthweight of ≥95th percentile, whereas ultrasound for the estimation of fetal weight detected 76.2% (66.9-84.0) of birthweight of ≥95th percentile. The positive predictive value was 29.9% (27.2-32.8) for the estimation of fetal weight using magnetic resonance imaging and 26.2% (23.2-29.4) for the estimation of fetal weight using ultrasound, and the negative predictive value was 99.6 (99.2-99.8) for the estimation of fetal weight using magnetic resonance imaging and 98.8 (98.4-99.2) for the estimation of fetal weight using ultrasound. The area under the receiver operating characteristic curves for the prediction of large-for-gestational-age neonates with birthweights of ≥90th, 97th, and 99th percentiles and small-for-gestational-age neonates with birthweights of ≤10th, 5th, and 3rd percentiles was significantly larger in prenatal magnetic resonance imaging than in ultrasound (P<.05 for all).

CONCLUSION

At 36 weeks' gestation, magnetic resonance imaging for the estimation of fetal weight performed significantly better than ultrasound for the estimation of fetal weight in the prediction of large-for-gestational-age neonates with birthweights of ≥95th percentile for gestational age and all other recognized cutoffs for large-for-gestational-age and small-for-gestational-age neonates (P<.05 for all).

Dioxin-like Activity in Pregnant Women and Indices of Fetal Growth: The ACCEPT Birth Cohort

Exposure to lipophilic persistent organic pollutants (lipPOPs) elicits a number of species- and tissue-specific toxic responses, many of which involve the aryl hydrocarbon receptor (AhR). This study aims to measure the combined serum dioxin-like activity of lipPOPs in Greenlandic Inuit pregnant women and the associations with fetal growth indices. The combined dioxin-like activity of serum lipPOPs extracts was determined using the AhR reporter gene bioassay and expressed as pico-gram (pg) TCDD equivalent (TEQ) per gram serum lipid [AhR-TEQ (pg/g lipid)]. Significant AhR-TEQ was found in >87% of serum samples with the median level of 86.2 pg TEQ/g lipid. The AhR-TEQ level positively correlated with the marine food intake biomarker n-3/n-6 polyunsaturated fatty acids ratio, while negatively correlated with body mass index and parity. Women giving birth to infants with low birth weight (<2500 g) and length (<50 cm) had higher AhR-TEQ level compared to those with normal weight and length infants. For previous smokers, we found significant inverse associations between maternal AhR-TEQ level and fetal growth indices. In conclusion, exposure of Greenlandic Inuit pregnant women to dioxin-like compounds through traditional marine food can adversely influence the fetal growth via induced AhR activity. Smoking might have modifying effects.

Induction of labor for a suspected large-for-gestational-age/macrosomic fetus

Fetal macrosomia is defined as a birth weight of >4000 g, while the term large for gestational age (LGA) is defined as an estimated fetal weight >90th centile for gestational age. Current data indicate that a significant proportion of the babies are LGA. Pregnancies involving LGA babies are associated with increased maternal and perinatal morbidity including caesarean section, postpartum hemorrhage, shoulder dystocia, and birth trauma. To reduce these complications, labor induction has been suggested as a possible solution. However, despite some high-quality evidence in favor of labor induction for suspected macrosomia/LGA, existing guidelines do not support routine induction of labor in this population. The aim of this paper is to critically appraise the available evidence and clinical practice recommendations and highlight the importance of shared decision making and individualized care based on clear counselling regarding the lack of a sensitive diagnostic tool for estimating fetal weight in the third trimester.

Diagnosis and Management of Gestational Diabetes Mellitus: An Overview of National and International Guidelines

Importance

Gestational diabetes mellitus (GDM) represents one of the most frequent complications of pregnancy and is associated with increased maternal and neonatal morbidity. Its incidence is rising, mostly due to an increase in maternal age and maternal obesity rate.

Objective

The aim of this study was to review and compare the recommendations of the most recently published guidelines on the diagnosis and management of this condition.

Evidence Acquisition

A descriptive review of guidelines from the National Institute for Health and Care Excellence (NICE), the International Federation of Gynecology and Obstetrics, the Australasian Diabetes in Pregnancy Society (ADIPS), the Society of Obstetricians and Gynecologists of Canada (SOGC), the American College of Obstetricians and Gynecologists (ACOG), the American Diabetes Association, and the Endocrine Society on gestational diabetes mellitus was carried out.

Results

The NICE guideline recommends targeted screening only for women with risk factors, whereas the International Federation of Gynecology and Obstetrics, ADIPS, SOGC, and the ACOG recommend screening for all pregnant women at 24 to 28 weeks of gestation in order to diagnose and effectively manage GDM; they also state that women with additional risk factors should be screened earlier (ie, in the first trimester) and retested at 24 to 28 weeks, if the initial test is negative. These guidelines describe similar risk factors for GDM and suggest the same thresholds for the diagnosis of GDM when using a 75-g 2-hour oral glucose tolerance test. Of note, the NICE only assesses the fasting and the 2-hour postprandial glucose levels for the diagnosis of GDM. Moreover, the SOGC and the ACOG do not recommend this test as the optimal screening method. The Endocrine Society alone, on the other hand, recommends the universal testing of all pregnant women for diabetes before 13 weeks of gestation or as soon as they attend the antenatal service and retesting at 24 to 28 weeks if the initial results are normal. In addition, there is a general consensus on the appropriate ultrasound surveillance of pregnancies complicated with GDM, and all the medical societies, except the ADIPS, recommend self-monitoring of capillary glucose to assess the glycemic control and set the same targets for fasting and postprandial glucose levels. There is also agreement that lifestyle modifications should be the first-line treatment; however, the reviewed guidelines disagree on the medical management of GDM. In addition, there are controversies regarding the timing of delivery, the utility of hemoglobin A_1c measurement, and the postpartum and lifelong screening for persistent hyperglycemia and type 2 diabetes. However, all the guidelines state that all women in pregnancies complicated by GDM should undergo a glycemic test at around 6 to 12 weeks after delivery. Finally, there is a universal consensus on the importance of breastfeeding and preconception screening before future pregnancies.

Conclusions

As GDM is an increasingly common complication of pregnancy, it is of paramount importance that inconsistencies between national and international guidelines should encourage research to resolve the issues of controversy and allow uniform international protocols for the diagnosis and management of GDM, in order to safely guide clinical practice and subsequently improve perinatal and maternal outcomes.

Noninvasive Fetal Genotyping by Droplet Digital PCR to Identify Maternally Inherited Monogenic Diabetes Variants

BACKGROUND

Babies of women with heterozygous pathogenic glucokinase (GCK) variants causing mild fasting hyperglycemia are at risk of macrosomia if they do not inherit the variant. Conversely, babies who inherit a pathogenic hepatocyte nuclear factor 4α (HNF4A) diabetes variant are at increased risk of high birth weight. Noninvasive fetal genotyping for maternal pathogenic variants would inform pregnancy management.

METHODS

Droplet digital PCR was used to quantify reference and variant alleles in cell-free DNA extracted from blood from 38 pregnant women heterozygous for a GCK or HNF4A variant and to determine fetal fraction by measurement of informative maternal and paternal variants. Droplet numbers positive for the reference/alternate allele together with the fetal fraction were used in a Bayesian analysis to derive probability for the fetal genotype. The babies' genotypes were ascertained postnatally by Sanger sequencing.

RESULTS

Droplet digital PCR assays for GCK or HNF4A variants were validated for testing in all 38 pregnancies. Fetal fraction of ≥2% was demonstrated in at least 1 cell-free DNA sample from 33 pregnancies. A threshold of ≥0.95 for calling homozygous reference genotypes and ≤0.05 for heterozygous fetal genotypes allowed correct genotype calls for all 33 pregnancies with no false-positive results. In 30 of 33 pregnancies, a result was obtained from a single blood sample.

CONCLUSIONS

This assay can be used to identify pregnancies at risk of macrosomia due to maternal monogenic diabetes variants.

Universal late pregnancy ultrasound screening to predict adverse outcomes in nulliparous women: a systematic review and cost-effectiveness analysis

BACKGROUND

Currently, pregnant women are screened using ultrasound to perform gestational aging, typically at around 12 weeks' gestation, and around the middle of pregnancy. Ultrasound scans thereafter are performed for clinical indications only.

OBJECTIVES

We sought to assess the case for offering universal late pregnancy ultrasound to all nulliparous women in the UK. The main questions addressed were the diagnostic effectiveness of universal late pregnancy ultrasound to predict adverse outcomes and the cost-effectiveness of either implementing universal ultrasound or conducting further research in this area.

DESIGN

We performed diagnostic test accuracy reviews of five ultrasonic measurements in late pregnancy. We conducted cost-effectiveness and value-of-information analyses of screening for fetal presentation, screening for small for gestational age fetuses and screening for large for gestational age fetuses. Finally, we conducted a survey and a focus group to determine the willingness of women to participate in a future randomised controlled trial.

DATA SOURCES

We searched MEDLINE, EMBASE and the Cochrane Library from inception to June 2019.

REVIEW METHODS

The protocol for the review was designed a priori and registered. Eligible studies were identified using keywords, with no restrictions for language or location. The risk of bias in studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool. Health economic modelling employed a decision tree analysed via Monte Carlo simulation. Health outcomes were from the fetal perspective and presented as quality-adjusted life-years. Costs were from the perspective of the public sector, defined as NHS England, and the costs of special educational needs. All costs and quality-adjusted life-years were discounted by 3.5% per annum and the reference case time horizon was 20 years.

RESULTS

Umbilical artery Doppler flow velocimetry, cerebroplacental ratio, severe oligohydramnios and borderline oligohydramnios were all either non-predictive or weakly predictive of the risk of neonatal morbidity (summary positive likelihood ratios between 1 and 2) and were all weakly predictive of the risk of delivering a small for gestational age infant (summary positive likelihood ratios between 2 and 4). Suspicion of fetal macrosomia is strongly predictive of the risk of delivering a large infant, but it is only weakly, albeit statistically significantly, predictive of the risk of shoulder dystocia. Very few studies blinded the result of the ultrasound scan and most studies were rated as being at a high risk of bias as a result of treatment paradox, ascertainment bias or iatrogenic harm. Health economic analysis indicated that universal ultrasound for fetal presentation only may be both clinically and economically justified on the basis of existing evidence. Universal ultrasound including fetal biometry was of borderline cost-effectiveness and was sensitive to assumptions. Value-of-information analysis indicated that the parameter that had the largest impact on decision uncertainty was the net difference in cost between an induced delivery and expectant management.

LIMITATIONS

The primary literature on the diagnostic effectiveness of ultrasound in late pregnancy is weak. Value-of-information analysis may have underestimated the uncertainty in the literature as it was focused on the internal validity of parameters, which is quantified, whereas the greatest uncertainty may be in the external validity to the research question, which is unquantified.

CONCLUSIONS

Universal screening for presentation at term may be justified on the basis of current knowledge. The current literature does not support universal ultrasonic screening for fetal growth disorders.

FUTURE WORK

We describe proof-of-principle randomised controlled trials that could better inform the case for screening using ultrasound in late pregnancy.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42017064093.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 15. See the NIHR Journals Library website for further project information.

Gestational Diabetes: Overview with Emphasis on Medical Management

With the rising trend in obesity, the incidence of gestational diabetes mellitus (GDM) and perinatal complications associated with the condition are also on the rise. Since the early 1900s, much knowledge has been gained about the diagnosis, implications, and management of gestational diabetes with improved outcomes for the mother and fetus. Worldwide, there is variation in the definition of GDM, methods to screen for the condition, and management options. The International Association of Diabetes in Pregnancy Study Groups has published recommendations for a one-step approach to screen pregnant women for GDM, in order to develop outcome-based criteria that can be used internationally. However, management of GDM continues to be varied, and currently several options are available for treatment of hyperglycemia during pregnancy. A review of various aspects of GDM is discussed with a focus on the medical management during pregnancy, as practiced in the United States.

ADIPS 2020 guideline for pre-existing diabetes and pregnancy

This is the full version of the Australasian Diabetes in Pregnancy Society (ADIPS) 2020 guideline for pre-existing diabetes and pregnancy. The guideline encompasses the management of women with pre-existing type 1 diabetes and type 2 diabetes in relation to pregnancy, including preconception, antepartum, intrapartum and postpartum care. The management of women with monogenic diabetes or cystic fibrosis-related diabetes in relation to pregnancy is also discussed.

First trimester fasting plasma glucose screen in advanced maternal age women: a cost-effectiveness analysis

BACKGROUND

The prevalence of preexisting type 2 diabetes mellitus (T2DM) in the United States is on the rise. Women of advanced maternal age (AMA, ≥35 years) are more likely to have preexisting T2DM in pregnancy because glucose intolerance increases with age. Diabetes in pregnancy is associated with significant maternal and neonatal morbidity and mortality, and earlier treatment initiation improves pregnancy outcomes. However, maternal age is not currently recognized as an independent risk factor that warrants diabetes screening prior to the traditional screen at 24-28 weeks gestation.

OBJECTIVE

To evaluate the cost-effectiveness of screening all AMA women with a first trimester fasting plasma glucose (FPG) test for earlier diagnosis and management of preexisting T2DM.

STUDY DESIGN

A decision-analytic model was created to compare pregnancy outcomes in AMA women who undergo a first trimester FPG test vs third trimester oral glucose tolerance test alone. Probabilities were obtained from the literature. Outcomes examined included preeclampsia, preterm delivery, macrosomia, shoulder dystocia, brachial plexus injury (BPI), intrauterine fetal demise (IUFD), cerebral palsy, and neonatal death. The cost, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratio of the first trimester screening strategy were examined as well. Sensitivity analyses and a Monte Carlo simulation were performed to test the model's robustness.

RESULTS

In AMA women, screening for preexisting T2DM in the first trimester with an FPG test resulted in fewer cases of preeclampsia, preterm delivery, BPI, IUFD, cerebral palsy, and neonatal death compared to performing a third trimester oral glucose tolerance test alone, and is cost-effective. Monte Carlo analysis incorporating the distribution of all probabilities showed that first trimester FPG screening remained cost-effective as long as the incremental cost of initiating diabetes treatment in the first trimester was less than $150,000 and the cost of the FPG screen was less than $2700.

CONCLUSION

Compared to third trimester oral glucose tolerance test alone, performing a first trimester FPG screen in AMA women is cost-saving and more effective.

Antenatal awareness and obstetric outcomes in large fetuses: A retrospective evaluation

INTRODUCTION

There is currently no consensus on the management of large fetuses in order to minimize fetal complications. The aim of this study was to assess whether antenatal recognition of large-for-gestational age (LGA) reduced poor obstetric newborn outcomes in a hospital where expectant management was used.

MATERIAL AND METHODS

A retrospective cohort study was made of two delivery units at Karolinska University Hospital, Stockholm, Sweden, using expectant management of LGA. All deliveries > 37⁺⁰ weeks of gestation during an 8-year period (2002-2009) were included. The main outcome was severe adverse outcome, a composite variable including neonatal trauma (brachial plexus birth palsy [BPBP] and fractures) and asphyxic sequelae (severe asphyxia, cerebral damage, and fetal/infant death).

RESULTS

The study population consisted of 63,542 appropriate-for-gestational age (AGA) and 3,343 LGA pregnancies (of which 21 % were identified before delivery). Compared to AGA, LGA pregnancies showed a five-fold increased risk of neonatal trauma (OR 5.1, 95 % CI 4.0 - 6.4), but no differences were seen regarding asphyxic sequelae. LGA fetuses identified antenatally had adverse outcomes in 3.7 % of all cases, compared to 3.5 % where LGA was not identified (OR 1.07 95 % CI 0.7 - 1.7). When adjusted for newborn weight deviation, the OR was 0.96, 95 % CI 0.6 - 1.5. There was a three-fold higher risk (OR 3.0, 95 % CI 1.2 - 7.4) of neonatal trauma among non-identified LGA cases > 41⁺⁰ gestational weeks. A total of 81 % of those with LGA were identified after a week 41 routine ultrasound. Out of 68 cases with planned vaginal delivery and expected birth weight > 5000 g, 7.4 % suffered BPBP, representing a 31-fold increase in risk, compared to 0% BPBP among those delivered by elective caesarean section.

CONCLUSION

Antenatal awareness of LGA did not lower the risk of severe adverse outcomes in a unit using expectant management, but those identified postdate were at a lower risk of neonatal trauma. For every 14 fetuses with an expected birth weight > 5000 g delivered by cesarean section, one case of BPBP could be avoided.

What is known and what remains unresolved regarding gestational diabetes mellitus (GDM)

Gestational diabetes mellitus (GDM) has become a major public health issue and one of the most discussed topics in contemporary obstetrics. Due to rising prevalence of GDM worldwide impact and importance of this medical condition in good quality antenatal care is growing. GDM is associated with serious adverse perinatal outcomes and unfavorable long-term health consequences for both, mother and her child. Despite a great amount of knowledge accumulated regarding GDM, medical community remains indecisive and still debates the most appropriate diagnostic strategy, screening policy, and treatment options for pregnancies complicated with GDM. These unresolved issues generate controversies, motivate further research and contribute to the growing interest surrounding GDM. In this review we will discuss and try to explain some of them.

Management of Birth Brachial Plexus Injury Including Use of Distal Nerve Transfers

Birth Brachial plexus injury continues to remain a problem despite significant care from obstetricians to prevent it. Many children show spontaneous recovery but a significant proportion do not have adequate recovery. This review article discusses, etiology, assessment, investigations and overall strategy to treat the condition. Surgical strategy consists of primary intraplexal repair as the standard of care but of late the distal nerve transfers used in adult plexus injuries are increasingly being used in infants too. We discuss the history, current usage and pros and cons of distal nerve transfers, the usage of Botulinum Toxin and finally given an overall algorithm for the management.

Risk factors associated with neonatal brachial plexus palsy in the United States

Neonatal brachial plexus palsy (NBPP) is a birth injury that can cause severe functional loss in the affected limb. The purpose of this study was to determine the temporal changes in the national incidence of this condition and whether associated risk factors have changed over time. Children born via vaginal delivery were identified in the Kids' Inpatient Database (KID) from 1997 to 2012, and those with NBPP were identified. The trend in incidence and risk factors were assessed through the study period. The nationwide incidence of NBPP decreased during the study period. Infants with shoulder dystocia, fetal macrosomia, and gestational diabetes had the highest risk of developing NBPP, while multiple birth mates during delivery had a protective effect. Multiple risk factors, including shoulder dystocia, macrosomia, and heavy for dates became less predictive of the development of NBPP over time. Several risk factors predispose children to the development of NBPP, and the effect of these risk factors has been changing. This information can guide obstetric treatment to help prevent NBPP. Level of evidence is diagnostic, level 3.

Risk factors for neonatal brachial plexus palsy: a systematic review and meta-analysis

AIM

To provide a comprehensive update on the most prevalent, significant risk factors for neonatal brachial plexus palsy (NBPP).

METHOD

Cochrane CENTRAL, MEDLINE, Web of Science, Embase, and ClinicalTrials.gov were searched for relevant publications up to March 2019. Studies assessing risk factors of NBPP in relation to typically developing comparison individuals were included. Meta-analysis was performed for the five most significant risk factors, on the basis of the PRISMA statement and MOOSE guidelines. Pooled odds ratios (ORs), 95% confidence intervals (CIs), and across-study heterogeneity (I² ) were reported. Reporting bias and quality of evidence was rated. In addition, we assessed the incidence of NBPP.

RESULTS

Twenty-two observational studies with a total sample size of 29 419 037 live births were selected. Significant risk factors included shoulder dystocia (OR 115.27; 95% CI 81.35-163.35; I² =92%), macrosomia (OR 9.75; 95% CI 8.29-11.46; I² =70%), (gestational) diabetes (OR 5.33; 95% CI 3.77-7.55; I² =59%), instrumental delivery (OR 3.8; 95% CI 2.77-5.23; I² =77%), and breech delivery (OR 2.49; 95% CI 1.67-3.7; I² =70%). Caesarean section appeared as a protective factor (OR 0.13; 95% CI 0.11-0.16; I² =41%). The pooled overall incidence of NBPP was 1.74 per 1000 live births. It has decreased in recent years.

INTERPRETATION

The incidence of NBPP is decreasing. Shoulder dystocia, macrosomia, maternal diabetes, instrumental delivery, and breech delivery are risk factors for NBPP. Caesarean section appears as a protective factor.

WHAT THIS PAPER ADDS

The overall incidence of neonatal brachial plexus palsy is 1.74 per 1000 live births. The incidence has declined significantly. Shoulder dystocia, macrosomia, maternal diabetes, instrumental delivery, and breech delivery are the main risk factors. Prevention is difficult owing to unpredictability and often labour-related risk.

Pregestational diabetes in pregnancy: Complications, management, surveillance, and mechanisms of disease-A review

Diabetes is an increasingly common diagnosis among pregnant women. Pregestational diabetes is associated with an increase in many adverse pregnancy outcomes, which impact both on the woman and her fetus. The models of pregnancy care for women with diabetes are based largely on observational data or consensus opinion. Strategies for aneuploidy screening and monitoring for fetal well-being should be modified in women with diabetes. There is an increasing understanding of the mechanisms by which congenital anomalies and disorders of fetal growth occur, involving epigenetic modifications, changes in gene expression in critical developmental pathways, and oxidative stress. This knowledge may lead to pathways for improved care for these high-risk pregnancies.

Identification of newborns with birthweight ≥ 4,500g: Ultrasound within one- vs. two weeks of delivery

OBJECTIVE

Our objective was to compare the diagnostic characteristics of sonographic estimated fetal weight (SEFW) done within 7 versus 8-14 days before delivery for detection of fetal macrosomia (birthweight ≥ 4500 g).

STUDY DESIGN

We performed a multicenter, retrospective cohort study of all non-anomalous singletons with SEFW ≥ 4000 g by Registered Diagnostic Medical Sonographers conducted within 14 days of delivery. Cohorts were grouped by time interval between ultrasound and delivery: 0-7 days versus 8-14 days. The detection rate (DR) and false positive rate (FPR) for detection of birthweight (BW) ≥ 4500 g were compared between groups with subgroup analysis for diabetic women. Area under the receiver operator curve (AUC) was calculated to analyze all possible SEFW cutoffs within our cohort.

RESULTS

A total of 330 patients met inclusion criteria with 250 (75.8 %) having SEFW within 7 days and 80 (24.2 %) with SEFW 8-14 days prior to delivery. The rate of macrosomia was 15.1 % (N = 51). The DR for macrosomia was significantly higher when SEFW was performed within 7 days of delivery compared to 8-14 days among non-diabetic (73.0 % vs 7.1 %; p < 0.001) and diabetic women (76.5 % vs 16.7 %; p = 0.02). There was no significant change in FPR in either group. The AUC for detection of macrosomia was significantly higher when SEFW was performed within 7 days versus 8-14 days (0.89 vs 0.63; p < 0.01).

CONCLUSION

With SEFW ≥ 4000 g, the detection of BW ≥ 4500 g is significantly higher when the sonographic examination is within 7 days of birth irrespective of maternal diabetes.

Management of Gestational Diabetes Mellitus

Once a woman is diagnosed with gestational diabetes mellitus (GDM), two strategies are considered for management; life-style modifications and pharmacological therapy. The management of GDM aims to maintain a normoglycemic state and to prevent excessive weight gain in order to reduce maternal and fetal complications. Lifestyle modifications include nutritional therapy and exercise. Calorie restriction with a low glycemic index diet is recommended to avoid postprandial hyperglycemia and to reduce insulin resistance. Blood glucose levels, HbA1c levels, and ketonuria are monitored to analyze the efficacy of conservative management. Pharmacological treatment is initiated if conservative strategies fail to provide expected glucose levels during follow-ups.Insulin has been the first choice for the treatment of diabetes during pregnancy. Recently, metformin has been used more commonly in diabetic pregnant women in cases when insulin cannot be prescribed, after its safety has been proven. However, a high percentage of women, which may be up to 46% may require additional insulin to maintain expected blood glucose levels. The evidence on the long-term safety of other oral anti-diabetics has been lacking yet.Women with diet-controlled GDM can wait for spontaneous labor expectantly in case there are no obstetric indications for birth. However, in women with GDM under insulin therapy or with poor glycemic control, elective induction at term is recommended by authorities.The women who have GDM during pregnancy should be counseled about their increased risks of impaired glucose tolerance, type 2 diabetes mellitus, hypertensive disorders, cardiovascular diseases, and metabolic syndrome.

The cost-effectiveness of universal late-pregnancy screening for macrosomia in nulliparous women: a decision analysis

Objective

To identify the most cost‐effective policy for detection and management of fetal macrosomia in late‐stage pregnancy.

Design

Health economic simulation model.

Setting

All English NHS antenatal services.

Population

Nulliparous women in the third trimester treated within the UK NHS.

Methods

A health economic simulation model was used to compare long‐term maternal–fetal health and cost outcomes for two detection strategies (universal ultrasound scanning at approximately 36 weeks of gestation versus selective ultrasound scanning), combined with three management strategies (planned caesarean section versus induction of labour versus expectant management) of suspected fetal macrosomia. Probabilities, costs and health outcomes were taken from literature.

Main outcome measures

Expected costs to the NHS and quality‐adjusted life‐years (QALYs) gained from each strategy, calculation of net benefit and hence identification of most cost‐effective strategy.

Results

Compared with selective ultrasound, universal ultrasound increased QALYs by 0.0038 (95% CI 0.0012–0.0076), but also costs by £123.50 (95% CI 99.6–149.9). Overall, the health gains were too small to justify the cost increase given current UK thresholds cost‐effective policy was selective ultrasound coupled with induction of labour where macrosomia was suspected.

Conclusions

The most cost‐effective policy for detection and management of fetal macrosomia is selective ultrasound scanning coupled with induction of labour for all suspected cases of macrosomia. Universal ultrasound scanning for macrosomia in late‐stage pregnancy is not cost‐effective.

Tweetable abstract

Universal late‐pregnancy ultrasound screening for fetal macrosomia is not warranted.

Universal late‐pregnancy ultrasound screening for fetal macrosomia is not warranted.

Updates in Gestational Diabetes Prevalence, Treatment, and Health Policy

PURPOSE OF REVIEW

Gestational diabetes (GDM) is associated with adverse pregnancy and neonatal outcomes and increased maternal risk for subsequent type 2 diabetes. The best diagnostic strategy for GDM is debated and the role of oral antidiabetic medications (OAD) for treatment is unclear. In this paper, we review methods of GDM diagnosis, updates in GDM therapy, and interventions to reduce future type 2 diabetes in women with a history of GDM.

RECENT FINDINGS

A "one-step" screening protocol for GDM using 75-g, 2-h oral glucose tolerance testing at 24-28 weeks gestation is recommended by the International Association of the Diabetes and Pregnancy Study Groups, the American Diabetes Association, and the Endocrine Society. This strategy identifies a milder degree of hyperglycemia and thus increases GDM prevalence. Studies indicate that in these cases of mild hyperglycemia, treatment decreases pregnancy and neonatal complications. Insulin analogues including detemir, aspart, and lispro have been shown to be safe in pregnancy with a pregnancy category B classification. Growing literature suggests that sulfonylureas cross the placenta and are associated with increased incidence of macrosomia and neonatal hypoglycemia. Telephone or online diabetes prevention program (DPP)-based interventions for women with GDM have shown encouraging results in pilot studies. Insurance coverage remains a barrier. Additional studies are needed to determine the safety of OAD in pregnancy. Public policy supporting DPP could help improve patient access to these proven interventions.

Protocol for the prospective observational clinical study: estimation of fetal weight by MRI to PREdict neonatal MACROsomia (PREMACRO study) and small-for-gestational age neonates

INTRODUCTION

Macrosomia refers to growth beyond a specific threshold, regardless of gestational age. These fetuses are also frequently referred to as large for gestational age (LGA). Various cut-offs have been used but for research purposes, a cut-off above the 95th centile for birth weight is often preferred because it defines 90% of the population as normal weight. The use of centiles, rather than estimated weights, also accommodates preterm macrosomic infants, although most of the complications, maternal and fetal, arise during the delivery of large babies at term. This means that accurate identification of LGA fetuses (≥95th centile) may play an important role in guiding obstetric interventions, such as induction of labour or caesarean section. Traditionally, identification of fetuses suspected of macrosomia has been based on biometric measurements using two-dimensional (2D) ultrasound (US), yet this method is rather sub-optimal. We present a protocol (V.2.1, date 19 May 2016) for the estimation of fetal weight (EFW) by MRI to PREdict neonatal MACROsomia (PREMACRO study), which is a prospective observational clinical study designed to determine whether MRI at 36 + 0 to 36 + 6 weeks of gestation, as compared with 2D US, can improve the identification of LGA neonates ≥95th centile.

METHODS AND ANALYSIS

All eligible women attending the 36-week clinic will be invited to participate in the screening study for LGA fetuses ≥95th centile and will undergo US-EFW and MRI-EFW within minutes of each other. From these estimations, a centile will be derived which will be compared with the centile of birth weight used as the gold standard. Besides birth weight, other pregnancy and neonatal outcomes will be collected and analysed. The first enrolment for the study was in May 2016. As of September 2018, 2004 women have been screened and recruited to the study. The study is due to end in April 2019.

ETHICS AND DISSEMINATION

The study will be conducted in accordance with the International Conference on Harmonisation for good clinical practice and the appropriate regulatory requirement(s). A favourable ethical opinion was obtained from the Ethics Committee of the University Hospital Brugmann, reference number CE2016/44. Results will be published in peer-reviewed journals and disseminated at international conferences.

TRIAL REGISTRATION NUMBER

NCT02713568.

A modified model can improve the accuracy of foetal weight estimation by magnetic resonance imaging

PURPOSE

To determine whether birth weight can be reliably estimated using three-dimensional (3D) magnetic resonance imaging (MRI) foetal body volume at term.

METHOD

Foetuses between 37⁺⁵ weeks and 41 weeks of gestation were delivered within 7 days after MRI and ultrasound (US) examinations. 3D foetal models were reconstructed from MRI data, and body volume was calculated. The MRI-based weight estimations were calculated using the Baker equation and the modified Baker equation with a higher density coefficient. The US-based weight estimations were determined using the formula by Hadlock. Estimations based on MRI and US were compared with the birth weights.

RESULTS

Among 22 foetuses that underwent both US and MRI evaluations within 48 h before labour, the mean random errors for the estimated weight based on US, the Baker equation and the modified Baker equation were 6.5%, 4.8%, and 4.8%, respectively, and these methods correctly estimated the weights of 77.3%, 86.4% and 100% of the foetuses to within 10% of the actual birth weight. The weights of 95.5% of the foetuses were underestimated by the Baker equation. Similar findings were observed among 103 estimations based on both US and MRI within 7 days before delivery. The mean relative error of the MRI-determined estimate of foetal weight using the modified Baker equation was not significantly associated with foetal sex, birth weight, gestational age at MRI examination, the MRI-to-delivery interval or the type of MRI scanner.

CONCLUSION

A modified Baker equation with a high-density coefficient can improve the accuracy of foetal weight estimation based on 3D MRI foetal volume at term, and its accuracy was not significantly affected by foetal characteristics or the type of MRI scanner among births occurring within 7 days after examinations.

ACOG Practice Bulletin No. 190: Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is one of the most common medical complications of pregnancy. However, debate continues to surround the diagnosis and treatment of GDM despite several recent large-scale studies addressing these issues. The purposes of this document are the following: 1) provide a brief overview of the understanding of GDM, 2) review management guidelines that have been validated by appropriately conducted clinical research, and 3) identify gaps in current knowledge toward which future research can be directed.

Prenatal prediction of postnatal large-for-dates neonates using a simplified MRI method: comparison with conventional 2D ultrasound estimates

OBJECTIVE

To evaluate the performance of a simple semi-automated method for estimation of fetal weight (EFW) using magnetic resonance imaging (MRI) as compared with two-dimensional (2D) ultrasound (US) for the prediction of large-for-dates neonates.

METHODS

Data of two groups of women with singleton pregnancy between March 2011 and May 2016 were retrieved from our database and evaluated retrospectively: the first group included women who underwent US-EFW and MRI-EFW within 48 h before delivery and the second group included women who had these evaluations between 35 + 0 weeks and 37 + 6 weeks of gestation, more than 48 h before delivery. US-EFW was based on Hadlock et al. and MRI-EFW on the formula described by Baker et al. For MRI-EFW, planimetric measurement of the fetal body volume (FBV) was performed using a semi-automated method and the time required for measurement was noted. Outcome measure was the performance of MRI-EFW vs US-EFW in the prediction of large-for-dates neonates, both ≤ 48 h and > 48 h before delivery. Receiver-operating characteristics (ROC) curves for each method were compared using the DeLong method.

RESULTS

Of the 270 women included in the first group, 48 (17.8%) newborns had birth weight ≥ 90^th centile and 30 (11.1%) ≥ 95^th centile. The second group included 83 women, and nine (10.8%) newborns had birth weight ≥ 95^th centile. Median time needed for FBV planimetric measurements in all 353 fetuses was 3.5 (range, 1.5-5.5) min. The area under the ROC curve (AUC) for prediction of large-for-dates neonates by prenatal MRI performed within 48 h before delivery was significantly higher than that by US (for birth weight ≥ 90^th centile, difference between AUCs = 0.085, standard error (SE) = 0.020, P < 0.001; for birth weight ≥ 95^th centile, difference between AUCs = 0.036, SE = 0.014, P = 0.01). Similarly, MRI-EFW was better than US-EFW in predicting birth weight ≥ 95^th centile when both examinations were performed > 48 h prior to delivery (difference between AUCs = 0.077, SE = 0.039, P = 0.045).

CONCLUSION

MRI planimetry using our purpose-designed semi-automated method is not time-consuming. The predictive performance of MRI-EFW performed immediately prior to or remote from delivery is significantly better than that of US-EFW for the prediction of large-for-dates neonates. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Universal vs selective ultrasonography to screen for large-for-gestational-age infants and associated morbidity

OBJECTIVES

To compare the diagnostic effectiveness of selective vs universal ultrasonography as a screening test for large-for-gestational-age (LGA) infants, and to determine whether previously described ultrasound markers of excessive fetal growth could identify suspected LGA fetuses that are at increased risk of adverse neonatal outcome.

METHODS

Data from the Pregnancy Outcome Prediction study, a prospective cohort study of nulliparous women with a viable singleton pregnancy at the time of the dating ultrasound scan, were analyzed. Women were selected for clinically indicated ultrasound assessment in the third trimester as per routine clinical care, and the results of these scans were reported ('selective ultrasonography'). In addition, all participants underwent research ultrasound scans, including estimated fetal weight (EFW) assessment, at around 36 weeks' gestation, in which both the women and their clinicians were blinded to the results ('universal ultrasonography'). Participants who attended the 36-week research scan and had a live birth at the Rosie Hospital were included in the study. Screen positive for LGA was defined as EFW > 90^th percentile at ≥ 34 weeks.

RESULTS

The current analysis included 3866 eligible women, of whom 1354 (35%) had a clinically indicated ultrasound scan at or after 34 weeks' gestation. A total of 177 (4.6%) infants had a birth weight > 90^th percentile. The sensitivity for detection of LGA infants was 27% for selective ultrasonography and 38% for universal ultrasonography. The specificity of both approaches was high (99% and 97%, respectively). Using universal ultrasonography, neonatal outcome differed (P for interaction) by abdominal circumference growth velocity (ACGV) for both any neonatal morbidity (P = 0.08) and severe adverse neonatal outcome (P = 0.03). LGA fetuses with increased ACGV had a relative risk of any neonatal morbidity of 2.0 (95% CI, 1.1-3.6; P = 0.04) and of severe adverse neonatal outcome of 6.5 (95% CI, 2.0-21.1; P = 0.01), whereas LGA fetuses with normal ACGV were not at increased risk.

CONCLUSIONS

Third-trimester screening of nulliparous women by universal ultrasound fetal biometry increases the detection rate of LGA infants and, combined with ACGV, identifies those at increased risk of adverse neonatal outcome. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Sonographic Examination of The Fetus Vis-à-Vis Shoulder Dystocia: A Vexing Promise

Since antepartum and intrapartum risk factors are poor at identifying women whose labor is complicated by shoulder dystocia, sonographic examination of the fetus holds promise. Though there are several measurements of biometric parameters to identify the parturient who will have shoulder dystocia, none are currently clinically useful. Three national guidelines confirm that sonographic measurements do not serve as appropriate diagnostic tests to identify women who will have shoulder dystocia with or without concurrent injury. In summary, biometric measurements of the fetus should not be used to alter clinical management with the aim of averting shoulder dystocia.

Accelerated fetal growth in early pregnancy and risk of severe large-for-gestational-age and macrosomic infant: a cohort study in a low-risk population

INTRODUCTION

Our objective was to examine the association between fetal growth in early pregnancy and risk of severe large-for-gestational-age (LGA) and macrosomia at birth in a low-risk population.

MATERIAL AND METHODS

Cohort study that included 68 771 women with non-anomalous singleton pregnancies, without history of diabetes or hypertension, based on an electronic database on pregnancies and deliveries in Stockholm-Gotland Region, Sweden, 2008-2014. We performed multivariable logistic regression to estimate the association between accelerated fetal growth occurring in the first through early second trimester as measured by ultrasound and LGA and macrosomia at birth. Restricted analyses were performed in the groups without gestational diabetes and with normal body mass index (18.5-24.9 kg/m² ).

RESULTS

When adjusting for confounders, the odds of having a severely LGA or macrosomic infant were elevated in mothers with fetuses that were at least 7 days larger than expected as compared with mothers without age discrepancy at the second-trimester scan (adjusted odds ratio 1.80; 95% CI 1.23-2.64 and adjusted odds ratio 2.15; 95% CI 1.55-2.98, respectively). Additionally, mothers without gestational diabetes and mothers with normal weight had an elevated risk of having a severely LGA or macrosomic infant when the age discrepancy by second-trimester ultrasound was at least 7 days.

CONCLUSIONS

In a low-risk population, ultrasound-estimated accelerated fetal growth in early pregnancy was associated with an increased risk of having a severely LGA or macrosomic infant.

Practice Bulletin No. 173: Fetal Macrosomia

Suspected fetal macrosomia is encountered commonly in obstetric practice. As birth weight increases, the likelihood of labor abnormalities, shoulder dystocia, birth trauma, and permanent injury to the neonate increases. The purpose of this document is to quantify those risks, address the accuracy and limitations of methods for estimating fetal weight, and suggest clinical management for a pregnancy with suspected fetal macrosomia.

Pregnancy outcomes in relation to different types of diabetes mellitus and modes of delivery in macrosomic foetuses in Bahrain

Objectives

The mode of delivery in diabetic patients is debatable. This study was designed to assess the pattern of delivery of macrosomic babies with a high prevalence of diabetes mellitus in Bahrain.

Methods

This retrospective analysis was conducted on mothers who delivered babies weighing ≥4.0 Kgs from 2001 to 2011 at Bahrain Defence Force Hospital. Data regarding patients' age, weight, mode of delivery, diabetic status, gestational age and parity were recorded. The main outcome was the effect of diabetes mellitus on the decision to allow vaginal delivery for macrocosmic babies. Other outcomes were failed trial of labour, parity, maternal age and foetal weight on the trial of labour and neonatal morbidity associated with vaginal births.

Results

The incidence of macrosomic babies was 2.2% of total births. Pre-existing diabetes mellitus was 3.9% of the study cohort. The rate of elective Caesarean section increased from 12.5% in non-diabetic mothers to 50% in patients with pre-existing diabetes. In cases of allowing a trial of labour, approximately 70% of patients with pre-existing diabetes had successful vaginal delivery. Patients with a previous delivery were less likely to undergo emergency procedures, but had the same probability for elective Caesarean compared with primigravida. Patient's age and foetal weight had no influence on successful trial of vaginal birth.

Conclusions

There was a trend to offer more elective Caesarean sections in patients with macrosomic babies in the presence of pre-existing diabetes. The majority of patients who were offered a trial of labour achieved vaginal delivery with minimal morbidity.

Implications of maternal obesity on fetal growth and the role of ultrasound

Over fifty percent of women entering pregnancy are overweight or obese. This has a significant impact on short and long term maternal and infant health outcomes, and the intergenerational effects of obesity are now a major public health problem globally. Areas covered: There are two major pathways contributing to fetal growth. Glucose and insulin directly affect growth, while other substrates such as leptin, adiponectin and insulin-like growth factors indirectly influence growth through structural and morphological effects on the placenta, uteroplacental blood flow, and regulation of placental transporters. Advances in ultrasonography over the past decade have led to interest in the prediction of the fetus at risk of overgrowth and adiposity utilizing both standard ultrasound biometry and fetal body composition measurements. However, to date there is no consensus regarding the definition of fetal overgrowth, its reporting, and clinical management. Expert commentary: Maternal dietary intervention targeting the antenatal period appear to be too late to sufficiently affect fetal growth. The peri-conceptual period and early pregnancy are being evaluated to determine if the intergenerational effects of maternal obesity can be altered to improve newborn, infant and child health.

A multistate population-based analysis of linked maternal and neonatal discharge records to identify risk factors for neonatal brachial plexus injury

OBJECTIVE

To evaluate the interaction and contribution of maternal and fetal risk factors associated with neonatal brachial plexus injury (BPI).

METHODS

In a case-control study, matched maternal and neonatal discharge records were accessed from US State Inpatient Databases for New Jersey (2010-2012), Michigan (2010-2011), and Hawaii (2010-2011). Univariate and multivariate logistic regressions were used to evaluate associations between risk factors and BPI. Area under the receiver operating characteristic curve was used to build predictive models, including two stratified models evaluating deliveries among obese and diabetic cohorts.

RESULTS

Among 376 325 deliveries, BPI was diagnosed in 274 (0.1%). Significant BPI risk factors included maternal obesity (odds ratio [OR] 2.7, 95% confidence interval [CI] 1.7-4.4), maternal diabetes (OR 4.6, 95% CI 3.0-7.0), use of forceps (OR 4.6, 95% CI 2.3-9.0), and vacuum assistance (OR 2.3, 95% CI 1.7-3.3). After adjusting for shoulder dystocia and other predictive factors, cesarean reduced the risk of BPI by 88% (OR 0.1, 95% CI 0.07-0.2). When stratified by obesity and diabetes, the ORs for BPI increased significantly for macrosomia, forceps, and vacuum assistance.

CONCLUSION

The analysis confirms and quantifies more precisely the impact of risk factors for neonatal BPI, and provides a reliable basis for evidence-based clinical decision-making models.

Recurrent Shoulder Dystocia: Risk Factors and Counseling

A prior history of delivery complicated by shoulder dystocia confers a 6-fold to nearly 30-fold increased risk of shoulder dystocia recurrence in a subsequent vaginal delivery, with most reported rates between 12% and 17%. Whereas prevention of shoulder dystocia in the general population is neither feasible nor cost-effective, directing intervention efforts at the particular subgroup of women with a prior history of shoulder dystocia has merit. Potentially modifiable risk factors and individualized management strategies that may reduce shoulder dystocia recurrence and its associated significant morbidities are reviewed.

Prediction of large-for-gestational-age neonates: screening by maternal factors and biomarkers in the three trimesters of pregnancy

OBJECTIVE

To develop a model based on maternal characteristics and medical history (maternal factors) for the prediction of delivery of large-for-gestational-age (LGA) neonates, and to examine the potential value of first-, second- and third-trimester fetal biometry and biomarkers in improving such a model.

METHODS

This was a screening study in 76 300, 54 999, 25 727 and 6181 singleton pregnancies at 11-13, 19-24, 30-34 and 35-37 weeks' gestation, respectively. The a-priori risk for LGA with birth weight > 95(th) percentile (LGA > 95(th) ) was calculated using multivariable logistic regression analysis to determine which of the maternal factors had a significant contribution. Regression analysis was then used to determine whether screening by a combination of maternal factors, fetal biometry and various biophysical and biochemical markers had significant contribution in predicting delivery of LGA neonates.

RESULTS

The likelihood of LGA > 95(th) increased with increasing maternal weight and height and was lower in women of Afro-Caribbean and South Asian racial origins, in cigarette smokers and in nulliparous women. The risk was higher in women with pre-existing diabetes mellitus Type I and lower in those with chronic hypertension. In parous women, the risk increased with birth-weight Z-score in previous pregnancy and prior history of gestational diabetes and decreased with interpregnancy interval. Screening by maternal factors at 11-13 weeks predicted 32%, 44% and 60% of LGA > 95(th) at false-positive rates (FPRs) of 5%, 10% and 20%, respectively. With the addition of fetal biometry, the detection rates improved to 37%, 51% and 68% at 19-24 weeks, 50%, 65% and 81% at 30-34 weeks and 60%, 73% and 85% at 35-37 weeks at FPRs of 5%, 10% and 20%, respectively. The addition of biomarkers did not improve the detection rates achieved when screening by a combination of maternal factors and fetal biometry.

CONCLUSION

Combined screening by maternal factors and fetal biometry can predict a high proportion of pregnancies that will deliver LGA neonates. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.