Early third-trimester ultrasound screening in gestational diabetes to determine the risk of macrosomia and labor dystocia at term

Food taboos during pregnancy: meta-analysis on cross cultural differences suggests specific, diet-related pressures on childbirth among agriculturalists

Pregnancy is the most delicate stage of human life history as well as a common target of food taboos across cultures. Despite puzzling evidence that many pregnant women across the world reduce their intake of nutritious foods to accomplish cultural norms, no study has provided statistical analysis of cross-cultural variation in food taboos during pregnancy. Moreover, antenatal practices among forager and agriculturalists have never been compared, despite subsistence mode being known to affect staple foods and lifestyle directly. This gap hinders to us from understanding the overall threats attributed to pregnancy, and their perceived nutritional causes around the world. The present study constitutes the first cross-cultural meta-analysis on food taboos during pregnancy. We examined thirty-two articles on dietary antenatal restrictions among agricultural and non-agricultural societies, in order to: (i) identify cross-culturally targeted animal, plant and miscellaneous foods; (ii) define major clusters of taboo focus; (iii) test the hypothesis that food types and clusters of focus distribute differently between agricultural and non-agricultural taboos; and (iv) test the hypothesis that food types distribute differently across the clusters of taboo focus. All data were analysed in SPSS and RStudio using chi-squared tests and Fisher's exact tests. We detected a gradient in taboo focus that ranged from no direct physiological interest to the fear of varied physiological complications to a very specific concern over increased birth weight and difficult delivery. Non-agricultural taboos were more likely to target non-domesticated animal foods and to be justified by concerns not directly linked to the physiological sphere, whereas agricultural taboos tended to targed more cultivated and processed products and showed a stronger association with concerns over increased birth weight. Despite some methodological discrepancies in the existing literature on food taboos during pregnancy, our results illustrate that such cultural traits are useful for detecting perception of biological pressures on reproduction across cultures. Indeed, the widespread concern over birth weight and carbohydrate rich foods overlaps with clinical evidence that obstructed labor is a major threat to maternal life in Africa, Asia and Eurasia. Furthermore, asymmetry in the frequency of such concern across subsistence modes aligns with the evolutionary perspective that agriculture may have exacerbated delivery complications. This study highlights the need for the improved understanding of dietary behaviors during pregnancy across the world, addressing the role of obstructed labor as a key point of convergence between clinical, evolutionary and cultural issues in human behavior.

Sonographic and other nonglycemic factors can predict large-for-gestational-age infants in diet-managed gestational diabetes mellitus: A retrospective cohort study

BACKGROUND

Gestational diabetes mellitus (GDM) is one of the most common complications of pregnancy. Left untreated or poorly controlled, GDM results in adverse infant outcomes such as large for gestational age (LGA). This study aims to identify nonglycemic maternal and fetal factors predictive of LGA outcomes in pregnancies complicated by diet-managed GDM.

METHODS

This was a retrospective cohort study of singleton pregnancies complicated by diet-managed GDM from 2004 to 2015. Multiple logistic regression analysis was performed on maternal and perinatal factors to identify risk factors for LGA. In addition, a subset univariate analysis was conducted for pregnancies in which fetal ultrasound abdominal circumference measurements were available at gestational weeks 18 to 22, 24 to 28, and 29 to 33.

RESULTS

A total of 1064 women were included, delivering 123 LGA infants. Women with higher parity (odds ratio [OR] 1.44; CI, 1.23-1.68; P < .001) and higher prepregnancy body mass index (BMI) (OR 1.09; CI, 1.06-1.12; P < .001) were more likely to have LGA infants. Maternal smoking (OR 0.30; CI, 0.14-0.62; P = .001) and higher gestational age at birth (OR 0.91; CI, 0.84-0.99; P = .018) were associated with reduced risk. Subset univariate analysis showed that fetal abdominal circumference measurements at weeks 24 to 28 and 29 to 33 beyond the 75th percentile (OR 5.92 and 13.74, respectively) and 90th percentile (OR 4.57 and 15.89, respectively) were highly predictive of LGA.

CONCLUSIONS

Parity, smoking status, maternal BMI, gestational age, and ultrasound fetal abdominal circumference measurements were identified as useful predictors of LGA. Presence of these predictors may prompt closer monitoring of pregnancy and early therapeutic intervention to improve management and reduce the risk of adverse fetal and maternal outcomes.

The test accuracy of antenatal ultrasound definitions of fetal macrosomia to predict birth injury: A systematic review

OBJECTIVES

To determine which ultrasound measurement for predicted fetal macrosomia most accurately predicts adverse delivery and neonatal outcomes.

STUDY DESIGN

Four biomedical databases searched for studies published after 1966. Randomised trials or observational studies of women with singleton pregnancies, resulting in a term birth who have undergone an index test of interest measured and recorded as predicted fetal macrosomia ≥28 weeks. Adverse outcomes of interest included shoulder dystocia, brachial plexus injury (BPI) and Caesarean section.

RESULTS

Twenty-five observational studies (13,285 participants) were included. For BPI, the only significant positive association was found for Abdominal Circumference (AC) to Head Circumference (HC) difference > 50 mm (OR 7.2, 95 % CI 1.8-29). Shoulder dystocia was significantly associated with abdominal diameter (AD) minus biparietal diameter (BPD) ≥ 2.6 cm (OR 4.2, 95 % CI 2.3-7.5, PPV 11 %) and AC > 90th centile (OR 2.3, 95 % CI 1.3-4.0, PPV 8.6 %) and an estimated fetal weight (EFW) > 4000 g (OR 2.1 95 %CI 1.0-4.1, PPV 7.2 %).

CONCLUSIONS

Estimated fetal weight is the most widely used ultrasound marker to predict fetal macrosomia in the UK. This study suggests other markers have a higher positive predictive value for adverse outcomes associated with fetal macrosomia.

Polyhydramnios or Excessive Fetal Growth Are Markers for Abnormal Perinatal Outcome in Euglycemic Pregnancies

OBJECTIVE

 This study aims to investigate the perinatal outcome of fetuses with polyhydramnios and/or accelerated growth among women with a normal oral glucose challenge test (oGCT).

METHODS

 Singleton, nonanomalous pregnancies with an oGCT(< 130 mg/dL) at 24 to 28 weeks, who subsequently demonstrate polyhydramnios (amniotic fluid index > 24 cm or maximum vertical pocket > 8 cm) and/or accelerated growth (abdominal circumference > 95th percentile) on two-third trimester examinations were studied. Maternal demographics, delivery, and neonatal information were recorded. Cases were compared with a reference group (normal oGCT with neither abnormal third-trimester growth nor polyhydramnios).

RESULTS

 A total of 282 pregnancies were in the study group, and 663 were in the reference group. Deliveries in the study group were at a higher risk for birth weight (BW)% > 90%, standard deviation, and postpartum hemorrhage when compared with the reference group (adjusted odds ratio: 2.3-5.6). Pregnancies complicated by both polyhydramnios and accelerated fetal growth were significantly more likely to result in a BW% > 90% (odds ratio [OR]: 18.5; 95% confidence interval [CI]: 8.9-38.6) and PPH (OR: 4.2; 95% CI: 2.4-7.6).

CONCLUSION

 Pregnancies with normal oGCT that develop polyhydramnios and accelerated growth are at higher risk for maternal and neonatal complications. Isolated polyhydramnios without accelerated growth increases the risk for delivery complications but not neonatal morbidity.

The FL/AC ratio for prediction of shoulder dystocia in women with gestational diabetes

PURPOSE

To determine if sonographic variables, including fetal femur length to abdominal circumference (FL/AC) ratio, are associated with shoulder dystocia in women with gestational diabetes.

METHODS

This was a retrospective cohort study of women with gestational diabetes who delivered singleton infants at Parkland Hospital from 1997 to 2015. Diagnosis and treatment of gestational diabetes were uniform including sonography at 32-36 weeks. Biometric calculations were evaluated for correlation with shoulder dystocia.

RESULTS

During the study period, 6952 women with gestational diabetes underwent a sonogram at a mean gestation of 34.8 ± 1.8 weeks. Of 4183 vaginal deliveries, 66 experienced shoulder dystocia (16/1000). The FL/AC was associated with shoulder dystocia (p < 0.001) with an AUC of 0.70 (95% CI: 0.64-0.77). This was similar to age-adjusted AC and head circumference to AC ratio (HC/AC) (both with an AUC of 0.72). All other measurements, including estimated fetal weight, were inferior. When examining the 257 women with multiple sonograms after 32 weeks' gestation, FL/AC was stable with advancing gestational age (p = 0.54) whereas age-adjusted AC and HC/AC were not (p < 0.001).

CONCLUSIONS

The FL/AC is associated with shoulder dystocia in women with gestational diabetes. Additionally, it is a simple ratio that is independent of the reference used and remains stable, unlike age-adjusted AC and HC/AC ratio.

Translation of fetal abdominal circumference-guided therapy of gestational diabetes complicated by maternal obesity to a clinical outpatient setting

OBJECTIVE

To evaluate the effectiveness of fetal abdominal circumference-guided therapy for gestational diabetes (GDM) in an outpatient population characterized by highly-prevalent maternal obesity.

METHODS

Data for this translational retrospective cohort study come from medical records. Fetal abdominal circumference was assessed by ultrasound in late second trimester, and sex- and gestational age-specific percentiles assigned. Taking fetal abdominal circumference percentile as a marker for adequacy of fetal growth, maternal glucose targets were set accordingly: loose, moderate or tight. Associations between mother's targets and neonatal outcomes (small for gestational age (SGA), large for gestational age (LGA), macrosomia, neonatal intensive care unit (NICU) admission, and neonatal hypoglycemia) were assessed using unconditional logistic regression, controlling for pre-gravid body mass index (BMI) and gestational weight gain.

RESULTS

In 419 consecutive pregnancies complicated by GDM, neonatal outcomes compared favorably with previous randomized trials of intensive GDM management. Importantly, adverse outcomes were observed less often than might be expected in an obese GDM population. BMI did not have an independent effect on neonatal outcomes.

CONCLUSIONS

Ultrasound-guided therapy of GDM, in general clinic use, can limit excess macrosomia and LGA, even in a population with significant maternal obesity.

Association between fetal abdominal circumference and birthweight in maternal hyperglycemia

OBJECTIVES

To compare fetal abdominal circumference and its relationship with birthweight at increasing gestational ages in the context of maternal hyperglycemia of varying severity.

DESIGN

Retrospective cohort study.

SETTING

Two centers participated in building one database.

POPULATION

A total of 1538 Korean pregnant women were subjected to a two-step approach to diagnose gestational diabetes mellitus.

METHODS

Pregnant women were classified into gestational diabetes mellitus, borderline gestational diabetes mellitus, and normal groups. Fetal abdominal circumferences, which were measured with ultrasound at 4-week intervals starting at 16 weeks of gestation and ending prior to delivery, were evaluated in the groups.

MAIN OUTCOME MEASURE

The significance of fetal abdominal circumferences as predictors or risk factors of macrosomia/large-for-gestational age.

RESULTS

Fetal abdominal circumferences measured from 16 weeks of gestation until prior to delivery predicted birthweight in all groups with some exceptions. Fetal abdominal circumferences measured from 32 weeks of gestation until prior to delivery were predictive of macrosomia in all groups. Fetal abdominal circumferences measured from 28 weeks of gestation until prior to delivery were predictive of neonates being large-for-gestational age in all groups. Fetal abdominal circumferences measured at 16 and 24 weeks of gestation were also predictive of large-for-gestational age in the borderline gestational diabetes mellitus group. Fetal abdominal circumference measured at 24 weeks of gestation was also a predictor of macrosomia/large-for-gestational age in normal women.

CONCLUSIONS

Fetal abdominal circumferences measured during the second and especially third trimesters were significantly associated with excessive birthweight, irrespective of the severity of maternal glucose intolerance.

Antepartum A1C, maternal diabetes outcomes, and selected offspring outcomes: an epidemiological review

Between 1989 and 2004, the prevalence of gestational diabetes mellitus (GDM) in the United States increased by 122%. Glycated haemoglobin, as measured by haemoglobin A1C (A1C), can potentially identify pregnant women at high risk for adverse outcomes associated with GDM including macrosomia and post-partum glucose intolerance. Our objective was to systematically review the literature with respect to A1C levels during pregnancy and associated maternal and offspring outcomes. We used MEDLINE to identify relevant publications from 1975 to 2009. We included articles if they met the following criteria: original full text articles in English; primary exposure of antepartum A1C; women with GDM at baseline or who developed GDM during the study; primary outcome of GDM, insulin use, post-partum abnormal glucose or type 2 diabetes (T2DM), birthweight, macrosomia or large for gestational age. Case series and case reports were excluded. Twenty studies met our criteria. A1C at GDM diagnosis was positively associated with post-partum abnormal glucose. Women with post-partum T2DM or impaired glucose tolerance had mean A1C at GDM diagnosis higher than those with normal post-partum glucose (P ≤ 0.002) and a 1% increase in A1C at GDM diagnosis was associated with 2.36 times higher odds of post-partum abnormal glucose 6 weeks after delivery [95% confidence interval 1.19, 4.68]. The association of A1C and birthweight varied substantially between studies, with correlation coefficients ranging from 0.11 to 0.51. A1C, a less burdensome and costly measure than an oral glucose tolerance test, appears to be an attractive measure for identifying women at high risk of adverse outcomes associated with GDM.

How many sonograms are needed to reliably predict the absence of fetal overgrowth in gestational diabetes mellitus pregnancies?

OBJECTIVE

Serial measurements of the fetal abdominal circumference have been used to guide metabolic management of pregnancies complicated by gestational diabetes mellitus (GDM). A reduction in the number of repeat ultrasound examinations would save resources. Our purpose was to determine the number of serial abdominal circumference measurements per patient necessary to reliably predict the absence of fetal overgrowth.

RESEARCH DESIGN AND METHODS

Women who had GDM were asked to return for repeat ultrasound at 3- to 4-week intervals starting at initiation of care (mean 26.9 ± 5.7 weeks). Maternal risk factors associated with fetal overgrowth were determined.

RESULTS

A total of 4,478 ultrasound examinations were performed on 1,914 subjects (2.3 ± 1.2 per pregnancy). Of the 518 women with fetal abdominal circumference >90th percentile, it was diagnosed in 73.9% with the first ultrasound examination at entry and in 13.1% with the second ultrasound examination. Of the fetuses, 85.9 and 86.9% of the fetuses were born non-large for gestational age (LGA) when abdominal circumference was <90th percentile at 24-27 weeks and 28-32 weeks, respectively, and 88.0% were born non-LGA when both scans showed normal growth. For those women who had no risk factors for fetal overgrowth (risk factors: BMI >30 kg/m², history of macrosomia, and fasting glucose > 100 mg/dl), the accuracy of prediction of a non-LGA neonate was 90.0, 89.5, and 95.2%. The predictive ability did not increase with more than two normal scans.

CONCLUSIONS

The yield of sonographic diagnosis of a large fetus drops markedly after the finding of a fetal abdominal circumference <90th percentile on two sonograms, which excludes with high reliability the risk of a LGA newborn. The ability was enhanced in women who had no risk factors for neonatal macrosomia.

[Obstetrical care in gestational diabetes and management of preterm labor]

OBJECTIVES

Search for data necessary to elaborate recommendations for obstetrical care in gestational diabetes and management of preterm labor.

METHODS

Systematic review of the literature and levels of evidence.

RESULTS

In case of gestational diabetes and in the absence of disease or other risk factor associated, there is no evidence to support a systematic rate of clinical follow up different from other pregnancy. The relevance of ultrasound estimates of fetal weight is limited. No formula is superior to others or to the simple measurement of abdominal circumference for the prediction of macrosomia (EL3). The usefulness of the research septal hypertrophy is not demonstrated (EL4). The systematic application of umbilical Doppler has no proven benefits in the absence of growth restriction or hypertension associated (EL4). Monthly ultrasound monitoring of the fetus can be proposed for diabetics on insulin or poorly controlled. In cases of gestational diabetes controlled by diet, cardiotocography of fetal heart rate has not proven useful. In poorly controlled diabetes and/or on insulin, the registration may be discussed taking into account other risk factors associated (EL4). A weekly recording of fetal heart rate is often recommended in case of type 2 diabetes discovered during pregnancy. In case of preterm labor, calcium channel blockers and oxytocin antagonists can be used without specific precautions. The risk of using beta-adrenergic outweighs the benefit. Administration of corticosteroid can be done under glycemic control, with insulin therapy if necessary. Screening test for gestational diabetes should not be performed within few days after last steroid injection.

The fetus of a diabetic mother: sonographic evaluation

Maternal hyperglycemia is responsible for many fetal adverse outcomes. Ultrasound examination of these pregnancies aims at an early detection of congenital malformations, assessment of fetal well-being, and fetal growth. This evaluation will influence clinical decision in determining the best time and mode of delivery. We reviewed data from the literature on accuracy, usefulness, and indications of ultrasound examinations in pregnancies complicated with diabetes mellitus, whether pregestational or gestational.

Early rapid growth, early birth: accelerated fetal growth and spontaneous late preterm birth

The past two decades in the United States have seen a 24% rise in spontaneous late preterm delivery (34-36 weeks) of unknown etiology. This study tested the hypothesis that fetal growth was identical prior to spontaneous preterm (n = 221, median gestational age at birth 35.6 weeks) and term (n = 3706) birth among pregnancies followed longitudinally in Santiago, Chile. The hypothesis was not supported: Preterm-delivered fetuses were significantly larger than their term-delivered peers by mid-second trimester in estimated fetal weight, head, limb, and abdominal dimensions, and they followed different growth trajectories. Piecewise regression assessed time-specific differences in growth rates at 4-week intervals from 16 weeks. Estimated fetal weight and abdominal circumference growth rates slowed at 20 weeks among the preterm-delivered, only to match and/or exceed their term-delivered peers at 24-28 weeks. After an abrupt growth rate decline at 28 weeks, fetuses delivered preterm did so at greater population-specific sex and age-adjusted birth weight percentiles than their peers from uncomplicated pregnancies (P < 0.01). Growth rates predicted birth timing: one standard score of estimated fetal weight increased the odds ratio for late preterm birth from 2.8 prior to 23 weeks, to 3.6 (95% confidence interval, 1.82-7.11, P < 0.05) between 23 and 27 weeks. After 27 weeks, increasing size was protective (OR: 0.56, 95% confidence interval, 0.38-0.82, P = 0.003). These data document, for the first time, a distinctive fetal growth pattern across gestation preceding spontaneous late preterm birth, identify the importance of mid-gestation for alterations in fetal growth, and add perspective on human fetal biological variability.

Detection and prevention of macrosomia

It is overly simplistic to try to identify optimal glycemic thresholds, fetal growth characteristics, and methods of detection in the prevention of fetal overgrowth and its attendant morbidities that can be applied to all pregnancies. We can only hope that, as our understanding of the pathophysiology of diabetes in pregnancy grows, we can "fine-tune" our therapy and surveillance to meet the needs of an individual woman who has diabetes and her fetus.

Flexible treatment of Gestational Diabetes modulated on ultrasound evaluation of intrauterine growth: a controlled randomized clinical trial

OBJECTIVES

In order to prevent abnormalities of fetal growth still characterizing pregnancies complicated by Gestational Diabetes (GDM), in the present study we evaluated a therapeutic strategy for GDM based on ultrasound (US) measurement of fetal insulin-sensitive tissues.

METHODS

All GDM women diagnosed before 28th week immediately started diet and self-monitoring of blood glucose; after 2 weeks they were randomized to conventional (C) or modified (M) management. In C the glycemic target (GT) was fixed at 90 fasting/120 post-prandial mg/dl; in M GT varied, according to US measurement of the Abdominal Circumference (AC) centile performed every 2 weeks: 80/100 if AC > or =75th, 100/140 if AC<75th. Therapy was tailored to mean fasting (FG) and postprandial glycemia (PPG).

RESULTS

Globally, 229 women completed the study, 78 in C, 151 in M. Use of insulin was 16.7% in C, 30.4% in M (total groups), significantly more frequent in M than in C (59.7% vs 15.4%) when considering only women with AC > or =75th c. Mean metabolic data were similar in the 2 groups, but in M a tightly-optimized subgroup, resulting from the lowering of GT due to AC > or =75th, coexisted with a less-controlled one, whose higher GT was justified by AC<75th. Pregnancy outcome was better in M, with lower (p<0.05*) rate of LGA* (7.9% vs 17.9%), SGA (6.0% vs 9.0%) and Macrosomia* (3.3% vs 11.5%).

CONCLUSIONS

Our data show the value of a flexible US-based approach to the treatment of GDM. This model does not necessarily involve a generalized aggressive treatment, allowing to concentrate therapeutical efforts on a small subgroup of women showing indirect US evidence of fetal hyperinsulinization. Such a selective approach allowed to obtain a near-normalization of fetal growth, with clear advantages on global pregnancy outcome.

Amniotic fluid insulin levels and fetal abdominal circumference at time of amniocentesis in pregnancies with diabetes

AIMS

Fetal hyperinsulinism is a strong predictor for excessive growth and fetopathy in pregnancies complicated by diabetes. We examined (i). the relationship between measurements of amniotic fluid insulin (AF insulin) and fetal abdominal circumference (AC) at the time of amniocentesis, and (ii). whether there is a threshold for fetal AC percentiles which can identify low vs. high-risk levels of AF insulin without performing an amniocentesis.

METHODS

In a retrospective study, AF insulin from 121 pregnant diabetic women (32 pregestational; 89 gestational) was measured during the 3rd trimester as part of a diabetes management protocol. AC measurements were transformed into a continuous variable of percentile growth for gestational age (Hadlock). Division of the cohort according to deciles or quartiles of AC percentiles was performed to identify a threshold AC with a significant increase in elevated AF insulin, previously defined as AF insulin >or= 7 microU/ml. A receiver operator characteristic (ROC) curve was created and the negative predictive value (NPV) of the determined threshold was calculated.

RESULTS

AF insulin levels were significantly correlated with the AC percentiles (r = 0.3, P = 0.0005) by linear regression. No AC threshold could reliably identify a moderate elevated AF insulin >or= 7 microU/ml (NPV 77.2%), but an AC threshold >or= 75th percentile could identify with fetal hyperinsulinism with an AF insulin >or= 16 microU/ml. All 10 cases of AF insulin >or= 16 microU/ml were identified with a NPV of 100% (74/74).

CONCLUSIONS

Our data indicate that an AC >or= 75th percentile determined by a 3rd trimester ultrasound examination may discriminate between pregnancies at low vs. high risk for AF insulin >or= 16 microU/ml. This AF insulin concentration corresponds to a level of hyperinsulinism reported to be associated with considerable neonatal and long term morbidity.

Maternal obesity not maternal glucose values correlates best with high rates of fetal macrosomia in pregnancies complicated by gestational diabetes

AIM

The current therapeutic strategies to reduce macrosomia rates in gestational diabetes (GDM) have focused on the normalizing of maternal glucose levels. The aim of our study was 1.) to compare maternal glycemic values with the presence of fetal macrosomia at different gestational ages (GA) and with LGA at birth in a cohort of women with glucose intolerance and standard diabetic therapy.

METHODS

306 women with GDM and 97 with impaired glucose tolerance underwent ultrasound examinations at entry and, after initiation of therapy, monthly in addition to standard diabetic therapy. Measurements from the entry diagnostic oGTT, glucose profile and HbA1c and from subsequent glucose profiles obtained within 3 days of the ultrasound at 5 categories of GA age (20-23, 24-27 etc) were retrospectively compared between pregnancies with and without fetal macrosomia, defined as an abdominal circumference (AC) > or = 90th percentile. Maternal prepregnancy BMI was adjusted for and BMI > or = 30 kg/m2 was defined as obesity.

RESULTS

At entry, neither the hourly oGTT values, HbA1c, nor the entry glucose profile differed significantly between pregnancies with and without fetal macrosomia. In a total of 919 pairs of ultrasound/glucose profiles there was no significant difference in glucose levels at every GA category neither in lean nor in obese woman except for the fasting glucose of 32-35 GA. The fetal macrosomia rate in each GA category and the rate of LGA were significantly higher in obese women: e.g. 14.5 vs 28% at diagnosis, 15.7 vs 26.7% at 32-35 weeks, 15.5 vs 25.0% at birth (p < 0.05 for each comparison).

CONCLUSION

The association of maternal glucose values and fetal macrosomia was limited to the fasting glucose values between 32-35 weeks while maternal obesity appeared to be a strong risk factor for macrosomia throughout pregnancies with GDM. In obese women the high fetal macrosomia rate did not appear be normalized by therapy based on maternal euglycemia.

Determinants of fetal growth at different periods of pregnancies complicated by gestational diabetes mellitus or impaired glucose tolerance

OBJECTIVE

To determine maternal parameters with the strongest influence on fetal growth in different periods of pregnancies complicated by an abnormal glucose tolerance test (GTT).

RESEARCH DESIGN AND METHODS

Retrospective study of 368 women with gestational diabetes mellitus (GDM; > or = 2 abnormal GTT values, n = 280) and impaired glucose tolerance (IGT; one abnormal value, n = 88) with 869 ultrasound examinations at entry to and during diabetic care. Both groups were managed comparably. Abdominal circumference (AC) > or = 90th percentile defined fetal macrosomia. Maternal historical and clinical parameters, and diagnostic and glycemic values of glucose profiles divided into five categories of 4 weeks of gestational age (GA; <24 weeks, 24 weeks/0 days to 27 weeks/6 days, 28/0-31/6, 32/0-35/6, and 36/0-40/0 [referred to as <24 GA, 24 GA, 28 GA, 32 GA, and 36 GA categories, respectively]) were tested by univariate and multiple logistic regression analysis for their ability to predict an AC > or = 90th percentile at each GA group and large-for-gestational-age (LGA) newborn. Data obtained at entry were also analyzed separately irrespective of the GA.

RESULTS

Maternal weight, glycemia after therapy, rates of fetal macrosomia, and LGA were not significantly different between GDM and IGT; thus, both groups were analyzed together. LGA in a previous pregnancy, (odds ratio [OR] 3.6; 95% CI 1.8-7.3) and prepregnancy obesity (BMI > or = 30 kg/m(2); 2.1; 1.2-3.7) independently predicted AC > or = 90th percentile at entry. When data for each GA category were analyzed, no predictors were found for <24 GA. Independent predictors for each subsequent GA category were as follows: at 24 GA, LGA history (OR 9.8); at 28 GA, LGA history (OR 4.2), and obesity (OR 3.3); at 32 GA, fasting glucose of 32 GA (OR 1.6 per 5-mg/dl increase); at 36 GA, fasting glucose of 32 GA (OR 1.6); and for LGA at birth, LGA history (OR 2.7), and obesity (OR 2.4).

CONCLUSIONS

In the late second and early third trimester, maternal BMI and LGA in a previous pregnancy appear to have the strongest influence on fetal growth, while later in the third trimester coincident with the period of maximum growth described in diabetic pregnancies, maternal glycemia predominates.

Choosing route of delivery for the macrosomic infant of a diabetic mother: Cesarean section versus vaginal delivery

The macrosomic fetus of a diabetic woman faces increased risk for injury at the time of vaginal birth. Cesarean section offers the promise of avoiding trauma to the fetus, but can result in increased morbidity in the mother as compared to vaginal delivery. In this article, the advantages and disadvantages of the two routes of delivery for the overgrown fetus of a diabetic mother are discussed. Specifically, data regarding risk of permanent neurological damage to the infant from vaginal delivery, and maternal morbidity from elective, pre-labor Cesarean delivery are critically examined. In addition, methods for diagnosing macrosomia by ultrasound are discussed, along with the benefits and pitfalls of ultrasonic fetal weight estimation in the setting of diabetes. Finally, management approaches for selecting route of delivery for the macrosomic fetus are described and analyzed.

Delivery of the macrosomic infant: cesarean section versus vaginal delivery

The macrosomic fetus of a diabetic woman faces increased risk for injury at the time of birth. Cesarean section offers the potential for avoiding trauma to the fetus, but can result in increased morbidity in the mother as compared to vaginal delivery. In this article, the advantages and disadvantages of the 2 routes of delivery for the overgrown fetus of a diabetic mother are discussed. In addition, methods for diagnosing macrosomia by ultrasound are examined, along with the benefits and pitfalls of ultrasonic fetal weight estimation in the setting of diabetes. Finally, management approaches for selecting route of delivery for the macrosomic fetus are described and analyzed.

A randomized controlled trial using glycemic plus fetal ultrasound parameters versus glycemic parameters to determine insulin therapy in gestational diabetes with fasting hyperglycemia

OBJECTIVE

To compare management based on maternal glycemic criteria with management based on relaxed glycemic criteria and fetal abdominal circumference (AC) measurements in order to select patients for insulin treatment of gestational diabetes mellitus (GDM) with fasting hyperglycemia.

RESEARCH DESIGN AND METHODS

In a pilot study, 98 women with fasting plasma glucose (FPG) concentrations of 105-120 mg/dl were randomized. The standard group received insulin treatment. The experimental group received insulin if the AC, measured monthly, was > or =70th percentile and/or if any venous FPG measurement was >120 mg/dl. Power was projected to detect a 250-g difference in birth weights.

RESULTS

Gestational ages, maternal glycemia, and AC percentiles were similar at randomization. After initiation of protocol, venous FPG (P = 0.003) and capillary blood glucose levels (P = 0.049) were significantly lower in the standard group. Birth weights (3,271 +/- 458 vs. 3,369 +/- 461 g), frequencies of birth weights >90th percentile (6.3 vs 8.3%), and neonatal morbidity (25 vs. 25%) did not differ significantly between the standard and experimental groups, respectively. The cesarean delivery rate was significantly lower (14.6 vs. 33.3%, P = 0.03) in the standard group; this difference was not explained by birth weights. In the experimental group, infants of women who did not receive insulin had lower birth weights than infants of mothers treated with insulin (3,180 +/- 425 vs. 3,482 +/- 451 g, P = 0.03).

CONCLUSIONS

In women with GDM and fasting hyperglycemia, glucose plus fetal AC measurements identified pregnancies at low risk for macrosomia and resulted in the avoidance of insulin therapy in 38% of patients without increasing rates of neonatal morbidity.

Sonographic and clinical methods in the diagnosis of macrosomia

Receiver operator characteristic curves for both clinical and sonographic predictions of macrosomia subsume areas between 0.81 and 0.95, significantly larger than the area of 0.5 that indicates a useless test. Thus, these tests are defined as useful from a statistical point of view. Prediction of macrosomia by clinical or imaging techniques, however, is limited by the substantial false-positive and false-negative rates inherent in these tests. We recommend that physicians continue to use clinical methods to estimate fetal weight, including asking women with parity to provide their own estimates. We recognize that the relative error associated with clinical or sonographic estimates of fetal weight limits their use in clinical practice. Sonographic laboratories may improve their results by performing ROC curve analysis on their own data and by selecting cutoff values that best predict macrosomia in their setting. Serial sonographic measurements that are above the limits chosen to define macrosomia increase the likelihood that a birth weight will be macrosomic. Separate ROC curves must be generated for twins and breech presentations and for patients with diabetes to answer weight-related clinical questions such as mode and timing of delivery. Three-dimensional ultrasound and magnetic resonance imaging are expected to generate ROC curves for estimates of fetal weight that are better than those for two-dimensional ultrasound or clinical estimates. Such analyses have yet to be published.

Abdominal circumference vs. estimated weight to predict large for gestational age birth weight in diabetic pregnancy

Early third trimester fetal abdominal circumference and sonographic fetal weight estimates were compared to predict large for gestational age birth weight in diabetic pregnancy. Both parameters have similar sensitivity, specificity, and predictive values. However, the optimal percentile cutoff values differ. Choice of birth weight standard significantly influences test characteristics. Negative prediction of large birth weight is more accurate than positive prediction. At third trimester sonography with maternal diabetes, the abdominal circumference percentile is potentially useful and should be routinely reported.

Prophylactic cesarean delivery for fetal macrosomia diagnosed by means of ultrasonography--A Faustian bargain?

Both our previously performed decision analysis and more recent clinical data considered in the context of our decision analytic framework support the claim that in the pregnancies of women without diabetes the level of intervention and the economic costs of prophylactic cesarean delivery for fetal macrosomia diagnosed by means of ultrasonography are predicted to be excessive. Under the most plausible assumptions, a prophylactic cesarean policy with either a 4000- or 4500-g macrosomia threshold would require more than 1000 cesarean deliveries and millions of dollars to avert a single permanent brachial plexus injury. In the pregnancies of diabetic women, although such policies would be expected to perform appreciably better, their use would nevertheless entail considerable intervention for any benefit achieved. Under most assumptions, hundreds of cesarean deliveries and hundreds of thousands of dollars would be required to avert a single permanent brachial plexus injury. In light of the available data, optimizing the management of shoulder dystocia seems at present to be the most immediate and tenable approach to the prevention of birth-related brachial plexus injury.

Ultrasound growth parameters in relation to levels of amniotic fluid insulin in women with diabetes type-I

The aim of the study was to investigate the correlation between ultrasound parameters and levels of amniotic fluid insulin (AF-insulin) in pregnancies complicated by insulin-dependent diabetes mellitus (IDDM). In 129 women with IDDM amniocentesis was performed between 28 and 35 weeks of gestation. The levels of AF-insulin were measured by radioimmunoassay (Pharmacia RIA 100) and were correlated with biparietal diameter (BPD), abdominal diameter (AD), abdominal circumference (AC), and femur length (FL). The women were maintained at good glycemic control (fructosamine level: mean +/- S.D.: 236.3 +/- 40 micromol/l) and delivered infants with a mean (+/- S.D.) birth weight of 3477 +/- 640 g. The sensitivity of BPD, AD, AC and FL to detect fetuses with pathological levels of AF-insulin was 50%, 62%, 67% and 49%, respectively. The sensitivities of AD and AC in a selected group (n = 14) with highly pathological levels of AF-insulin (> 20 microU/ml) were both 80%, whereas the specificity was 56% and 46%, respectively. In women with IDDM, fetal biparietal diameter, abdominal diameter, abdominal circumference, and femur length are not reliable markers for the identification of fetal hyperinsulinism. Only cases with highly pathological levels of AF-insulin can be detected by abdominal measurements.

Clinical and ultrasound prediction of macrosomia in diabetic pregnancy

OBJECTIVE

To study prospectively the prediction power, at different gestations, of clinical and ultrasound measurements for fetal size in diabetic pregnancy.

SETTING

A large combined obstetric diabetic clinic in a teaching hospital.

PARTICIPANTS

One hundred and eighty-one pregnancies in which women had scans at least two of three specific time points and who were delivered of singletons after 34 weeks: 73% were pre-gestational insulin-dependent diabetics, the others were pre-gestational White class A or gestational diabetics.

INTERVENTIONS

Clinical estimates of fundal height and fetal size and ultrasound estimates of abdominal circumference and head circumference were routinely carried out at gestational ages of 28, 34 and 38 weeks or before delivery.

MAIN OUTCOME MEASURES

Standardised birthweight, corrected for gestation and parity. The relation with clinical and ultrasound measurements was investigated using multiple linear regression and the capability of the measurements to predict macrosomic births (> 95th centile of normals) using receiver-operator characteristic curves.

RESULTS

All measurements are poor predictors of eventual standardised birthweight. Prediction improves with closeness to delivery. Prediction is significantly improved by adding ultrasound to clinical information, but at 34 weeks or later this only contributes 8% of the variance. There is no difference in the prediction power for macrosomia between clinical and ultrasound measurements.

CONCLUSIONS

Even regular serial scanning and clinical examination will not always diagnose the macrosomic fetus in diabetic pregnancy. In our hands, clinical examination is as predictive as ultrasound measurements. Ultrasound does add to clinical prediction power but only to a small extent. Ultrasound should be used in a selected way, as defined by clinical findings, and with recognition and understanding of the errors and biases involved.

Growth and endocrine function after near total pancreatectomy for hyperinsulinaemic hypoglycaemia

Seven children, with a mean (SD) age of 4.6 (2.1) years, who as infants (21 (7.5) days) underwent near total (95-98%) pancreatectomy for persistent hyperinsulinaemic hypoglycaemia of infancy (PHHI) were studied. At birth all the infants were macrosomic. Four infants had been born after a difficult labour, of whom three had moderate birth asphyxia and respiratory distress. All had normal thyroid function. After surgery transient hyperglycaemia was manifest in six of the children and required insulin treatment for 5.8 (3.8) weeks, and transient hypoglycaemia was encountered in one child and responded well to increased carbohydrate intake and diazoxide for three weeks. Six of the children rapidly crossed down their length and weight centiles during the first year after surgery. At the end of the first year these children were at or below the 5th centile of height and weight for their age and gender. After a period of 4.6 (2.1) years, their mean (SD) height score was -2.57 (0.5), growth velocity 3.9 (0.75) cm/year, and growth velocity SD score -2.1 (0.55)l these were significantly low and denoted significant growth retardation. The growth hormone peak responses to provocation with clonidine were normal (13.5 (2.8) micrograms/l). However, the circulating insulin-like growth factor-I (IGF-I) concentrations were significantly decreased (79 (34) ng/ml). Three of the children developed diabetes at two and a half, five, and seven years after surgery, two others had impaired oral glucose tolerance and six out of the seven children had an impaired C peptide response to glucagon. Defective insulin secretion in these children might directly inhibit IGF-I synthesis in the liver. The body mass index of the pancreatectomised children was 14.9 (0.5) and was normal for age and gender; they had a normal 72 hour faecal fat content and normal serum albumin concentration. These data indicated grossly adequate exocrine pancreatic function. It appears that children requiring near total pancreatectomy for PHHI have normal developmental milestones but defective linear growth with impaired insulin secretion and low IGF-I production despite normal growth hormone response to provocation.

Diabetes in pregnancy

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Insulin-requiring diabetes in pregnancy: a randomized trial of active induction of labor and expectant management

OBJECTIVE

Our purpose was to assess whether a program of expectant management of uncomplicated pregnancies in mothers with insulin-requiring gestational or pregestational class B reduces the incidence of cesarean birth.

STUDY DESIGN

Two hundred women with uncomplicated, insulin-requiring diabetes at 38 weeks' gestation who were compliant with care and whose infants were judged appropriate for gestational age were randomly assigned to (1) active induction of labor within 5 days or (2) expectant management. The expectant management group was monitored with weekly physical examination and twice-weekly nonstress tests and amniotic fluid volume estimation until delivery.

RESULTS

Expectant management increased the gestational age at delivery by 1 week. Approximately half (49%) of the mothers in the expectant management group required induction of labor for obstetric indications. The cesarean delivery rate was not significantly different in the expectant management group (31%) from the active induction group (25%). The mean birth weight (3672 +/- 407 gm) and percentage large for gestational age, as defined by birth weight > or = 90th percentile, of infants in the expectantly managed group (23%) was greater than those in the active induction group (3466 +/- 372 gm, p < 0.0001, 10% large for gestational age). This difference persisted after controlling for gestational age and maternal age and body weight (p < 0.01).

CONCLUSION

In women with uncomplicated insulin-requiring gestational or class B pregestational diabetes, expectant management of pregnancy after 38 weeks' gestation did not reduce the incidence of cesarean delivery. Moreover, there was an increased prevalence of large-for-gestational-age infants (23% vs 10%) and shoulder dystocia (3% vs 0%). Because of these risks, delivery should be contemplated at 38 weeks and, if not pursued, careful monitoring of fetal growth must be performed.

Fetal growth disturbances

IUGR is a fetal disorder characterized by diminished fetal growth, especially in the third trimester. Growth retardation may be due to primary placental insufficiency or may result from a variety of maternal or fetal causes and is associated with elevated perinatal mortality and morbidity. Numerous conventional and Doppler ultrasound criteria have been proposed for diagnosing IUGR prenatally, but none on its own permits confident diagnosis of this condition. Diagnosis or exclusion of IUGR can best be achieved by the combined use of three parameters: estimated fetal weight, amniotic fluid volume, and maternal hypertension. When IUGR is suspected based on these parameters, Doppler ultrasound can help to determine the prognosis. Large fetuses, particularly those weighing more than 4,000 grams at birth, are at risk for perinatal morbidity and mortality due to obstetrical complications. These fetuses occur more frequently and are at especially high risk in diabetic mothers. The estimated fetal weight is the most direct parameter for diagnosing LGA and macrosomia and is moderately accurate with positive predictive values up to 67% in the general population and 77% in diabetics. It can be an important factor in deciding on the route of delivery in diabetic mothers.

Macrosomia in the postdate pregnancy: is routine ultrasonographic screening indicated?

Macrosomia is a potential but often overlooked consequence of the postdate pregnancy. A total of 317 consecutive patients with well-dated pregnancies who were seen because of fetal surveillance at greater than 41 weeks' gestation had an estimation of the fetal weight based on femur length and abdominal circumference at the initial visit. The incidence of macrosomia at 41 weeks' gestation was 25.5%. There was a higher incidence of cesarean section because of arrest and protraction disorders in the postdate pregnancies in which the infant was macrosomic (22%) versus those in which the infant was not macrosomic (10%, p less than 0.01). In a control group of 100 consecutive women delivered between 38 and 40 weeks' gestation, the incidence of macrosomia was 4%, significantly lower than the rate in the postdate patients (p less than 0.01). Incidence of cesarean section because of arrest and protraction disorders was significantly lower in this group (6%, p less than 0.05). The sensitivity and specificity of an estimated fetal weight greater than 4000 gm to predict a birth weight greater than 4000 gm were 60.5% and 90.7%, respectively, with a positive predictive value of 70% and a negative predictive value of 87%. We conclude that routine ultrasonographic screening for macrosomia may be a valuable adjunct to current fetal surveillance protocols used in the postdate pregnancy.