The effect of maternal glycemic control on fetal growth in diabetic pregnancies

In this prospective study, we examined the effect of maternal glycemic control on fetal growth in pregnancies complicated by pregestational diabetes. One hundred and sixty-five pregestational diabetic pregnancies were studied with serial ultrasound scans and fetal growth was examined as a function of maternal glycemic control. There was a significant, although small, reduction in fetal biparietal diameter growth rate in the presence of poor maternal glycemic control during the first half of the pregnancy. In the second half of pregnancy, maternal hyperglycemia contributed to fetal macrosomia. We conclude that in pregnancies with pregestational diabetes, maternal hyperglycemia affects fetal growth in a biphasic manner. As a result of that, although babies born to diabetic mothers appear of relatively overall normal size and weight, they may have smaller heads than their potential and more fat.

Growth patterns of large-for-gestational-age and appropriate-for-gestational-age infants of gestational diabetic mothers and control mothers at age 1 year

OBJECTIVE

The purpose of this study was to explore the development of adiposity in macrosomic and normosomic infants of mothers with gestational diabetes mellitus (GDM) and control subjects between birth and age 1 year, and assess its relation to maternal prenatal factors and neonatal factors.

RESEARCH DESIGN AND METHODS

This was a prospective observational study of 192 infants, including 47 large-for-gestational-age (LGA) infants of GDM mothers, 47 appropriate-for-gestational-age (AGA) infants of GDM mothers, 55 LGA control infants, and 44 AGA control infants who were evaluated at birth and age 1 year. Maternal prenatal and pregnancy anthropometric measurements were recorded. Multiple infant anthropometric measurements, including skinfold thicknesses, were obtained at birth and age 1 year. Regression models were run to detect the independent effects of various maternal and infant factors on 1-year child adiposity, adjusting for their effects at birth.

RESULTS

LGA infants of GDM mothers had a higher BMI, waist circumference, and abdominal skinfold at age 1 year compared with all other study groups. Among infants of GDM mothers, the mean 2-h postprandial glucose value for the second and third trimester correlated with waist circumference (r = 0.28, P < 0.04) and subscapular skinfold (r = 0.37, P < 0.007), and correlated marginally with 1-year sum of four skinfolds. Among infants of GDM mothers, a regression of 1-year sum of four skinfolds was significantly related to maternal prepregnancy weight after controlling for sum of skinfolds at birth. For control infants, the maternal glucose screen value was significantly associated with 1-year sum of skinfolds adjusted for the birth sum of skinfolds.

CONCLUSIONS

We concluded that macrosomic infants of GDM mothers have unique patterns of adiposity that are present at birth and persist at age 1 year. Further, we concluded that maternal factors, including adiposity and intrauterine fuel environment, influence the presence and distribution of adiposity for both infants of GDM mothers and control infants.

Incidence of persistent birth injury in macrosomic infants: association with mode of delivery

OBJECTIVE

Our purpose was to determine the incidence of birth injury in a cohort of macrosomic infants (birth weight >4000 gm) and analyze the association between persistent injury and delivery method.

STUDY DESIGN

Deliveries of 2924 macrosomic infants were reviewed. Outcomes were compared with those of 16,711 infants with birth weights between 3000 and 3999 gm.

RESULTS

Macrosomic infants had a sixfold increase in significant injury relative to controls (relative risk 6.7,95% confidence interval 6.5 to 6.9). Risk of trauma correlated with delivery mode: forceps were associated with a fourfold risk of clinically persistent findings compared with spontaneous vaginal delivery or cesarean section. However, the overall incidence of persistent cases remained low (0.3%); a policy of elective cesarean section for macrosomia would necessitate 148 to 258 cesarean sections to prevent a single persistent injury. Avoidance of operative vaginal delivery would require 50 to 99 cesarean sections per injury prevented.

CONCLUSIONS

These findings support a trial of labor and judicious operative vaginal delivery for macrosomic infants.

Behavior of macrosomic and appropriate-for-gestational-age newborns

OBJECTIVE

To compare the behavior of macrosomic newborns who were vaginally delivered of healthy mothers without diabetes with that of non-macrosomic, appropriate-for-gestational-age (AGA) newborns.

DESIGN/SETTING

Newborns were recruited conveniently from a tertiary hospital. Newborns were examined at 12-24 and 36-48 hours of age, using the Brazelton Neonatal Behavioral Assessment Scale (NBAS).

PARTICIPANTS

Thirty macrosomic newborns who were delivered vaginally were matched with AGA newborns for ethnicity, maternal education, parity, and obstetric medications.

MAIN OUTCOME MEASURES

Dimensions scores derived from the individual NBAS items measured reflex functioning, response decrement, orientation, motor processes, range of state, autonomic stability, and regulation of state.

RESULTS

Macrosomic newborns performed weaker than AGA newborns on the reflex and motor dimensions. Both groups displayed improved motor scores on Day 2, but regulation of state scores were weaker. For orientation, AGA newborns scored higher on Day 1, and macrosomic newborns scored higher on Day 2.

CONCLUSIONS

Increased head, limb, and body mass of macrosomic newborns, compared with adjacent and overall muscle strength, might have interfered with the execution of coordinated movements. Nurses can inform mothers of changes they can expect in their newborns' behavior.

Impaired glucose tolerance during pregnancy is associated with increased fetal mortality in preceding sibs

OBJECTIVES

To analyze whether women with a diagnosis of gestational diabetes in the current pregnancy had an increased rate of stillbirths or of large for gestational age infants in previous pregnancies without an overtly present/diagnosed gestational diabetes.

DESIGN

A case-control analysis with two controls for each case, matched for year of delivery, maternal age (5 year class), and parity.

MATERIAL AND METHODS

All women with a diagnosis of gestational diabetes and delivered between 1987 and 1992 were identified from the Swedish Medical Birth Registry. For each woman, the first delivery with that diagnosis was used as proband case (n = 3,958). To each case and control, all previous sibs since 1973 were identified. Comparisons were made between cases and controls but also between sibs of cases and sibs of controls.

RESULTS

No significant difference was found in stillbirth rate between cases and controls (OR 1.33, CL 0.64;2.77). The rate of intrauterine deaths was significantly increased among previous sibs of the cases compared with the sibs of the controls: after stratification for year of birth, maternal age and parity an odds ratio of 1.56 (95% CL 1.12;2.19) was found. Infants born of women with gestational diabetes were heavier (mean 145 g, 95% CL 123;168 g). Similar differences were seen between immediately previous sibs of cases and controls (mean 155 g, 95% CL 127;183 g).

CONCLUSIONS

The figures indicate that in pregnancies before a delivery with gestational diabetes the perinatal prognosis was significantly poorer than expected which could be due to the presence of undiagnosed and untreated gestational diabetes. The results argue for an improved screening for gestational diabetes during pregnancy.

When is fetal macrosomia (> or = 4500 g) an indication for caesarean section?

Caesarean and vaginal deliveries of macrosomic infants weighing > or = 4500 g were studied, and pregnant women analysed by indication for caesarean section, presentation, parity and age. Both maternal and neonatal injuries occurred. Puerperal morbidity was noted in women delivered either by caesarean section or vaginally. The control group consisted of 321 parity- and age-matched pregnant women and their newborn infants weighing 3000-3499 g. The two groups were studied according to the same criteria. In the maternity unit of the General Hospital in Sibenik, Croatia, 10852 newborn infants were delivered (only singleton pregnancies included) between 1 January 1984 and 31 December 1993, of whom 321 (2.96%) weighed > or = 4500 g (290 weighing 4500-4999 g, and 31 weighing > or = 5000 g). Caesarean section was performed in 36 (11.2%) and 14 (4.4%) in the macrosomic and control groups, respectively (X2 = 10.50; P < 0.01). Of the 321 women with a macrosomic infant, 10 (3.1%) had a caesarean section for cephalopelvic disproportion and 7 (2.2%) for breech presentation. Caesarean section for vertex presentation was used more frequently in the macrosomic than in the control group (9.0% vs. 3.3%) (P < 0.01), as well as it was used for breech presentation (77.8% vs. 16.7%) (P < 0.01). As regards transverse and oblique lies, no difference was observed. The rates of macrosomic infants delivered from primiparous and grand multiparous women by caesarean section (i.e., 23.1% vs. 5.9% vs. 18.2%) were highly significant (X2 = 19.07; P < 0.001), as were the rates in adolescent pregnant women, in those of optimal childbearing age and in old pregnant women (60.0% vs. 9.0% vs. 26.9%) (X2 = 18.67; P < 0.001). Injuries were sustained by 28 (9.8%) women with a macrosomic infant delivered vaginally and by 12 (3.9%) controls (X2 = 6.25; P < 0.05). No maternal injuries were reported with caesarean delivery in either group. There was no birth trauma in the macrosomic and control infants delivered by caesarean section. With vaginal delivery birth trauma involved clavicular fracture (5.6%), brachial plexus palsy (2.8%) and central nervous system syndrome (2.1%). A total of 30 (10.5%) macrosomic infants and 4 (1.3%) controls, were identified as having birth trauma (X2 = 20.99; P < 0.001). No difference in puerperal morbidity rates were observed between the two groups with regard to caesarean and vaginal delivery (P > 0.05), showing significantly lower rates for vaginally delivered macrosomic infants (12.3% vs. 30.6%) (X2 = 8.51; P < 0.01). There was no perinatal death among those delivered by caesarean section in either group; however, when delivered vaginally, the rates were 0.70% (2 of 285) and 0.65% (2 of 307) for the macrosomic and control infants, respectively (P > 0.05). No women in either the macrosomic or control group died. In conclusion, decision making on management options when delivering a macrosomic infant depends on fetal presentation and maternal age and parity. Vertex presenting macrosomic infants weighing > or = 4500 g should be delivered vaginally, but liberal judgement is suggested in resorting to caesarean section delivery. Abnormal presentation, as well as malpresentations in primiparous women, are an absolute indication for caesarean section, whereas malpresentations in multiparous women are a relative (underlying) indication for caesarean section.

Resolving polyhydramnios: clinical significance and subsequent neonatal outcome

The objective of this study was to determine the clinical significance and neonatal outcome of patients with polyhydramnios that subsequently resolved prior to delivery. A retrospective review of 275 cases of polyhydramnios, defined as an amniotic fluid index of > or = 25.0 cm, identified 41 cases in which the amniotic fluid volume returned to normal prior to delivery. A total of 40 out of 41 patients with resolving polyhydramnios had a mild to moderate excess of amniotic fluid. There was a significant difference in the distribution of neonatal delivery weights between the study group and a matched control group. Twelve of 41 (29.3%) neonates from the study vs. none of the neonates in the control group were large for gestational age (p < 0.001). A total of 21 of 41 patients (51.2%) in the study group vs. three of 41 (7.3%) patients in the control group had at least minimal glucose intolerance (p < 0.01). We conclude that patients with resolving polyhydramnios have a significantly higher prevalence of glucose intolerance and fetal macrosomia than patients with normal pregnancies.

Gestational diabetes

The complication of diabetes during pregnancy can be a disaster for both mother and child. However, proper management of diabetes prior to conception and during pregnancy has enabled diabetics to have normal infants nearly as often as non-diabetic women. This article reviews the historical aspects of gestational diabetes, the magnitude of the problem, carbohydrate metabolism during pregnancy, appropriate therapy, and offers some suggestions about how gestational diabetes and non-insulin dependent diabetes might be prevented.

The outcome of macrosomic infants weighing at least 4500 grams: Los Angeles County + University of Southern California experience

OBJECTIVE

To describe the maternal and neonatal outcome of macrosomic infants weighing at least 4500 g.

METHODS

Maternal and neonatal records of infants with birth weights of at least 4500 g were identified during 1991. Outcome variables included the mode of delivery and incidence of maternal and perinatal complications.

RESULTS

The study sample consisted of 227 infant and mother pairs. Mean (+/- standard deviation) birth weight was 4706 +/- 219 g. A trial of labor was allowed in 192 women, and elective cesarean delivery was performed in 35 patients. The overall cesarean rate, including elective cesarean delivery and failed trial of labor, was 30.8% (70 of 227). Of those undergoing a trial of labor, 82% (157) delivered vaginally. Shoulder dystocia occurred 29 times, for an incidence of 18.5% in vaginal deliveries for macrosomia. There were seven cases each of Erb palsy and clavicular fracture, and one humeral fracture. By 2 months of age, all affected infants were without permanent sequelae. There was no birth asphyxia or perinatal mortality related to delivery for macrosomia. Maternal complications included increased risk of lacerations requiring repair (especially third- or fourth-degree lacerations) when vaginal delivery was complicated by shoulder dystocia (relative risk [RR] 5.4, 95% confidence interval [CI] 3.1-9.4). There was no statistically significant difference with respect to hemorrhage or hospital stay for women who had a vaginal delivery (with or without shoulder dystocia) compared with women who had a cesarean delivery. However, infectious morbidity increased significantly in those patients who underwent a cesarean after a trial of labor compared with women who had a vaginal delivery (RR 7.1, 95% CI 3.9-13.1) or elective cesarean birth (RR 5.4, 95% CI 3.1-9.4). Ninety-one percent of patients undergoing elective cesarean delivery had no complications.

CONCLUSION

Vaginal delivery is a reasonable alternative to elective cesarean for infants with estimated birth weights of at least 4500 g, and a trial of labor can be offered.

Estimators of birth weight in pregnant women requiring insulin: a comparison of seven sonographic models

OBJECTIVE

To determine if the relative accuracy of the sonographic estimate of birth weight among diabetic gravidas requiring insulin improves significantly as more fetal measurements are used.

METHODS

We studied 172 diabetic women requiring insulin who had sonographic measurements of fetal parts within 7 days of delivery. Friedman nonparametric analysis of variance followed by Dunn multiple comparison and chi 2 were used to assess the relative accuracy of the seven models. Prediction limits were calculated to determine the estimate of fetal weight that would ensure (with 90% accuracy) that the newborn was macrosomic (at least 4 kg).

RESULTS

The mean (+/- standard deviation [SD]) birth weight was 3388 +/- 727 g, and the frequency of macrosomia at term gestation was 19.4% (29 of 149). The mean standardized absolute error (g/kg) based on abdominal circumference (AC) and femur length (FL) (86 +/- 72 g/kg) was not significantly different from the other models (range 84 +/- 72 to 116 +/- 99 g/kg, P > .05). The percent of estimate within 10% of actual birth weight using AC and FL (65%) was similar to the other models (53.4-66.2%). Regardless of the White classification, the estimation of fetal weight using AC and FL had an accuracy similar to the other six regression equations. To ensure that the birth weight is at most 3999 g, the estimated fetal weight should be 3200 g, and, conversely, if the predicted weight is 4700 g, then the newborn is macrosomic.

CONCLUSION

Among patients requiring insulin, estimation of birth weight using AC and FL is as accurate as more complicated models. The ability to detect macrosomia by ultrasound is limited.

Altered diastolic function in infants of mothers with gestational diabetes: no relation to macrosomia

In a previous study, asymptomatic infants of mothers with gestational diabetes (IGDMs) were observed to have altered left ventricular (LV) filling. In the present study, we reanalyzed the data to examine whether the observed abnormalities were related to maternal diabetes or due to the greater preponderance of macrosomic infants (32%) in the gestational diabetes group. No echocardiographic (systolic or diastolic) differences were observed when the data were compared in 16 large-for-gestational-age (LGA) and 24 appropriate-for-gestational-age (AGA) infants among IGDM. Comparison of 16 LGA IGDM and 17 LGA infants of control mothers revealed lower LV size during diastole and systole in the IGDM. The present analysis suggests that the cardiac alterations in the IGDMs are not due to the preponderance of macrosomia but, rather, the consequence of altered in utero metabolic environment.

Macrosomia--maternal and fetal risk factors

Risk factors associated with fetal macrosomia were studied in 348 pregnancies resulting in the delivery of an infant weighing 4,000 g or more in a black population. Identifiable maternal risk factors included a mother in her 3rd decade of life, multiparity, maternal weight of 70 kg or more at the end of pregnancy, prolonged or post-term pregnancy, abnormal glucose tolerance and previous history of a macrosomic infant. Male infants had a higher risk of being macrosomic. Macrosomic infants accounted for 3.4% of all singleton deliveries, with their caesarean section rate of 33.9% being almost three times that of control infants. The importance of antenatal prediction of fetal weight is emphasised and suggestions for reduction of the high perinatal mortality and morbidity rates, as well as maternal morbidity, are discussed.

[Fetal development in late gestosis and nicotine consumption]

In pre-eclamptic and in smoking women, the foetus often develops growth retardation. Hence, nicotine as vasoconstrictive substance increases the blood pressure, therefore causes a higher incidence for pre-eclamptic toxaemia in smoking pregnant women. By means of perinatal inquiry in Baden-Württemberg, not only the frequency of preeclamptic toxaemia was proven in smoking women, but also the frequency of toxaemia in mothers with low, of normal and high weight of the newborn. Hypertension is more frequent in mothers with overweight babies than in mothers with babies of normal weight. In case of overweight newborns, toxaemia is less often caused by proteinuria than in underweight babies. Hypertension is less frequent in smoking pregnant women than in non-smoking women. These findings can be explained by a new theory, which interprets pre-eclamptic toxaemia as a compensatory mechanism in foetal growth retardation. For the foetus, which is insufficiently supplied by the placenta, this regulatory mechanism enhances the blood supply of the placenta. The higher incidence of toxaemia in pregnant women with overweight babies is explained by an increased demand on the placenta, which causes a better foetal blood supply of the placenta in developing the toxaemia. In this case, the toxaemia is compensated. In the stage of decompensation with foetal growth retardation, all reserves are mobilised by an increased permeability of the vessels, which leads to an improved passage through the placenta, but also to proteinuria and increased incidence of oedema.(ABSTRACT TRUNCATED AT 250 WORDS)

Fetal macrosomia--pregnancy and delivery

The authors have studied pregnancy, delivery and early neonatal status of macrosomic infants (> or = 4000 g) delivered between January 1, 1984, and December 31, 1992. The control group comprised age--and parity--matched pregnant women and their newborns weighing 3000 to 3999 g. From 9980 singleton pregnancies, 2021 (20.3%) macrosomics were delivered. The incidence of macrosomia was 16.7% in the primiparous group, 23.1% in the parity 2-4 group, and 28.2% in the multiparous group (parity > or = 5) (P < 0.001). The rates of macrosomic infants for pregnant adolescents (aged < or = 19 years), pregnant women aged 20-34 years and old pregnant women (> or = 35 years) were 12.0%, 20.6% and 21.5%, respectively (P < 0.001). Macrosomia was not influenced by occupation and antenatal visits (P > 0.05). The rates of > or = 16 kg weight gain in the macrosomic and control groups were 36.2% (mean 14.30 +/- 4.66 kg) and 16.7% (mean 12.18 +/- 4.82 kg), respectively (t = 12.05; P < 0.001). Of 546 pregnant women with fetal macrosomia subjected to oral GT testing, glucose intolerance was found in 20.0% and gestational diabetes in 4.8%. The rates of glucose intolerance and gestational diabetes in 259 control subjects were 13.9% and 2.3%, respectively (P < 0.05). Light (index 1-4) and moderate (index 5-7) forms of EPH gestosis were more common in the macrosomic group, whereas no difference was observed for severe forms (index > or = 8) between the groups (P > 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Hyperinsulinemia in macrosomic infants of nondiabetic mothers

OBJECTIVE

We tested the hypothesis that macrosomic infants of nondiabetic mothers are more likely to have hyperinsulinemia and increased subcutaneous fat.

RESEARCH DESIGN AND METHODS

Plasma insulin concentrations were measured in cord blood from 50 macrosomic infants and 32 normal-sized (control), term infants. All mothers had had a normal 50-g 1-h GCT. Skin-fold measurements of the triceps and subscapular area were done on 44 macrosomic infants with a Halpern caliper.

RESULTS

No difference was observed in GCT between mothers of macrosomic (5.8 +/- 1.0 mM) and normal (5.7 mM) infants. The insulin level in macrosomic infants (18.75 +/- 19.08 microU/ml) was significantly higher than in control infants (8.67 +/- 6.64 microU/ml). Macrosomia was a predictor of hyperinsulinemia and vice versa (R2 = 0.26). Maternal height, prepregnancy weight, and weight gain were predictors for macrosomia (R2 = 0.26). No differences were noted in anthropometric measurements between hyperinsulinemic and normoinsulinemic infants.

CONCLUSIONS

A subset of macrosomic infants have hyperinsulinemia. Maternal anthropometric factors as well as hyperinsulinemia are correlated with macrosomia. The macrosomia may be causally related to the high insulin levels.

Diabetic fetal macrosomia: significance of disproportionate growth

Fetal hyperinsulinism in infants of diabetic mothers (IDMs) produces increased fetal growth leading to macrosomia, which may or may not be proportionate. Disproportionate macrosomia refers to excessive weight characterized by a high weight/length ratio. We tested the hypotheses that (1) macrosomia in IDMs would be characterized by a high ponderal index (defined as weight/length ratio) and (2) infants with macrosomia who have a high ponderal index would have increased neonatal morbidity--specifically, hyperbilirubinemia, hypoglycemia, polycythemia, and acidosis. We studied 170 IDMs and 510 non-IDMs matched 1:3 for gestational age, race, and year of delivery. Forty-five percent of IDMs had macrosomia compared with 8% of control infants (p = 0.001), and 19% of IDMs had disproportionate macrosomia compared with 1% of control infants (p = 0.001). The rates of hyperbilirubinemia (p = 0.02), hypoglycemia (p = 0.01), and acidosis (p = 0.01) were greatest in infants with disproportionate macrosomia and least in nonmacrosomic infants. The incidence of polycythemia was not significantly different between the groups. We suggest that disproportionate macrosomia in the IDM is associated with an increased likelihood of neonatal complications.

Detection of the fetus at risk

Successful reproduction has ensured the survival of the human race despite disease and famine. However, a good standard of living, combined with a well-balanced diet, is closely related to low maternal, perinatal and infant mortality rates. In the third world, anaemia, rheumatic heart disease, tuberculosis and other infections are still common and the poorly nourished are more susceptible to them. In the Western world food is plentiful but often the individual's diet is poorly balanced. Invariably the fetus takes all the nutrients required from the mother and, if a deficiency occurs, this is reflected in the maternal reserves only. The weight of the baby at birth has a wide biological variation and correlates in the extremes with maternal weight but there are many other factors responsible for fetal growth. In early pregnancy the developing embryo may be susceptible to specific dietary deficiencies and structural malformations may result. A clear link has recently been established between folic acid supplementation and the prevention of recurrence of neural tube defects. Excessive doses of vitamin A should be avoided.

Sonographic diagnosis of IUGR-macrosomia

Many sonographic methods have been suggested for identification of the fetus with a growth abnormality. Clearly, optimal management depends on early diagnosis. In recent years, advances in sonography have improved the ability to identify abnormal growth patterns and evaluate fetal well-being. When abnormal fetal growth is suspected, a thorough sonographic evaluation should be performed. This evaluation includes measurements of the abdominal circumference, femur length,) BPD, HC, AC, FL, and amniotic fluid volume. If these measurements confirm the suspicion of abnormal fetal growth, careful search for anomalies is mandatory. If there is no evidence of fetal compromise that would warrant delivery, measurements should be repeated in 2-3 weeks to evaluate interval growth. The following conclusions could be drawn from this literature review: 1. Intrauterine growth retardation and macrosomia are multifactorial diseases with varying degrees of severity. It is unlikely that a single sonographic parameter will allow an accurate diagnosis of all cases. 2. The type and degree of growth retardation and macrosomia depend on the intensity and duration of the underlying disease. Thus, an ultrasound assessment performed long before delivery may be of limited value. 3. Most of the sonographic parameters reviewed in this chapter are gestational age dependent. Unfortunately, gestational age is often unknown. Gestational age independent indices such as the amniotic fluid volume, FL/AC ratio, and the rate of fetal growth should be helpful in this situation. 4. The constitutionally small infant whose only problem is low birth weight should not be expected to present with any abnormal indices other than a low EFW. On the other hand, newborns who appear to be malnourished but whose birth weight is at or slightly above the tenth percentile for gestational age, may present with abnormal indirect indices indicating growth retardation (ie, HC/AC, FL/AC, Doppler velocimetry or oligohydramnios) despite a normal estimate of fetal weight. In addition, if the diagnosis of IUGR is made only with the use of birthweight for gestational age criteria, these infants are likely to be misclassified and labelled AGA. However, an abnormal ponderal index would indicate that these neonates are growth retarded. It can be concluded from this review that the use of sonographic measurements for diagnosing IUGR or macrosomia is associated with a high specificity and a somewhat lower sensitivity. Therefore, it would seem that the current ultrasound methods are more useful for excluding the possibility of abnormal fetal growth rather than for confirming it.

Biphasic effects of maternal metabolism on fetal growth. Quintessential expression of fuel-mediated teratogenesis

More than a decade ago, Norbert Freinkel postulated that alterations in the maternal metabolic milieu at any time during gestation can influence intrauterine development and also may have long-term consequences for certain tissues such as adipocytes, myocytes, pancreatic beta-cells, and neurons. This review illustrates that metabolic alterations early in gestation, such as those that occur in diabetes mellitus, may impair growth of the embryo and increase the risk of dysmorphogenesis. Such delayed growth of the embryo may in turn influence size at birth. In midgestation, metabolic perturbations may accelerate functional maturation of fetal pancreatic beta-cells. Fetal beta-cell development is very sensitive to alterations in the nutrient milieu and may be enhanced in gestational diabetes mellitus (GDM) with only minimal elevations of plasma glucose and minor alterations in other nutrient fuels, including insulinogenic amino acids. Data are reviewed that suggest that the ensuing fetal hyperinsulinemia may promote the development of macrosomia even if metabolic control is satisfactory during late gestation. The overall potential influences of metabolic alterations on intrauterine growth are different in pregnancies complicated by diabetes mellitus throughout gestation (pregestational) and GDM. However, the implications in an individual pregnancy may be defined by the degree of metabolic control at the specific stages of gestation when growth of the embryo, development of fetal beta-cell function, and growth of insulin-sensitive tissues are most critically influenced by the metabolic milieu.

Cerebral blood flow velocity and cardiac output in infants of insulin-dependent diabetic mothers

Cardiac output and cerebral blood flow velocity in the anterior cerebral and internal carotid arteries were investigated in eight large-for-date infants of insulin-dependent diabetic mothers and 12 healthy term infants during the first four days of life using two-dimensional/pulsed Doppler ultrasound. Temporal mean flow velocity was used as an indicator of changes in cerebral blood flow. Six of the eight infants of diabetic mothers had ventricular septal hypertrophy with reduced cardiac outputs and stroke volumes. Mean flow velocity in both cerebral vessels showed a comparable pattern in both groups throughout the study period and was independent of mean arterial pressure, suggesting unaltered cerebral hemodynamics in the infants of diabetic mothers.

Detection of macrosomia by the individual fetal growth curve assessment method

The value of the Rossavik growth model [P = c(t)k + s(t)] was evaluated in 39 patients with singleton pregnancy who had neonatal weight outcome above the 90th percentile of our birth weight distribution for gestational age. Individual fetal growth curve standards for head and abdominal circumferences, femur diaphysis length, and weight were determined from the data of two scans obtained before 26.1 weeks' gestation and separated by an interval of at least 5 weeks. Projected crown-heel lengths were calculated from projected femur diaphysis length values. Comparisons between actual and predicted birth characteristics were expressed by the Growth Potential Realization Index (GPRI) and Neonatal Growth Assessment Score (NGAS). Excessive growth at birth was seen in almost all cases as indicated by high GPRI for weight and abdominal circumference and abnormal NGAS values. In eight of the 33 patients who delivered after 38 weeks, excessive growth was detected only by comparing birth characteristics to their predicted values at 38 weeks' gestation. Our data suggest that individual growth curve standards may identify several patterns of excessive fetal growth that could represent different pathophysiologic mechanisms, ie, failure to terminate growth after 38 weeks versus a defect in a still unknown growth regulator. The individual fetal growth curve standards method gives additional information and discriminates well between normal and excessive fetal growth.

Infants of diabetic mothers with accelerated fetal growth by ultrasonography: are they all alike?

We studied longitudinal ultrasonographic growth patterns (abdominal circumference, biparietal diameter) initiated early in gestation in 52 pregnancies complicated by pregestational diabetes mellitus and 19 controls. Three predominant patterns of growth were ascertained including a heretofore unrecognized pattern characterized by accelerated abdominal circumference growth (greater than 90th percentile) before 24 weeks' gestational age. Maternal and neonatal anthropometric and metabolic parameters were contrasted for the three patterns. The findings suggest that in some cases of diabetic macrosomia that can be recognized before 24 weeks' gestation, augmented growth may be influenced by factors other than fetal hyperinsulinism.