Fetal growth: a review of terms, concepts and issues relevant to obstetrics

The perinatal literature includes several potentially confusing and controversial terms and concepts related to fetal size and growth. This article discusses fetal growth from an obstetric perspective and addresses various issues including the physiologic mechanisms that determine fetal growth trajectories, known risk factors for abnormal fetal growth, diagnostic and prognostic issues related to restricted and excessive growth and temporal trends in fetal growth. Also addressed are distinctions between fetal growth 'standards' and fetal growth 'references', and between fetal growth charts based on estimated fetal weight vs those based on birth weight. Other concepts discussed include the incidence of fetal growth restriction in pregnancy (does the frequency of fetal growth restriction increase or decrease with increasing gestation?), the obstetric implications of studies showing associations between fetal growth and adult chronic illnesses (such as coronary heart disease) and the need for customizing fetal growth standards.

Characteristics of infants at risk of hypoglycaemia secondary to being 'infant of a diabetic mother'

BACKGROUND

Infants of diabetic mothers (IDMs) are at risk of hypoglycaemia in the neonatal period. The prediction of which of these infants are at higher risk of developing hypoglycaemia is complex.

AIMS

To determine the characteristics of infants of diabetic mothers who are more likely to need an admission to the neonatal intensive care unit to manage their hypoglycaemia.

METHODS

Retrospective chart review of maternal and infant characteristics of 'at-risk' infants. Electronic patient records and neonatal and obstetric database accessed to obtain data.

RESULTS

A total of 326 infants were identified in a study period accessible to electronic patient records. Macrosomia was present in 15% of the infants. Hypoglycaemic episodes occurred in 109 (33.4%) infants. Maternal diabetes type, HbA1c, prematurity, macrosomia, and temperature instability were identified as risk factors most commonly associated in infants who actually went on to develop hypoglycaemia.

CONCLUSIONS

A weighted risk score to predict hypoglycaemia in this at-risk population may serve to rationalise admission to the neonatal unit and management of IDMs.

Trends in maternal BMI, glycaemic control and perinatal outcome among type 1 diabetic pregnant women in 1989-2008

AIMS/HYPOTHESIS

Our objective was to examine the trends in prepregnancy BMI and glycaemic control among Finnish type 1 diabetic patients and their relation to delivery mode and perinatal outcome.

METHODS

We analysed the obstetric records of 881 type 1 diabetic women with a singleton childbirth during 1989-2008. Maternal prepregnancy weight and height were obtained from the maternity cards, where they are recorded as reported by the mother.

RESULTS

Maternal BMI increased significantly during 1989-2008 (p < 0.001). The mean HbA(1c) in the first trimester remained unchanged, but the midpregnancy and the last HbA(1c) before delivery increased (p = 0.009 and 0.005, respectively). Elective Caesarean sections (CS) decreased (p for trend <0.001), while emergency CS increased (p for trend <0.001). The mean umbilical artery (UA) pH decreased in vaginal deliveries (p for trend <0.001). The frequency of UA pH <7.15 and <7.05 increased (p for trend <0.001 and 0.008, respectively). The macrosomia rate remained at 32-40%. Neonatal intensive care unit (NICU) admissions increased (p for trend 0.03) and neonatal hypoglycaemia frequency decreased (p for trend 0.001). In multiple logistic regression analysis, maternal BMI was associated with macrosomia and NICU admission. The last HbA(1c) value before delivery was associated with delivery before 37 weeks' gestation, UA pH <7.15, 1 min Apgar score <7, macrosomia, NICU admission and neonatal hypoglycaemia.

CONCLUSIONS/INTERPRETATION

Self-reported pregestational BMI has increased and glycaemic control during the second half of pregnancy has deteriorated. Poor glycaemic control seems to be associated with the observed increases in adverse obstetric and perinatal outcomes.

[Growth follow-up of infants born macrosomia at their life of 0 to 18 months]

OBJECTIVE

To study the growth of macrosomic infants, the incidence of overweight and the factors related to overweight at 18 months old.

METHODS

Eighty-four macrosomic infants without underlying diseases were enrolled in this study. Their growth was followed up regularly. Factors related to overweight at 18 months old were investigated.

RESULTS

Twenty infants (24%) showed as overweight at 18 months old. More male infants were overweight than female infants (30% vs 11%; P<0.05). The overweight infants at 18 months old had a higher proportion of overweight at 6 months (80% vs 22%; P<0.01) and at 12 months old (80% vs 13%; P<0.01) than non-overweight infants at 18 months. The spearman correlation analysis demonstrated that weight-for-length Z score at 18 months old was positively correlated with birth weight and weight gain between 0 to 6 months, 7 to 12 months and 13 to 18 months (P<0.05). The strongest correlation was observed between weight gain form 0 to 6 months and weight-for-length Z score at 18 months old (r=0.597, P<0.01).

CONCLUSIONS

More attention should be given to the aspect of rapid weight gain in the first 6 months of life in macrosomic infants, especially males, to prevent obesity in early childhood.

Gestational diabetes and subsequent growth patterns of offspring: the National Collaborative Perinatal Project

Our objective was to test the hypothesis that intrauterine exposure to gestational diabetes [GDM] predicts childhood growth independent of the effect on infant birthweight. We conducted a prospective analysis of 28,358 mother-infant pairs who enrolled in the National Collaborative Perinatal Project between 1959 and 1965. The offspring were followed until age 7. Four hundred and eighty-four mothers (1.7%) had GDM. The mean birthweight was 3.2 kg (range 1.1-5.6 kg). Maternal characteristics (age, education, race, family income, pre-pregnancy body mass index and pregnancy weight gain) and measures of childhood growth (birthweight, weight at ages 4, and 7) differed significantly by GDM status (all P < 0.05). As expected, compared to their non-diabetic counterparts, mothers with GDM gave birth to offspring that had higher weights at birth. The offspring of mothers with GDM were larger at age 7 as indicated by greater weight, BMI and BMI z-score compared to the offspring of mothers without GDM at that age (all P < 0.05). These differences at age 7 persisted even after adjustment for infant birthweight. Furthermore, the offspring of mothers with GDM had a 61% higher odds of being overweight at age 7 compared to the offspring of mothers without GDM after adjustment for maternal BMI, pregnancy weight gain, family income, race and birthweight [OR = 1.61 (95%CI:1.07, 1.28)]. Our results indicate that maternal GDM status is associated with offspring overweight status during childhood. This relationship is only partially mediated by effects on birthweight.

Fetal hemodynamic development in macrosomic growth

OBJECTIVE

To determine the venous and arterial hemodynamics underlying macrosomic fetal growth.

METHODS

Fifty-eight healthy women who previously had given birth to a large neonate were included in a prospective longitudinal study. Of these, 29 gave birth to neonates with birth weight ≥ 90th percentile and were included in the statistical analysis. Umbilical vein blood flow and Doppler measurements of the ductus venosus, left portal vein and the hepatic, splenic, superior mesenteric, cerebral and umbilical arteries were repeated at 3-5 examinations during the second half of pregnancy and compared with the corresponding reference values. Ultrasound biometry was used to estimate fetal weight.

RESULTS

Umbilical blood flow increased faster in macrosomic fetuses, showed less blunting near term and was also significantly higher when normalized for estimated fetal weight (P < 0.0001). The portocaval perfusion pressure of the liver (expressed by the ductus venosus systolic blood velocity) and the left portal vein blood velocity (expressing umbilical venous distribution to the right liver lobe) were significantly higher. Systolic velocity was higher in the splenic, superior mesenteric, cerebral and umbilical arteries, while the pulsatility index was unaltered in the cerebral, hepatic, splenic and mesenteric arteries, but lower in the umbilical artery.

CONCLUSIONS

There is an augmented umbilical flow in macrosomic fetuses particularly near term, also when normalized for estimated fetal weight, providing increased liver perfusion, including the right liver lobe. Signs of increased vascular cross section and flow are also seen on the arterial side but not expressed in the pulsatility index of organs with prominent auto-regulation (i.e., brain, liver, spleen and gut).

Preeclampsia and the risk of large-for-gestational-age infants

OBJECTIVE

We sought to compare the risk of giving birth to large-for-gestational-age (LGA) infants in women with and without preeclampsia, after adjustment for obesity and glucose intolerance.

STUDY DESIGN

We conducted secondary analysis of a prospective database of pregnant women with and without preeclampsia who delivered infants from 1998 through 2006 at Massachusetts General Hospital (n = 17,465).

RESULTS

The risk of LGA was similar in women with and without preeclampsia (odds ratio, 0.81; 95% confidence interval, 0.59-1.14). After adjustment for body mass index, glucose intolerance, and other factors, the risk of LGA was significantly lower in women with preeclampsia compared to those without preeclampsia (odds ratio, 0.69; 95% confidence interval, 0.49-0.96). Stratified analysis in groups with a higher risk of LGA revealed that preeclampsia has a similar effect on the risk of LGA regardless of maternal obesity, glucose intolerance, parity, and race.

CONCLUSION

Preeclampsia appears to be characterized by reduced, and not increased, fetal growth.

Fetal growth trajectories in Type-1 diabetic pregnancy

OBJECTIVE

To describe the individual intrauterine growth patterns of fetuses of insulin-dependent (Type-1) diabetic women and to examine determinants of overgrowth (macrosomia) and its timing.

METHODS

This retrospective longitudinal study examined the developmental trajectories of fetal abdominal circumference (AC) and biparietal diameter in 76 Type-1 diabetic women with singleton pregnancies. Latent class analysis was used to identify subgroups of patients with a shared fetal AC growth trajectory. Subsequently, maternal factors, including glycemic control as assessed by glycosylated hemoglobin (HbA1c), were examined to see whether they had any effect on fetal growth.

RESULTS

Four subgroups with different AC growth patterns were identified. Differences in birth weight between the distinct subgroups were related to the shape of the AC growth velocity curve over gestation. Acceleration of AC growth commencing before or after 25 weeks' gestation was associated with the birth of a heavy or large-for-dates baby in 94 and 56% of cases, respectively. Poor glycemic control (HbA1c > 7.0%) during the periconception period or before 12 weeks' gestation was a modest predictor of midtrimester growth in AC. Other diabetes-related factors, fetal sex, parity, or maternal weight/obesity were unrelated to the fetal growth pattern.

CONCLUSION

The findings suggest that an individual fetus's growth trajectory is set early in gestation and that the contemporaneous degree of maternal glycemia plays a role in determining birth weight.

Caesarean section and macrosomia increase transient tachypnoea of the newborn in type 1 diabetes pregnancies

We determined whether transient tachypnoea of the newborn (TTN) is more common in macrosomic versus normal weight infants and in those delivered by caesarean section versus vaginally, in a retrospective cohort analysis of 212 type 1 diabetes pregnancies. Caesarean section and macrosomia were both associated with higher TTN rates.

A systematic review of outcomes of maternal weight gain according to the Institute of Medicine recommendations: birthweight, fetal growth, and postpartum weight retention

This systematic review focuses on outcomes of gestational weight gain, specifically birthweight, fetal growth, and postpartum weight retention, for singleton pregnancies with respect to the 1990 Institute of Medicine weight gain recommendations. A total of 35 studies met the inclusion criteria and were reviewed. There was strong evidence to support associations between excessive gestational weight gain and increased birthweight and fetal growth (large for gestational age) as well as inadequate gestational weight gain and decreased birthweight and fetal growth (small for gestational age). There was moderate evidence to support the association between excessive gestational weight gain and postpartum weight retention. Clear clinical recommendations based on this review are challenging because of several limitations in the literature. Improvements in future research include the use of consistent definitions of gestational weight gain and outcomes of interest, assessment of confounders, and better collection of weight and weight gain data.

[Relationship of adiponectin and visfatin with fetus intrauterine growth]

OBJECTIVE

To explore the correlation between adipocyte factors (adiponectin and visfatin) and fetus intrauterine growth.

METHODS

Enzyme immunoassay was used to measure the adiponectin and visfatin levels in maternal and umbilical serum from 14 women with fetal growth restriction (FGR group), 14 women with macrosomia (macrosomia group) and 14 normal pregnant women (control group). The correlations of cord serum adiponectin and visfatin with maternal serum adiponectin and visfatin were analyzed.

RESULTS

(1) Serum visfatin levels in FGR mothers [(41.4 +/- 5.5)] microg/L were significantly higher than that in control women [(34.7 +/- 4.9) microg/L] and macrosomia mothers [(37.3 +/- 4.4) microg/L; P < 0.01, P < 0.05]. Serum adiponectin levels in macrosomia mothers [(4.1 +/- 1.3) mg/L] were significantly lower than that in control women [(6.6 +/- 1.5) mg/L] and FGR mothers [(6.4 +/- 1.3) mg/L; P < 0.01]. (2) Serum visfatin levels in FGR babies [(58.1 +/- 7.6) microg/L] were significantly increased than that in control newborns [(42.6 +/- 7.8) microg/L] and macrosomia babies [(48.5 +/- 9.1) microg/L; P < 0.01, P < 0.05]. Serum adiponectin levels in macrosomia babies [(6.5 +/- 1.3) mg/L] were significantly decreased than that in control newborns [(7.7 +/- 1.5) mg/L] and FGR babies [(7.7 +/- 1.0) mg/L; P < 0.05, P < 0.05]. (3) Maternal serum visfatin levels were positively correlated with umbilical serum visfatin levels (r = 0.720, P < 0.01). Umbilical serum adiponectin levels were higher than that in maternal serum, but there were no relationship between them (r = 0.301, P > 0.05).

CONCLUSION

The changes of visfatin and adiponectin levels may be related to the occurrence of FGR and fetal macrosomia.

Is severe macrosomia manifested at 11-14 weeks of gestation?

OBJECTIVE

To determine the association between fetal biometry in the first or early second trimester and severe macrosomia at delivery.

METHODS

This case-control study included 30 term severely macrosomic neonates; 90 appropriate-for-gestational age (AGA) neonates served as controls. All pregnancies underwent nuchal translucency (NT) screening at 11-14 weeks' gestation. Pregnancies were dated by accurate last menstrual period consistent with crown-rump length (CRL) measurements at the time of screening, early pregnancy CRL or date of fertilization. The association between birth weight and the difference between the measured and the expected CRL at the time of NT screening was analyzed.

RESULTS

The difference between measured and expected CRL, expressed both in mm and in days of gestation, was statistically greater in the severely macrosomic neonates compared with controls (mean, 6.66 +/- 4.78 mm vs. 1.17 +/- 4.6 mm, P < 0.0001 and 3 +/- 2.2 days vs. 0.5 +/- 2.3 days, P < 0.0001, respectively). Furthermore, there were significant correlations between the extent of macrosomia and the discrepancy between expected and measured fetal size at the time of NT screening (r = 0.47, P < 0.01 and r = 0.48, P < 0.01, respectively).

CONCLUSION

Severe macrosomia apparently manifests as early as 11-14 weeks' gestation.

Labor and delivery management for women with diabetes

Diabetes in pregnancy confers a number of risks for both the mother and her baby, and many of these risks are encountered in the labor and delivery unit. The obstetric provider caring for women with diabetes should be alert to the risk of hypertension and the potential for difficult delivery due to an overgrown fetus. Women with preexisting diabetes or poor glycemic control are at increased risk for poor obstetrical outcomes such as stillbirth or delivery of a malformed infant. Meticulous attention to avoiding maternal hyperglycemia during labor can prevent neonatal hypoglycemia.

Maternal glycated haemoglobin, pre-gestational weight, pregnancy weight gain and risk of large-for-gestational-age babies: a Danish cohort study of 209 singleton Type 1 diabetic pregnancies

AIMS

To examine the association between maternal glycated haemoglobin in the second half of diabetic pregnancies and the relative risk of delivering large-for-gestational-age (LGA) babies, controlling for maternal body mass index (BMI) before pregnancy, weight gain, age, White class and smoking habits.

METHODS

We identified all pregnant diabetic women in North Jutland County, Denmark from 1985 to 2003. Data on HbA(1c) values from the 20th gestational week to term were collected from medical records and the babies were classified as large, normal or small for gestational age. The association between glycated haemoglobin (HbA(1c)) and relative risk of delivering an LGA baby was quantified based on logistic regression models and stratified analysis controlling for the five covariates.

RESULTS

We included 209 singleton pregnancies with assessable HbA(1c) values of which 59%[95% confidence interval (CI) 52-65%] terminated with an LGA baby. Increasing levels of HbA(1c), BMI and weight gain were all associated with increasing risk of delivering an LGA baby. Analyses stratified according to maternal BMI showed that the association between HbA(1c) and risk of delivering an LGA baby was restricted to pregnancies with pre-pregnancy BMI > 23 kg/m(2). We found no association between HbA(1c) and risk of delivering an LGA baby in pregnancies with lower BMI.

CONCLUSION

The positive association between glycated haemoglobin and birth of an LGA baby seems to be restricted to women with BMI > 23 kg/m(2).

Type 2 diabetes: hypoinsulinism, hyperinsulinism, or both?

The author discusses a new study reporting the birth weight of patients carrying a mutation in either of two closely related genes associated with maturity-onset diabetes of the young, testing the hypothesis that the primary defect caused by these genes results in decreased insulin secretion.

Macrosomia and hyperinsulinaemic hypoglycaemia in patients with heterozygous mutations in the HNF4A gene

BACKGROUND

Macrosomia is associated with considerable neonatal and maternal morbidity. Factors that predict macrosomia are poorly understood. The increased rate of macrosomia in the offspring of pregnant women with diabetes and in congenital hyperinsulinaemia is mediated by increased foetal insulin secretion. We assessed the in utero and neonatal role of two key regulators of pancreatic insulin secretion by studying birthweight and the incidence of neonatal hypoglycaemia in patients with heterozygous mutations in the maturity-onset diabetes of the young (MODY) genes HNF4A (encoding HNF-4alpha) and HNF1A/TCF1 (encoding HNF-1alpha), and the effect of pancreatic deletion of Hnf4a on foetal and neonatal insulin secretion in mice.

METHODS AND FINDINGS

We examined birthweight and hypoglycaemia in 108 patients from families with diabetes due to HNF4A mutations, and 134 patients from families with HNF1A mutations. Birthweight was increased by a median of 790 g in HNF4A-mutation carriers compared to non-mutation family members (p < 0.001); 56% (30/54) of HNF4A-mutation carriers were macrosomic compared with 13% (7/54) of non-mutation family members (p < 0.001). Transient hypoglycaemia was reported in 8/54 infants with heterozygous HNF4A mutations, but was reported in none of 54 non-mutation carriers (p = 0.003). There was documented hyperinsulinaemia in three cases. Birthweight and prevalence of neonatal hypoglycaemia were not increased in HNF1A-mutation carriers. Mice with pancreatic beta-cell deletion of Hnf4a had hyperinsulinaemia in utero and hyperinsulinaemic hypoglycaemia at birth.

CONCLUSIONS

HNF4A mutations are associated with a considerable increase in birthweight and macrosomia, and are a novel cause of neonatal hypoglycaemia. This study establishes a key role for HNF4A in determining foetal birthweight, and uncovers an unanticipated feature of the natural history of HNF4A-deficient diabetes, with hyperinsulinaemia at birth evolving to decreased insulin secretion and diabetes later in life.

Fetal Macrosomia – A Continuing Obstetric Challenge

BACKGROUND

Macrosomic fetuses represent a continuing challenge in obstetrics.

OBJECTIVES

We studied maternal risk factors of fetal macrosomia and maternal and infant outcome in such cases.

METHODS

A retrospective cohort study was carried out with a total of 26,961 singleton pregnancies between 1989 and 2001. Records of 886 mothers who gave birth to live born infants weighing > or =4,500 g were compared to those of 26,075 mothers with normal weight (<4,500 g) infants. Multiple regression analysis was used to identify independent reproductive risk factors. Perinatal complications were also assessed.

RESULTS

The incidence of fetal macrosomia was 3.4%. Diabetes, previous macrosomic birth, postdatism (>42 weeks of gestation), obesity (BMI > 25 before pregnancy), male infant, gestational diabetes mellitus, and non-smoking were independent risk factors of fetal macrosomia, with adjusted risks of 4.6, 3.1, 3.1, 2.0, 1.9, 1.6, 1.4, respectively. In the macrosomic group, birth and maternal traumas occurred significantly more often than in the control group. However, records of subsequent pregnancies (n = 250) after the study period showed that a previous uncomplicated birth appeared to decrease complication risks.

CONCLUSIONS

Most cases of fetal macrosomia occur in low-risk pregnancies and evaluation of maternal risks cannot accurately predict which women will eventually give birth to an overweight newborn. After an uncomplicated birth of a macrosomic infant, vaginal delivery may be a safe option for the infant and mother.

Lipid profile, glucose homeostasis, blood pressure, and obesity-anthropometric markers in macrosomic offspring of nondiabetic mothers

OBJECTIVE

The study was to determine whether being the macrosomic offspring of a mother without detected glucose intolerance during pregnancy has an impact on lipid profile, glucose homeostasis, and blood pressure during childhood.

RESEARCH DESIGN AND METHODS

Plasma total, HDL, and LDL cholesterol; triglycerides; apolipoprotein (Apo) A-1, -B, and -E; lipoprotein (a); fasting glucose and insulin; homeostasis model assessment of insulin resistance (HOMA-IR) index; blood pressure; BMI; and detailed anthropometry were evaluated in 85 children aged 3-10 years old, born appropriate for gestational age (AGA; n = 48) and large for gestational age (LGA; n = 37) of healthy mothers.

RESULTS

At the time of the assessment, body weight, height, skinfold thickness, BMI, waist circumference, and blood pressure did not differ between the LGA and AGA groups with the exception of head circumference (P < 0.01). There were no significant differences in plasma total or LDL cholesterol; triglycerides; Apo A-1, -B, or -E; lipoprotein (a); Apo B-to-Apo A-1 ratio; or glucose levels between the groups. The LGA group had significantly higher HDL cholesterol levels (P < 0.01), fasting insulin levels (P < 0.01), and HOMA-IR index (P < 0.01) but lower values of the glucose-to-insulin ratio (P < 0.01) as compared with the AGA group.

CONCLUSIONS

Children born LGA of mothers without confirmed impaired glucose tolerance during pregnancy show higher insulin concentrations than AGAs.

Modulation of lipid metabolism by n-3 polyunsaturated fatty acids in gestational diabetic rats and their macrosomic offspring

The time course of changes in lipid metabolism by dietary n-3 PUFAs (polyunsaturated fatty acids) in streptozotocin-induced diabetic rats during pregnancy (days 12 and 21) and their macrosomic offspring at birth (day 0) and through adulthood (days 60 and 90) was studied with respect to adipose tissue, liver and serum lipid concentrations, and fatty acid composition. Glucose and insulin levels were also assessed in order to characterize the diabetic state of macrosomic offspring. Pregnant diabetic and control rats were fed either an Isio-4 or EPAX diet (enriched with n-3 PUFA). The same diets were also consumed by pups at weaning. Compared with control rats, during pregnancy diabetic rats had a significant elevation in liver and serum triacylglycerol (triglyceride) and cholesterol concentrations. At birth, macrosomic pups had higher serum insulin and glucose levels than control pups. The macrosomic rats maintained accelerated postnatal growth combined with high adipose tissue weight and lipid content through the first 12 weeks of age. The macrosomic pups from diabetic rats fed the Isio-4 diet also showed a significant enhancement in liver and serum triacylglycerol and cholesterol levels at birth and during adulthood. Feeding the EPAX diet to diabetic mothers as well as their macrosomic pups increased serum and liver levels of EPA (eicospentaenoic acid) and DHA (docosahexaenoic acid) with a reduction in arachidonic acid. The EPAX diet induced a significant decrease in liver and serum triacylglycerol and cholesterol concentrations in mothers during pregnancy and in their macrosomic pups during adulthood. Since the EPAX diet improves lipid anomalies considerably in diabetic mothers and their macrosomic offspring, it may prevent long-term metabolic abnormalities associated with macrosomia.

Comment informer sur la voie d'accouchement une patiente ayant un antécédent de césarienne ?

A trial of labor after prior cesarean delivery is associated with a greater perinatal risk than is elective repeated cesarean delivery without labor, although absolute risks are low. Information and counselling aim to estimate specific risks and to balance these risks according to individual factors. Therefore, the physician has to answer two questions: (i) which would be the probability of successful vaginal delivery? (ii) which would be the risk of uterine rupture with a trial of labor? The risk factors for failure of trial of labor are: increased maternal age, obesity, and fetal macrosomia. The risk factors for uterine rupture are: increased maternal age, postpartum fever after the previous cesarean delivery, short interdelivery interval, history of at least two previous cesarean deliveries, and a history of classical incision. Conversely, other factors are of good prognosis: a prior vaginal delivery and, particularly, a prior VBAC (Vaginal Birth After Caesarean) are associated with a higher rate of successful trial of labor compared with patients with no prior vaginal delivery; ultrasonographic measurement of the lower uterine segment thickness>3.5 mm has an excellent negative predictive value for the risk of uterine defect. Finally, the wish for additional pregnancies following a cesarean section must be considered as an argument in favour of a trial of labor after accounting for the increasing risks correlated with repeated elective cesarean deliveries.

Shoulder dystocia: a comparison of patients with and without diabetes mellitus

BACKGROUND

The study was aimed to compare pregnancies complicated with shoulder dystocia, of patients with and without diabetes mellitus.

METHODS

A comparison of all singleton, vertex, term deliveries between the years 1988-1999, complicated with shoulder dystocia with and without diabetes mellitus was performed. Statistical analysis was done using receiver operating characteristic curve analysis.

RESULTS

Using a receiver operating characteristic curve analysis, the area under the curve for birth weight was 0.92 (95% CI 0.90-0.93). However, for birth weight of 4,000 g the sensitivity was only 56% with specificity of 95%. While comparing shoulder dystocia between patients with (n=38) and without diabetes mellitus (n=207), neonates of the diabetic patients were significantly heavier (mean birth weight 4,244.2+/-515.1 vs. 4,051.6+/-389.5; P=0.008) and had higher rate of Apgar scores lower than 7 at 1 min (50.0% vs. 25.9%; P=0.030), but not at 5 min (2.6% vs. 2.0%; P=0.083) when compared to the non-diabetic group. No significant differences were noted regarding perinatal mortality between the groups (0% vs. 4.3%; P=0.362).

CONCLUSIONS

The newborn of the diabetic mother complicated with shoulder dystocia does not appear to be at an increased risk for perinatal morbidity compared with the newborn of the non-diabetic mother.

Animal evidence for the transgenerational development of diabetes mellitus

The mammalian fetus develops inside the uterus of its mother and is completely dependent on the nutrients supplied by its mother. Disturbances in the maternal metabolism that alter this nutrient supply from mother to fetus can induce structural and functional adaptations during fetal development, with lasting consequences for growth and metabolism of the offspring throughout life. This effect has been investigated, by several research groups, in different experimental models where the maternal metabolism during pregnancy was experimentally manipulated (maternal diabetes and maternal malnutrition) and the effect on the offspring was investigated. The altered maternal/fetal metabolism appears to be associated with a diabetogenic effect in the adult offspring, including gestational diabetes. This diabetic pregnancy in the offspring again induces a diabetogenic effect into the next generation, via adaptations during fetal development. These experimental data in laboratory animals are confirmed by epidemiological studies on infants of mothers suffering from diabetes or malnutrition during pregnancy. It can be concluded that fetal development in an abnormal intra-uterine milieu can induce alterations in the fetal metabolism, with lasting consequences for the glucose tolerance of the offspring in adult life. The most marked effect is the development of gestational diabetes, thereby transmitting the diabetogenic tendency to the next generation again. The concept of fetal origin of adult diabetes therefore is of major significance for public health in the immediate and the far future.

Clinical and molecular studies on two further families with Simpson-Golabi-Behmel syndrome

The Simpson-Golabi-Behmel syndrome (SGBS) (OMIM 312870) is an overgrowth/multiple congenital anomalies syndrome caused by a semi-dominant X-linked gene encoding glypican 3 (GPC3). It shows great clinical variability, ranging from mild forms in carrier females to lethal forms with failure to thrive in males. The most consistent findings in SGBS are pre- and postnatal macrosomia, characteristic facial anomalies and abnormalities affecting the internal organs, skeleton, and on some occasions, mental retardation of variable degree. SGBS is also associated with an increased risk of developing embryonal tumors, mostly Wilms and liver tumors. We describe two molecularly-confirmed families with SGBS. All patients had typical manifestations of SGBS including some female relatives who had minor manifestations of the disorder. Some patients had novel findings such as a deep V-shaped sella turcica and six lumbar vertebrae. Molecular studies in affected patients showed a deletion of exon 6 in family 1 and an intronic mutation in family 2.

[Overweight and obesity as common risk factors for gestational diabetes mellitus (GDM), perinatal macrosomy in offspring and type-2 diabetes in mothers]

Gestational diabetes mellitus (GDM) affects about 5% of all pregnancies and results in an increased incidence of Caesarean sections, perinatal traumas and neonatal complications. Macrosomy, i.e., an excessive birth-weight is observed in newborns from these pregnancies. In the majority of cases, diabetes regression is observed directly after pregnancy termination, however, in 15-60% of these patients, diabetes mellitus develops in later years of life. The goal of the study was an assessment of the risk factors for GDM development in gestation, perinatal macrosomy in offspring from GDM-affected pregnancies and overt diabetes mellitus in women after GDM. MATERIAL AND METHODS. The study involved 146 women with GDM and 1806 women with normal carbohydrate metabolism during pregnancy, 506 newborns of gestational diabetic mothers and 993 newborns of healthy mothers, as well as 200 women with a history of GDM during the years 1990-1999 (the mean time period after GDM - 3.1 +/- 6.0 years). The recognized risk factors of GDM and perinatal macrosomy were evaluated, together with the incidence of overt diabetes mellitus after GDM-affected pregnancy.

RESULTS

An analysis of multifactor logistic regression demonstrated that the independent risk factors for GDM include: BMI 3 25 kg/m2 before pregnancy (OR - 2.38), the history of diabetes in family (OR - 1.67), and the third pr further pregnancy (OR - 1.81) - p < 0.05. In turn, experienced obstetric failures and delivery of child with macrosomy features revealed insignificant - p > 0.05. Perinatal macrosomy correlated with mother's BMI and glycaemia during the 2nd hour of diagnostic test (75 g OGTT). No correlations were observed among mother's age, fasting glycaemia levels and HbA1c in mothers. In the group of GDM-affected women, diabetes mellitus type 2 was diagnosed in 34 (17.0%) patients. The the actual BMI > 25 kg/m2 and glycaemia values in the 2nd hour of diagnostic test in the course of GDM diagnosis (p < 0.05). The risk of diabetes was not enhanced in that group of women by family history of diabetes, the age of GDM onset (< 25 years of life), the week of gestation when GDM was diagnosed (< 25 hbd), and the type of GDM therapy (insulin vs. diet) p > 0.05

CONCLUSIONS

Overweight and obesity are both risk factors of gestational diabetes mellitus, delivery of child with macrosomy features and of overt diabetes mellitus later in life.