Fetal hyperinsulinism at 14-20 weeks and subsequent gestational diabetes

Is There a Correlation between Apelin and Insulin Concentrations in Early Second Trimester Amniotic Fluid with Fetal Growth Disorders?

INTRODUCTION

Fetal growth disturbances place fetuses at increased risk for perinatal morbidity and mortality. As yet, little is known about the basic pathogenetic mechanisms underlying deranged fetal growth. Apelin is an adipokine with several biological activities. Over the past decade, it has been investigated for its possible role in fetal growth restriction. Most studies have examined apelin concentrations in maternal serum and amniotic fluid in the third trimester or during neonatal life. In this study, apelin concentrations were examined for the first time in early second-trimester fetuses. Another major regulator of tissue growth and metabolism is insulin.

MATERIALS AND METHODS

This was a prospective observational cohort study. We measured apelin and insulin concentrations in the amniotic fluid of 80 pregnant women who underwent amniocentesis in the early second trimester. Amniotic fluid samples were stored in appropriate conditions until delivery. The study groups were then defined, i.e., gestations with different fetal growth patterns (SGA, AGA, and LGA). Measurements were made using ELISA kits.

RESULTS

Apelin and insulin levels were measured in all 80 samples. The analysis revealed statistically significant differences in apelin concentrations among groups (p = 0.007). Apelin concentrations in large for gestational age (LGA) fetuses were significantly lower compared to those in AGA and SGA fetuses. Insulin concentrations did not differ significantly among groups.

CONCLUSIONS

A clear trend towards decreasing apelin concentrations as birthweight progressively increased was identified. Amniotic fluid apelin concentrations in the early second trimester may be useful as a predictive factor for determining the risk of a fetus being born LGA. Future studies are expected/needed to corroborate the present findings and should ideally focus on the potential interplay of apelin with other known intrauterine metabolic factors.

Second trimester maternal plasma and amniotic fluid adipokines in women who will develop gestational diabetes mellitus

OBJECTIVE

To study the adipokines concentration and glucose homoeostasis in the early-second trimester of women who will develop gestational diabetes mellitus (GDM).

MATERIALS AND METHODS

Maternal plasma and fetal amniotic fluid samples were prospectively collected between 2006 and 2007 at the time of mid-trimester amniocentesis. Eight patients found to be affected by GDM were compared with 10 control patients with a normal pregnancy course. Adipokines leptin and adiponectin, as well as insulin and glucose concentration both in amniotic fluid and maternal plasma were compared between cases and controls. HOMA-IR (homeostatic model assessment for insulin resistance) was also calculated both for amniotic fluid and maternal serum.

RESULTS

The amniotic fluid adiponectin concentration was higher in women who would develop GDM than in controls (29.9 ng/ml, 95% CI 26.7-49.8 ng/ml, versus 14.9 ng/ml, 95% CI 13.5-18.8 ng/ml), p < 0.05). No difference was shown for leptin both in amniotic fluid and maternal serum. Insulin concentrations in the amniotic fluid were found to be lower in GDM than in controls, while HOMA-IR-index resulted lower in amniotic fluid and higher maternal serum (p < 0.05).

CONCLUSIONS

Our data suggests that an earlier alteration in the fetal glucose metabolism will precede the glucose dysmetabolism in pregnancies later complicated by GDM.

Amniotic fluid insulin and C-peptide as predictive markers for fetal macrosomia, birth injuries, and delivery complications?

Background

Gestational diabetes mellitus (GDM) occurs in 3–5% of all pregnancies. GDM increases both maternal and fetal risks, causes fetal macrosomia, and hence increases the rates of caesarean sections and delivery complications such as shoulder dystocia. An early predictive marker and consequent early treatment could be beneficial, so amniotic fluid insulin and C-peptide have been examined in several studies. Increased amniotic fluid insulin in early amniocentesis between the 14^th and 20^th gestational week predicted a later GDM. A potential direct association with fetal macrosomia remains to be determined.

Material/Methods

This retrospective study investigated amniotic fluid insulin/C-peptide from amniocenteses between 14 and 20 weeks of gestation in correlation with fetal birth weight, type of delivery, and complications. To focus on effects of fetal hyperinsulinism apart from therapeutic confounders, we included patients who did not participate in GDM screening. Insulin and C-peptide were measured in 144 samples of frozen amniotic fluid. Birth weight, type of delivery, complications, and birth injuries were noted.

Results

Birth weights ranged from 760 g to 4410 g with a mean weight of 3424 g at an average of 40 weeks gestation. The mean amniotic fluid insulin was 4.36 μU/ml and the mean C-peptide concentration was 0.076 ng/ml. There was no correlation between amniotic fluid insulin or C peptide and birth weight, type of delivery, complications, and birth injuries.

Conclusions

Amniotic fluid insulin and C-peptide are unsuitable as predictive marker for fetal macrosomia, type of delivery, complications, or birth injuries.

Fetal exposure to altered amniotic fluid glucose, insulin, and insulin-like growth factor-binding protein 1 occurs before screening for gestational diabetes mellitus

OBJECTIVE

We explored the possibility that perturbations in amniotic fluid glucose, insulin, and insulin-like growth factor-binding protein 1(IGFBP1) and/or metabolic acids exist before routine screening for GDM.

RESEARCH DESIGN AND METHODS

We selected consenting mother-infant pairs (n = 408) who met our inclusion criteria (singleton pregnancy, no genetic abnormalities, and no preexisting diabetes) and for whom sufficient amniotic fluid and appropriate medical information were available. We compared birth outcomes and second trimester amniotic fluid glucose, insulin, IGFBP1 concentrations, and amniotic fluid lactic, β-hydroxybutyric, and uric acids of mothers with gestational diabetes mellitus (GDM) (n = 52) with those of mothers with no diagnosis of GDM at >24 weeks (n = 356).

RESULTS

Higher amniotic fluid glucose, lactic acid, uric acid, and insulin and lower IGFBP1 concentrations were present by 15.1 ± 0.1 weeks in mothers in whom GDM was subsequently diagnosed. However, logistic regression showed that second trimester amniotic fluid glucose, but not insulin, IGFBP1, or metabolic acids was associated with an increased odds ratio (1.2 [95% CI 1.052-1.338]) for diagnosis of GDM at 24-28 weeks. In addition, probability contour maps that accounted for nonlinear relationships among the dynamically changing amniotic fluid constituents showed an increased risk for GDM with elevated second trimester amniotic fluid glucose in combination with either elevated amniotic fluid insulin or low amniotic fluid IGFBP1

CONCLUSIONS

Fetuses are exposed to increased amniotic fluid glucose before 15 weeks of gestation, suggesting that metabolic perturbations are underway before diagnosis and that earlier screening and intervention may be warranted.

Impact of maternal obesity on offspring obesity and cardiometabolic disease risk

The prevalence of obesity among pregnant women is increasing. In addition to the short-term complications of obesity during pregnancy in both mother and child, it is now recognised that maternal obesity has long-term adverse outcomes for the health of her offspring in later life. Evidence from both animal and human studies indicates that maternal obesity increases the risk for the offspring in developing obesity and altering body composition in child- and adulthood and, additionally, it also has an impact on the offspring's cardiometabolic health with dysregulation of metabolism including glucose/insulin homoeostasis, and development of hypertension and vascular dysfunction. Potential mechanisms include effects on the development and function of adipose tissue, pancreas, muscle, liver, the vasculature and the brain. Further studies are required to elucidate the mechanisms underpinning the programming of disease risk in the offspring as a consequence of maternal obesity. The ultimate aim is to identify potential targets, which may be amenable to prevention or early intervention in order to improve the health of this and future generations.

Midtrimester amniotic fluid leptin and insulin levels and subsequent gestational diabetes

AIMS

To evaluate midtrimester amniotic fluid leptin levels in pregnancies subsequently complicated by gestational diabetes.

METHODS

We studied 32 pregnant women with gestational diabetes and a control group of 43 normal pregnancies with an adequate gestational age fetus. All underwent a midtrimester amniocentesis: leptin and insulin were measured in the amniotic fluid. Data were compared with the Mann-Whitney U-test.

RESULTS

Median leptin concentrations in the amniotic fluid of the gestational diabetes mellitus patients were significantly higher than in the control group (15.1 vs. 7.9 ng/ml) (p = 0.001); amniotic insulin concentrations were also higher in the gestational diabetes mellitus than in the control group (0.67 vs. 0.38 microU/ml) (p = 0.02). Furthermore, amniotic fluid leptin levels were directly correlated with amniotic insulin concentrations; instead, there was no correlation with maternal BMI and birth weight.

CONCLUSION

Our data suggest that in pregnancies subsequently complicated by gestational diabetes, amniotic fluid leptin and insulin levels are higher in the early fetal period.

Decreased plasma adiponectin concentrations in women with gestational diabetes mellitus

OBJECTIVE

Adiponectin is an adipocyte-specific protein that has been found to be associated with insulin sensitivity and obesity. Because gestational diabetes mellitus is associated with obesity and decreased insulin sensitivity, we have analyzed plasma adiponectin levels in women with gestational diabetes mellitus.

STUDY DESIGN

Twenty women with gestational diabetes mellitus and 21 unaffected women were included in the study. Plasma adiponectin levels were analyzed with the use of enzyme-linked immunosorbent assay.

RESULTS

Women with gestational diabetes mellitus were significantly older (34.3 years vs 29.4 years; P < .001) than unaffected women. Adiponectin plasma levels were significantly lower in women with gestational diabetes mellitus when compared with women without gestational diabetes mellitus (5827 +/- 1988 ng/mL vs 8085 +/- 3816 ng/mL; P = .02). Adiponectin plasma levels were correlated negatively with plasma glucose concentrations of the oral glucose tolerance test ( r > -0.38; P < .04) and correlated positively with gestational age ( r = 0.36; P = .03).

CONCLUSION

Our data show that decreased plasma adiponectin levels were found in women with gestational diabetes mellitus compared with unaffected women.

Perinatal 'programming' of insulin resistance in childhood: critical impact of neonatal insulin and low birth weight in a risk population

AIM

Low birth weight may predispose to later insulin resistance and hyperinsulinaemia, but the pathophysiological mechanisms are unclear. The perinatal endocrine situation may play an important role, but has been little studied. Children of mothers with diabetes during pregnancy are an important risk population for later insulin resistance and hyperinsulinaemia. We therefore examined relationships between birth weight, insulin and insulin resistance at birth, and insulin secretion and insulin resistance in infancy in these children.

METHODS

We studied 104 infants of mothers with Type 1 diabetes mellitus during pregnancy. Oral glucose tolerance tests (area under the curve of glucose, AUCG) with determination of insulin (area under the curve of insulin, AUCI) were performed at 1-5 years of age. Using correlation and regression analysis, birth data were related to insulin secretion (AUCI) and stimulated insulin/glucose ratio (AUCI/AUCG) in childhood.

RESULTS

Children with an AUCI in the highest tertile of distribution had the lowest birth weights. Birth weight was negatively correlated to AUCI in childhood (P = 0.03). Insulin/glucose ratio at birth was raised in infants with an AUCI in the upper tertile, accompanied by a positive correlation between insulin/glucose ratio at birth and AUCI (P = 0.02). Insulin and insulin/glucose ratio at birth were both positively correlated to AUCI/AUCG (P = 0.04 and P = 0.02 respectively), while the correlation between birth weight and AUCI/AUCG was not significant (P = 0.12). In a stepwise regression analysis, insulin/glucose ratio contributed as much as birth weight to AUCI in childhood. Birth weight, however, was significantly negatively related to AUCI/AUCG only when the insulin/glucose ratio at birth was included in the regression model.

CONCLUSIONS

Insulin and insulin resistance at birth show a positive relation to insulin secretion and insulin resistance in later life, in addition to the influence of a low birth weight, but independent of it. Perinatal and neonatal insulin, known to be of critical importance for long-term outcome, should be evaluated in future studies on the 'small baby syndrome'.

Amniotic fluid insulin at 14-20 weeks' gestation: association with later maternal glucose intolerance and birth macrosomia

OBJECTIVE

To examine the hypothesis that early second trimester amniotic fluid (AF) insulin concentration is elevated and later fetal growth is augmented in gravidas demonstrating later oral glucose intolerance.

RESEARCH DESIGN AND METHODS

In this prospective observational cohort study, AF was sampled at 14-20 weeks' gestation in 247 subjects, and 1-h 50-g oral glucose challenge tests (GCTs) were performed at > or = 24 weeks. AF insulin was assayed by an automated immuno-chemiluminometric assay (8). Macrosomia was defined as birth weight above the 90th centile.

RESULTS

AF insulin concentration (range 1.4-44.5 pmol/l) correlated positively with gestational age and maternal weight. A logistic regression analysis, adjusted for maternal age and midpregnancy weight, showed increased AF insulin multiples of gestational age-specific medians to be associated with subsequently diagnosed gestational diabetes mellitus (GDM) (OR 1.9, CI 1.3-2.4, P = 0.029). Among 60 subjects with GCT values > 7.2 mmol/l, each unit increase in AF insulin multiple of median (MOM) was associated with a threefold increase in fetal macrosomia incidence (3.1, 1.3-4.9, P = 0.048).

CONCLUSIONS

An elevated AF insulin concentration at 14-20 weeks' gestation is associated with subsequently documented maternal glucose intolerance. Among gravidas with GCT values > 7.2 mmol/l, elevated early AF insulin concentration is associated with fetal macrosomia. Maternal glucose intolerance may affect fetal insulin production before 20 weeks' gestation.

Effect of fetal hyperinsulinism on oral glucose tolerance test results in patients with gestational diabetes mellitus

OBJECTIVE

This study was undertaken to evaluate the impact of the fetoplacental glucose steal phenomenon on the results of oral glucose tolerance testing in pregnancies complicated by gestational diabetes mellitus with fetal hyperinsulinism.

STUDY DESIGN

This was an analysis of the cases of 34 patients with two consecutive abnormal oral glucose tolerance test results and amniotic fluid insulin measurement before institution of insulin therapy. Patients were divided into groups on the basis of normal versus elevated amniotic fluid insulin concentrations.

RESULTS

Oral glucose tolerance tests were done at a mean (+/-SD) of 24.9 +/- 5.7 and 30.7 +/- 3.2 weeks' gestation, and amniotic fluid insulin measurements were done at 31.1 +/- 3.2 weeks' gestation. In 13 women with gestational diabetes mellitus with normal amniotic fluid insulin concentration, maternal postload blood glucose levels at 1 hour increased by 12 mg/dL (168 vs 180 mg/dL; 9.3 vs 10.0 mmol/L; P = .0006) during the course of 6 weeks. In contrast, in 21 women with gestational diabetes mellitus with elevated amniotic fluid insulin levels (>7 microU/mL; >42 pmol/L), 1-hour postload blood glucose levels decreased by 22 mg/dL (201 vs 179 mg/dL; 11.2 vs 9.9 mmol/L; P = .002) during the same period. The higher the amniotic fluid insulin level, the larger the decrease (R = 0.504; P =.02). Although low amniotic fluid insulin levels were correlated significantly with 1-hour glucose levels of the first and second oral glucose tolerance tests, high insulin levels were no longer correlated with the second oral glucose tolerance test.

CONCLUSION

Exaggerated fetal glucose siphoning may provide misleading oral glucose tolerance test results in pregnancies complicated by fetal hyperinsulinism by blunting maternal postload glucose peaks. Consequently, oral glucose tolerance test results in a pregnancy complicated by gestational diabetes mellitus with a fetus that already has hyperinsulinemia may erroneously be considered normal.

A high-sensitivity assay for amniotic fluid insulin at 14-20 weeks' gestation

OBJECTIVE

To examine sensitivity, precision, and sample stability of an immunochemiluminomimetric insulin assay in 14-20 week amniotic fluid (AF) and fetal age distribution of second-trimester AF insulin concentrations.

METHODS

We assayed fresh specimens from 576 gravidas who had amniocentesis at 14-20 weeks' gestation because of maternal age. In a preliminary study, samples were divided into aliquots and stored at 4C and -20C for 24 hours to assess freezing effect. Some samples stored at 4C were assayed repeatedly during a 14-day period and others, stored at -20C, were assayed after a 70-day period.

RESULTS

This assay reliably measured AF insulin to a detection limit of 0.03 microIU/mL. Insulin could be measured in all amniotic fluid samples and demonstrated a log10 Gaussian distribution, ranging from 0.24 to 7.41 microIU/mL. Interassay coefficients of variation ranged from 4.4 to 8.9% at concentrations of 0.4-2.0 microIU/mL. Linearity of dilution from 1.5 to 10 times was 99.2 +/- 8.6%. Spike recovery of 10 microIU/mL was from 92-109%. Recovery after freezing to -20C for 24 hours (101%) and 70 days (97%) and after storage at 4C for 14 days (97%) demonstrated no significant loss.

CONCLUSION

A two-site, dual monoclonal, immunochemiluminomimetric insulin assay was sufficiently sensitive and precise within the lower range of measured AF insulin concentrations to investigate clinical associations of 14-20 week AF insulin with maternal and fetal conditions. The insulin stability in this matrix suggests that assays can be reliable on specimens stored up to 70 days.

IGF-I, IGF-II, IGF binding protein 1, and C-peptide in second trimester amniotic fluid are dependent on gestational age but do not predict weight at birth

Previous data suggested that small for gestational age newborns have increased levels of IGF binding protein 1 (IGFBPI) in amniotic fluid (AF) at 15-16 wk of pregnancy. In this study, we developed an RIA for IGFBP1 and measured IGFBP1 concentrations in 209 AF samples with normal fetal karyotype between 14 and 20 wk; we measured IGF-I, IGF-II, and C-peptide in the same samples. Concentrations of these growth-modulating factors were all positively correlated with gestational age at sampling (p < 0.0001). After correcting for gestational age, AF IGFBP1 remained strongly correlated with IGF-I and IGF-II (both p < 0.0001); their concentrations were many times higher in AF than in cord serum during the third trimester. None of the growth-modulating factors in AF correlated with birth weight, after correction for gestational age; birth weight percentile distribution was comparable in two groups of newborns who had AF values of IGF-I, IGF-II, IGFBP1, or C-peptide that were either less than or equal to the 50th percentile or more than the 50th percentile at sampling. However, placenta weight and the placenta weight to birth weight percentage were negatively correlated with AF IGF-I, IGF-II, and IGFBP1; placenta weight to birth weight percentage was lower in pregnancies with IGFBP1 values more than the 50th percentile compared with those less than or equal to the 50th percentile at sampling. In conclusion, AF concentrations of IGFBP 1 increase gradually between 14 and 20 wk gestational age and correlate with IGF-I and IGF-II levels; high IGFBP1 levels do not predict small for gestational age newborns, but are associated with lower placenta weight.

Effect of maternal diabetes on the fetal exocrine pancreas

To test the hypothesis that fetal pancreatic exocrine and endocrine function are stimulated in parallel in the diabetic pregnancy, 68 mothers with gestational and pregestational diabetes who underwent amniocenteses after 34 weeks' for the evaluation of fetal lung maturity were enrolled. Amniotic fluid specimens were analyzed for C-peptide and trypsin content. Amniotic fluid specimens were obtained from 92 non-diabetic women undergoing amniocenteses for lung maturity, preterm labor, or premature rupture of membranes. Groups were compared using the Wilcoxon rank-sum test, Kruskal Wallis rank sum test, and Spearman's rank correlation test. C-peptide amniotic fluid concentrations were significantly greater in diabetics (median 0.6 ng/ml) than non-diabetics (median 0.4 ng/ml, P= 0.0001), in pregestational (median 0.6 ng/ml) vs. gestational diabetics (median 0.4 ng/ml, P = 0.006), and greater in proportion to severity of disease according to diabetic class (A1 = 0.4 ng/ml, A2 = 0.55 ng/ml, B = 0.6 ng/ml, C = 0.7 ng/ml, D = 0.85 ng/ml, P = 0.04). No significant differences were detected in amniotic fluid trypsin between the diabetic and non-diabetic or the gestational and non-gestational diabetic groups. There was no correlation between C-peptide and trypsin within the diabetic groups. Stimulation of the exocrine and endocrine pancreas does not occur in parallel in the fetus of the diabetic mother. Although originating as a single organ, pancreatic exocrine and endocrine functions are distinct in both physiologic and pathologic conditions.

Amniotic fluid insulin testing in gestational diabetes: safety and acceptance of amniocentesis

OBJECTIVES

We analyzed the safety and patient acceptance of amniotic fluid insulin measurements by third-trimester amniocentesis in women with gestational diabetes mellitus.

STUDY DESIGN

We studied the rate of early uterine contractions, need for tocolysis, premature rupture of membranes, mode of delivery, length of gestation, and fetal weight and length at birth in 194 women with gestational diabetes mellitus who underwent third-trimester amniocentesis and 268 controls. Patient acceptance of amniocentesis was assessed prospectively with a visual rating scale and a semistructured interview comparing 50 women with gestational diabetes mellitus to 50 women undergoing second-trimester amniocentesis for fetal karyotyping.

RESULTS

Only the length of gestation differed significantly but without clinical relevance (39.5 +/- 1.9 vs 40.0 +/- 2.0, P = .006) between women with gestational diabetes mellitus who had amniocentesis and controls. Patient acceptance was equally high both for second-trimester and third-trimester amniocentesis.

CONCLUSIONS

Third-trimester amniocentesis for measuring amniotic fluid insulin is safe and well accepted by the patients. This is important information both for treating and counseling women with gestational diabetes mellitus.

Fetal growth in diabetic pregnancy

In summary, fetal macrosomia occurs in almost one third of diabetic pregnancies regardless of class. Abnormal fetal fat stores lead to difficult labor, dystocia, and birth injury as well as postnatal metabolic transition. The abnormal body fat distribution at birth may destine some of these infants to lifelong obesity. Abnormal fetal growth in diabetic pregnancy appears to occur with any elevations in maternal glucose levels, however modest. Detection of macrosomia is therefore a major goal of diabetic pregnancy management.

Assessment of the quality of general movements in fetuses and infants of women with type-I diabetes mellitus

The effect of type-I diabetes on the quality of general movements (GMs) was studied longitudinally in 12 human fetuses. GMs were analysed at two-weekly intervals from 16 weeks until delivery. A pregnancy optimality-score and a diabetes optimality-score were used to cover the course of the pregnancy and delivery and the severity of diabetes. GMs of infants were analysed 1, 4-6, and 12-18 weeks after birth and the Bayley developmental test was performed at 10 months. All fetuses showed normal GMs at 16 weeks. From 20 weeks onwards until delivery five fetuses developed abnormal GMs. The diabetes optimality-score was significantly lower in the group with abnormal GMs (P = 0.018) whereas the pregnancy optimality-score did not differ between fetuses with normal and abnormal GMs. Our results indicate that type-I diabetes can have a negative impact on prenatally observed GMs. Consistently normal GMs indicate normal neurodevelopmental outcome at 10 months whereas in the group with abnormal GMs reduced Bayley-scores may occur.