The effect of metabolic control on fetal nuchal translucency in women with insulin-dependent diabetes: a preliminary study

First-Trimester Nuchal Translucency Screening in Pregnant Women Who Subsequently Developed Gestational Diabetes

OBJECTIVE

To compare the nuchal translucency (NT) thickness at 11-14 weeks of gestation in women who will later develop gestational diabetes mellitus (GDM) with that of women with normal glucose tolerance (NGT) in the second trimester of pregnancy.

METHODS

Four hundred sixty-four women underwent NT screening at 11-14 weeks of gestation according to the standards of the Fetal Medicine Foundation. They all underwent an oral glucose tolerance test (OGTT) between 24 and 28 weeks.

RESULTS

Women with GDM (n = 135) were significantly older (34.0 years [+/-4.8] vs 29.4 years [+/-5.2]; P < .001), had a significantly higher body mass index (BMI) (28.2 kg/m2 [+/-6.0] vs 24.4 [+/-5.0]; P < .001), and had a significantly higher serum concentration of hemoglobin A1c (HbA1c) at the time of the NT measurement (5.38% [+/-0.6] vs 4.95% [+/-0.4]; P < .001] than women with NGT (n = 329). There is no significant difference in the NT measurement at 11 to 14 weeks of gestation between women with GDM and NGT after correction for crown rump length (CRL) (r = -.08, P = .45). We performed multiple linear regression analysis with NT as the dependent variable, and BMI, maternal age, CRL, and GDM/NGT as independent variables. CRL (P < .001) was significantly related to the NT measurement, whereas GDM/NGT, BMI, and maternal age were not.

CONCLUSION

As no significant difference in the NT measurement between women with GDM and NGT was observed, the risk estimation for chromosomal abnormality derived from the maternal age and NT measurement can also be used in women with glucose disorders.

First-trimester detection of fetal anomalies in pregestational diabetes using nuchal translucency, ductus venosus Doppler, and maternal glycosylated hemoglobin

OBJECTIVE

The frequency of fetal anomalies in women with pregestational diabetes correlates with their glycemic control. This study aimed to assess the predictive performance of first-trimester fetal nuchal translucency (NT), ductus venosus (DV) Doppler, and hemoglobin A1c (HbA1c) to predict fetal anomalies in women with pregestational diabetes.

STUDY DESIGN

This was a prospective observational study of patients undergoing first-trimester NT with DV Doppler. Screening performance was tested for first-trimester parameters to detect fetal anomalies.

RESULTS

Of 293 patients, 17 had fetal anomalies (11 cardiac, 7 major, 3 multisystem). All anomalous fetuses were suspected prenatally. One had NT >95th centile, 2 had reversed DV a-wave, and 13 had HbA1c >7.0%. The HbA1c was the primary determinant of anomalies (r(2), 0.15; P < .001) and >8.35% was the optimal cutoff for prediction of anomalies with an area under the curve of 0.72 (95% confidence interval, 0.57-0.88). Therefore, first-trimester prediction of anomalies was best in women with increased NT or HbA1c >8.3% (sensitivity 70.6%, specificity 77.4%, positive predictive value 16.2%, negative predictive value 97.7%, P < .001).

CONCLUSION

In women with pregestational diabetes and poor glycemic control, an increased NT increases risks for major fetal anomalies. Second-trimester follow-up is required to achieve accurate prenatal diagnosis.

Can first-trimester screening program detect women at high risk for gestational diabetes mellitus?

This study was designed to compare first-trimester maternal serum biochemical markers of aneuploidy and fetal nuchal translucency in pregnancies complicated by gestational diabetes mellitus and those of a control group. The study included 60 gestational diabetic and 60 control women who attended the first-trimester combined screening program for Down syndrome between 11 and 14 gestational weeks with complete follow-up data and delivered in our institution. Maternal serum free β-human chorionic gonadotropin, pregnancy-associated plasma protein-A and fetal nuchal translucency were investigated. The combined risks, double test risks and age risks were calculated by PRISCA software version 4.0. Comparison of the results between the two groups yielded no significant differences in serum levels of free β-human chorionic gonadotropin and fetal nuchal translucency. However, women who developed gestational diabetes mellitus had significantly lower pregnancy-associated plasma protein-A. And also, the combined risks and double test risks calculated by PRISCA software were statistically higher in gestational diabetic women than normal pregnant women. These results suggest that differences can be seen between diabetic and healthy pregnant women in first-trimester maternal serum biochemical markers of aneuploidy.

Increased nuchal translucency is associated with large for gestational age neonates in singleton pregnancies

OBJECTIVE

To evaluate the correlation between sonographic measurements of nuchal translucency (NT) and neonatal birth weight in non-diabetic population.

METHODS

A retrospective analysis was performed on all singleton term pregnancies delivered at our hospital between 2004 and 2008. Data collected included maternal age, parity, NT measurement, results of glucose challenge test, birth weight, gestational age at delivery, and fetal gender.

RESULTS

The study population comprised of 1649 patients. The mean NT was 1.3 ± 0.5 mm. Male fetuses had a significantly thicker NT (1.3 ± 0.5 vs. 1.2 ± 0.4; P<0.001). NT significantly correlated to birth weight (P=0.002). This correlation was independent of neonatal gender. The median NT in the large for gestational age (LGA) neonates was significantly higher than in the non-LGA neonates (1.4 mm vs. 1.2 mm, P=0.001). Equations for the predicted probability for delivering LGA neonates were derived using either NT alone or in combination with parity. An increase in 0.1 mm in the NT has the odd ratio of 1.042 for delivering an LGA neonate (P=0.02).

CONCLUSIONS

NT correlated with LGA neonates in term non-diabetic patients. This correlation was independent of the neonatal gender. The predictive clinical impact of NT was limited to LGA neonates.

First-trimester prediction of macrosomia

OBJECTIVE

To determine if combinations of maternal characteristics and measurements of parameters used in screening for aneuploidies at 11-13 weeks provide significant prediction of macrosomia.

METHOD

Maternal characteristics, fetal nuchal translucency (NT), free β-human chorionic gonadotrophin (β-hCG) and pregnancy-associated plasma protein-A (PAPP-A) were recorded at 11(+0)-13(+6) weeks in 36,743 singleton pregnancies. Regression analysis was used to determine if in predicting macrosomia significant contributions are provided by maternal factors, fetal NT, free β-hCG and PAPP-A.

RESULTS

The risk for macrosomia increased with maternal weight and height and was higher in parous women with previous delivery of a macrosomic baby and in those with diabetes mellitus; the risk was lower in women of African and South Asian racial origins, in cigarette smokers and in those with chronic hypertension. In the macrosomic group compared to the unaffected group there were higher Δ-NT (0.167 vs. 0.116 mm), free β-hCG (1.010 vs. 0.964 MoM) and PAPP-A (1.103 vs. 1.003 MoM). Prediction of macrosomia provided by maternal factors was significantly improved by fetal NT, free β-hCG and PAPP-A (34.4 vs. 33.1% at a false-positive rate of 10%).

CONCLUSION

Prediction of macrosomia is provided in the first trimester of pregnancy by a combination of maternal characteristics and measurements of parameters used in screening for aneuploidies.

Can increased nuchal translucency in the first trimester of pregnancy predict gestational diabetes mellitus

The current study was designed to evaluate whether increased nuchal translucency can predict gestational diabetes mellitus. This was a prospective observational study. Among the pregnant women at 11-14 weeks of pregnancy who came to our prenatal unit for a first trimester screening test, 389 pregnant women whose nuchal translucency above 95th centile were selected as the study group and 386 age-matched pregnant women whose nuchal translucency were within the normal range were enrolled as a control group. First, subjects underwent a 50 g glucose screening test; if it was positive then a 100 g oral glucose tolerance test was performed. The main outcome measures were the prevalence of gestational diabetes mellitus and impaired glucose tolerance and the number of macrosomic infants. Impaired glucose tolerance was more common in pregnant women whose nuchal translucency was above the 95th centile (p = 0.048). In addition, macrosomic infants were also more common in pregnant women with a fetal nuchal translucency above the 95th centile (p = 0.045). Macrosomia was more common in the study group with gestational diabetes mellitus (p = 0.046). In conclusion, increased nuchal translucency seems to be predictive for impaired glucose tolerance and macrosomia, which are associated with gestational diabetes mellitus.

The influence of maternal insulin-dependent diabetes on fetal nuchal translucency thickness and first-trimester maternal serum biochemical markers of aneuploidy

OBJECTIVE

To evaluate the influence of maternal insulin dependent diabetes mellitus (IDDM) on maternal serum free beta-hCG, PAPP-A and fetal nuchal translucency (NT), thickness at 11 to 13(+6) weeks of gestation in a large cohort of women screened prospectively for chromosomal anomalies.

METHODS

Information on maternal IDDM status, maternal serum biochemical marker levels and fetal NT were collected from the prenatal screening computer records in two first-trimester screening centres. In total the control group included 33 301 pregnancies of which 16 366 had NT and maternal serum biochemistry results and 16 305 with NT only. The IDDM group included 195 pregnancies of which 79 had NT and maternal serum biochemistry results and 127 with NT only. The median maternal weight corrected free beta-hCG and PAPP-A, expressed as multiple of the median (MoM), and fetal NT, expressed as delta values, in the IDDM and non-IDDM groups were compared.

RESULTS

There were no significant differences between the IDDM and non-IDDM groups in median maternal weight corrected free beta-hCG (IDDM 0.87 MoM, 95% Confidence Interval 0.75 to 1.16 MoM, non-IDDM 1.00 MoM), median maternal weight corrected PAPP-A (IDDM 1.02 MoM, 95% Confidence Interval 0.83 to 1.05 MoM, non-IDDM 1.01 MoM), or mean delta NT (IDDM 0.0358 mm, non-IDDM 0.0002 mm).

CONCLUSIONS

In pregnancies with maternal IDDM, first-trimester screening for chromosomal defects does not require adjustments for the measured fetal NT. However, more data are required before the possible reduction in maternal serum free beta-hCG and the reduction of PAPP-A suggested by the published world series can be considered sufficiently important to take into account in the calculation of risks for chromosomal defects.

Nuchal translucency and other first-trimester sonographic markers of chromosomal abnormalities

There is extensive evidence that effective screening for major chromosomal abnormalities can be provided in the first trimester of pregnancy. Prospective studies in a total of 200,868 pregnancies, including 871 fetuses with trisomy 21, have demonstrated that increased nuchal translucency can identify 76.8% of fetuses with trisomy 21, which represents a false-positive rate of 4.2%. When fetal nuchal translucency was combined with maternal serum free-beta-human chorionic gonadotropin and pregnancy-associated plasma protein-A in prospective studies in a total of 44,613 pregnancies, including 215 fetuses with trisomy 21, the detection rate was 87.0% for a false-positive rate of 5.0%. Studies from specialist centers with 15,822 pregnancies, which included 397 fetuses with trisomy 21, have demonstrated that the absence of the nasal bone can identify 69.0% of trisomy 21 fetuses, which represents a false-positive rate of 1.4%. It has been estimated that first-trimester screening by a combination of sonography and maternal serum testing can identify 97% of trisomy 21 fetuses, which represents a false-positive rate of 5%, or that the detection rate can be 91%, which represents a false-positive rate of 0.5%. In addition to increased nuchal translucency, important sonographic markers for chromosomal abnormalities, include fetal growth restriction, tachycardia, abnormal flow in the ductus venosus, megacystis, exomphalos and single umbilical artery. Most pregnant women prefer screening in the first, rather than in the second, trimester. As with all aspects of good clinical practice, those care givers who perform first-trimester screening should be trained appropriately, and their results should be subjected to external quality assurance.