The significance of maternal blood pregnancy-associated plasma protein A (PAPP-A) and free beta-subunit of human chorionic gonadotropin (β-hCG) levels for the risk assessment of fetal trisomy 18 during the first prenatal testing between 11 and 13+6 weeks of pregnancy

OBJECTIVE

The aim of the study was to evaluate the significance of the maternal blood level of pregnancy-associated plasma protein A (PAPP-A) and free beta-subunit of human chorionic gonadotropin (β-hCG), to estimate the risk of fetal trisomy 18 and their correlation with the assessment of nuchal translucency (NT) during the first prenatal testing.

MATERIAL AND METHODS

Examinations of 93 pregnant women between 11 and 13+6 weeks of pregnancy were conducted, which included determination of β-hCG and PAPP-A concentrations in the maternal serum and ultrasound assessment of fetal nuchal translucency. Concentrations of biochemical parameters were expressed as multiples of median (MoM) for the appropriate gestational age. The risk assessment of trisomy 18 was analyzed using Astraia software. Pregnant women with a high (≥ 1:300) risk of trisomy 18 were offered a genetic amniocentesis with an examination of fetal karyotype. Twenty cases were healthy and 23 with trisomy 18.

RESULTS

PAPP-A and β-hCG MoM values < 0.3 were found in 61% cases of fetal trisomy 18. In 26% of cases, PAPP-A and β-hCG MoM values < 0.2 were NT-independent risk factors for trisomy 18. There were no significant differences between groups with normal fetal karyotype (40%) and trisomy 18 (35%) in PAPP-A and β-hCG MoM 0.2-0.5 range.

CONCLUSIONS

Maternal free β-hCG MoM was found to change parallelly to fetal NT widening in case of trisomy 18 diagnosis. Maternal β-hCG and PAPP-A MoM results presented less then 0.2 might be used independently of NT widening in fetus for trisomy 18 risk evaluation. Above 0.2 for PAPP-A and β-hCG MoMs, fetal NT measurement was an requirment.

Predictive values of clinical parameters and biophysical and biochemical markers in the first trimester for the detection of small-for-gestational age fetuses

OBJECTIVES

To evaluate the predictive values of maternal characteristics, biophysical parameters (mean arterial pressure [MAP] and Doppler uterine artery measurements), and biochemical parameters (pregnancy-associated plasma protein A [PAPP-A] and placental growth factor [PlGF]) alone and in association for small-for-gestational age (SGA) fetuses.

METHODS

We performed a retrospective analysis of a prospective observational study that evaluated 615 pregnant women in the first trimester using ultrasonography. For all the women, information regarding clinical and obstetric histories, MAP, and uterine artery mean pulsatility index (UtA-PI), and blood samples for analysis of biochemical markers (PAPP-A and PlGF) were obtained. The patients were grouped according to birth weight as follows: group I (n=571), >10th percentile (control); group II (n=44), <10th percentile; and group III (n=34), <5th percentile. The predictive values of the variables for the detection of SGA fetuses were calculated using a logistic regression model and an analysis of the area under the receiver-operating characteristic curve (AUC).

RESULTS

The sensitivity rates of the maternal characteristics, biophysical markers (MAP and UtA-PI), biochemical markers (PAPP-A and PlGF), and the association between them were: 23.3, 32.5, 25, and 30% respectively, at a false-positive (FP) rate of 10%, in group II and 26.5, 26.5, 23.5, and 23.5%, respectively, at a FP rate of 10% in group III.

CONCLUSIONS

The predictive performances of the combination of maternal characteristics and biophysical and biochemical parameters were unsatisfactory, with a slight improvement in the predictive capacity for SGA fetuses <10th percentile.

First Trimester Combined Test (FTCT) as a Predictor of Gestational Diabetes Mellitus

Background—The first trimester combined test (FTCT) is an effective screening tool to estimate the risk of fetal aneuploidy. It is obtained by the combination of maternal age, ultrasound fetal nuchal translucency (NT) measurement, and the maternal serum markers free β-human chorionic gonadotropin (β-hCG) and pregnancy-associated plasma protein A (PAPP-A). However, conflicting data have been reported about the association of FTCT, β-hCG, or PAPP-A with the subsequent diagnosis of gestational diabetes mellitus (GDM). Research design and methods—2410 consecutive singleton pregnant women were retrospectively enrolled in Calabria, Southern Italy. All participants underwent examinations for FTCT at 11–13 weeks (plus 6 days) of gestation, and screening for GDM at 16–18 and/or 24–28 weeks of gestation, in accordance with current Italian guidelines and the International Association Diabetes Pregnancy Study Groups (IADPSG) glycemic cut-offs. Data were examined by univariate and logistic regression analyses. Results—1814 (75.3%) pregnant women were normal glucose tolerant, while 596 (24.7%) were diagnosed with GDM. Spearman univariate analysis demonstrated a correlation between FTCT values and subsequent GDM diagnosis (ρ = 0.048, p = 0.018). The logistic regression analysis showed that women with a FTCT <1:10000 had a major GDM risk (p = 0.016), similar to women with a PAPP-A <1 multiple of the expected normal median (MoM, p = 0.014). Conversely, women with β-hCG ≥2.0 MoM had a reduced risk of GDM (p = 0.014). Conclusions—Our findings indicate that GDM susceptibility increases with fetal aneuploidy risk, and that FTCT and its related maternal serum parameters can be used as early predictors of GDM.

First-trimester serum biomarker screening for fetal Down syndrome as a predictor of preterm delivery: a population-based study

Objective: To examine the relationship between the first-trimester serum biomarker levels (pregnancy-associated plasma protein A:PAPP-A; and free beta-human chorionic gonadotropin: b-hCG) and preterm birth; and to create the predictive models for preterm birth in case of strong correlation.Methods: Secondary analysis on a large prospective database of singleton pregnancies undergoing first-trimester serum screening with complete follow-up for pregnancy outcomes. The multiples of medians (MoM) of the biomarkers were compared between the group of term and preterm/early preterm birth. Predictive models were developed based on adjusted MoMs and logistic regression analysis, and then diagnostic performances in predicting preterm birth were assessed.Results: Of 24,611 pregnancies eligible for analysis, 1908 (7.8%) and 500 (2.0%) had preterm and early preterm birth, respectively. Medians MoMs of both biomarkers were significantly lower in preterm and early preterm birth group. The predictive models were constructed. Performance in predicting preterm birth of these models yielded the area-under-ROC-curve of 0.560, 0.652, and 0.653 for b-hCG, PAPP-A, and combined biomarkers, respectively. In predicting early preterm birth, the areas-under-the-curve were found to be 0.551, 0.675, and 0.674 for b-hCG, PAPP-A, and combined biomarkers, respectively.Conclusion: The routine first-trimester serum screening of fetal Down syndrome could also be used as a tool of risk identification of preterm birth. We could take advantage of the screening by incorporating the predictive models into the Down syndrome screening software to report the preterm risk in the same test without extra effort and extra cost.