Free Beta-human Chorionic Gonadotropin Levels Research Articles

Second-trimester maternal serum screening for fetal Down syndrome: As a screening test for hemoglobin Bart's disease: A prospective population-based study.

The purpose of this study is to determine the effectiveness of second-trimester maternal serum screening for Down syndrome as a screening test for fetal hemoglobin (Hb) Bart's disease among an unselected population. A secondary analysis of a large prospective database (20254 pregnancies) was conducted to compare the levels of maternal serum screening, alpha-fetoprotein (AFP), free beta-human chorionic gonadotropin, and unconjugated estriol between pregnancies with Hb Bart's disease and unaffected pregnancies. The median AFP levels were much higher among affected fetuses (1.96 vs 1.12 multiple of the median; P<.001), yielding a sensitivity of 81.6% and specificity of 86.4%. Thus, AFP measurement is effective in predicting fetal Hb Bart's disease among an unselected population when using a cutoff value of 1.5 multiple of the median. The serum free beta-human chorionic gonadotropin levels were slightly, but significantly, higher in the affected pregnancies, while the serum unconjugated estriol levels were minimally, but significantly, lower among the affected pregnancies. Second-trimester maternal serum AFP levels were significantly elevated in cases of fetal Hb Bart's disease. Pregnancies with unexplained elevated serum AFP levels in areas of high prevalence of Hb Bart's disease should always undergo a detailed ultrasound examination to detect any early signs of fetal anemia before development of hydrops fetalis.

The efficiency of first-trimester serum analytes and maternal characteristics in predicting fetal growth disorders

To evaluate the association between first-trimester serum analytes, pregnancy-associated plasma protein A and free beta-human chorionic gonadotropin, and fetal growth disorders, and to determine whether a prediction model for these growth disorders can be developed. Retrospective cohort study of patients seen for first-trimester aneuploidy screening. Pregnancy-associated plasma protein A and free beta-human chorionic gonadotropin multiples of the median were evaluated for association with small- and large-for-gestational-age infants in combination with maternal characteristics. Univariate and backward stepwise logistic regression analyses were performed and the area under the receiver-operator curves used to determine the best prediction models. Neither pregnancy-associated plasma protein A nor free beta-human chorionic gonadotropin levels were associated with an increased risk of large-for-gestational-age infants. For small-for-gestational-age infants, the final model included black race, free beta-human chorionic gonadotropin multiples of the median >90th percentile, and pregnancy-associated plasma protein A multiples of the median <5th percentile as significant predictors (area under the curve = 0.58). Low pregnancy-associated plasma protein A and high free beta-human chorionic gonadotropin levels are associated with a small-for-gestational-age growth pattern; however, additional factors to improve the prediction model are needed.

First trimester screening for Down's syndrome after assisted reproductive technology: non-male factor infertility is associated with elevated free beta-human chorionic gonadotropin levels at 10–14 weeks of gestation

We retrospectively compared the first trimester Down's syndrome serum screening markers free beta-hCG (fbetahCG) and pregnancy-associated plasma protein-A (PAPP-A) at 11-14 weeks of gestation in 4,088 women with naturally conceived pregnancies and in women pregnant after ICSI (n = 163), IVF (n = 59) and frozen-thawed embryo transfer (n = 31), and we searched for a potential relationship between infertility cause and marker levels. We found lower serum PAPP-A levels in pregnancies after IVF and ICSI compared with spontaneously conceived pregnancies and non-male factor infertility was associated with elevated serum fbetahCG levels at 11-14 weeks of gestation.

Does a “vanishing twin” affect first-trimester biochemistry in Down syndrome risk assessment?

The purpose of this study was to evaluate the impact of spontaneous reduction in multifetal pregnancy on first-trimester maternal serum biochemistry. We evaluated first-trimester pregnancy associated plasma protein-A (PAPP-A) and free beta-human chorionic gonadotropin levels in singleton euploid pregnancies. Biochemical values in pregnancies with evidence of spontaneous reduction were compared to other singleton pregnancies. Mann-Whitney U, Student t test, Fisher exact test, and logistic regression analysis were used for statistical comparison. There were 41 cases (0.9%) of spontaneous reduction. Though spontaneous reduction was not associated with different levels of either analyte, reduction within 4 weeks was associated with higher levels of both PAPP-A (1.79 vs 1.18; P = .002) and free beta-hCG (1.28 vs 0.96; P = .03) compared with other pregnancies. Spontaneous reduction was associated with a higher frequency of PAPP-A >95th %ile (17.1 vs 4.7%; P = .003) and free beta-hCG >95th %ile (17.1% vs 5.0%; P = .004). Logistic regression identified independent associations between spontaneous reduction and both high PAPP-A and high free beta-hCG. Recent spontaneous reduction is associated with higher values of PAPP-A and free beta-hCG. These differences have the potential to affect risk assessment for fetal aneuploidy.

Elevated Second-Trimester Maternal Urine Free Beta-Human Chorionic Gonadotropin Levels in Asian Pregnancies with Fetal Chromosomal Abnormalities

Objectives: To investigate the second trimester maternal urine free beta-human chorionic gonadotropin (hCG) levels of chromosomally abnormal pregnancies in Asians. Methods: Free beta-hCG levels were analyzed from the urine samples of 110 control and 17 chromosomally abnormal pregnancies, including 11 cases of Down syndrome, 1 case of trisomy 18, and other chromosomal abnormalities (one mosaic deletion and 4 translocations) from the second trimester of pregnancy. Results were normalized to urine creatinine (Cr) concentration and converted to the multiple of the median (MOM) level for the appropriate gestation. Gestational age of all cases was determined by ultrasound parameters. Results: The median free beta-hCG MOM levels of Down syndrome (4.02 MOM) and other chromosomally abnormal pregnancies (2.03 MOM) are significantly higher than that of normal pregnancies (0.99 MOM) (p = 0.002 and p = 0.024, respectively). Nine of 11 (81.8%) Down syndrome cases, one trisomy 18 case, and 2 of 5 (40%) other chromosomally abnormal cases would be expected to be above the 95th centile of the control values (2.95 MOM cut-off). Conclusion: Urine free beta-hCG could be a potential and useful marker in the detection of fetal Down syndrome and other chromosomal abnormalities in Asians.