To determine the association between second-trimester serum Down syndrome screening (alpha-fetoprotein [AFP] free beta-human chorionic gonadotropin [b-hCG] unconjugated estriol [uE3]) and preterm birth and to create predictive models for preterm birth.
To establish gestational age-specific and body weight-specific mid-trimester normal median equations for the prenatal serum markers α-fetoprotein (AFP), free β subunit human chorionic gonadotropin (fβHCG), and unconjugated oestriol (uE3) for a Chinese population; to compare and replace the median equations built in LifeCycle software; to evaluate the effect of equations used for gestation correction on estimating risk in Down's syndrome, Edward's syndrome, and neural tube defect (NTD).A total of 353,065 cases of prenatal screening data of pregnant women were screened by 13 prenatal screening institutions in China.
Because maternal serum markers (pregnancy-associated plasma protein A, human chorionic gonadotropin free β subunit, and alpha-fetoprotein) used for Down syndrome (DS) screening have been described as predictors of obstetrical complications and because assisted reproductive technology (ART) pregnancies are known to be at increased risk for obstetrical complications, it is unclear whether or not correction factors should be applied to the calculated risk of DS.
A western blot analysis confirmed the LC-ESI-MS/MS data that combined detection of Apolipoprotein A-II (apo A-II) and alpha-fetoprotein (AFP) could be a potential tool for diagnosing DS cases.
We report a new mutation in exon 5 of the AFP gene, leading to a total absence of AFP on 2nd-trimester maternal serum screening for Down syndrome, confirmed on the amniotic fluid.
There are also occasional reports of prenatal diagnosis of IAD by findings on the maternal triple-marker screen (TMST), a combined serum analyte test that measures levels of alpha-fetoprotein, human chorionic gonadotropin, and unconjugated estriol for the detection of Down syndrome and open neural-tube defects.
Amniocentesis was performed at 18 weeks' gestation because of an increased risk for Down syndrome based on maternal serum alpha-fetoprotein and human chorionic gonadotrophin screening.
Chromosomal analysis showed a normal female karyotype, despite a high estimated risk for Down syndrome suggested by the low maternal serum alpha-fetoprotein level.
The efficiency of six maternal serum markers for Down's syndrome (DS), alpha fetoprotein (AFP), human chorionic gonadotropin (hCG), free beta-hCG, pregnancy-associated plasma protein-A (PAPP-A), the proform of eosinophil major basic protein (ProMBP), pregnancy-specific-beta-1-glycoprotein (SP(1)), and combinations thereof, was examined.
Down's syndrome risks are estimated between 15 and 20 completed weeks' gestation (cGW) using an algorithm involving maternal age and serum alpha-fetoprotein (AFP), chorionic gonadotrophin and unconjugated oestriol levels, each expressed as a multiple of the median level (MoM) at the cGW.
Information on maternal age and maternal serum alpha-fetoprotein, unconjugated oestriol (uE3), and human chorionic gonadotrophin (hCG) levels was used to investigate retrospectively the effect of estimating Edward's syndrome risk in women having multi-marker screening for Down's syndrome.
In a previous year in which maternal serum alpha-fetoprotein alone was used, 3.6% had positive screening tests (Down syndrome risk > or = 270); the detection rate for all aneuploidies was one in 57 amniocenteses, and for trisomy 21 it was one in 114.
Significant correlations were found for AFP and UE3 in the controls and for intHCG and F beta HCG in both the control and the Down's syndrome pregnancies.
Fetal weight does not seem to account for the lower maternal serum alpha-fetoprotein levels seen in fetuses with Down syndrome but may partially account for the lower levels seen in fetuses with trisomy 18.