ABSTRACT
BACKGROUND: One of main targets of prenatal diagnosis is Down's syndrome. Biochemical and sonographic markers together are efficient. The use of a single marker has not shown the same efficiency, although it has not been sufficient evaluated. OBJECTIVE: To shown results of PAPP-A as a single marker in first pregnancy trimester. MATERIALS AND METHODS: Prospective, cross-sectional and random study, which evaluated 400 women with biochemical marker PAPP-A in the first pregnancy trimester. RESULTS: PAPP-A detected a true positive case (0.3%), 28 false positive cases (7.0%) and 371 true negative cases (92.8%), there were no false negative cases. Between 9 to 11 weeks, rate of false positives fluctuated between 5.5 and 6.7%, in 12th week it was 1.2% and in 13th week 18.2%. PAPP-A has 95.1% of specificity (weeks 9 to 12) and 82.2% of maternal age. DISCUSSION: A 5% of false positive rate is acceptable for prenatal diagnosis markers. It has been reported that PAPP-A is less discriminatory at 10 weeks of gestation. In this study the rate fluctuated between 6 and 7% (weeks 9 to 11), which increased at 13th week. Markers with low false positive rate stimulate the use of prenatal screening. CONCLUSIONS: The use of combined markers: biochemical (free fraction of beta-hGC, PAPP-A) and sonographic, are most recommendable in the first trimester of the pregnancy because of them low rate of false positives. PAPP-A can be used as a single marker between 9 to 11 weeks; false positive cases must be studied with combined markers.
Subject(s)
Down Syndrome/diagnosis , Pregnancy-Associated Plasma Protein-A/analysis , Prenatal Diagnosis/methods , Adult , Biomarkers/blood , Cross-Sectional Studies , Female , Humans , Pregnancy , Pregnancy Trimester, First , Prospective Studies , Young AdultABSTRACT
BACKGROUND: During the second trimester of 21 trisomy pregnancies, median of maternal serum concentrations of alpha-fetoprotein, not conjugated estriol, beta fraction, and inhibin A differ from normal values, and it can be used to select high risk patients. OBJECTIVE: To evaluate specificity of different forms of second trimester biochemical markers association in a group of healthy pregnant women and determine levels considered as low risk. PATIENTS AND METHODS: Random and cross-sectional study in 363 pregnant women with prenatal diagnosis to evaluate specificity of different combinations of biochemical markers. Down's syndrome and defects of neural tube rates of detection were defined as the percentage of pregnancies with tests of detection of true negatives and false positives. RESULTS: Total beta fraction has differences during weeks 13 to 14, with 70% of cases between 23,000 to 70,000 units, with 1.38% of false positives; alpha-fetoprotein fluctuated between 22 to 30 units, with 5.2% of false positives; conjugated estriol increases between 1.2 to 2.2 units during 2nd quarterly, with 6.3% of false positives; and inhibin has an increase, with 70% of cases located between 125 to 486.5 units, with 10.44% of false positives. CONCLUSIONS: Marker formula with greater specificity was type IV, included alpha-fetoprotein, not conjugated estriol and beta fraction. In the isolated form, alpha-fetoprotein marker demonstrates greater specificity.
Subject(s)
Down Syndrome/diagnosis , Estriol/blood , Inhibins/blood , Neural Tube Defects/diagnosis , Prenatal Diagnosis , alpha-Fetoproteins/analysis , Adult , Biomarkers , Cross-Sectional Studies , False Positive Reactions , Female , Gestational Age , Humans , Pregnancy , Pregnancy Trimester, Second , Sensitivity and SpecificityABSTRACT
Se presentan siete casos con hidropesía fetal no inmune (HFNI), que corresponden a una tasa de un caso por 4,200 nacidos vivos (1995-1997) y de 0.6 por ciento de las autopsias (1984-1997). La edad materna promedio fue de 26.7 (15-40) años. Seis de los casos fueron de término con peso X= 3763.5 (3000-4500)g; sexo masculino, 3:1; mal control prenatal en cuatro casos; durante el embarazo se identificaron varias alteraciones como: infección de vías urinarias, preeclampsia, políhidramnios, sangrado transvaginal, leucorrea, hipertermia, amenaza de parto pretérmino o trastornos en el feto; en todos los casos se hizo cesárea, presentaron anasarca y derrame en una o dos de las cavidades serosas. Dos casos se asociaron con malformaciones múltiples, un caso a cardiomiopatía hipertrófica dos casos a infección por citomegalovirus y en los dos restantes no se encontró enfermedad subyacente (criptogénicos). Cuatro niños fallecieron durante el primer día de vida.
