Second-trimester Maternal Serum Alpha-fetoprotein 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.

Elevated maternal second‐trimester serum alpha‐fetoprotein as a risk factor for placental abruption

To analyze the association of second-trimester maternal serum alpha-fetoprotein (MSAFP) and free beta human chorionic gonadotrophin (MSbeta-hCG) levels to placental abruption. Fifty-seven women with placental abruption and 108 control women without placental abruption were tested for second-trimester MSAFP and MSbeta-hCG levels as a part of a trisomy 21 screening program. Discriminatory cutoff levels for MSAFP were sought to predict placental abruption. The median of the MSAFP multiples of median (MoM) (1.21) was significantly higher in the abruption group than in the control group (1.07) (p = 0.004). In multivariate analysis, elevated MSAFP remained an independent risk factor for placental abruption when adjusting for other risk factors (parity >/= 3, smoking, previous placental abruption, preeclampsia, bleeding in II or III trimester, and placenta previa). MSAFP >/= 1.5 MoM had a sensitivity of 29% and a false-positive rate of 10%. The levels of the MSbeta-hCG MoM did not differ between the cases and the controls. Although second-trimester MSAFP levels are higher in women with subsequent placental abruption, the clinical usefulness of this test is limited due to low sensitivity and high false-positive rate.

Second-trimester maternal serum levels of alpha-fetoprotein and the subsequent risk of sudden infant death syndrome.

Unexplained stillbirth and the sudden infant death syndrome (SIDS) share some features. A raised maternal serum level of alpha-fetoprotein during the second trimester of pregnancy is a marker of placental dysfunction and a strong predictor of the risk of unexplained stillbirth. It is unknown whether alpha-fetoprotein levels also predict the risk of SIDS. We linked a prenatal-screening database for women in western Scotland with databases of maternity, perinatal death, and birth and death certifications to assess the association between second-trimester levels of maternal serum alpha-fetoprotein and the subsequent risk of SIDS. Among 214,532 women with singleton births, there were 114 cases of SIDS (incidence, 2.7 per 10,000 births among women with alpha-fetoprotein levels in the lowest quintile and 7.5 per 10,000 births among those with levels in the highest quintile). When the lowest quintile was used as a referent, the unadjusted odds ratios for SIDS for the second through fifth quintiles were 1.7 (95 percent confidence interval, 0.8 to 3.5), 1.8 (95 percent confidence interval, 0.9 to 3.7), 2.5 (95 percent confidence interval, 1.3 to 4.8), and 2.8 (95 percent confidence interval, 1.4 to 5.4), respectively (P for trend = 0.001). The risk of SIDS varied inversely with the birth-weight percentile and the gestational age at delivery; after adjustment for these factors, the odds ratios for SIDS were 1.7 (95 percent confidence interval, 0.8 to 3.5), 1.7 (95 percent confidence interval, 0.8 to 3.5), 2.2 (95 percent confidence interval, 1.1 to 4.4), and 2.2 (95 percent confidence interval, 1.1 to 4.3), respectively (P for trend = 0.01). There is a direct association between second-trimester maternal serum alpha-fetoprotein levels and the risk of SIDS, which may be mediated in part through impaired fetal growth and preterm birth.

Second-trimester maternal serum alpha-fetoprotein levels and the risk of subsequent fetal death

Second-trimester maternal serum alpha-fetoprotein levels and the risk of subsequent fetal death

Second-Trimester Maternal Serum Alpha-Fetoprotein Levels and the Risk of Subsequent Fetal Death

The finding of an elevated level of maternal serum alpha-fetoprotein during the second trimester of pregnancy may indicate that the fetus has died or is about to die. It is uncertain, however, whether the finding is associated with an increased risk of fetal death later in gestation independent of known causes of elevation, such as the presence of neural-tube defects or multiple gestation. To address this question, we performed a case-control study of 612 women whose pregnancies ended in fetal death and 2501 women who gave birth to live infants, using reports from California vital statistics for 1987. All the women had signleton pregnancies and alpha-fetoprotein screening in the second trimester. Women with elevated levels of serum alpha-fetoprotein in the second trimester of pregnancy had an increased risk of fetal death, and the risk was increased until term. Women with the highest levels of serum alpha-fetoprotein--greater than or equal to 3.0 times the median value--had a very high risk of fetal death (odds ratio, 10.4; 95 percent confidence interval, 4.9 to 22.0) as compared with women who had normal levels of alpha-fetoprotein. Maternal serum alpha-fetoprotein levels that were 2.0 to 2.9 times the median were also associated with an elevated risk of fetal death (odds ratio, 2.4; 95 percent confidence interval, 1.7 to 3.4). Elevated levels of alpha-fetoprotein were especially likely to be associated with fetal death in cases in which maternal hypertension or placental infarction was also present. CONCLUSIONs. An unexplained elevated level of maternal serum alpha-fetoprotein in the second trimester of pregnancy is associated with an increased risk of subsequent fetal death, up to four to five months after alpha-fetoprotein screening.

Prenatal diagnosis of exstrophy of the cloaca.

While screening for neural tub defects, three cases of exstrophy of the cloaca were found through elevated second-trimester maternal serum alphafetoprotein levels. Measurement of amniotic fluid alphafetoprotein and examination of the structure of rapidly adhering cells confirmed the abnormalities, and the pregnancies were terminated. Subsequent studies of cholinesterase isozymes by acrylamide electrophoresis showed an abnormal acetylcholinesterase band in each of the three amniotic fluids. During the same period, two more cases of exstrophy of the cloaca were identified in spontaneous abortions and another one in a stillbirth. It is suggested that the condition is more common than has been previously suspected and is often misclassified as omphalocele.