Maternal Serum Alpha-fetoprotein Testing Research Articles

Timing of maternal serum alpha fetoprotein testing in pregnancy and association with adverse perinatal outcomes

Elevated maternal serum alpha-fetoprotein (MS-AFP ≥2.5MoM) is associated with adverse pregnancy outcomes (APO); however, there is limited data on the association of gestational age [GA] timing of the MS-AFP assay and APO. We sought to determine if there was an optimal GA for the MS-AFP assay in the second trimester that best predicts APO.

Prophylactic Cerclage to Prevent Preterm Birth after Conization: A Cohort Study Using Data from the National Health Insurance Service of Korea.

PurposeTo investigate potential differences in the frequency of preterm births (PTB) between pregnancies with or without prophylactic cerclage in women with a history of conization.Materials and MethodsWe identified women who had their first singleton delivery after conization between 2013 and 2018 using records in the National Health Insurance Service of Korea claims database. We only included women who had undergone a health examination and interview within 2 years before delivery. We used timing of maternal serum alpha-fetoprotein (MSAFP) tests to differentiate early (before) from late (after the MSAFP test) cerclage. The frequency of adverse pregnancy outcomes, including PTB, preterm labor and premature rupture of membranes, antibiotics and tocolytics use, cesarean delivery, and number of admissions before delivery, were compared.ResultsA total of 8322 women was included. Compared to the no cerclage group (n=7147), the risks of adverse pregnancy outcomes were higher in the cerclage group (n=1175). After categorizing patients with cerclage into two groups, the risk of PTB was still higher in the early cerclage group than in the no cerclage group after adjusting for baseline factors (4.48%, 30/669 vs. 2.77%, 159/5749, odds ratio 2.42, 95% confidence interval 1.49, 3.92). Other adverse pregnancy outcomes were also more frequent in the early cerclage group than the no cerclage group.ConclusionEarly cerclage performed before MSAFP testing does not prevent PTB in pregnancy with a history of conization, but increases the risk of adverse pregnancy outcomes, including PTB.

Is the ratio of maternal serum to amniotic fluid AFP superior to serum levels as a predictor of pregnancy complications?

The use of maternal serum alpha fetoprotein (MSAFP) levels as a predictor of pregnancy complications (PC) is well established. We hypothesized that the ratio between the MSAFP/AFAFP levels (RATIO) will more accurately predict PC than MSAFP levels alone. Women who had a MSAFP test followed by amniocentesis were divided into two groups: those who had PC comprised the study group and those who had an uneventful pregnancy served as the control group. Data regarding pregnancy and delivery course were collected. The RATIO between the study and the control groups was compared. 166 women were included in the study, of which 24 had PC. A significant correlation was found between the RATIO and intrauterine growth restriction (IUGR) and week of delivery. Six pregnancies had elevated MSAFP levels; two with RATIO below 2 had uneventful pregnancies. Among the other four pregnancies with RATIO above two, one had IUGR and the other, placental abruption. Our data suggest that the RATIO might serve as a predictor of IUGR and week of delivery. Although the number of patients in the current study was relatively small, the novelty of the proposed simple marker implies that a larger scale study is warranted. Such studies may confirm this finding and a possible advantage of using this RATIO instead of or in addition to MSAFP values for better prediction of pregnancies at risk for PC.

Routine Ultrasonography Compared With Maternal Serum Alpha-fetoprotein for Neural Tube Defect Screening

This study was done to estimate the value of prenatal maternal serum alpha-fetoprotein (MSAFP) screening compared with that of routine ultrasonography in the diagnosis of neural tube defects (NTDs). An integrated database was used retrospectively to identify cases of NTDs among 219,000 consecutive pregnancy outcomes observed during a 7-year period at 40 Kaiser Permanente facilities in Northern California. We specifically examined types of NTD and the tests used to diagnose cases. We identified 189 NTD cases, 102 of which had received MSAFP screening. Results of MSAFP testing were negative in 25 (25%) of these 102 cases. Without other testing, these 25 NTD diagnoses would have been missed. These included 15 (38%) of the 40 spina bifida cases screened, 6 (67%) of the 9 encephalocele cases screened, and 4 (8%) of the 53 anencephaly cases screened. Of the 186 NTD cases diagnosed prenatally, 115 (62%) were initially detected by routine ultrasonography administered during the second trimester without knowledge of MSAFP values; 69 (37%) were diagnosed by targeted ultrasonography after MSAFP screening indicated a higher risk for NTD; and 2 (1%) were diagnosed by pathology examination after miscarriage. Compared with MSAFP performed alone for screening, routine second-trimester ultrasonography was more likely to discover an NTD.

Influence of provider characteristics and insurance status on maternal serum alpha-fetoprotein screening.

The maternal serum alpha-fetoprotein test (MSAFP) was developed to screen for neural tube defects. Little is known about the adoption of the MSAFP test. This study examines the effect of provider specialty and geographic location and patient insurance status on MSAFP test use in Washington State. We conducted a retrospective cohort study of MSAFP use in low-risk obstetric patients of five provider groups. MSAFP use was examined for Medicaid and privately insured patients, as well as for the patients of the five provider types. Patients of urban and rural obstetrician-gynecologists were most likely to have MSAFP testing (80.4 percent and 77.0 percent, respectively); patients of urban certified nurse midwives and rural family physicians were least likely to have MSAFP testing (64.2 percent and 62.2 percent, respectively). Patients of certified nurse midwives were more likely to decline MSAFP testing when offered (26.1 percent). Medicaid-insured women were significantly less likely to have MSAFP testing than privately insured women (60.5 percent versus 79.1 percent, P < or = 0.05). Providers and patients did not uniformly use MSAFP screening. Efforts should be made to ensure that all patients are adequately informed of screening tests for neural tube defects.

Characteristics of women who refuse an offer of prenatal diagnosis: Data from the California maternal serum alpha fetoprotein blood test experience

This paper presents data from the California maternal serum alpha fetoprotein (MSAFP) program in order to explore the effect and interaction of various factors, especially ethnicity, abortion history and attitudes, religion, and religiosity on MSAFP test decision. The intent is to describe which women are more likely to reject MSAFP screening and also to understand the reasons for refusal and the meanings associated with it. We obtained data on sociodemographics and reproductive history from 595 obstetrical patient charts; we conducted semistructured interviews with an additional 158 pregnant women who were European-American, English-speaking Latina, or Spanish-speaking Latina. All of the women had been offered screening within the context of California's MSAFP Program. We found that women who had never terminated a pregnancy, Spanish-speaking Latinas, and women who scored high on a religiosity scale were significantly more likely to refuse testing. However, we found that all of those factors were strongly mediated by the effects of ethnicity and acculturation, producing different patterns of association in different groups of women.

Characteristics of women who refuse an offer of prenatal diagnosis: Data from the California maternal serum alpha fetoprotein blood test experience

This paper presents data from the California maternal serum alpha fetoprotein (MSAFP) program in order to explore the effect and interaction of various factors, especially ethnicity, abortion history and attitudes, religion, and religiosity on MSAFP test decision. The intent is to describe which women are more likely to reject MSAFP screening and also to understand the reasons for refusal and the meanings associated with it. We obtained data on sociodemographics and reproductive history from 595 obstetrical patient charts; we conducted semistructured interviews with an additional 158 pregnant women who were European-American, English-speaking Latina, or Spanish-speaking Latina. All of the women had been offered screening within the context of California's MSAFP Program. We found that women who had never terminated a pregnancy, Spanish-speaking Latinas, and women who scored high on a religiosity scale were significantly more likely to refuse testing. However, we found that all of those factors were strongly mediated by the effects of ethnicity and acculturation, producing different patterns of association in different groups of women. Am. J. Med. Genet. 78:433–445, 1998. © 1998 Wiley-Liss, Inc.

Informed Consent for Maternal Serum Alpha-fetoprotein Screening in an Inner City Population: How Informed Is It?

To determine if women who received information from a provider and viewed a videotape about maternal serum alpha-fetoprotein (MSAFP) screening understood enough to sign informed consent. A prospective qualitative design using tape recorded interviews of women who were provided information regarding MSAFP testing from a provider and from viewing a videotape. Fifty-three inner city pregnant women (58% Hispanic, 39% African-American, 3% white). Two women answered all questions correctly; no one answered all questions incorrectly. Sixty-two percent correctly answered "What is MSAFP?" Sixteen percent thought "something has to be taken from my belly" for the test. Fifty-nine percent understood that children with spina bifida could have difficulty walking or urinary problems. Seventy-two percent thought their infant would be healthy in all respects if the test was negative. Only 45% could describe the follow-up to a positive test. Eighty percent planned to have the test. Many misconceptions were apparent, and for some knowledge items, as many as 80% of the women answered incorrectly. Obtaining truly informed consent for a complex test is not a simple process. Participants met a few, but not all, of the criteria for informed consent. Women understood that the test was voluntary, but their comprehension of the meaning and implication of a positive test results was deficient. Despite this, they signed the informed consent document. The larger question of just how much comprehension is required to consider a woman "informed" has not been answered.

Why women say yes to prenatal diagnosis

Despite considerable concern of bioethicists, disabilities rights activists, feminists and others about the spread of prenatal diagnostic technologies, their routine acceptance in many parts of the world continues at a rapid pace. Yet, there is wide variation by country and region in rates of acceptance of prenatal diagnosis. We draw on John McKinlay's model of how a medical innovation becomes routinized to explore the circumstances that led to the widespread use of one prenatal diagnostic screen—the maternal serum alpha fetoprotein (MSAFP) test for the detection of neural tube defects and other developmental disabilities. As predicted by McKinlay's model, analysis of published data suggests that strong institutional or provider support is the best predictor of women's level of MSAFP test acceptance. Data collected at a health maintenance organization in California illuminate the processes through which medico-legal and institutional forces affect the use of MSAFP screening. By examining the language women use to talk about MSAFP screening, we show how providers also shape women's understandings of the meaning and purpose of MSAFP screening. These data ultimately shed light on how the very ethical issues which concern critics of prenatal diagnosis become obscured in the processes by which this screening test becomes accepted as routine.

Fetal karyotyping for chromosome abnormalities after an unexplained elevated maternal serum alpha-fetoprotein screening

To study the chromosome abnormality rate among women with elevated levels of maternal serum alpha-fetoprotein (MSAFP) and the types of chromosome abnormalities in this population, and to compare this rate with reports in the literature and the rate observed in the general population. We studied 8097 women who chose to undergo amniocentesis and fetal karyotyping after having an elevated MSAFP test of 2.5 multiples of the median (MOM) or higher. All abnormal karyotypes were reviewed and grouped according to whether the elevated MSAFP value could be explained by a ventral wall or neural tube defect. The overall chromosome abnormality rate was 13.83 per 1000 amniocenteses. The rate in the "unexplained" group was 10.92 per 1000 amniocenteses. Just over half (53%) of the abnormal karyotypes were autosomal anomalies, and 47% were sex chromosome abnormalities. The autosomal aneuploidies observed most frequently were triploidy and trisomy 13. The sex chromosome abnormalities observed most frequently were the XXY and XYY karyotypes. Women who have unexplained elevated MSAFP values of 2.5 MOM or greater have a twofold increase in the rate of chromosome abnormalities in their fetuses compared with the general population (P < or = .001). This rate is consistent with other studies that used a 2.5 MOM cutoff. Studies that used a 2.0 MOM cutoff have reported chromosome abnormality rates that do not vary from general population estimates.

MSAFP levels and oesophageal atresia

This study was undertaken to evaluate the relationship between maternal serum alpha-fetoprotein (MSAFP) levels and oesophageal atresia (OA). OA occurred in 16 fetuses of mothers who had an MSAFP test in the study interval. The multiple of the median (MOM) value for MSAFP averaged 1.54 +/- 0.65 (range 0.5-2.9 MOM), which was significantly higher than the value seen in controls. The median MOM was 1.35. Using a cut-off of 2.5 MOM, the sensitivity of MSAFP for detecting OA was 19 per cent. Although OA should be considered in the differential diagnosis of an elevated MSAFP level, MSAFP cannot be considered an appropriate screening test for OA given the low sensitivity.

Screening maternal serum alpha-fetoprotein levels and human parvovirus antibodies.

The association between gestational infection with human parvovirus (B19) and fetal loss has increased interest in this virus and demand for diagnostic testing. However, serological assays for B19 are not yet widely available. Maternal serum alpha-fetoprotein (MSAFP) testing is commonly used during the second trimester to screen for various fetal defects. We attempted to determine whether an elevated level of MSAFP would be an appropriate indication for B19-specific tests. Over a 26-month period, MSAFP tests were performed at Michigan State University for 21 392 women. Sera remaining after that testing were stored frozen. Of these, 22 cases samples--from women with MSAFP levels greater than 3.0 multiples of the median (MOM) and pregnancies that ended in fetal loss--and 44 matched control samples--from women with MSAFP levels greater than 0.4 and less than 2.2 MOM and live births at term--were tested for B19 antibodies. None of the 66 samples was IgM positive, while 33 (50 per cent) were IgG positive. The presence of IgG was not significantly associated with case or control status (matched odds ratio = 0.77, 95 per cent confidence interval 0.28-2.11). These findings are consistent with other studies indicating prior infection in approximately half of adults and suggest that elevated screening MSAFP levels, in the absence of other evidence of B19 infection, should not prompt B19-specific testing.

Mid-Trimester Maternal Serum Alpha2-Macroglobulin and Pregnancy Outcome in a Non-Indigent Population

Alpha2-macroglobulin is a 725,000 d glycoprotein involved in proteolytic enzyme inhibition and immunoregulation. Previously, we demonstrated an association between increased maternal serum alpha2-macroglobulin and intrauterine growth retardation (IUGR) in two distinct population samples. In this study, we sought to determine whether elevated maternal levels of alpha2-macroglobulin were associated with IUGR, preterm delivery (PTD), or low birth weight (LBW) in a non-indigent population. We measured alpha2-macroglobulin concentrations in serum obtained at the time of maternal serum alpha-fetoprotein testing in a sample of 549 patients enriched for IUGR (14%), PTD (24%), and cigarette smoking (16%). Subjects were selected from local private care settings. Mean serum alpha2-macroglobulin concentration (± standard deviation) was 3.16 (± 0.85) g/L. Similar to our previous studies, in the upper quartile of alpha2-macroglobulin, 20.4% of subjects delivered a growth retarded infant vs. 12.4% in the lower three qua...

Evaluation of multiple-marker screening for Down syndrome in a statewide population

Our purpose was to evaluate our experience with a statewide, multiple-marker Down syndrome screening program. The results of 18,712 screening tests performed from July 1, 1991, to Oct. 31, 1992, were reviewed. Amniocentesis and aneuploidy detection rates were compared with the experience of a previous year (1989-1990) in which material serum alpha-fetoprotein was used for detection of Down syndrome. Positive screening tests (Down syndrome risk > or = 1/190) occurred in 665 of 18,712 (3.5%) patients; 516 of 665 (78%) patients accepted amniocentesis. Fifteen aneuploidies were identified: 12 trisomy 21, one trisomy 18, one trisomy 13, and one 48,XXXY. The overall detection rate was one in 34 amniocenteses performed; for trisomy 21 it was one in 43. 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. The expanded maternal serum alpha-fetoprotein test was well accepted by clinicians, with 36% of gravid state residents undergoing screening. The multiple marker test is a good screening tool and is superior to material serum alpha-fetoprotein alone.

Patient Attitudes Toward Testing for Maternal Serum Alpha-Fetoprotein Values When Results Are False-Positive or True-Negative

We investigated the attitudes toward the maternal serum alpha-fetoprotein (MSAFP) test of patients whose results from MSAFP testing were either false-positive or true-negative. Forty-six women who had previous false-positive results from MSAFP testing and 46 who had previous true-negative values participated. Patients were matched for age and socioeconomic status, and all were delivered of normal neonates. A significantly larger number of patients in the group with false-positive results believed they had not understood the MSAFP test than in the group with true-negative results (19.6% vs 0%). Significantly more women in the "false-positive" group felt that the test caused anxiety than in the "true-negative" group (65.2% vs 17.4%). Fewer women in the false-positive group than in the true-negative group said they would have MSAFP testing in a subsequent pregnancy (58.7% vs 91.3%). Further, the women in the false-positive group were less likely than those in the true-negative group to recommend MSAFP testing to a friend (52.1% vs 80.4%). In patients whose results were false-positive, there was a significant relationship between the patient's perception of understanding the MSAFP test and her attitude toward MSAFP testing.

Guidelines for Establishing a Maternal Serum Alpha-Fetoprotein Screening Program

Maternal serum alpha-fetoprotein (MSAFP) screening of all pregnant women between 15 and 20 weeks gestational age is generally recognized as a standard of care in current obstetric practice. There are many factors to consider when deciding to establish MSAFP testing as an in-house procedure versus ship-out testing by a reference laboratory at fee-for-service cost. In this report, we review clinical and analytical aspects of MSAFP testing, along with appropriate guidelines for establishing an on-site MSAFP screening program.

Prenatal screening for Down syndrome with maternal serum human chorionic gonadotropin levels

Human chorionic gonadotropin levels in midtrimester pregnancies may be predictive of Down syndrome. A commercially available enzyme immunoassay kit was used to measure the beta-subunit of human chorionic gonadotropin in maternal sera from 38 Down syndrome pregnancies and 114 gestational age matched controls. The human chorionic gonadotropin levels were also assayed in 236 normal sera and plasma samples to determine normative values and appropriate individual corrections. Serum and plasma human chorionic gonadotropin levels are closely correlated and are stable at room temperature, during refrigeration, and throughout freeze-thaw cycles. There is no correlation between the human chorionic gonadotropin level and maternal age, weight, or race. However, the human chorionic gonadotropin level decreases with each week of gestation from 15 to 19 weeks. Medians for each week of gestation were established to account for this variable. Up to 63% of the Down syndrome pregnancies were detected with a cutoff of 2.0 multiples of the normal median. A computational combination of human chorionic gonadotropin and maternal serum alpha-fetoprotein testing will detect additional Down syndrome pregnancies and decrease the false-positive rate. The measurement of human chorionic gonadotropin appears to be a valuable addition to maternal serum alpha-fetoprotein screening programs that can significantly increase the proportion of Down syndrome cases diagnosed.

Long-bone growth in fetuses with Down syndrome

Short stature is a well-recognized component of Down syndrome. The femur lengths of affected fetuses have been observed to be shorter than normal, with a ratio of actual to expected femur length of less than 0.91 indicating a high risk of trisomy. To further evaluate this finding we have determined the relationship between limb lengths and gestational age in 37 postmortem fetal specimens with trisomy 21. Control values were obtained from 174 normal fetuses. Measurements of the femur, tibia, fibula, humerus, radius, and ulna were made from roentgenograms or by direct measurement of the bone. Most measurements for each bone of the affected fetuses fell below the normal regression line for that bone, but only 3/37 femurs, 4/32 tibias, 5/32 fibulas, 9/32 humeri, 10/32 radii, and 7/32 ulnas fell more than 2 SDs below the mean. The ratios of actual to expected femur lengths were computed and six fetuses with Down syndrome (16.2%) had ratios less than 0.91. The bones of the extremities of fetuses with trisomy 21 are shorter than normal, but the differences are relatively small. The ratio of actual/expected femur lengths was a less efficient predictor of Down syndrome than were either maternal age or maternal serum alpha-fetoprotein tests. The upper extremity bones were shorter than normal more often than were the bones of the lower extremity, and this finding should be explored further in a prospective study.

Prenatal screening and diagnosis of neural tube defects in England and Wales in 1985.

A survey was carried out to determine the effect of prenatal screening and therapeutic abortion on births in 1985 with anencephaly and spina bifida in England and Wales. Maternal serum alpha-fetoprotein tests were done on 399,288 women (60 per cent of pregnant women): 4 per cent were reported as being screen-positive and 1 per cent had an amniocentesis. An estimated 534 pregnancies associated with anencephaly were terminated and an estimated 445 pregnancies associated with spina bifida (but without anencephaly) were terminated. Most (63 per cent) of the anencephalic pregnancies were first suspected from an ultrasound examination; 57 per cent of the spina bifida pregnancies were first suspected from a positive maternal serum alpha-fetoprotein test, 35 per cent by ultrasound, and the remaining 8 per cent by other means. The birth prevalence of anencephaly declined by 94 per cent between 1964-1972 and 1985, but when the terminations of pregnancy on account of having a fetus with anencephaly are added to the births the decline in prevalence was only 50 per cent. The birth prevalence of spina bifida declined by 68 per cent over the same period but when the terminations were added to the births the decline in prevalence was only 32 per cent. Among births with anencephaly 66 per cent had had no screening or diagnostic tests in early pregnancy, but in those that did nearly all were positive--usually in twin pregnancies where one fetus was affected but not the other. Among births with spina bifida, 48 per cent had no tests and in those that did the results were mainly negative.(ABSTRACT TRUNCATED AT 250 WORDS)

Prenatal ascertainment of triploidy by maternal serum alpha‐fetoprotein screening

We report our experience in ascertaining fetal triploidy during routine maternal serum alpha-fetoprotein (MSAFP) screening. Three cases were identified after elevated MSAFP tests. Two of the three had normal amniotic fluid alpha-fetoprotein (AFAFP). The third had amniocentesis too late for AFAFP interpretation. Three additional cases were detected by amniocentesis without prior MSAFP screening and none had an elevated AFAFP. A literature review revealed eight triploid fetuses detected as a result of an elevated MSAFP. Of the five with AFAFP quantitation, only one had an abnormal value and the elevation was minimal. In these 14 cases from our own and other reports, ultrasound findings of placental and fetal abnormalities were often noted, but a pattern diagnostic of triploidy was not present. We conclude that, for optimal prenatal detection of triploidy, fetal karyotyping should be included when an amniocentesis is performed for elevated MSAFP.