Maternal Serum Alpha-fetoprotein Values Research Articles

Reconsidering Race Adjustment in Prenatal Alpha-Fetoprotein Screening.

Black racial designation is the only race for which adjustment is recommended for maternal prenatal serum alpha-fetoprotein (AFP) screening. The objective of this study is to reevaluate the relationship between maternal race and maternal serum AFP values in prenatal analyte screening. This was a single-center retrospective analysis of patients who underwent prenatal analyte screening between January 2007 and December 2020. Nomograms for raw maternal serum AFP values by gestational age were created and compared between patients identified as "Black" and "non-Black" on the laboratory requisition. Multivariable linear regression models were created to evaluate the relationship among gestational age, maternal weight, and maternal race on maternal serum AFP levels. The new models were compared with the laboratory-derived calculations, which used historically determined race adjustments. A total of 43,997 patients underwent analyte screening, and 27,710 patients had complete data for analysis. Of these, 6% were identified as Black. Black patients had laboratory blood draws at a mean gestational age of 123 days, compared with 120 days in non-Black patients ( P <.001), and had higher maternal weight (mean 170 vs 161 lbs, P <.001). Nomograms for raw maternal serum AFP values did not differ between Black and non-Black patients ( P =.065). When adjusted for gestational age and maternal weight, no difference in maternal serum AFP values was identified between Black and non-Black individuals ( P =.81). No difference in maternal serum AFP values was identified between Black and non-Black pregnant individuals when adjusted by maternal weight and gestational age at blood draw. These findings suggest that routine race-based adjustment of maternal serum AFP screening should be discontinued.

Comparative study between 1st and 2nd trimester screening for neural tube defects using US markers and maternal serum alpha fetoportein

Background; Neural tube defects, the commonest central nervous system congenital anomalies, are a heterogeneous group of malformations resulting from failure of normal neural tube closure. Aim and objectives; to assess the potential value of combined maternal serum alpha-fetoprotein and ultrasound markers at 11-13weeks of gestation in early screening for fetal neural tube defects in comparison to the standard second trimester screening of neural tube defects. Subjects and methods; This prospective study will be conducted at the Prenatal Diagnosis and Fetal Medicine Department – National Research Centre and Obstetrics and Gynecology Department in Kasr Al Ainy Teaching Hospital. Result; Number of patients with MSAFP ≥ 2.0 MoM in the study population was 50 (25%). Number of patients with MSAFP &lt; 2.0 MoM in the study population was 150 (75%). Conclusion; Combined maternal serum alpha-fetoprotein and ultrasound markers at 11-13 weeks of gestation can be used as early screening for fetal neural tube defects as well as the standard second trimester screening of neural tube defects, the second trimester ultrasound is more sensitive than that of the first trimester for the diagnoses of neural tube defects.

Does the Predictive Value of Maternal Serum Alpha-Fetoprotein on Adverse Pregnancy Outcomes Vary by Race/Ethnicity?

Elevated 2nd trimester maternal serum alpha-fetoprotein (MSAFP; ≥2.5 multiples of the median [MoM]) is associated with adverse pregnancy outcomes such as preeclampsia (PreE), fetal growth restriction, and stillbirth. However, there is no well-defined predictive threshold. We evaluated the association of elevated MSAFP with adverse pregnancy outcomes, how well the MSAFP values predict these outcomes and whether prediction varies by race/ethnicity.

Outcomes of pregnancies diagnosed with circumvallate placenta, and use of uterine artery pulsatility index and maternal serum alpha-fetoprotein for prediction of adverse outcomes

ObjectivesTo evaluate the outcomes, and predictive value of uterine artery pulsatility index (UtA-PI) and second-trimester maternal serum alpha-fetoprotein (MSAFP) for adverse obstetric outcomes in cases with morphologically confirmed circumvallate placenta by comparison with normal pregnancies. Study designThis prospective study was conducted in a tertiary referral hospital between January 2017 and December 2019. During the study period, 77 patients with a circumvallate placenta and 77 patients without any placental or feto-maternal diseases or abnormalities were evaluated. The final diagnosis was made based on macroscopic examination of the placenta soon after birth. Demographic characteristics, MSAFP, obstetric complications, haemoglobin after delivery, gestational week of birth, fetal sex, 1- and 5-min Apgar scores, postnatal complications and type of delivery were retrieved from hospital records. Bilateral mean transabdominal UtA-PI and MSAFP were evaluated for the prediction of adverse outcomes. SPSS Version 21.0 for Windows was used for statistical analysis, and receiver operating characteristic (ROC) curves were used for the prediction model of adverse outcomes. ResultsSmoking rate, MSAFP, preterm birth and intrauterine growth restriction (IUGR) were higher in the patients with a circumvallate placenta (p = 0.005, 0.00, 0.025 and 0.027, respectively). The cut-off value of MSAFP was 1.41 (0.60–3.32) and the cut-off value of UtA-PI was 1.2 using the ROC curves, and had sensitivity of 73.7 % and specificity of 71.9 %, and sensitivity of 73.7 % and specificity of 76.3 %, respectively (p < 0.05). ConclusionsCircumvallate placenta was associated with a higher rate of IUGR, preterm birth and bleeding at the time of delivery. In patients with a circumvallate placenta, UtA-PI and MSAFP may be valuable as predictors of IUGR.

Correlation and diagnostic value of maternal serum alpha-fetoprotein level, predelivery age and body mass with gestational diabetes mellitus

To investigate the correlation and diagnostic value of maternal serum alpha-fetoprotein (MSAFP) level, predelivery age and body mass with gestational diabetes mellitus (GDM) at 9 ∼ 13 + 6 weeks (early pregnancy) and 15 ∼ 20 + 6 weeks (middle pregnancy). 486 normal and 1290 GDM women were examined for serum pregnancy-associated plasma protein A (PAPP-A), MSAFP, free β-subunit of human chorionic gonadotropin (free β-hCG) and nuchal transparency (NT) levels. Binary logistic regression analysis was used to analyze the risk factors and calculate the Odds ratio (OR) of each relevant variable. In GDM group, the predelivery age, body mass in early pregnancy and middle pregnancy were statistically higher than that in control group. The level of MSAFP in GDM group was 0.97(0.54–1.86) MOM, higher than that in control group 0.92 (0.51–1.78), (z = 3.159, p = .002). Area under curve (AUC) of MSAFP, age and body mass to GDM was 0.549, 0.645 and 0.625, respectively. The level of MSAFP, predelivery age and body mass are associated with GDM, which may be helpful for the prediction of GDM in late pregnant women. However, PAPP-A, NT and free β-hCG during pregnancy have no predicting value for GDM.

Pregnancy outcomes of women with elevated second-trimester maternal serum alpha-fetoprotein

ObjectiveThe aim of this study was to investigate the overall distribution of pregnancy outcomes in women with elevated second-trimester maternal serum alpha-fetoprotein (MS-AFP), and to determine the risk of adverse pregnancy outcomes (APOs) by MS-AFP level. Materials and methodsWe retrospectively analyzed the clinical data of 429 women with elevated MS-AFP (≥2.5 multiple of the median (MOM)) and 1555 women with normal MS-AFP (0.5–2.49MOM) from a total of 46,741 prenatally screened singleton pregnant women. The overall distribution of APOs of the two groups, the risk of APOs by MS-AFP level, and the predictive value of elevated MS-AFP to APOs were analyzed. ResultsThe incidence rate of APOs in elevated MS-AFP group was significantly higher than that in normal MS-AFP group (42.89 vs. 8.23%). In elevated MS-AFP group, the top three APOs, in term of incidence rate, were structural fetal abnormalities (7.93%), spontaneous abortion (7.46%) and preterm birth (7.23%); regarding to the risk, the top three APOs were stillbirth, spontaneous abortion and early-onset preeclampsia (odds ratio 35.98, 20.81 and 8.58 respectively). For structural fetal abnormalities, MS-AFP had predictive values for fetal open neural tube defects (ONTDs), gastroschisis and multiple malformations. ConclusionElevated MS-AFP is associated with increased risks of APOs. ONTDs complicate merely a small proportion of pregnancies with elevated MS-AFP, and the rest of them have high risks of obstetric complications. MS-AFP can help to identify these women at high risk of APOs in earlier second-trimester.

Is unexplained elevated maternal serum alpha-fetoprotein still important predictor for adverse pregnancy outcome?

The purpose of this study was to determined the predictive value of maternal serum alpha-fetoprotein (MSAFP) as a marker for adverse pregnancy outcomes. This study was carried out at Dr. Zekai Tahir Burak Women's Health Education and Research Hospital between 2009 and 2010. This study included a total of 1,177 pregnant women, including 170 in the study group and 1,007 in the control group. Pregnancy outcomes and characteristics were analyzed with regard to the MSAFP value. Gestational week, birth weight and APGAR scores were significantly lower in the elevated MSAFP group (p < 0.001). Adverse pregnancy outcomes, such as preterm delivery, preterm premature rupture of membranes (PPROM), oligohydramnios and intrauterine growth restriction (IUGR) rates were increased in the elevated MSAFP group. Although ultrasound outweighs as a screening method for neural tube defects and non-invasive prenatal testing outweighs for aneuploidy screening MSAFP level in the second trimester is still an important predictor for poor maternal/fetal outcomes.

Maternal serum alpha fetoprotein and free β-hCG of second trimester for screening of fetal gastroschisis and omphalocele

To assess the detection of maternal serum alpha fetoprotein (MSAFP) and free beta-HCG levels of second trimester for screening of fetal gastroschisis and omphalocele. Clinical data of 622 639 pregnant women from 5 prenatal screening centers in Hangzhou during October 2007 and September 2016 were analyzed retrospectively. Thirty cases of gastroschisis and 30 cases of omphalocele diagnosed by ultrasonography and postmortem findings were enrolled in the study and 116 cases of pregnant women with normal fetal development during the same period were selected as control group. The cut-off value and area under ROC curve (AUC) of MSAFP and free β-hCG for diagnosis of fetal gastroschisis and omphalocel were analyzed. MSAFP levels of women with fetal gastroschisis and omphalocele were 4.41 (0.88-11.69) MOM and 2.31 (0.72-23.20) MOM, which were significantly higher than that of control group[0.98 (0.41-2.26) MOM, all P<0.01]. Free β-hCG level of women with fetal gastroschisis was 1.25 (0.35-19.94) MOM, which was significantly higher than that of control group[0.86 (0.17-6.11) MOM, P<0.05). But there were no significant difference in free β-hCG between fetal omphalocele group[1.03(0.21-8.95)]and control group (P>0.05). The AUCs of MSAFP for diagnosis of gastroschisis and omphalocele were 0.897 (95% CI:0.822-0.972) and 0.852(95% CI:0.762-0.942), respectively (all P<0.01). Taking 1.655 MOM as the cut-off value of MSAFP for abdominal wall defects (gastroschisis and omphalocele), the sensitivity was 68.30%, specificity was 99.60% and Youden index was 0.649. MSAFP of second trimester is a better biomarker than free β-hCG in screening abdominal wall defects.

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.

Acetabulum of the hip bone: A morphometric study in south coastal region

To evaluate the outcomes, and predictive value of uterine artery pulsatility index (UtA-PI) and second-trimester maternal serum alpha-fetoprotein (MSAFP) for adverse obstetric outcomes in cases with morphologically confirmed circumvallate placenta by comparison with normal pregnancies.This prospective study was conducted in a tertiary referral hospital between January 2017 and December 2019. During the study period, 77 patients with a circumvallate placenta and 77 patients without any placental or feto-maternal diseases or abnormalities were evaluated. The final diagnosis was made based on macroscopic examination of the placenta soon after birth. Demographic characteristics, MSAFP, obstetric complications, haemoglobin after delivery, gestational week of birth, fetal sex, 1- and 5-min Apgar scores, postnatal complications and type of delivery were retrieved from hospital records. Bilateral mean transabdominal UtA-PI and MSAFP were evaluated for the prediction of adverse outcomes. SPSS Version 21.0 for Windows was used for statistical analysis, and receiver operating characteristic (ROC) curves were used for the prediction model of adverse outcomes.Smoking rate, MSAFP, preterm birth and intrauterine growth restriction (IUGR) were higher in the patients with a circumvallate placenta (p = 0.005, 0.00, 0.025 and 0.027, respectively). The cut-off value of MSAFP was 1.41 (0.60–3.32) and the cut-off value of UtA-PI was 1.2 using the ROC curves, and had sensitivity of 73.7 % and specificity of 71.9 %, and sensitivity of 73.7 % and specificity of 76.3 %, respectively (p < 0.05).Circumvallate placenta was associated with a higher rate of IUGR, preterm birth and bleeding at the time of delivery. In patients with a circumvallate placenta, UtA-PI and MSAFP may be valuable as predictors of IUGR.

First-Trimester Screening for Neural Tube Defects Using Alpha-Fetoprotein

Objective: To assess the potential value of maternal serum alpha-fetoprotein (AFP) at 11–13 weeks’ gestation in early screening for fetal neural tube defects (NTDs). Methods: Maternal serum AFP at 11–13 weeks’ gestation was measured in 32 cases of fetal NTDs, including 18 cases of acrania and 14 cases of spina bifida, and 1,500 unaffected controls. The measured serum AFP was converted into multiple of the expected median (MoM) after adjustment for gestational age and maternal characteristics and Mann-Whitney test was used to determine the significance of difference in the mean MoM of serum AFP in the NTD group to that in the controls. Results: The mean AFP MoM in the NTD group (1.76, 95% CI 1.39–2.23) was significantly higher than in the controls (p < 0.0001). The mean AFP MoM was not significantly different between the cases of acrania and cases of spina bifida (1.78 vs. 1.75; p = 0.722). The detection rates of NTD in screening by serum AFP were 50.0% (95% CI 31.9–68.1) and 37.5% (95% CI 21.1–56.3) at fixed false-positive rates of 10 and 5%, respectively. Conclusion: Measurement ofmaternal serum AFP at 11–13 weeks’ gestation may be useful in screening for fetal NTDs.

Adjustment of maternal serum alpha‐fetoprotein levels in women with pregestational diabetes

Decreased second trimester levels of maternal serum alpha-fetoprotein (MSAFP) have been reported in women with pregestational diabetes leading some laboratories to use a correction factor. The aim of this study is to determine if MSAFP levels in pregnant women with diabetes managed on oral antidiabetic agents is lower than non-diabetic controls and require adjustment similar to those on insulin. We performed a nested case/control study of an existing dataset using women with pregestational diabetes who had routine MSAFP values available. Before adjusting the MSAFP value for weight, both the diabetic patients who used insulin (n = 68) and those who used oral antidiabetic agents (n = 37) showed a non-significant trend toward a lower multiples of the median (MoM) as compared with controls (n = 244). After converting the raw MSAFP values to race-adjusted MoM and adjusting for weight, the median MSAFP MoM for women taking insulin (1.01) versus those on oral antidiabetic agents (1.00) were essentially the same. Furthermore, both of the diabetic groups were virtually identical to non-diabetic controls. In our study, women with pregestational diabetes managed on either insulin or oral antidiabetic agents had weight-adjusted MSAFP MoM levels equivalent to those in control pregnancies and did not require a correction factor.

Maternal serum alpha-fetoprotein values in type 1 and type 2 diabetic patients

Maternal serum alpha-fetoprotein (MSAFP) values are reported to be lower in type 1 diabetic patients, and a correction factor is often applied. We sought to determine whether type 2 diabetic patients require the same MSAFP adjustments as type 1 diabetic patients. We performed a retrospective review of MSAFP levels from a university laboratory in type 1 and type 2 diabetic patients between July 2000 and August 2006, matched 1:2 with controls. Groups were compared using analysis of variance and Student t testing. Seventy-seven type 1 and 75 type 2 diabetic patients were compared with 304 controls. Type 1 and type 2 diabetic patients differed significantly from each other and controls before corrections. Diabetic patients were similar to each other, but significantly lower than controls, after weight corrections. These differences were eliminated by a 10% correction factor. Type 1 and type 2 diabetic patients require both weight and diabetes corrections to adjust MSAFP values to nondiabetic levels.

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.

Historical Perspectives

This month’s Historical Perspectives is in a slightly different format, but should be of considerable interest to readers of NeoReviews. Professor Nicholas Wald is an epidemiologist who has evaluated and written about a variety of topics, but he is best known for his work on screening methods, particularly in the area of maternal serum alpha-fetoprotein (AFP) and fetal abnormalities. Because of his continuing heavy commitments and to minimize the disruption of his schedule, I posed a number of questions to him, to which he responded with detailed answers. Before moving to his responses, some background information seems in order. Shortly before publication of the article highlighted this month, evaluation of amniotic fluid in cases of open spina bifida and other neural tube defects had shown increased levels of AFP. (1) Somewhat later, it was shown that abdominal wall defects, as well as neural tube defects, could contribute to increased levels of amniotic fluid AFP. (2) In his responses, Professor Wald documents the sequence of events that followed, noting that Professor David Brock in Edinburgh described the association of increased levels of maternal serum alpha-fetoprotein (MSAFP) with fetal anencephaly, which triggered the idea that this also might be true of open spina bifida. Thus, MSAFP was used as a screening tool for the detection of neural tube and abdominal wall defects. Elevated MSAFP levels were noted in other “at-risk” pregnancies (3) and twin pregnancies. (4) To provide better standardization, Professor Wald introduced the concept of “multiples of the median” (MoM) at different gestational ages. Approximately a decade passed before the association was made between low MoMs for AFP and chromosomal defects, particularly Down syndrome. Soon thereafter, several other serum markers for Down syndrome were described, and by linking them to maternal age, screening became increasingly valuable. In the early 1980s, Dr …

Impact of Folic Acid Fortification in the United States: Markedly Diminished High Maternal Serum Alpha-Fetoprotein Values

Folic acid fortification of breads and grains was implemented in the United States in 1998 in an attempt to reduce the incidence of neural tube defects. Outcome data from birth registries have shown a 20% drop-less than originally predicted. In this study, we ascertain if the impact of folic acid fortification is better seen at the time of midtrimester prenatal diagnosis by looking at incidence of high maternal serum alpha-fetoprotein (MSAFP) values. Data regarding MSAFP levels in 61,119 patients undergoing maternal serum screening at a large commercial laboratory were categorized by multiples of the median (MoM). The data were compared between 2 groups: before mandatory supplementation in the United States in 1997 and after mandatory supplementation in 2000. High MSAFP values were further categorized as high (2.75-4.00 MoM) or very high (more than 4.00 MoM). Data were analyzed by chi(2) analysis. Comparative data showed a 32% decrease of patients with MoM greater than 2.75 + (2.5% -1.7%). Further categorizations revealed similar decreases. The introduction of folic acid fortification has produced a profound decrease in the number of high MSAFP values, reflective of a decreased incidence of neural tube defects. Our results help to validate the decision to fortify food with folic acid, which represents a highly successful public health policy for primary prevention of birth defects. II-2

Impact of folic acid supplementation in the United States: markedly diminished high maternal serum AFPs

Objective: Folic acid supplementation of breads and grains was implemented in the United States in 1998 to try to reduce the incidence of neural tube defects (NTDs). Complete birth registry outcome data will take several years to accumulate. Here we sought to use high maternal serum alpha-fetoprotein (MSAFP) values as a surrogate for likelihood of NTDs, both before and after folic acid supplementation. Methods: From 1997 and 2000, 61,119 AFP values were assessed for MOM at Quest Diagnostics Laboratory, Teterboro, NJ. Patients were characterized by MOM value. Results: Comparative data show a 42% decrease of patients with MOMs of 3.00+ (1.7% –1.33%). Further categorization revealed similar decreases. n ≤2.75 2.76–4.00 4.00+ n % n % n % 1997 27,020 26,330 97.4 488 1.80 202 0.75 2000 34,099 33,511 98.3 409 1.20 179 0.52 % decrease 61,119 59,841 — 897 33% 381 30% Conclusions: The introduction of folic acid supplementation has produced a profound decrease in the number of high AFPs, reflective of a decreased incidence of NTDs. This represents a highly successful public health policy for birth defect prevention.

Second-trimester maternal serum alpha-fetoprotein and risk of adverse pregnancy outcome

Objective: To determine the risk of adverse pregnancy outcome by maternal serum alpha-fetoprotein (MSAFP) level. Methods: We followed 77,149 pregnant women and their infants from MSAFP screening in the 15th to 20th week of gestation until 1 year after birth. Information on pregnancy outcome was obtained from national registries. The relative risks (RRs) and 95% confidence intervals (CIs) for adverse pregnancy outcome were estimated according to the level of MSAFP, with adjustment for confounders. Results: A total of 638 pregnancies resulted in spontaneous abortion, 289 in stillbirth, and 437 in infant death. Compared with women with MSAFP levels at 0.75–1.24 multiples of the median (MoM), those with MSAFP levels greater than or equal to 2.5 MoM had an increased risk of spontaneous abortion (RR 12.5; 95% CI 9.7, 16.1), preterm birth (RR 4.8; 95% CI 4.1, 5.5), small for gestational age (RR 2.8; 95% CI 2.4, 3.2), low birth weight (RR 5.8; 95% CI 5.0, 6.6), and infant death (RR 1.9; 95% CI 1.2, 2.8). Women with MSAFP levels below 0.25 MoM had an increased risk of spontaneous abortion (RR 15.1; 95% CI 9.3, 24.8), preterm birth (RR 2.2; 95% CI 1.3, 3.8), and stillbirth (RR 4.0; 95% CI 1.0, 16.0); those with levels less than 0.5 MoM had an increased risk of infant death (RR 1.9; 95% CI 1.2, 3.0). The increased risk of infant death remained after the subtraction of recognized conditions associated with extreme MSAFP values. Conclusion: Pregnant women with extreme MSAFP values in the second trimester have an increased risk of fetal and infant deaths. Obstet Gynecol 2001;97:277–82.

Second-Trimester Maternal Serum Alpha-Fetoprotein and Risk of Adverse Pregnancy Outcome

In Brief Objective To determine the risk of adverse pregnancy outcome by maternal serum alpha-fetoprotein (MSAFP) level. Methods We followed 77,149 pregnant women and their infants from MSAFP screening in the 15th to 20th week of gestation until 1 year after birth. Information on pregnancy outcome was obtained from national registries. The relative risks (RRs) and 95% confidence intervals (CIs) for adverse pregnancy outcome were estimated according to the level of MSAFP, with adjustment for confounders. Results A total of 638 pregnancies resulted in spontaneous abortion, 289 in stillbirth, and 437 in infant death. Compared with women with MSAFP levels at 0.75–1.24 multiples of the median (MoM), those with MSAFP levels greater than or equal to 2.5 MoM had an increased risk of spontaneous abortion (RR 12.5; 95% CI 9.7, 16.1), preterm birth (RR 4.8; 95% CI 4.1, 5.5), small for gestational age (RR 2.8; 95% CI 2.4, 3.2), low birth weight (RR 5.8; 95% CI 5.0, 6.6), and infant death (RR 1.9; 95% CI 1.2, 2.8). Women with MSAFP levels below 0.25 MoM had an increased risk of spontaneous abortion (RR 15.1; 95% CI 9.3, 24.8), preterm birth (RR 2.2; 95% CI 1.3, 3.8), and stillbirth (RR 4.0; 95% CI 1.0, 16.0); those with levels less than 0.5 MoM had an increased risk of infant death (RR 1.9; 95% CI 1.2, 3.0). The increased risk of infant death remained after the subtraction of recognized conditions associated with extreme MSAFP values. Conclusion Pregnant women with extreme MSAFP values in the second trimester have an increased risk of fetal and infant deaths. Pregnant women with extreme serum alpha-fetoprotein values in the second trimester have an increased risk of fetal and infant deaths.

Reducción de la prevalencia de los defectos de cierre del tubo neural mediante un programa regional de cribado con alfafetoproteína en suero materno

ObjectiveOptimization of a maternal serum alphafetoprotein screening as a regional programme, in order to reduce neural tube defect prevalence in the Principado de Asturias (Spain) Patients and methodsThe participants are pregnant women from everywhere in Asturias regardless their origin, public or private asistance. We have studied 63,163 pregnancies between 1987 and 1998. All the biochemical techniques were performed at the Biochemistry Laboratory in San Agustín Hospita ResultsWe have optimized the maternal serum alphafetoprotein screening programme with low percentages of false positives as well as performed amniocentesis, 1.9% and 0.5% respectively. We have observed that maternal serum alphafetoprotein values are higher in the presence of anencephaly than in a fetus with open spina bifida. The prevalence of these defects was diminished from 1.3% to near zero ConclusionsIt is necessary a multidisciplinary team in a screening programme like this, in order to be successful. After several years, the obstetricians and gynecologists are using the maternal serum alphafetoprotein as a routine screening tool in the pregnancy protocol. This screening programme has achieved to diminish the prevalence of open neural tube defects and it has let to know a lot more about these defects in Asturias