Normal Maternal Serum Alpha-fetoprotein Levels Research Articles

Twin pregnancies in the second trimester in women in an alpha-fetoprotein screening program: sonographic evaluation and outcome.

We correlated sonographic findings with fetal outcomes in women with unsuspected twin pregnancies who had sonography in the second trimester as part of a screening program for maternal serum alpha-fetoprotein (MSAFP) level and history of neural tube defect. The study group consisted of 97 women with twin pregnancies who participated in a screening program for MSAFP level and history of neural tube defect. Seventy-three had normal MSAFP levels, 21 had elevated MSAFP levels, and two had low MSAFP levels. One patient had a family history of anencephaly. All 97 patients had sonography during their second trimester of pregnancy. Sonographic findings were reviewed retrospectively for information on gestational age, fetal anomalies, sex of the fetus, location of the placenta, presence and thickness of a dividing membrane, and interpretation of amnionicity and chorionicity. Information on fetal outcome included gestational age at delivery, survival, birth weight, sex, congenital anomalies, obstetric complications, amnionicity, chorionicity, and placental abnormalities. Amnionicity and chorionicity were correctly detected on sonograms in 44 (90%) of 49 diamniotic-dichorionic gestations, 23 (72%) of 32 diamniotic-monochorionic gestations, and two (50%) of four monoamniotic-monochorionic gestations. Fetal anomalies were present at delivery in five neonates and had been correctly detected at sonography in one (hemivertebra); one fetus with duodenal atresia had abnormal sonographic findings in the third trimester. Missed anomalies included absent forearm, cleft lip and palate, and imperforate anus. Sex of the fetuses was correctly predicted on the basis of sonographic findings in 40 of 43 pairs. Nine twin pairs had possible twin-twin transfusion syndrome suspected sonographically on the basis of abnormal fluid volumes, discrepant growth measurements, and abnormal findings on Doppler studies. Outcomes included two confirmed cases of the syndrome (two survivors, two deaths) and three probable cases (six deaths); four pregnancies resulted in eight survivors who were delivered after 34.4 weeks' gestation and had birth weights in the 25th percentile or higher. Survival rates for diamniotic-dichorionic, diamniotic-monochorionic, and monoamniotic-monochorionic gestations were 90%, 91%, and 50%, respectively. Fetuses in women with MSAFP levels greater than 4.5 multiples of the median and with monochorionic placentation had lower survival rates than fetuses in women with normal MSAFP levels and monochorionic placentation (67% vs 96%). Half the fetuses delivered after 20 weeks' gestation had birth-weight discordance of less than 10%. Premature deliveries occurred in 56% of pregnancies. The results suggest that (1) sonography is useful in predicting placentation, (2) placentation may be helpful in predicting fetal outcome, (3) increased MSAFP levels correlate with increased perinatal mortality in diamniotic-monochorionic pregnancies, and (4) caution should be taken in diagnosing and determining prognosis for suspected twin-twin transfusion syndrome in the second trimester.

Circulating intercellular adhesion molecule-1 in amniotic fluid, maternal serum α-fetoprotein levels, and intrauterine growth retardation

Our purpose was to determine if circulating intercellular adhesion molecule-1, a marker of chronic inflammation, is present in amniotic fluid in midtrimester, is increased in patients with elevated maternal serum alpha-fetoprotein level, and is associated with intrauterine growth retardation. Amniotic fluid circulating intercellular adhesion molecule-1 levels were assayed by enzyme-linked immunoassay in 273 samples obtained by midtrimester amniocentesis in gestations involving a single, structurally normal fetus. The control group consisted of 108 patients with normal maternal serum alpha-fetoprotein levels and 165 patients with elevated levels. Intrauterine growth retardation was diagnosed if birth weight was < 10th percentile for the clinically estimated gestational age. Circulating intercellular adhesion molecule-1 was detectable in amniotic fluid in 105 of 273 samples (38%). In the control group it was detectable in amniotic fluid in seven of 108 (6%). In patients with elevated maternal serum alpha-fetoprotein 97 of 164 (59%) had detectable levels (p < 0.001). Of the 273 cases 38 (14%) had intrauterine growth retardation. Of these 23 (59%) had detectable circulating intercellular adhesion molecule-1 levels (p < 0.001). Of the seven cases of intrauterine growth retardation with normal maternal serum alpha-fetoprotein levels, one (14%) had detectable circulating intercellular adhesion molecule-1. Of the 31 cases of intrauterine growth retardation with elevated maternal serum alpha-fetoprotein 22 (71%) had detectable circulating intercellular adhesion molecule-1. When circulating intercellular adhesion molecule-1 was detectable in amniotic fluid, increasing levels was significantly related to decreasing gestational age at delivery (p < 0.005). Midtrimester amniotic fluid from normal pregnancies does not generally contain detectable circulating intercellular adhesion molecule-1. Detectable amniotic fluid levels are significantly related to a birth weight < 10th percentile at delivery and to elevated midtrimester maternal serum alpha-fetoprotein levels. Increasing circulating intercellular adhesion molecule-1 levels are related to shortened length of gestation. This test may contribute to risk assessment for intrauterine growth retardation and prematurity. Circulating intercellular adhesion molecule-1 is a known marker of inflammatory processes; its further study may also improve understanding of the pathophysiologic mechanisms of certain cases of intrauterine growth retardation and prematurity.

Maternal serum alpha‐fetoprotein levels and fetal outcome in early second‐trimester oligohydramnios

Early second-trimester oligohydramnios was associated with normal maternal serum alpha-fetoprotein (MSAFP) levels in nine out of 26 cases (35 per cent). Congenital malformations of the fetal urinary tract resulting in fetal anuria were present in nine cases; in seven of them, normal MSAFP levels were measured. In contrast, normal MSAFP levels were established in only 2 out of the 17 cases without fetal malformations. These data suggest that fetal urine is the major source of elevated AFP in the maternal compartment in early second-trimester oligohydramnios. This is further supported by the lack of any relationship between concentrations of MSAFP non-reactive with Concanavalin A, originating mainly from the yolk sac-derived amniotic fluid AFP pool, and the presence of fetal diuresis. Three out of 26 women had experienced early second-trimester oligohydramnios in a previous pregnancy, suggesting the existence of a recurrence risk for this condition.

Unexplained elevated maternal serum α-fetoprotein is not predictive of adverse perinatal outcome in an indigent urban population

The null hypothesis of this study is that in an urban, indigent obstetric population at high risk for adverse perinatal outcome, unexplained elevations of maternal serum alpha-fetoprotein are not an additional predictor of adverse perinatal outcome. Perinatal outcomes of 72 patients from a clinic for indigent patients with unexplained elevated maternal serum alpha-fetoprotein levels were compared with those of matched controls from the same population with normal maternal serum alpha-fetoprotein levels. Subjects and controls were matched for age, race, parity, and presence or absence of Hollister risk factors. The frequency of adverse perinatal outcome in the two groups was subjected to matched-pair chi 2 analysis. Adverse perinatal outcome occurred in 38.9% (28 of 72) of subjects with unexplained elevated maternal serum alpha-fetoprotein levels greater than or equal to 2.5 multiples of the median, compared with 31.9% (23 of 72) of controls with normal maternal serum alpha-fetoprotein levels (p = 0.5). No statistically significant difference in adverse perinatal outcomes was found. Elevated maternal serum alpha-fetoprotein levels offer little if any additional predictive value for adverse perinatal outcome in populations already at high risk for such outcomes on the basis of obstetric or socioeconomic criteria.

The impact of maternal serum alpha fetoprotein screening on open neural tube defect births in North‐East Scotland

Over the three years period 1980-1982, 18 256 pregnancies in the Grampian Region of N-E Scotland including the islands of Orkney and Shetland were screened for raised levels of maternal serum alpha fetoprotein (MSAFP) in the second trimester. Thirty six cases of fetal open neural tube defect in singletons were detected (18 anencephaly and 18 spina bifida). Four additional cases of open spina bifida were associated with normal MSAFP levels although two of these were detected by amniotic fluid AFP measurement when amniocentesis was carried out because of previous NTD history. A further three cases of open spina bifida and two of anencephaly occurred in unscreened pregnancies. The MSAFP screening programme alone was thus instrumental in reducing the birth incidence of open neural tube defects by 36 out of 45 cases (80 per cent) in singletons.

Results and Benefits of a Maternal Serum α-Fetoprotein Screening Program

Maternal serum alpha-fetoprotein (MSAFP) screening was offered in a private suburban practice to 21,000 nondiabetic and 442 diabetic women with apparently normal pregnancies. Using 2.5 or greater multiples of the median as the normal upper limit, 249 (1.2%) had a raised MSAFP level. There were 25 neural tube defects (NTDs) (1.2/1,000 births); 18 were detected by screening and two by ultrasound scanning. Three had closed spina bifida lesions. Two had anencephaly with normal MSAFP levels, but were studied at more than 24 weeks' gestation. An additional 13 with raised MSAFP levels had other congenital defects. One in 400 women screened had a recommended amniocentesis; 26.4% of them had a fetus with an NTD or major malformation. Our detection efficiency before 24 weeks' gestation for anencephaly was 85.7% (12/14), 62.5% (5/8) for open and closed spina bifida, and 1/1 for encephalocele. A raised MSAFP level occurred in ten (2.3%) of the 442 diabetic women, four (0.9%) of whom had a fetus with an open NTS. A screening program should be established only where there is linked excellent interdisciplinary support among obstetrician, laboratory, clinical geneticist, ultrasonographer, and an identified program coordinator.

Fetal growth achievement and elevated maternal serum alpha-fetoprotein.

Maternal serum alpha-fetoprotein (AFP) was measured by radioimmunoassay in 7223 unselected patients between 16 and 20 weeks gestation. In 141 patients an elevated AFP level (greater than 2.5 multiples of the median for gestation) was found in the absence of a primary cause. When the birthweights of the 137 liveborn infants were corrected for maternal height and weight, sex and birth rank, 37 (27%) fell below the 10th centile of normal birthweight standards. No excess of premature deliveries was found, but there was a significant association with primiparity. Patients delivered of their second infant showed a significant decrement in mean birthweight when compared with their first-born infants and with a matched control group (normal maternal serum AFP levels). There was a highly significant association between elevated serum AFP and subsequent placental abruption.