Second- and third-trimester serum levels of placental proteins in preeclampsia and small-for-gestational age pregnancies

BACKGROUND: Poor placentation may perpetuate preeclampsia, but the presence of a major placental pathology has been questioned in cases of preeclampsia where the newborn has an appropriate birthweight for gestational age. On the other hand, poor placentation is also observed in the absence of preeclampsia, in pregnancies with small-for-gestational-age (SGA) fetuses. In late gestation, maternal serum levels of placental protein hormones are changed in both preeclampsia and SGA, but no longitudinal pre-onset studies are available for pregnancy-associated plasma protein A (PAPP-A), pregnancy-specific beta1-glycoprotein (SP1) or human placental lactogen (HPL). METHODS: In a nested case-control study we compared maternal serum levels of PAPP-A, SP1, HPL and placenta growth factor (PLGF) at 17, 25 and 33 weeks in pregnancies developing preeclampsia without fetal growth restriction (n = 28), or characterized by a growth-retarded fetus (n = 25), with gestation-matched controls (n = 65). The proteins were quantified using microplate enzyme immunometric assays and the serum levels at 17, 25 and 33 weeks compared between the three groups by nonparametric statistical tests. RESULTS: In pregnancies with subsequent preeclampsia PAPP-A, SP1, HPL and PLGF were reduced at 17 weeks of gestation whereas at 25 and 33 weeks only PLGF remained below the controls. In growth-restricted pregnancies PAPP-A, SP1 and HPL were reduced at 17 weeks, and only HPL continued to be strongly affected thereafter. CONCLUSION: The reduced serum levels of the placental proteins PAPP-A, SP1 and HPL in the early second trimester (17 weeks) in pregnancies with subsequent preeclampsia or with fetal growth restriction involve an underlying role for the placenta in either pathology independent from the other.     

Placental expression of insulin-like growth factor-I,fibroblast growth factor-basic,and neural cell adhesion molecule in preeclampsia

Objective. To investigate placental expression of insulin-like growth factor-I (IGF-I), fibroblast growth factor-basic (FGF-b), and neural cell adhesion molecule (N-CAM) in preeclampsia.

Study design. An immunohistochemical analysis using IGF-I, FGF-b, and N-CAM antibodies was conducted on 4% paraformaldehyde-fixed placental tissues of preeclamptic patients (N = 14) and normotensive pregnant subjects (N = 10). Immunostaining patterns of chorionic villi and amniochorionic membranes were assessed.

Results. Significantly increased FGF-b and N-CAM immunoreactivities in cytotrophoblasts and increased FGF-b immunoreactivity in capillary endothelium of chorionic villi of preeclamptic subjects were noted. Significantly increased FGF-b and decreased N-CAM immunoreactivities in extravillous trophoblasts and decidual cells of amniochorionic membranes obtained from preeclamptic subjects were demonstrated. Additionally, a significantly increased IGF-I immunoreactivity was shown in decidual cells of preeclamptic cases.

Conclusion. Investigation of the regional distribution of IGF-I, FGF-b, and N-CAM at the maternal–fetal interface establishes a better understanding of cell-specific altered growth processes, which may be associated with the pathogenesis of preeclampsia.     

Decreased first trimester PAPP-A is a predictor of adverse pregnancy outcome

OBJECTIVE: Low levels of maternal serum pregnancy associated plasma protein-A (PAPP-A) have been linked to chromosome anomalies such as trisomy 21, 13 and 18, triploidy and sex chromosome aneuploidy. Low levels of PAPP-A have also been implicated in spontaneous miscarriage. The purpose of this study was to evaluate whether low levels of first trimester PAPP-A are predictive of other adverse pregnancy outcomes. STUDY DESIGN: The study included patients with singleton pregnancies who underwent combined first trimester screening using nuchal translucency (NT) and maternal serum free beta-human chorionic gonadotrophin (free beta-hCG) and PAPP-A at 10-13 weeks' gestation. Patients with chromosome aberrations or fetal anomalies were excluded. Serum marker levels were expressed as gestational age-specific multiples of the median (MoMs). The incidences of various adverse pregnancy outcomes (spontaneous preterm labor, fetal growth restriction (FGR), proteinuric and non-proteinuric pregnancy induced hypertension (PIH), intrauterine fetal demise, oligohydramnios, spontaneous miscarriage and placental abruption) were evaluated, according to maternal PAPP-A MoM levels. RESULTS: Of the 1622 patients in the study, pregnancy complications were observed in 184 (11.3%). Patients with PAPP-A < or =0.25 MoM had significantly higher rates of FGR (RR = 3.12), proteinuric PIH (RR = 6.09), spontaneous miscarriage (RR = 8.76). No statistically significant differences were noted for other adverse outcomes evaluated Women with PAPP-A < or =0.50 MoM also had significantly higher rates of FGR (RR = 3.30) and spontaneous miscarriage (RR = 3.78). CONCLUSIONS: We conclude that decreased levels of first trimester maternal serum PAPP-A are predictive not only of chromosome anomalies but also of adverse pregnancy outcome.     

Human chorionic gonadotropin and testosterone in normal and preeclamptic pregnancies in relation to fetal sex

OBJECTIVE: The aim of the present study was to evaluate the effects of fetal gender on serum human chorionic gonadotropin (hCG) and testosterone in normotensive and preeclamptic pregnancies. METHODS: The study consisted of 137 women with singleton pregnancies in the third trimester. Seventy-three pregnancies were uncomplicated; among those were 35 male and 38 female fetuses. Sixty-four pregnancies were complicated by preeclampsia; among those were 33 male and 31 female fetuses. Human chorionic gonadotropin and total testosterone were measured in maternal peripheral blood. RESULTS: In male-bearing pregnancies, maternal hCG and testosterone serum levels were significantly higher in preeclamptic than normotensive mothers (P <.001). In female-bearing pregnancies, testosterone levels were significantly higher in preeclamptic than normotensive mothers (P <.001), whereas the hCG levels were not significantly different. Male-bearing preeclamptic women had significantly higher testosterone levels than female-bearing preeclamptic women (P <.02), whereas the hCG levels were not significantly different. In uncomplicated pregnancies the hCG levels were significantly higher in female-bearing than in male-bearing mothers (P <.005), whereas the testosterone levels were not significantly different. CONCLUSION: In preeclamptic pregnancies with male fetuses, the maternal serum hCG levels were significantly higher than in uncomplicated pregnancies. Total testosterone levels were significantly higher in pregnancies with either gender and significantly higher in male-bearing than in female-bearing pregnancies. This may indicate an androgen influence on the pathophysiologic mechanism of preeclampsia.     

Altered placental tryptophan metabolic pathway in human fetal growth restriction

IntroductionTryptophan is a substrate for kynurenine pathway metabolism in the placenta. We investigated if kynurenine metabolites change over gestation, if they are different between pregnancies with normal and fetal growth restriction (FGR), and if the oxygen environment modulated kynurenine pathway activity in the human placenta.MethodsTryptophan, kynurenine, and downstream kynurenine metabolites were determined in maternal venous blood, umbilical cord blood, and placental samples obtained in 1st and 3rd trimester pregnancies including FGR, and in the media of placental explants incubated with 20% or 5–8% O₂ for 24, 48 or 72 h.ResultsAll the major kynurenine metabolites were present in cord blood, and in general were higher than in maternal blood. IDO and TDO mRNA and protein expression, responsible for kynurenine production from tryptophan, were significantly lower in placentas from FGR pregnancies compared with control. Explants prepared from 1st and 3rd trimester placentas actively produced all the major kynurenine pathway metabolites which, together with expression of IDO, TDO, KYN-OHase and 3HAO mRNAs, were significantly lower after 24 h exposure to 5–8% O₂ compared to 20% O₂ConclusionsExpression and activity of the kynurenine pathway is present in the placenta from early gestation, and is down-regulated by hypoxia and in FGR pregnancies.     

Pregnancy associated plasma protein-A2: A novel biomarker for down syndrome

IntroductionIn an effort to improve prenatal screening for Trisomy 21, we evaluated pregnancy associated plasma protein-A2 (PAPP-A2) as a potential novel second trimester biomarker for Trisomy 21.MethodsTrisomy 21 and normal control mid-trimester placental samples were subjected to quantitative rt PCR analysis of seven genes we had previously found to be differentially expressed in Trisomy 21 placentae. The localization and differential expression of PAPP-A2 in second trimester placentae from normal and Trisomy 21 pregnancies was determined by immunohistochemistry. PAPP-A2 maternal serum protein levels in ten Trisomy 21 and ten diploid pregnancies were compared by Western blotting. Maternal serum PAPP-A2 levels were measured in 30 Down syndrome cases and 142 normal controls, using ELISA. Regression analysis was used to determine the correlation of PAPP-A2 with other existing markers of Trisomy 21.ResultsPAPP-A2 (aka PLAC 3) mRNA and protein expression were both increased in Down syndrome placentae as compared to diploid placentae. PAPP-A2 was also increased in maternal serum from Down syndrome pregnancies as compared to diploid pregnancies. PAPP-A2 expression correlated weakly with established markers.DiscussionThis work takes advantage of our previously performed systematic approach to the discovery of novel maternal serum biomarkers for Trisomy 21, using cDNA microarray analysis. Beginning with the validation of the microarray results, we have tracked PAPP-A2 overexpression in Down syndrome from placental mRNA to maternal serum protein.ConclusionPAPP-A2 could serve as an additional maternal serum marker in prenatal screening for Trisomy 21.     

Altered Global Gene Expression in First Trimester Placentas of Women Destined to Develop Preeclampsia

BackgroundPreeclampsia is a pregnancy-specific disorder that remains a leading cause of maternal, fetal and neonatal morbidity and mortality, and is associated with risk for future cardiovascular disease. There are no reliable predictors, specific preventative measures or treatments other than delivery. A widely held view is that the antecedents of preeclampsia lie with impaired placentation in early pregnancy. Accordingly, we hypothesized dysregulation of global gene expression in first trimester placentas of women who later manifested preeclampsia.MethodsSurplus chorionic villus sampling (CVS) tissues were collected at 10–12 weeks gestation in 160 patients with singleton fetuses. Four patients developed preeclampsia, and their banked CVS specimens were matched to 8 control samples from patients with unaffected pregnancies. Affymetrix HG-U133 Plus 2.0 GeneChips were utilized for microarray analysis. Naïve Bayes prediction modeling and pathway analysis were conducted. qRT-PCR examined three of the dysregulated genes.ResultsThirty-six differentially expressed genes were identified in the preeclampsia placentas. qRT-PCR verified the microarray analysis. Thirty-one genes were down-regulated. Many were related to inflammation/immunoregulation and cell motility. Decidual gene dysregulation was prominent. No evidence was found for alterations in hypoxia and oxidative stress regulated genes.ConclusionsTo our knowledge, this is the first study to show dysregulation of gene expression in the early placentas of women ～6 months before developing preeclampsia, thereby reinforcing a placental origin of the disorder. We hypothesize that placentation in preeclampsia is compromised in the first trimester by maternal and fetal immune dysregulation, abnormal decidualization, or both, thereby impairing trophoblast invasion. Several of the genes provide potential targets for the development of clinical biomarkers in maternal blood during the first trimester. Supplementary materials are available for this article via the publisher's online edition.     

Placental system A amino acid transport is reduced in pregnancies with small for gestational age (SGA) infants but not in preeclampsia with SGA infants

Preeclampsia and intrauterine growth restriction (IUGR) are both associated with abnormal remodeling of maternal spiral arteries perfusing the placental site. This would be expected to be associated with reduced fetal growth, yet only one third of infants of mothers with preeclampsia are growth restricted. Infants with IUGR have decreased concentrations of amino acids in their blood and system A amino acid transporter activity is reduced in their placentas. Since infants of preeclamptic pregnancies have increased circulating amino acids, we tested system A amino acid transport activity of placental villous fragments from pregnancies with small for gestational age (SGA) infants with and without maternal preeclampsia and from uncomplicated and preeclamptic pregnancies with normal sized infants. We confirm the reduced uptake of amino acids in SGA pregnancies without preeclampsia but report that placental amino acid uptake of SGA infants with maternal preeclampsia is not reduced and is identical to uptake by normal and preeclamptic pregnancies with normal weight infants.     

Evaluation of maternal and umbilical serum TNFα levels in preeclamptic pregnancies in the intrauterine normal and growth-restricted fetus

Objective.?The aim of this study was to carry out a comparative analysis of the maternal and umbilical cord TNFα serum levels in pregnancies complicated by severe preeclampsia with normal intrauterine fetal growth, in preeclamptic pregnancies with intrauterine growth restriction (IUGR), and in normotensive pregnant patients.

Patients and methods.?The study was carried out on eight patients with severe preeclampsia complicated by IUGR and 18 preeclamptic patients with normal intrauterine fetal growth. The control group consisted of 18 healthy normotensive patients with singleton uncomplicated pregnancies. Maternal and umbilical serum TNFα concentrations were estimated using a sandwich ELISA assay.

Results and conclusions.?Pregnant women with severe preeclampsia had significantly higher maternal and umbilical serum TNFα levels than those in the normotensive controls. Our findings and other reports indicate that TNFα may participate in the pathogenesis and sequelae of preeclampsia with and without IUGR. The results of excessive umbilical serum activity of tumor necrosis factor α (TNFα) in preeclamptic pregnancy complicated by intrauterine growth restriction (IUGR) may suggest additional changes and dysfunction of the placental–fetal unit and deterioration of placental function, leading to fetal hypotrophia in the course of preeclampsia.     

Prevention of cardiovascular risk in women who had hypertension during pregnancy after 36 weeks gestation

Objective. The aim of our study was to investigate a possible correlation between the expression of the placenta-secreted hormones, β-subunit of human chorionic gonadotrophin (βhCG) and pregnancy-associated plasma protein A (PAPP-A), during the first trimester screening and the development of preeclampsia. Methods. A total of 155 patients between 11 + 0 and 13 + 6 weeks of gestation were enrolled in this study. PAPP-A and βhCG levels were measured using the KRYPTOR® system. Results. The serum levels of βhCG were significantly higher in pregnancies which subsequently developed preeclampsia. The PAPP-A concentration did not differ significantly in pregnancies complicated by preeclampsia than in uncomplicated pregnancies. Conclusion. These results might contribute to developing new tests in the prediction of preeclampsia.     

The unique pathophysiology of early-onset severe preeclampsia: role of decidual T regulatory cells

Immunological mechanisms play a pivotal role in the pathophysiology of preeclampsia. T regulatory cells (Treg cells, FoxP3(+)) suppress the cytotoxic T cell (CD8(+)) and natural killer (NK) cell response, thereby promoting immunological tolerance to the fetus. In peripheral blood, Treg cells are elevated during pregnancy, decrease throughout gestation, and are decreased in preeclampsia. To determine their role at the implantation site, we characterized the proportion of decidual Treg and CD8+ cells, and compared these with placental histology, villous sFlt expression, and chorionic trophoblast apoptotic index in normal and preeclamptic pregnancies. Decidua from first (n=5) and second (n=4) trimester terminations and chorioamniotic membranes, containing decidua, from term deliveries (n=14), early-onset (≤ 34 weeks) (n=12), and late-onset (>34 weeks) (n=14) severe preeclampsia were evaluated. Immunohistochemistry for CD3, CD8, and FoxP3 was performed: CD8(+) and FoxP3(+) cells were calculated as a proportion of CD3(+) cells. Placental tissue was evaluated for villous hypermaturity and sFlt staining. Chorioamniotic membranes were evaluated, via TUNEL assay, for chorionic trophoblast apoptosis. Decidual Treg cells were seen to peak in second trimester and decrease with advancing gestational age and were lower in early-onset (0.46%) compared with late-onset severe preeclampsia (3.34%) and term pregnancies (5.21%). The proportion of CD8(+) cells was higher in cases of severe preeclampsia. Early-onset severe preeclamptic cases had the highest sFlt score, placental insufficiency score, and apoptotic index. Our data suggest that early-onset severe preeclampsia has a unique pathophysiology involving defective immunoregulatory pathways, potentially causing vascular and trophoblast damage at the implantation site.     

Essential fatty acid patterns in preeclampsia

Fatty acid patterns were determined for maternal and cord sera from normal and preeclamptic pregnancies using gas liquid chromatography. Ten normal and 11 preeclamptic maternal sera were used; 6 preeclamptic and 6 normal cord sera were measured. Fatty acid patterns were measured in the nonesterified fatty acids (NEFA), the triglycerides (TG), the cholesterol esters (CE), and the phospholipids (PL). Preeclampsia showed significant differences in the essential fatty acid patterns in the maternal and cord sera compared to normal pregnancy. Oleic acid, an early indicator of essential fatty acid deficiency, made up a significantly greater proportion of preeclamptic cord blood NEFA, TG, and PL than in normal cord blood. Abnormalities in essential fatty acid patterns may be associated with decreased prostacyclin production and dysmaturity which may be seen with preeclampsia.     

Altered villus vessel fibronectin in preeclampsia

Fibronectin is a high molecular-weight glycoprotein found in most tissues and body fluids. Maternal plasma fibronectin levels have been shown to be elevated in preeclampsia, but little is known about placental fibronectin in preeclampsia. Fibronectin tissue distribution in placental villi was "blindly" graded by two examiners using placentas from eight nonpreeclamptic and six preeclamptic pregnancies. Selected frozen sections of normal-appearing areas from each placenta were incubated with rabbit antihuman fibronectin antiserum and then stained with fluorescein isothiocyanate-conjugated goat antirabbit immunoglobulin G and examined by fluorescent microscopy. We found less intensity of fetal vessel fibronectin staining in villi from placentas from preeclamptic pregnancies than in those of normal pregnancies (p less than 0.02, Mann-Whitney U test). It is unclear why fetal villous vessels in preeclampsia have decreased tissue fibronectin, but this may reflect an additional vascular abnormality associated with the preeclampsia syndrome.     

Preeclampsia is associated with reduced serum levels of placenta growth factor

Objectives: Adequate vascular development of the placental bed is essential for normal pregnancy. We assessed serum levels of placenta growth factor, an angiogenic factor, throughout normal pregnancy and determined its association with preeclampsia. Study Design: Serum samples were collected from (1) 308 healthy pregnant women throughout normal gestation, (2) at delivery from 30 each gestational age–matched patients with normal pregnancy and preeclampsia, and (3) maternal and cord blood samples from normal deliveries with and without labor (n = 37 each). Placenta growth factor levels were determined with an antigen-capture enzyme-linked immunosorbent assay. Results: Maternal placenta growth factor levels during normal pregnancy increased from the first trimester to the late second trimester; they subsequently declined from 30 weeks’ gestation to delivery. Significantly less maternal placenta growth factor (P < .0001) was found in pregnancies complicated by preeclampsia, and labor significantly lowered placenta growth factor levels in both maternal (P = .0189) and cord serum samples (P < .0001). Conclusion: Decreased levels of placenta growth factor during preeclampsia could influence endothelial cell and trophoblast function, thereby contributing to the pathogenesis of the disease. (Am J Obstet Gynecol 1998;179:1539-44.)     

Evaluation of maternal and umbilical serum TNFalpha levels in preeclamptic pregnancies in the intrauterine normal and growth-restricted fetus.

OBJECTIVE: The aim of this study was to carry out a comparative analysis of the maternal and umbilical cord TNFalpha serum levels in pregnancies complicated by severe preeclampsia with normal intrauterine fetal growth, in preeclamptic pregnancies with intrauterine growth restriction (IUGR), and in normotensive pregnant patients. PATIENTS AND METHODS: The study was carried out on eight patients with severe preeclampsia complicated by IUGR and 18 preeclamptic patients with normal intrauterine fetal growth. The control group consisted of 18 healthy normotensive patients with singleton uncomplicated pregnancies. Maternal and umbilical serum TNFalpha concentrations were estimated using a sandwich ELISA assay. RESULTS AND CONCLUSIONS: Pregnant women with severe preeclampsia had significantly higher maternal and umbilical serum TNFalpha levels than those in the normotensive controls. Our findings and other reports indicate that TNFalpha may participate in the pathogenesis and sequelae of preeclampsia with and without IUGR. The results of excessive umbilical serum activity of tumor necrosis factor alpha (TNFalpha) in preeclamptic pregnancy complicated by intrauterine growth restriction (IUGR) may suggest additional changes and dysfunction of the placental-fetal unit and deterioration of placental function, leading to fetal hypotrophia in the course of preeclampsia.     

Immunocytochemical Localization of Endothelin-1 in Human Placenta from Normal and Preeclamptic Pregnancies

Objective. The aim of this study was to examine the distribution of endothelin-1 (ET-1) in the human placenta at different gestational ages and to determine whether differences in ET-1 immunoreactivity occurred in preeclamptic compared with uncomplicated pregnancies.

Methods. Localization of ET-1 was investigated by the immunoperoxidase technique in first-trimester, second-trimester, and term human placentas from normal pregnancies and in placentas from preeclamptic pregnancies.

Results. In normal placentas from all gestational ages studied, endothelin-1 immunoreactivity (ET-1 IR) was specifically detected in the endothelium of the fetal vessels and in the syncytiotrophoblast. ET-1 IR was also expressed by the villous cytotrophoblast of first- and second-trimester normal placentas. The extravillous cytotrophoblast of the basal and chorionic plates also exhibited ET-1 IR, but with varying degrees of intensity. In preeclamptic placentas, the expression of ET-1 IR was uneven with a negative staining in all placentas from pregnancies between the 29th and 32nd weeks of gestation. The expression of ET-1 IR was most intense in some syncytiotrophoblast tissue in the terminal villi after the 33rd week of gestation. In placentas from preeclamptic pregnancies between the 35th and the 36th weeks of gestation, strong ET-1 IR expression was evident in the endothelium of fetal vessels and in the syncytiotrophoblast. Regardless of gestational age, ET-1 IR was also observed in the extravillous cytotrophoblast of the basal and chorionic plates of preeclamptic placentas.

Conclusion. This study demonstrates that ET-1 IR is widely distributed in the human placenta and provides further evidence to support the concept that ET-1 plays an important role as a modulator of vascular tone in the uteroplacental and fetoplacental units and may participate in the pathogenesis of preeclampsia.     

In-vivo concentrations of inhibins, activin A and follistatin in human early pregnancy

The aims of this study were to investigate the relationship between inhibins, activin A and follistatin in first trimester fetal fluids, maternal serum, placenta and decidua, and to investigate if these hormones are present in the circulation of the early second trimester human fetus. Amniotic and coelomic fluid, maternal serum, placental villi and decidual tissue were obtained from normal pregnancies at 8-12 weeks. Fetal blood by cardiocentesis and maternal blood were collected at 14-16 weeks gestation. Placental extracts had higher concentrations of inhibins, activin A and follistatin compared with decidual extracts. In the second trimester, inhibins and follistatin were detectable in fetal blood at 14-16 weeks gestation. Maternal serum concentrations of inhibin A (P < 0.001) and follistatin (P < 0.05) were significantly higher than fetal serum whereas inhibin B (P < 0.01) and pro-alpha C concentrations (P < 0.001) were higher in fetal serum. Inhibin B concentrations were also higher in male fetal serum samples that had higher concentrations of testosterone. The presence of all molecular forms of inhibins, activin A and follistatin in the first trimester fetal fluids, placental and decidual extracts in the first trimester confirms other reports. In the second trimester, high concentrations of inhibin B with testosterone in the fetal circulation indicate that these hormones may interact in the development of the male fetal gonads.     

Prenatal diagnosis for multiple pregnancies

In multiple pregnancies, first trimester ultrasound is crucial to diagnose chorionicity, to detect major structural defects, and to screen for chromosomal abnormalities based on nuchal translucency measurement. The efficacy of nuchal translucency measurement screening in twins might be improved when combined with first trimester maternal serum screening. In twins as in singletons, the risk of fetal loss attendant to chorionic villi sampling and to amniocentesis are similar. When an invasive procedure is indicated in twins, chorionic villi sampling has, over amniocentesis, the advantage of allowing selective termination to be performed in the first trimester, when the procedure related risk of miscarriage is minimal. It has the disadvantage of leading to ambiguous results in up to 2% of cases. While chorionic villi sampling is the choice technique in pregnancies at very high risk, amniocentesis is still indicated in cases at more moderate risk. In monochorionic pregnancies, selective termination can now be performed using a variety of techniques including bipolar or monopolar cord coagulation, and, in acardiac twins, alcohol ablation. However, selective termination remains more hazardous in monochorionic than in dichorionic pregnancies. The outcome of the twin-to-twin transfusion syndrome has been substantially improved by laser photocoagulation of placental shunts and by amniodrainage, but randomized trials are needed to establish the optimal therapeutic strategy, and further pathophysiologic research might result in new treatments.     

Diagnosis of fetal acrania during the first trimester nuchal translucency screening for Down syndrome.

OBJECTIVES: Prenatal screening during the first-trimester using fetal nuchal translucency (NT) measurement and maternal serum levels of free beta-human chorionic gonadotropin (hCG) and pregnancy-associated plasma protein-A (PAPP-A) has become an established method for the detection of fetal Down syndrome. Increasing evidence has shown that some of the fetal structural abnormalities could be identified during NT scanning. Second trimester maternal serum alpha-fetoprotein (MSAFP) measurements and ultrasound scans have been widely used in clinical practice to identify fetal neural tube defects (NTDs). In this study, we evaluated the effectiveness of early diagnosis of fetal acrania during NT scanning. METHODS: We reviewed the medical records of 5890 pregnancies that were delivered in our hospital between January 1, 1999 and January 31, 2001. Among them, 3600 pregnant women received NT-based Down syndrome screening at 10-13 weeks' gestation. Pregnancies with fetal NTDs were evaluated and their maternal serum levels of free beta-hCG and PAPP-A were compared with those of the normal control pregnancies. RESULTS: Seven of the 3600 pregnancies were identified with fetal acrania and all of them were detected during first-trimester NT scanning. Among the seven cases, five had measurements of maternal serum concentration free beta-hCG and PAPP-A concentration, yet there were not significant difference between the pregnancies with fetal acrania and those of the control pregnancies (PAPP-A, 1.13 vs. 0.96; free beta-hCG, 1.10 vs. 1.06; P>0.05). Two of the seven affected patients did not have maternal serum biochemical measurements due to the immediate termination of pregnancies. CONCLUSIONS: We demonstrated that pregnancies with fetal acrania could be easily identified at the time of NT scanning. Careful ultrasound inspection of fetal structure during NT measurements at 10-13 weeks of gestation provides an encouraging advantage for early diagnosis of fetal acrania.