Efficacy and safety of cordocentesis for prenatal diagnosis

Comparative analysis of the application with the combination of CMA and karyotype in routine and late amniocentesis

PURPOSE

This is a retrospective comparative study. We aimed to analyze the results of karyotype and chromosomal microarray analysis (CMA) of amniotic fluid across different gestational weeks and evaluate the clinical value in prenatal diagnosis, particularly in the late pregnancies.

METHODS

Samples from 580 pregnant women of 18-23 weeks of gestation (mid-gestation group) and 196 pregnant women of 24-32 weeks of gestation (late group) were performed both standard G-band karyotype analysis and CMA.

RESULTS

Among the 580 pregnant women in the routine group, the most common indications were positive Down's screening (213/580, 36.7%), followed by advanced maternal age (196/580, 33.8%); while fetal structural anomalies on ultrasonography were the top reason for amniocentesis in the late group (56/196, 28.6%). In the routine group, the total detection rate was 12.1% (70/580), of which 4.1% (24/580) were identified by karyotype analysis and 11.2% (65/580) by CMA. The total detection rate was 15.3% (30/196) in the late group, of which 5.1% (10/196) were detected by karyotype analysis, and 14.3% (28/196) by CMA.

CONCLUSION

Karyotype analysis and CMA are complementary in detecting chromosomal abnormalities. Amniotic cavity puncture in the karyotype analysis in 18-23 weeks of gestation and 24-32 weeks of gestation is safe and effective, more obvious effect on the latter.

Parvovirus B19 Infection in Pregnancy-Course of the Disease, Fetal Complications and Management Tools: A Case Series and Literature Review

Parvovirus B19 is a virus that causes a common and usually harmless infection in both children and adults. If the virus is transmitted transplacentally during pregnancy, it can have serious consequences for both the pregnant woman and the fetus. Potential complications include severe fetal anemia, which can lead to intrauterine fetal death. A common ultrasound finding in fetuses affected by parvovirus B19 is fetal edema, which is associated with a poor prognosis. Additionally, a rare but serious complication in pregnant women with parvovirus B19 infection is mirror syndrome. The diagnosis of parvovirus B19 infection during pregnancy necessitates close monitoring of the fetal condition. If fetal anemia is suspected, intrauterine transfusion is indicated to increase fetal survival. This study presents eight cases of parvovirus B19 infection in pregnant women, highlighting the various maternal-fetal complications encountered, along with diagnostic and treatment strategies.

Maternal Risk Factors and Their Effect on Outcome and Procedure-Related Complications in Cordocentesis: A Multicenter Retrospective Study

BACKGROUND

Cordocentesis is used in clinical situations in which lower-risk diagnostic procedures do not deliver the desired results. The aim of this study was to evaluate the risk for procedure-related complications and fetal loss in correlation to maternal risk factors.

METHODS

This is a multicenter retrospective study investigating the complications, risk factors and perinatal outcome of diagnostic cordocentesis between 1998 and 2019 in three different centers.

RESULTS

A total of 1806 cordocenteses were performed and procedure-related complications (IUFD within 48 h, contractions, bradycardia, unsuccessful puncture, chorioamniotic separation) were noted in 1.6% of cases. Fetuses with chromosomal aberrations, intrauterine growth restriction and hydropic fetuses had a significantly higher rate of fetal loss compared to other indications. Fetal blood sampling (FBS) performed before 17+0 weeks of gestation was associated with a higher risk of procedure-related complications. Maternal BMI ≥ 40 increased the risk for fetal loss, whereas maternal age, number of previous miscarriages, number of previous abortions, history of vaginal bleeding or nicotine abuse did not affect the risk for complications or overall fetal loss rate.

CONCLUSIONS

In the hands of experienced operators, FBS is a safe way to further fetal diagnostics, and the risk of complications is low.

Thyroid autoantibodies

Thyroid-stimulating hormone (TSH) receptor antibody (TSH-R-Ab or TRAb) testing plays a pivotal role in arriving at the aetiological diagnosis in patients with thyrotoxicosis. A positive test establishes the diagnosis of Graves' disease (GD) while a negative result in conjunction with imaging studies supports other possible aetiologies. In patients with GD, TRAb levels at diagnosis and at the time of withdrawal of antithyroid drugs can identify patients who are unlikely to achieve remission and guide clinical management decisions. We provide an algorithm that incorporates TRAb in the decision-making process for the management of thyrotoxicosis. The utility of TRAb in predicting the risk of fetal and neonatal thyroid dysfunction is established and widely accepted in guidelines. TRAb may also help in the diagnosis of Graves' orbitopathy, especially in euthyroid or hypothyroid patients and its role in guiding its management is evolving as a useful adjunct to the clinical parameters used in making therapeutic decisions.Anti-thyroid peroxidase antibodies (TPOAb) and anti-thyroglobulin antibodies (TgAb) indicate thyroid autoimmunity. The most common use of TPOAb is to identify patients at a higher risk of progression to treatment-requiring hypothyroidism. They also aid the diagnosis of immune thyroiditis and Hashimoto's encephalopathy. Thyroglobulin measurement is used to help guide differentiated thyroid cancer treatment. TgAb is used as an accompanying test with thyroglobulin measurement as its presence can interfere with the thyroglobulin assay. A negative TgAb result reduces the likelihood of, but does not exclude, interference with thyroglobulin assay.

Invasive Prenatal Diagnostic Testing for Aneuploidies in Singleton Pregnancies: A Comparative Review of Major Guidelines

Sophisticated screening protocols for genetic abnormalities constitute an important component of current prenatal care, aiming to identify high-risk pregnancies and offer appropriate counseling to parents regarding their options. Definite prenatal diagnosis is only possible by invasive prenatal diagnostic testing (IPDT), mainly including amniocentesis and chorionic villous sampling (CVS). The aim of this comparative review was to summarize and compare the existing recommendations on IPDT from the most influential guidelines. All the reviewed guidelines highlight that IPDT is indicated based on a positive screening test rather than maternal age alone. Other indications arise from medical history and sonography, with significant variations identified between the guidelines. The earlier time for amniocentesis is unequivocally set at ≥15 gestational weeks, whereas for CVS, the earlier limit varies from ≥10 to ≥11 weeks. Certain technical aspects and the overall approach demonstrate significant differences. Periprocedural management regarding Rhesus alloimmunization, virologic status and use of anesthesia or antibiotics are either inconsistent or insufficiently addressed. The synthesis of an evidence-based algorithm for IPDT is of crucial importance to healthcare professionals implicated in prenatal care to avoid unnecessary interventions without compromising optimal prenatal care.

Risk of mother-to-child transmission of hepatitis B virus after fetal blood sampling: a report of six cases

BACKGROUND

Hepatitis B virus (HBV) remains a major global public health problem worldwide; in endemic areas, mother-to-child transmission (MTCT) of HBV is the most common transmission route. Previous studies have shown that amniocentesis for prenatal diagnosis increases the risk of MTCT of HBV among highly viraemic mothers. However, no data is available on MTCT related fetal blood sampling (FBS) because of the paucity of cases or lack of attention. We present a case series of HBV-infected women who underwent FBS with or without antiviral therapy during pregnancy and discuss the risk of MTCT after FBS.

CASE PRESENTATION

Six hepatitis B surface antigen (HBsAg)-positive pregnant women who underwent FBS for prenatal diagnosis were retrospectively reviewed. Their infants were followed up with HBV serology parameters until at least 12 months of age. Among 6 cases, two hepatitis B e-antigen (HBeAg)-positive mothers had high viral loads > 7.0 log₁₀ IU/mL, and one of them received antiviral therapy at 26^+ 3 gestational weeks and achieved an anticipated level of 4.52 log₁₀ IU/mL before FBS, while the other one did not receive any antiviral treatment. The other 4 cases were HBeAg-negative with low viral loads. Only a child born to the HBeAg-positive mother, who had no antiviral therapy with a viral load of 7.48 log₁₀ IU/mL before FBS, was found to have MTCT with HBsAg persistently positive from birth to 12 months of age. The other 5 children were both HBsAg-negative and HBsAb-positive at the end of follow-up.

CONCLUSIONS

FBS may increase the risk of MTCT of HBV in women with HBeAg-positive and high viral loads; therefore, FBS should be avoided in this high-risk population. Maternal HBV serologic testing and awareness of the potential risk of MTCT should be recommended before FBS. Antiviral therapy may be effective to decrease the risk of MTCT after FBS in highly viraemic women.

Introducing the non-invasive prenatal testing for detection of Down syndrome in China: a cost-effectiveness analysis

OBJECTIVE

This study aimed to compare the health economic value of a non-invasive prenatal testing (NIPT) strategy against a second-trimester triple screening (STS) strategy for the detection of Down syndrome based on real-world data from China.

DESIGN

A decision-analytical model was developed to compare the cost-effectiveness of five strategies from a societal perspective. Cost and probability input data were obtained from the real-world surveys and published sources.

SETTING

China.

PARTICIPANTS

Women with a singleton pregnancy.

INTERVENTIONS

The five strategies for screening were: (A) maternal age with STS (no NIPT); (B) STS plus NIPT screening; (C) age-STS plus NIPT screening (the currently referral strategy in China); (D) maternal age with NIPT screening and (E) universal NIPT screening.

MAIN OUTCOME MEASURES

Incremental cost-effectiveness ratios (ICERs) per additional Down syndrome case terminated, univariate and probabilistic sensitivity analysis and cost-effectiveness acceptability curves were obtained.

RESULTS

Strategy A detected the least number of Down syndrome cases. Compared with the cheapest Strategy B, Strategy D had the lowest ICER (incremental cost, US$98 944.85 per additional Down syndrome case detected). Strategy D had the highest probability of being cost-effective at the willingness-to-pay level between US$110 000.00 and US$535 000.00 per additional Down syndrome case averted. Strategy E would not be cost-effective unless the unit cost of the NIPT could be decreased to US$60.50.

CONCLUSION

Introducing NIPT screening strategies was beneficial over the use of STS strategy alone. Evaluating maternal age in combination with the NIPT screening strategy performs better than China's currently referral strategy in terms of cost-effectiveness and safety. Lowering the price of NIPT and optimising payment methods are effective measures to promote universal NIPT strategies in China.

Progress and Challenges in Laboratory-Based Diagnostic and Screening Approaches for Aneuploidy Detection during Pregnancy

Aneuploidy is caused by problems during cellular division and segregation errors during meiosis that lead to an abnormal number of chromosomes and initiate significant genetic abnormalities during pregnancy or the loss of a fetus due to miscarriage. Screening and diagnostic technologies have been developed to detect this genetic condition and provide parents with critical information about their unborn child. In this review, we highlight the complexities of aneuploidy as a disease as well as multiple technological advancements in testing that help to identify aneuploidy at various time points throughout pregnancy. We focus on aneuploidy diagnosis during preimplantation genetic testing that is performed during in vitro fertilization as well as prenatal screening and diagnosis during pregnancy. This review focuses on DNA-based analysis and laboratory techniques for aneuploidy detection through reviewing molecular- and engineering-based technical advancements. We also present key challenges in aneuploidy detection during pregnancy, including sample collection, mosaic embryos, economic factors, and the social implications of this testing. The goal of this review is to synthesize broad information about aneuploidy screening and diagnostic sample collection and analysis during pregnancy and discuss major challenges the field is still facing despite decades of advancements.

Trisomy 8 mosaicism in the placenta: A Danish cohort study of 37 cases and a literature review

OBJECTIVE

To evaluate the risk of fetal involvement when trisomy 8 mosaicism (T8M) is detected in chorionic villus samples (CVS).

METHODS

A retrospective descriptive study of registered pregnancies in Denmark with T8M in CVS identified through a database search and a review of published cases of T8M found through a systematic literature search and inclusion of cross references. Pregnancies with T8M in CVS and no additional numerical chromosomal aberrations were included.

RESULTS

A total of 37 Danish cases and 60 published cases were included. T8M detected in a CVS was associated with fetal involvement in 18 out of 97 pregnancies (18.6% [95%CI: 11.4-27.7]). Eight out of 70 (11.4% [95%CI: 5.1-21.3]) interpreted prenatally to be confined placental mosaicism (CPM) were subsequently found to be true fetal mosaicisms (TFM).

CONCLUSION

T8M detected in CVS poses a significant risk of fetal involvement, and examination of amniotic fluid (AF) and/or fetal tissue should be offered. However, a normal result of AF still has a considerable residual risk of fetal involvement. Genetic counselling at an early gestational age is essential, and follow-up ultrasonography should be performed to predict fetal involvement if possible.

The application of in utero magnetic resonance imaging in the study of the metabolic and cardiovascular consequences of the developmental origins of health and disease

Observing fetal development in utero is vital to further the understanding of later-life diseases. Magnetic resonance imaging (MRI) offers a tool for obtaining a wealth of information about fetal growth, development, and programming not previously available using other methods. This review provides an overview of MRI techniques used to investigate the metabolic and cardiovascular consequences of the developmental origins of health and disease (DOHaD) hypothesis. These methods add to the understanding of the developing fetus by examining fetal growth and organ development, adipose tissue and body composition, fetal oximetry, placental microstructure, diffusion, perfusion, flow, and metabolism. MRI assessment of fetal growth, organ development, metabolism, and the amount of fetal adipose tissue could give early indicators of abnormal fetal development. Noninvasive fetal oximetry can accurately measure placental and fetal oxygenation, which improves current knowledge on placental function. Additionally, measuring deficiencies in the placenta’s transport of nutrients and oxygen is critical for optimizing treatment. Overall, the detailed structural and functional information provided by MRI is valuable in guiding future investigations of DOHaD.

Cordocentesis-associated fetal loss and risk factors: single-center experience with 6650 cases

OBJECTIVES

To identify procedural risk factors associated with fetal loss following cordocentesis and to determine the rate of cordocentesis-related fetal loss associated with the current cordocentesis protocol used in our institution.

METHODS

This was a retrospective cohort study of pregnancies that underwent midpregnancy cordocentesis in a single center (a tertiary hospital, teaching school), between 1992 and 2018, based on data retrieved from our prospective database. All consecutive cases were validated to retrieve those meeting the eligibility criteria, which included: singleton pregnancy without underlying maternal disease, normal fetus (no structural or chromosomal abnormality or severe disorder), gestational age between 16 and 24 weeks at the time of the procedure and availability of pregnancy outcome. Cases that resulted in termination of pregnancy were excluded. We assessed the effect of prior cordocentesis model training on the fetal-loss rate and procedure-related complications, and evaluated potential risk factors of fetal loss secondary to cordocentesis, including procedure difficulty, placenta penetration, prolonged bleeding, fetal bradycardia, puncture site and early gestational age at procedure. Pregnancy outcomes were compared between the study group and a control group of women, who did not undergo cordocentesis, selected randomly at a 1:1 ratio from our obstetric database.

RESULTS

A total of 10 343 procedures were performed during the study period, of which 6650 met the eligibility criteria and were included in the analysis. The fetal-loss rate in the first 60 procedures (early practice) of six operators (n = 360 procedures), who did not have prior model training, was significantly higher than that during the early practice of 18 operators (n = 1080 procedures) with prior model training (6.9% vs 1.6%; P < 0.001); whereas the fetal-loss rate in the next 60 procedures of practice was comparable between the two groups. After excluding the first 360 procedures of the groups without prior model training, the overall fetal-loss rate in pregnancies that underwent cordocentesis was significantly higher than that in the control group (1.6% vs 1.0%; P < 0.001). Considering the fetal-loss rate in the normal controls as background loss, the incremental cordocentesis-associated fetal-loss rate was 0.6%. Penetration of the placenta (odds ratio (OR), 2.65 (95% CI, 1.71-4.10)), prolonged bleeding from the puncture site (OR, 10.85 (95% CI, 5.27-22.36)) and presence of fetal bradycardia (OR, 3.32 (95% CI, 1.83-6.04)) during cordocentesis were independent risk factors associated with fetal loss.

CONCLUSIONS

Cordocentesis model training markedly reduces fetal loss during the early learning curve of practice. Thus, cordocentesis practice without prior model training should not be acceptable. Significant procedural risk factors for fetal loss secondary to cordocentesis are placental penetration, prolonged bleeding and fetal bradycardia. Cordocentesis-related fetal loss may be only 0.6%, much lower than the rate reported previously. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Ultrasound Measurements of Fetal Thyroid: Reference Ranges from a Cohort of Low-Risk Pregnant Women

Background

Adequate thyroid function is essential for normal growth and development of the fetus. Sonographic recognition of alterations in fetal thyroid dimensions may be the first sign of thyroid dysfunction, permitting early diagnosis and intervention. The main goal of this study was to build curves with reference values for ultrasound measurements of the fetal thyroid from 14 to 40 weeks of gestation.

Methods

This is a prospective longitudinal study of 90 Brazilian pregnant women, complementary to a cohort multicentre study named “WHO multicentre study for the development of growth standards from fetal life to childhood: the fetal component.” Pregnant women without any pre-existing conditions that might affect fetal growth received antenatal care from the first trimester until childbirth, undergoing serial ultrasound evaluations of the fetus, including the thyroid. Longitudinal, anteroposterior, and transverse diameters of both thyroid lobes were measured in the fetus. Fetal thyroid lobe volume was also estimated. By quantile regression analysis, reference curves of measurements were fitted according to the gestational age.

Results

A reference standard of thyroid growth was defined during pregnancy by fitting curves of its measurements. Reference values for the 10^th, 50^th, and 90^th centiles of fetal thyroid measurements (longitudinal, anteroposterior, transverse diameters, and lobe volume) were defined, from 14 to 40 weeks of gestation.

Conclusion

We provided a reference curve of optimal thyroid development in a low-risk population that can be used as a standard of comparison to diagnose deviations from the norm. In addition, we demonstrated an alternative and simplified method for early recognition of thyroid morphological alterations by an individualized technique to evaluate the thyroid lobes.

Traditional Prenatal Diagnosis: Past to Present

In the nearly 60 years since prenatal diagnosis for genetic disease was first offered, the field of prenatal diagnosis has progressed far past rudimentary uterine puncture to provide fetal material to assess gender and interpret risk. Concurrent with the improvements in invasive fetal sampling came technological advances in cytogenetics and molecular biology that widened both the scope of genetic disorders that could be diagnosed and also the resolution at which the human genome could be interrogated. Nowadays, routine blood work available to all pregnant women can determine the risk for common chromosome abnormalities; chorionic villus sampling (CVS) and amniocentesis can be used to diagnose nearly all conditions with a known genetic cause; and the genome and/or exome of a fetus with multiple anomalies can be sequenced in an attempt to determine the underlying etiology. This chapter will discuss some of the major advances in prenatal sampling and prenatal diagnostic laboratory techniques that have occurred over the past six decades.

Improving pregnancy outcomes in humans through studies in sheep

Experimental studies that are relevant to human pregnancy rely on the selection of appropriate animal models as an important element in experimental design. Consideration of the strengths and weaknesses of any animal model of human disease is fundamental to effective and meaningful translation of preclinical research. Studies in sheep have made significant contributions to our understanding of the normal and abnormal development of the fetus. As a model of human pregnancy, studies in sheep have enabled scientists and clinicians to answer questions about the etiology and treatment of poor maternal, placental, and fetal health and to provide an evidence base for translation of interventions to the clinic. The aim of this review is to highlight the advances in perinatal human medicine that have been achieved following translation of research using the pregnant sheep and fetus.

Efficacy of Antenatal Intravenous Immunoglobulin Treatment in Pregnancies at High Risk due to Alloimmunization to Red Blood Cells

Background

Alloimmunization to red blood cells (RBCs) may result in fetal anemia prior to 20 weeks gestation. The question as to whether early commencement of antenatal treatment with high-dose intravenous immunoglobulins (IVIG) may prevent or at least delay the development of fetal anemia in the presence of alloantibodies to RBCs is highly relevant.

Patients and Results

Here we describe a patient with high-titer anti-K and two other severely affected pregnant women with a history of recurrent pregnancy loss due to high-titer anti-D or anti-D plus anti-C. Early commencement of treatment with IVIG (1 g/kg/week) resulted in prevention of intrauterine transfusion (IUT) in the former two cases, and in a significant delay of development of fetal anemia in the remaining case (26 weeks gestation).

Conclusion

Based on our findings and of previously published cases, early initiation of treatment of severely alloimmunized women with IVIG (1 g/kg/week) could potentially improve the outcome of fetuses at risk.

Comparison of biochemical analysis of fetal serum and fetal urine in the prediction of postnatal renal outcome in lower urinary tract obstruction

OBJECTIVES

To compare the prognostic value of fetal serum biochemistry and fetal urine biochemistry in predicting renal outcome in lower urinary tract obstruction (LUTO).

METHODS

We retrospectively studied renal outcome following a prenatal diagnosis of LUTO in cases for which both fetal blood and fetal urine were sampled. We classified the renal outcome as either "favorable," when postnatal renal function was normal, or "adverse," in the case of postnatal chronic renal failure or when renal histological lesions were present at autopsy in the case of termination of pregnancy. A prognostic model was constructed for urine and serum separately. β2-Microglobulin was the only remaining independent predictor in fetal urine. β2-Microglobulin in serum and urine were compared by using receiver operating characteristic curves.

RESULTS

In the 50 cases included, the rate of adverse outcome was 34 of 50(68%): autopsy confirmed severity of renal disease in all 27 cases who underwent termination of pregnancy, and among the 23 live born children, 7 developed renal failure. Fetal serum and urine markers were all significantly associated with renal outcome (P < .01). The receiver operating characteristic curves for fetal serum and fetal urinary β2-microglobulin were similar (area under the curve = 0.908 versus 0.909, P = .96).

CONCLUSION

Fetal serum biochemistry and fetal urine biochemistry are of similar prognostic value in predicting postnatal renal outcome in fetuses with LUTO.

Percutaneous umbilical blood sampling: current trends and outcomes

OBJECTIVES

To report our contemporary experience with PUBS, including indications and complications, stratified by the presence of hydrops fetalis.

STUDY DESIGN

All PUBS performed from 1988 to 2013 at a single tertiary care center were identified using a comprehensive ultrasound database. We recorded patient demographics, relevant obstetric, fetal and neonatal data, indication for and success of PUBS and any complications. Data were analyzed using SAS, version 9.3 (SAS Institute Inc., Cary, NC).

RESULTS

455 PUBS were performed on 208 pregnant women, 97.8% of which were successful. The average gestational age at the time of PUBS was 26.7 weeks (SD 5.1 weeks, range 17.5-41.3 weeks). Indications were available for 441: 245 (55.6%) isoimmunization, 77 (17.5%) non-immune hydrops fetalis (NIHF), 98 (22.2%) chromosomal diagnosis, and 21 (4.8%) other indications. Isoimmunization was a less common indication for PUBS in 2008-2013 as compared to 1988-1992 (51.7% vs 66.2%, p=0.07). Amongst PUBS performed in the setting of hydrops, isoimmunization was much less common in the later time period (61.1% vs 0%, respectively; p<0.01). The procedure complication rate (bradycardia or fetal demise at procedure) of 2.5% was stable over the study period and was most common with NIHF (2.0% without hydrops, 0% with immune hydrops and 6.3% with NIHF; p=0.04). Of the 208 women with a PUBS performed, 74 had more than one PUBS procedure (mean 2.2, max 18). Transfusions were performed in 233 of the 455 (51.2%). Overall, 10.2% of the pregnancies had an intrauterine fetal demise (IUFD) within 2 weeks of the procedure, which was most common in pregnancies with NIHF (3.2% without hydrops, 9.1% with immune hydrops and 31.7% with NIHF; p<0.01). The IUFD rate was 60% (3/5) in fetuses with parvovirus-mediated NIHF.

CONCLUSIONS

PUBS has a high likelihood of success with a relatively low complication rate. The complication rate is highest in pregnancies with NIHF, and these pregnancies are also at a significantly higher risk of IUFD, particularly those patients with parvovirus-mediated NIHF. Our findings can be used when counseling patients who are considering PUBS for diagnostic or therapeutic purposes.

MR Imaging-derived Oxygen-Hemoglobin Dissociation Curves and Fetal-Placental Oxygen-Hemoglobin Affinities

The authors of this study present a noninvasive approach for obtaining MR imaging–based oxygen-hemoglobin dissociation curves and for deriving oxygen tension values at which hemoglobin is 50% saturated and maps for the placenta and fetus in pregnant mice.

Purpose

To generate magnetic resonance (MR) imaging–derived, oxygen-hemoglobin dissociation curves and to map fetal-placental oxygen-hemoglobin affinity in pregnant mice noninvasively by combining blood oxygen level–dependent (BOLD) T2* and oxygen-weighted T1 contrast mechanisms under different respiration challenges.

Materials and Methods

All procedures were approved by the Weizmann Institutional Animal Care and Use Committee. Pregnant mice were analyzed with MR imaging at 9.4 T on embryonic days 14.5 (eight dams and 58 fetuses; imprinting control region ICR strain) and 17.5 (21 dams and 158 fetuses) under respiration challenges ranging from hyperoxia to hypoxia (10 levels of oxygenation, 100%–10%; total imaging time, 100 minutes). A shorter protocol with normoxia to hyperoxia was also performed (five levels of oxygenation, 20%–100%; total imaging time, 60 minutes). Fast spin-echo anatomic images were obtained, followed by sequential acquisition of three-dimensional gradient-echo T2*- and T1-weighted images. Automated registration was applied to align regions of interest of the entire placenta, fetal liver, and maternal liver. Results were compared by using a two-tailed unpaired Student t test. R1 and R2* values were derived for each tissue. MR imaging–based oxygen-hemoglobin dissociation curves were constructed by nonlinear least square fitting of 1 minus the change in R2*divided by R2*at baseline as a function of R1 to a sigmoid-shaped curve. The apparent P50 (oxygen tension at which hemoglobin is 50% saturated) value was derived from the curves, calculated as the R1 scaled value (x) at which the change in R2* divided by R2*at baseline scaled (y) equals 0.5.

Results

The apparent P50 values were significantly lower in fetal liver than in maternal liver for both gestation stages (day 14.5: 21% ± 5 [P = .04] and day 17.5: 41% ± 7 [P < .0001]). The placenta showed a reduction of 18% ± 4 in mean apparent P50 values from day 14.5 to day 17.5 (P = .003). Reproduction of the MR imaging–based oxygen-hemoglobin dissociation curves with a shorter protocol that excluded the hypoxic periods was demonstrated.

Conclusion

MR imaging–based oxygen-hemoglobin dissociation curves and oxygen-hemoglobin affinity information were derived for pregnant mice by using 9.4-T MR imaging, which suggests a potential to overcome the need for direct sampling of fetal or maternal blood.

Online supplemental material is available for this article.

Sonographic markers of fetal α-thalassemia major

α-Thalassemia prevails in Southeast Asia, where α-thalassemia major is a lethal type. Sonography is a helpful and cost-effective screening tool for detecting α-thalassemia major fetuses. The cardiothoracic ratio, placental thickness, and middle cerebral artery peak systolic velocity are most used in clinical practice. These sensitive markers are helpful for evaluation of the hemodynamic status and cardiovascular function of the affected fetuses. They can predict fetal α-thalassemia major and assess the efficacy of treatment noninvasively; therefore, the medical costs as well as the possibility of fetal loss caused by invasive procedures can be reduced. Other potentially useful sonographic markers need further studies, although previous preliminary research suggests their usefulness. This article will review those sonographic markers.

Rapid Flow cytometric prenatal diagnosis of primary immunodeficiency (PID) disorders

OBJECTIVES

Primary Immunodeficiency diseases (PID) are a heterogeneous group of inherited disorders of immune system. Immunophenotypic evaluation of PIDs using flowcytometry provides important clues for diagnosis of these disorders, though confirmation requires identification of underlying molecular defects. Prenatal diagnosis (PND) forms an important component of management in families affected with severe PID. However, molecular diagnostic facilities for each of these diseases are not available and may not be possible to perform in all cases. In such scenario we opted for phenotypic prenatal diagnosis by cordocentesis for families with index case having immunophenotypically well characterized PID.

METHODS

Normal reference ranges of lymphocyte subsets, CD 18/CD11 integrins on leukocytes, MHC class II expression and oxidative burst activity of fetal neutrophils at 18 weeks of gestation were previously established on 30 cord blood samples. PND was performed in 13 families with PIDs. Maternal contamination was ruled out by VNTR analysis.

RESULTS

Out of 13 fetuses, nine were found to be unaffected (three cases with leukocyte adhesion deficiency (LAD-I), four cases with severe combined immunodeficiency diseases (SCID), one with X-linked agammaglobulinemia (XLA), and one with chronic granulomatous disease (CGD)] and three were found to be affected (one with T-B+NK-SCID, one with MHC class II deficiency and one with LAD-I). Diagnosis was confirmed by testing the cord blood samples after delivery and further follow-up of the children. In one family diagnosis could not be offered due to maternal contamination. No procedure related complications were observed.

CONCLUSION

Flowcytometry offers rapid and sensitive method for prenatal diagnosis and genetic counseling for selected phenotypically well characterized PID in cases where molecular diagnostic facilities are not available.

Changes in human placental oxygenation during maternal hyperoxia estimated by blood oxygen level-dependent magnetic resonance imaging (BOLD MRI)

OBJECTIVES

To investigate changes in human placental oxygenation during maternal hyperoxia using non-invasive blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI).

METHODS

Eight healthy pregnant women with uncomplicated singleton pregnancies at gestational weeks 28-36 were examined with BOLD MRI, over two consecutive 5-min periods of different oxygenation: first normoxia (21% O2 ) and then hyperoxia (12 L O2 /min), achieved by controlling the maternal oxygen supply with a non-rebreather facial mask. Selecting three slices showing cross-sections of the central part of the placenta, we investigated total placental oxygenation by drawing regions of interest (ROIs) covering the entire placenta, and regional placental oxygenation by drawing smaller ROIs in the darker and brighter areas of the placenta. For each ROI, the difference in BOLD signal between the two episodes was determined and the percentage increase in BOLD signal during hyperoxia (ΔBOLD) was calculated.

RESULTS

In the BOLD image, the normoxic placenta appeared heterogeneous, with darker areas located to the fetal side and brighter areas to the maternal side. During hyperoxia, the placenta became brighter and the structure more homogeneous, and the BOLD signal of the total placenta increased (ΔBOLDtot , 15.2 ± 3.2% (mean ± SD), P < 0.0001). The increase was seen predominantly in the dark areas in the fetal part of the placenta (ΔBOLDfet , 32.1 ± 9.3%) compared with in the bright areas in the maternal part of the placenta (ΔBOLDmat , 5.4 ± 3.5%).

CONCLUSION

During hyperoxia, placental oxygenation was increased predominantly in the darker placental areas, which, given their anatomical location, represent the fetal circulation of the placenta. To our knowledge, this is the first study to successfully visualize changes in placental oxygenation using BOLD MRI.

Effectiveness of the model for prenatal control of severe thalassemia

OBJECTIVE

The aim of the research was to determine effectiveness of the model for prenatal control in reducing new cases of severe thalassemia.

METHODS

Pregnant women at six tertiary centers were recruited to follow the model, consisting of (1) carrier screening using mean corpuscular volume (for alpha-thal-1 and beta-thal) and CMU-E screen (for HbE trait), (2) carrier diagnosis, (3) the couples at risk were counseled and offered prenatal diagnosis, and (4) termination of affected pregnancy. All neonates were evaluated for thalassemia.

RESULTS

Of the 12,874 recruited pregnancies, 7008 were valid for analysis. Of them, 281 couples were identified to be at risk, Of the 281, 58 affected fetuses were identified and 55 pregnancies were terminated, whereas three did not accept pregnancy termination. All 6727 neonates at no risk were proven to be unaffected. The model had sensitivity and positive predictive value of 100% and 20%, respectively. The model could detect all of affected fetuses.

CONCLUSION

The model could prenatally identify affected fetuses with a detection rate and negative predictive value of 100%. The model was highly effective to prenatally detect affected fetuses with an acceptable false positive rate.

Effect of cord puncture site in cordocentesis at mid-pregnancy on pregnancy outcomes

OBJECTIVES

To compare the procedure and pregnancy outcomes of pregnancies undergoing cordocentesis between a group of cord insertion puncture and that of free loop puncture.

MATERIALS AND METHODS

Pregnancies undergoing cordocenteses meeting the following inclusion criteria were recruited: (1) singleton pregnancies at gestational ages of 18-22 weeks; (2) no fetal abnormalities; (3) the procedures performed by experienced operators; and (4) the procedures of no placenta penetration. The recruited cases were classified into two groups: a group of cordocenteses with puncture site at placental cord insertion (Group 1) and those with puncture site at cord free loop (Group 2). The primary outcomes to be compared were rates of fetal loss, newborns with low birth weight and preterm birth. The secondary outcomes included a rate of successful procedures, umbilical cord bleeding, fetal bradycardia, maternal blood contamination, and duration of the procedure time.

RESULTS

Of 6147 cordocenteses recruited, 2214 met inclusion criteria. The mean duration to complete the procedure in Group 1 was significantly shorter than that in Group 2 (4.5 ± 5.4 vs. 6.7 ± 8.5 min, Student's t-test; p = 0.001). The mean birth weight and gestational age at delivery were comparable between the two groups. No significant differences between the two groups were seen in rates of fetal loss, low birth weight, preterm birth, successful procedures, umbilical cord bleeding, or fetal bradycardia. However, the rate of maternal blood contamination was significantly higher in the group of puncture at the cord insertion site.

CONCLUSION

Of cordocenteses performed based on accessibility and quality of visualization, cord insertion puncture may cause more maternal blood contamination but free loop puncture may be associated with more difficult procedures, while the safety was comparable.

Midpregnancy cordocentesis training of maternal-fetal medicine fellows

OBJECTIVE

To describe systematic cordocentesis training among maternal-fetal medicine (MFM) fellows.

METHODS

During their 2-year training period, five MFM fellows, who had completed systematic model training, performed 1116 midpregnancy diagnostic cordocentesis procedures (mean, 223 (range, 185-259) procedures each) under expert supervision. The details of the procedures were recorded prospectively. Multiple pregnancies and those with fetal chromosomal or structural anomalies were excluded from analysis. The outcome measures included success rate, duration of the procedure, fetal loss and complications.

RESULTS

Of the 1116 procedures performed, 184 were excluded because of fetal abnormalities; the remaining 932 were available for analysis. Cordocentesis was performed on free-floating umbilical cord (79.3%) and at the placental insertion site (20.7%). There was an immediate complication of transient fetal bradycardia in 10% of cases. Individual success rates ranged from 98.1 to 100% and the mean cumulative success rate had plateaued by approximately 60 procedures. The overall fetal loss rate was 1.3%. The overall mean +/- SD duration of successful procedures was 4.4 +/- 4.7 min, individual mean durations ranging from 3.7 to 5.9 min.

CONCLUSIONS

MFM fellows with systematic training are able to perform cordocentesis with very high success rates, and with an acceptable procedure-related fetal loss rate. An intensive course of preclinical training with the model, and more than 60 procedures on patients under supervision is recommended.

High-throughput discovery and characterization of fetal protein trafficking in the blood of pregnant women

Although the measurement of fetal proteins in maternal serum is part of standard prenatal screening for aneuploidy and neural tube defects, attempts to better understand the extent of feto-maternal protein trafficking and its clinical and biological significance have been hindered by the presence of abundant maternal proteins. The objective of this study was to circumvent maternal protein interference by using a computational predictive approach for the development of a noninvasive, comprehensive, protein network analysis of the developing fetus in maternal whole blood. From a set of 157 previously identified fetal gene transcripts, 46 were classified into known protein networks, and 222 downstream proteins were predicted. Statistically significantly over-represented pathways were diverse and included T-cell biology, neurodevelopment and cancer biology. Western blot analyses validated the computational predictive model and confirmed the presence of specific downstream fetal proteins in the whole blood of pregnant women and their newborns, with absence or reduced detection of the protein in the maternal postpartum samples. This work demonstrates that extensive feto-maternal protein trafficking occurs during pregnancy, and can be predicted and verified to develop novel noninvasive biomarkers. This study raises important questions regarding the biological effects of fetal proteins on the pregnant woman.

Feasibility of ultrasound-guided percutaneous samplings in the pregnant baboon: a model for studies on transplacental transport

OBJECTIVE

A study was conducted to test the feasibility of cordocenteses and amniocenteses at different gestational ages in pregnant baboons.

STUDY DESIGN

Experiments were performed in 10 pregnant baboons at a median gestational age of 131 (range 92-169) days. At different time intervals, percutaneous samplings of amniotic fluid and fetal blood were performed under ultrasound guidance. Simultaneously, maternal blood samples were drawn.

RESULTS

With a median fetal weight of 431 g (range 111-690 g), 29 of 30 cordocenteses (96.6%) and all 30 amniocenteses and maternal samplings (100%) were successful in obtaining the required quantities for analysis. One cordocentesis was abandoned because of insufficient visualization of the umbilical cord due to a placental haemorrhage.

CONCLUSION

Percutaneous amniocentesis and cordocentesis can be performed with a high success rate in the pregnant baboon model. In combination with a 100% success rate in obtaining simultaneous maternal blood samples, this method is able to provide data on transplacental transport.

Fetal cardiocentesis: a review of indications, risks, applications and technique

OBJECTIVES

To review the indications, applications and technique of fetal cardiocentesis.

METHODS

Review of published case reports and case series of fetal cardiocentesis utilizing the PubMed search engine of the National Library of Medicine.

RESULTS

Case reports and case series demonstrate that fetal cardiocentesis may be an alternative method by which to facilitate prenatal diagnosis, intravascular therapy, multifetal and selective fetal reduction and in utero therapy of congenital heart disease. However, procedure-associated risk is higher than with cordocentesis and may limit use of this procedure.

CONCLUSIONS

Fetal cardiocentesis may be a reasonable option to obtain fetal intravascular access and facilitate therapeutic interventions when cordocentesis fails or is not feasible. However, expected benefit must clearly outweigh the procedure-associated risk.

An unusual cause of neonatal coagulopathy and liver disease

Congenital thyrotoxicosis is a rare and potentially fatal illness. We report a case in a preterm infant delivered to a mother known to have autoimmune endocrine disease. Diagnosis was difficult because the infant's presenting symptoms and signs closely resembled congenital viral infection with co-existent hepatic dysfunction and coagulopathy. The associated hepatic dysfunction was so severe that liver biopsy was scheduled before the diagnosis emerged. A high degree of clinical suspicion coupled with prenatal identification of pregnancies at risk of complication by congenital thyrotoxicosis is imperative to facilitate prompt diagnosis and treatment.