Procedure-related risk of miscarriage following chorionic villus sampling and amniocentesis

Willingness to pay for expanded non-invasive prenatal screening - An online discrete choice experiment from the perspective of women living in Western Australia

INTRODUCTION

Ongoing advances in genetic technology may soon provide prenatal screening for multiple genetic conditions.

AIMS

The aims were to investigate what prenatal screening test characteristics women prioritise and their willingness to pay for these tests.

METHODS

We designed an online survey incorporating a series of discrete choice scenarios. Dimensions and levels were selected based on existing prenatal tests and a hypothetical prenatal test that could non-invasively detect multiple genetic disorders in pregnancy. Participants were recruited from social media platforms. Data were analysed using conditional logistic regression and latent class analysis (LCA).

RESULTS

A total of 219 women completed the survey. Women with higher incomes and those with a tertiary education were willing to pay more than other groups. The maximum willingness to pay was AUD1870 (95% confidence interval: 1630, 2112) for a hypothetical non-invasive test to detect multiple genetic conditions in early pregnancy. An LCA demonstrated considerable heterogeneity in preferences, differing in both overall preference for testing and test characteristics considered most attractive. Among the participants, decision factors cited by 14.5% of participants were the risk of pregnancy loss, making them less likely to undergo testing; for 32.1% participants, accuracy was a major factor, and they were very likely to have testing; for 12.9%, test availability early in pregnancy was a decision factor.

CONCLUSIONS

If a non-invasive test that could detect the greatest number of genetic disorders in pregnancy was available, the priorities were test accuracy, risk of pregnancy loss and a test available early in pregnancy.

Perinatal and Delivery Outcomes Following Amniocentesis: A Case-Control Study in the Polish Population

Background: Amniocentesis is a widely used invasive prenatal diagnostic procedure, recognized for its high sensitivity and low risk of complications. This study aims to evaluate the association between amniocentesis and pregnancy outcomes, such as miscarriage, preterm rupture of membranes (PROM), and preterm birth, as well as perinatal outcomes. Methods: A case-control study was conducted at the Regional Hospital in Kielce, Poland, from 2016 to 2022, involving 1834 patients, 225 of whom underwent amniocentesis, while 1609 did not receive any invasive diagnostics. Data were collected from medical records and included maternal factors such as age, BMI, delivery mode, complications, and newborn condition. Results: The study found no statistically significant differences between the study and the control groups regarding pregnancy or perinatal characteristics. Miscarriage occurred in 1.9% of the patients in the amniocentesis group, with no cases in the control group. Rates of preterm delivery were similar between groups (8.33% in the study group vs. 5.74% in the control group, p > 0.05). Postnatal outcomes, such as birth term, birth weight, and Apgar scores, were comparable across both groups. Fetal growth restriction was slightly more frequent in the study group (2.8% vs. 0.8%). One neonatal death was observed in each group. The relative risk of complications following amniocentesis was 1.69 (CI 0.38-7.24). Conclusions: Amniocentesis is a safe invasive prenatal procedure. It should be offered to every pregnant woman when necessary. Before the procedure, the patient should be clearly informed of the risk related to amniocentesis but at the same time reassured that the complication rate is very low.

Effect of cannula insertion site during fetal endoscopic tracheal occlusion for congenital diaphragmatic hernia on preterm prelabor rupture of membranes

OBJECTIVE

To assess whether the cannula insertion site on the maternal abdomen during fetal endoscopic tracheal occlusion (FETO) for congenital diaphragmatic hernia (CDH) was associated with preterm prelabor rupture of membranes (PPROM) before balloon removal.

METHODS

This was a multicenter retrospective study of consecutive pregnancies with isolated left- or right-sided CDH that underwent FETO in four centers between January 2009 and January 2021. The site for balloon insertion was categorized as above or below the umbilicus. One propensity score was analyzed in both groups to calculate an average treatment effect (ATE) by inverse probability of treatment weighting. Logistic regression and Cox proportional hazard regression including the ATE weights were performed to examine the effect size of entry point on the frequency and timing of PPROM before balloon removal.

RESULTS

A total of 294 patients were included. The mean ± SD gestational age at PPROM was 33.45 ± 2.01 weeks and the mean rate of PPROM before balloon removal was 25.9% (76/294). Gestational age at FETO was later in the below-umbilicus group (mean ± SD, 29.47 ± 1.29 weeks vs 29.00 ± 1.25 weeks; P = 0.002) and the duration of FETO was longer in the above-umbilicus group (median, 14.49 min (interquartile range (IQR), 8.00-21.00 min) vs 11.00 min (IQR, 7.00-14.49 min); P = 0.002). After balancing for possible confounding factors, trocar entry point below the umbilicus did not increase the risk of PPROM before balloon removal (adjusted odds ratio, 1.56 (95% CI, 0.89-2.74); P = 0.120) and had no effect on the timing of PPROM before balloon removal (adjusted hazard ratio, 1.56 (95% CI, 0.95-2.55); P = 0.080).

CONCLUSION

There was no evidence that uterine entry site for FETO was correlated with the risk of PPROM before balloon removal. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Should non-invasive prenatal testing be recommended for patients who achieve pregnancy with PGT?

OBJECTIVE

To determine whether non-invasive prenatal testing is an alternative testing option to preimplantation genetic testing (PGT) in pregnant patients.

METHODS

This was a retrospective study of the clinical outcomes of patients who underwent PGT and invasive or non-invasive pregnancy testing after euploid blastocyst transfer at our IVF centre between January 2017 and December 2022.

RESULTS

In total, 321 patients were enrolled in this study, 138 (43.0%) received invasive pregnancy testing, and 183 (57.0%) patients underwent non-invasive testing. The mean age of the patients in Group 2 was higher than that of the patients in Group 1 (35.64 ± 4.74 vs. 31.04 ± 4.15 years, P < 0.001). The basal LH and AMH levels were higher in Group 1 than in Group 2 (4.30 ± 2.68 vs. 3.40 ± 1.88, P = 0.003; 5.55 ± 11.22 vs. 4.09 ± 3.55, P = 0.012), but the clinical outcomes were not significantly different. Furthermore, the clinical outcomes of patients undergoing invasive testing were similar to those of patients undergoing non-invasive testing with the same PGT indication.

CONCLUSION

Our results suggest that non-invasive pregnancy testing is a suitable alternative option for detecting the foetal chromosomal status in a PGT cycle. However, the usefulness of non-invasive testing in PGT-M patients is still limited.

DEGUM Recommendations on Diagnostic Puncture in Prenatal Medicine

Diagnostic puncture (amniocentesis, chorionic villus sampling, and fetal blood sampling) is an essential part of prenatal diagnostics and the only established and sufficiently scientifically evaluated possibility of diagnosing genetic diseases from pregnancy-specific cells. The number of diagnostic punctures in Germany, as in other countries, has fallen significantly. This is largely due to the introduction of first-trimester screening with further detailed ultrasound examination of the fetus and the analysis of cf-DNA (cell-free DNA) from maternal blood (noninvasive prenatal test - NIPT). On the other hand, knowledge about the incidence and appearance of genetic diseases has increased. The development of modern molecular genetic techniques (microarray and exome analysis) makes a differentiated investigation of these diseases increasingly possible. The requirements for education and counseling regarding these complex correlations have thus increased. The studies performed in recent years make it clear that diagnostic puncture performed in expert centers is associated with a low risk of complications. In particular, the procedure-related miscarriage risk hardly differs from the background risk for spontaneous abortion. In 2013, the Section of Gynecology and Obstetrics of the German Society for Ultrasound in Medicine (DEGUM) published recommendations on diagnostic puncture in prenatal medicine 1. The developments described above and new findings in recent years make it necessary to revise and reformulate these recommendations. The aim of this review is to compile important and current facts regarding prenatal medical puncture (including technique, complications, genetic examinations). It is intended to provide basic, comprehensive, and up-to-date information on diagnostic puncture in prenatal medicine. It replaces the publication from 2013 1.

Evaluation of Fetal and Maternal Outcomes in Chorion Villus Sampling (CVS)

Background

Chorionic villus sampling (CVS) is one of the invasive diagnostic methods used to diagnose chromosomal, genetic, and metabolic diseases in the embryonic period. The use of this method is associated with maternal and fetal consequences, the most serious of which is abortion. Therefore, the present study was conducted to investigate the incidence of these consequences and the factors affecting the incidence of abortion.

Materials and Methods

A cross-sectional study was performed on 98 pregnant women with CVS indications. Maternal and fetal outcomes including abortion, vaginal bleeding, subchorionic hematoma, premature rupture of membrane (PROM), chorioamnionitis, preterm delivery, limb abnormality, fetal growth retardation, and preeclampsia were recorded.

Results

The results of the present study showed that the incidence of fetal outcomes including fetal growth failure, premature rupture of membranes, abortion, and limb abnormalities was 4.1%, 7.1%, 3.1%, and 1%, and the incidence of maternal outcomes including preterm delivery, subchorionic hematoma, preeclampsia, and hemorrhage was 14.3%, 3.1%, 6.1%, and 10.2%, respectively. In addition, a decrease in free BHCG and an increase in NT were significantly associated with the occurrence of abortion (OR: 0.11 and 4.25, respectively, P value < 0.05).

Conclusion

It should be noted that due to a long time between placental sampling and the occurrence of vaginal bleeding, premature rupture of membrane, and preterm delivery, it seems that placental sampling has no effect. In addition, only a decrease in free BHCG or an increase in NT significantly increased the chance of miscarriage.

Implications for Prenatal Genetic Testing in the United States After the Reversal of Roe v Wade

Prenatal genetic screening and diagnostic testing should be offered to every pregnant individual, with methods varying based on gestational age. Since Roe v Wade was overturned in June 2022, many states have implemented gestational age-based abortion restrictions. It is critical that reproductive health care professionals be aware of the interaction between the timing of genetic screening and diagnostic testing and the availability of legal abortion services in their state. We examined individual state abortion restrictions per publicly available data from The New York Times and the Guttmacher Institute and reviewed which genetic screening and diagnostic tests could be performed to provide results in time for individuals to decide whether to terminate their pregnancies legally in each state. As of December 11, 2022, 14 states have restrictions in which no diagnostic testing could be completed before gestational age-based cutoffs. Gestational age-based abortion restrictions may also influence a patient to favor chorionic villous sampling (CVS) over amniocentesis. There are two states, Florida and Arizona, where CVS would be feasible before the state's gestational age limit on abortion but amniocentesis would not. Both CVS and amniocentesis are feasible in 35 states, with legal challenges pending in 8 of the 35. Seven states specifically prohibit abortion for fetuses with genetic abnormalities. Clinicians may be placed in the suboptimal position of counseling patients with screening results alone before the gestational age-based ban in their state. There are several potential downstream consequences of gestational age-based termination restrictions for current genetic screening and testing paradigms, from adjustments to counseling options to potentially higher CVS procedure rates. Clinicians should be prepared for practice patterns to change to best serve patients in this evolving legal context.

Reproductive options in mitochondrial disease

Mitochondrial diseases require customized approaches for reproductive counseling, addressing differences in recurrence risks and reproductive options. The majority of mitochondrial diseases is caused by mutations in nuclear genes and segregate in a Mendelian way. Prenatal diagnosis (PND) or preimplantation genetic testing (PGT) are available to prevent the birth of another severely affected child. In at least 15%-25% of cases, mitochondrial diseases are caused by mitochondrial DNA (mtDNA) mutations, which can occur de novo (25%) or be maternally inherited. For de novo mtDNA mutations, the recurrence risk is low and PND can be offered for reassurance. For maternally inherited, heteroplasmic mtDNA mutations, the recurrence risk is often unpredictable, due to the mitochondrial bottleneck. PND for mtDNA mutations is technically possible, but often not applicable given limitations in predicting the phenotype. Another option for preventing the transmission of mtDNA diseases is PGT. Embryos with mutant load below the expression threshold are being transferred. Oocyte donation is another safe option to prevent the transmission of mtDNA disease to a future child for couples who reject PGT. Recently, mitochondrial replacement therapy (MRT) became available for clinical application as an alternative to prevent the transmission of heteroplasmic and homoplasmic mtDNA mutations.

Personalized recurrence risk assessment following the birth of a child with a pathogenic de novo mutation

Following the diagnosis of a paediatric disorder caused by an apparently de novo mutation, a recurrence risk of 1-2% is frequently quoted due to the possibility of parental germline mosaicism; but for any specific couple, this figure is usually incorrect. We present a systematic approach to providing individualized recurrence risk. By combining locus-specific sequencing of multiple tissues to detect occult mosaicism with long-read sequencing to determine the parent-of-origin of the mutation, we show that we can stratify the majority of couples into one of seven discrete categories associated with substantially different risks to future offspring. Among 58 families with a single affected offspring (representing 59 de novo mutations in 49 genes), the recurrence risk for 35 (59%) was decreased below 0.1%, but increased owing to parental mixed mosaicism for 5 (9%)-that could be quantified in semen for paternal cases (recurrence risks of 5.6-12.1%). Implementation of this strategy offers the prospect of driving a major transformation in the practice of genetic counselling.

Trends in the prevalence, prenatal diagnosis, and outcomes of births with chromosomal abnormalities: a hospital-based study in Zhejiang Province, China during 2014-2020

BACKGROUND

To investigate the prevalence and prenatal diagnosis rate of chromosomal abnormalities (CA) in Zhejiang Province, China.

METHODS

We estimated the annual changes in the detected prevalence of CA and prenatal diagnosis rate among 681,590 births in Zhejiang Province, China, between 2014 and 2020. Data were derived from the provincial birth defects surveillance system, which represents 30% of annual births in Zhejiang Province. The effect of maternal age was also evaluated.

RESULTS

The detected prevalence of sex chromosomal abnormalities (1.70-7.30 per 10,000 births, P_trend < 0.001) and microdeletion and microduplication (0.30-6.81 per 10,000 births, P_trend < 0.001) gradually increased, contributing to an upward trend in overall CA (12.09-39.22 per 10,000 births). The diagnosis rate before 22 gestational weeks constantly increased from 20.8 to 70.1% for trisomy 21 (P_trend = 0.003). The prevalence rate ratio for maternal age of ≥ 35 years was higher than that for maternal age of 25-29 years for trisomy 21 (5.40, 95% confidence interval [CI] 4.59-6.35) and sex chromosomal abnormalities (3.28, 95% CI 2.48-4.33).

CONCLUSIONS

The rising prevalence of CA in China may be attributable to the elevated maternal age and the innovation of prenatal diagnosis tools, Thus, studies should pay attention to the rare CA that were previously ignored, and select rational screening tools.

Non-invasive prenatal testing in Germany: a unique ethical and policy landscape

Non-invasive prenatal testing (NIPT) has been available commercially in Europe since approximately 2012. Currently, many countries are in the process of integrating NIPT into their publicly funded healthcare systems to screen for chromosomal aneuploidies such as trisomy 21 (Down syndrome), with a variety of implementation models. In 2019, the German Federal Joint Committee (G-BA), which plays a significant role in overseeing healthcare decisions in Germany, recommended that NIPT be reimbursed through public insurance. Following this recommendation, NIPT will be offered on a case-by-case basis, when a pregnant woman, after being counselled, makes an informed decision that the test is necessary in her personal situation. This model differs significantly from many other European countries, where NIPT is being implemented either as a first-tier screening offer available for all pregnancies, or a contingent screen for those with a high probability of foetal aneuploidy (with varying probability cut-offs). In this paper we examine how this unique approach to implementing NIPT in Germany is produced by an ethical and policy landscape resulting from a distinctive cultural and historical context with a significant influence on healthcare decision-making. Due in part to the specific legal and regulatory environment, as well as strong objections from various stakeholders, Germany did not implement NIPT as a first-tier screen. However, as Germany does not currently publicly fund as standard other forms of prenatal aneuploidy screening (such as combined first trimester screening), neither can it be implemented as a screen contingent on specific probability cut-offs. We discuss how German policy reflects the echoes of the past shaping approaches to new biotechnologies, and the implications of this unique model for implementing NIPT in a public healthcare system.

Do online decision aids reflect new prenatal screening and testing options? An environmental scan and content analysis

Objective

Decision aids have been developed to help prospective parents make informed, shared decisions about medical tests, but these options are rapidly changing. This study aimed to identify and evaluate publicly available decision aids written in English for prospective parents seeking prenatal test information.

Methods

A systematic review process was followed using 3 sources: known decision aid repositories, fetal medicine organisations and Google. The search, screening process, quality assessment, and data extraction was performed by two independent researchers. The quality assessment of the decision aids was based on the International Patient Decision Aids Standards (IPDAS v.4.0).

Results

We identified 13 decision aids, which varied in the screening and diagnostic tests that they discussed. No decision aid met all the IPDAS v.4.0. criteria and no decision aid reported updated risk of miscarriage for amniocentesis and chorionic villus sampling (CVS). There was a lack of decision aids for some common decisions in the prenatal context.

Conclusion

We identified outdated content in current prenatal decision aids. The findings will inform healthcare professionals of the quality of current prenatal decision aids, which may facilitate their patients' informed decision-making about prenatal tests.

Innovation

Considerations for improving future decision aids are outlined.

Non-invasive prenatal diagnosis of single gene disorders by paternal mutation exclusion: 3 years of clinical experience

OBJECTIVES

Cell-free fetal DNA (cffDNA) analysis is performed routinely for aneuploidy screening, RhD genotyping or sex determination. Although applications to single gene disorders (SGD) are being rapidly developed worldwide, only a few laboratories offer cffDNA testing routinely as a diagnosis service for this indication. In a previous report, we described a standardised protocol for non-invasive exclusion of paternal variant in SGD. Three years later, we now report our clinical experience with the protocol.

DESIGN

Descriptive study.

SETTING

Multi-centre French.

POPULATION

Indications for referral included pregnancies at risk of 25% or 50% of paternally inherited SGD, and pregnancies associated with an increased risk of SGD due to a de novo variant, either from strongly suggestive ultrasound findings or from a possible parental germinal mosaicism in the context of a previously affected child.

METHODS

Non-invasive prenatal diagnosis was performed using custom assays for droplet digital PCR. Feasibility, diagnostic performance and turn-around time were evaluated.

RESULTS

Mean time for a new assay design and validation was evaluated at 14 days, and mean result reporting time was 6 days. All referred pathogenic variants could be targeted except one located in a complex genomic region. A result was obtained for every 198 referrals except two.

CONCLUSION

This service was successfully implemented as a routine laboratory practice. It has been widely adopted by French clinicians and patients for paternal variant exclusion in various disorders.

Amniocentesis in Twin Pregnancies: Risk Factors of Fetal Loss

This study aims to determine if second trimester amniocentesis in twin pregnancies provides a significant independent contribution in the prediction of miscarriage or fetal loss at any stage of pregnancy. This was a retrospective cohort study of women with twin gestations booked for routine prenatal care in four fetal medicine units in Poland in the years 2010-2020. The study population included: (1) twin pregnancies that underwent amniocentesis at 16-20 weeks' gestation; (2) twin pregnancies that did not require any further testing and were followed-up routinely. Univariable and multivariable regression analysis was used to define which maternal and pregnancy characteristics provided a significant independent contribution in the prediction of miscarriage and fetal loss at any stage of pregnancy. In the study period, 2645 twin pregnancies were eligible for analysis. There were 144 cases of miscarriage defined as fetal loss of one or both twins before 24 weeks and 40 cases of intrauterine death of one or both twins after 24 weeks. A total number of 162 twin pregnancies underwent amniocentesis at 16-20 weeks' gestation. The rate of miscarriage before 24 weeks and the rate of fetal loss at any stage of pregnancy in the group that underwent amniocentesis was 10.49% and 13.58%, respectively, compared to 5.11% and 6.52% that did not undergo amniocentesis. Multivariable regression analysis showed that factors providing a significant independent contribution in the prediction of miscarriage and fetal loss at any stage of pregnancy were monochorionicity (MC), large intertwin discordance in crown-rump length (CRL), low Pregnancy Related Plasma Protein (PAPP-A) MoM and nuchal translucency (NT) above 95th centile. Amniocentesis in twin pregnancies does not provide a significant contribution in the prediction of miscarriage or fetal loss at any stage of pregnancy.

Pregnancy outcomes of fetuses with congenital heart disease after a prenatal diagnosis with chromosome microarray

OBJECTIVE

To evaluate the pregnancy outcomes of fetuses with congenital heart disease (CHD) after chromosome microarray (CMA)-based prenatal diagnosis.

METHOD

Amniocentesis was performed in 1035 pregnant women carrying fetuses with CHD between September 2014 and December 2019. Chromosomal aberrations in fetuses with CHD were evaluated using CMA. The pregnancy outcomes were followed up from 6 months to 5 years.

RESULTS

The overall CHD detection rate by CMA was 10.1% (105/1035; 50 fetuses: aneuploidy, 55 fetuses: pathogenic or likely pathogenic copy number variations). Among 1003 fetuses who were followed up, 4, 236, 763, and 18 cases were of miscarriages, pregnancy termination, live births, and postnatal deaths, respectively. Self-healed CHD was observed in 401 (52.6%) fetuses. The pregnancy termination rate of fetuses with chromosomal anomalies was significantly higher than that of fetuses without chromosomal anomalies (93.1% vs. 15.5%, p < 0.001). However, other pregnancy outcomes, including mortality, preterm labor, and low-weight birth rate, were similar between the two groups.

CONCLUSION

The outcome of CMA is an important factor influencing parents' choice of whether to continue the pregnancy. Self-healing rate of prenatal diagnosed CHD is high. The mortality and morbidity of fetuses with CHD following prenatal CMA testing are relatively low.

Fetal Genetic Diagnosis by Chorionic Villus Sampling: Evaluation of the Five-Year Experience from a Single Center

We summarized our five-year chorionic villus sampling (CVS) experience with indications, detected chromosomal abnormalities and pregnancy outcomes. Materials and Methods: This retrospective study examined 552 patients underwent CVS for prenatal diagnosis between 2014 and 2018. Results: The most frequent patients undergoing CVS indications were abnormal aneuploidy screening results, increased nuchal translucency, and cystic hygroma/edema. Of 552 CVS, 385 were normal, 141 abnormal. Eight were contaminated with maternal cells, 4 were mosaics, in 12 the culture failed, and in 2 there was inadequate sampling. The most frequent chromosomal abnormalities were trisomy 21, trisomy 18 and 45,X. Of 246 followed pregnancies, there were 165 live-births (67,1%), 58 pregnancy terminations (23,6%), and 23 pregnancy losses (9,3%). There were 5 procedure-related losses (2%), 3 of which were chromosomally normal. Conclusion: Although significant advances have been made in noninvasive methods such as NIPT, CVS is still a reliable technique for cytogenetic diagnosis in early gestation.

Fetal loss after chorionic villus sampling in twin pregnancy

OBJECTIVE

To estimate the chorionic villus sampling (CVS)-related risk of fetal loss in twin pregnancy after adjustment for chorionicity, nuchal translucency thickness (NT), intertwin discordance in crown-rump length (CRL), maternal demographic characteristics and serum pregnancy-associated plasma protein-A (PAPP-A) and free β-human chorionic gonadotropin (β-hCG).

METHODS

This was a multicenter study from eight fetal medicine units in which the leadership were trained at the Harris Birthright Research Centre for Fetal Medicine in London, UK, and in which the protocols for screening, invasive testing and pregnancy management are similar. Data were obtained prospectively from women with twin pregnancy undergoing routine ultrasound examination at 11-13 weeks' gestation. Multivariable logistic regression analysis with backward stepwise elimination was used to examine whether CVS provided a significant independent contribution to the prediction of risk of fetal loss after adjusting for maternal and pregnancy characteristics, including maternal age, racial origin and weight, method of conception, smoking status, parity, chorionicity, intertwin discordance in CRL, fetal NT ≥ 95^th percentile and free β-hCG and PAPP-A multiples of the median. Similarly, within the CVS group, multivariable logistic regression analysis was used to investigate the effect of the number of intrauterine needle insertions and size of the needle on the risk of fetal loss.

RESULTS

The study population of 8581 twin pregnancies undergoing ultrasound examination at 11-13 weeks' gestation included 316 dichorionic and 129 monochorionic twins that had CVS. First, in twin pregnancies undergoing CVS, compared to those not undergoing CVS, there was a 2-fold increased risk of fetal loss at < 24 weeks' gestation and of loss at any stage in pregnancy. Second, the factors providing a significant independent contribution to the prediction of miscarriage or fetal loss in twin pregnancy were increased maternal weight, black racial origin, monochorionicity, and more so monoamnionicity, large intertwin discordance in CRL and increased fetal NT, and, in the case of fetal loss at any stage, there was also a contribution from assisted conception and low serum PAPP-A. Third, after adjustment for maternal and pregnancy characteristics, CVS did not provide a significant contribution to the risk of fetal loss. Fourth, in twin pregnancies that had CVS, there was no significant contribution to fetal loss from the number of intrauterine needle insertions or needle size.

CONCLUSION

The 2-fold increased risk of fetal loss following CVS in twin pregnancy can, to a great extent, be explained by maternal and pregnancy characteristics rather than the invasive procedure itself. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Fetal sex discordance

Fetal sex discordance is an entity that is becoming more frequent due to the expansion of the cfDNA for prenatal diagnosis. Its incidence can be estimated in 1/1500-2000 pregnancies, a frequency as high as that of some common chromosomopathies. The causes of this phenomenon are multiple and diverse, ranging from laboratory errors to important pathologies such as disorders of sexual differentiation. The management of a case of fetal sex discordance must be structured, starting with the review of the clinical history and the tests performed, and may require the performance of invasive tests to reach a diagnosis. Prevention through adequate pretest counseling and ultrasound confirmation can help to reduce its incidence.

Outcome of antenatal invasive diagnostic tests in a fetal medicine unit with low case load in North Wales, United Kingdom

The aim of this retrospective cohort study was to review rate of miscarriage following antenatal invasive diagnostic procedures from a unit where relatively low annual numbers of procedures are undertaken. Data were analysed for 201 chorionic villous samplings (CVSs) performed between January 2007 and June 2019 and 511 amniocenteses performed between January 2008 and June 2019, in singleton pregnancies. The miscarriage rates after CVS was 0% at 48 hours, 0.6% at 2 weeks and 2.5% up to 24 weeks of gestation. All four miscarriages following CVS had significant inherent high-risk features, therefore, it would be inappropriate to attribute these losses solely to the procedure itself. None of the women who had an amniocentesis had a miscarriage during the study period. We did not find a causal association between number of invasive procedures performed by an operator and miscarriage rate in our setting even with low annual numbers of invasive procedures.Impact StatementWhat is already known on this subject? Royal College of Obstetricians and Gynaecologists (RCOG) of UK recommends a minimum of at least 30 CVSs or amniocenteses procedures per year for a practitioner in order to maintain skills. A centre performing more fetal invasive procedures has lower miscarriage rates due to more experience of practitioners.What the results of this study add? This study is the first long-term audit data from a smaller fetal medicine unit with relatively low annual case load, suggesting that miscarriage risk may actually be lower than the current understanding. No additional risk of miscarriage or pregnancy loss following fetal invasive procedures even with relatively low annual numbers than that recommended by the RCOG.What the implications are of these findings for clinical practice and/or further research? The findings of this study are important in the era of non-invasive prenatal testing which will see the overall number of fetal invasive procedures decline with time. Competence in safely undertaking antenatal invasive procedure can possibly be maintained with lower annual procedure numbers. Units undertaking low number of antenatal invasive procedure must continuously audit their practice to ensure satisfactory standards and outcomes. More research is needed from smaller units to corroborate or refute the findings of this study.

Follow-up in Patients With Non-invasive Prenatal Screening Failures: A Reflection on the Choice of Further Prenatal Diagnosis

Background

Our aim was to provide a theoretical basis for clinicians to conduct genetic counseling and choose further prenatal diagnosis methods for pregnant women who failed non-invasive prenatal screening (NIPS).

Methods

A retrospective analysis was performed on pregnant women who had failed NIPS tests.

Results

Among the 123,291 samples, 394 pregnant women did not obtain valid results due to test failures. A total of 378 pregnant women were available for follow-up, while 16 patients were lost to follow-up. Of these 378, 135 pregnant women chose further prenatal diagnosis through amniocentesis, and one case of dysplasia was recalled for postpartum chromosome testing. The incidence rate of congenital chromosomal abnormalities in those who failed the NIPS was 3.97% (15/378), which was higher than that of the chromosomal abnormalities in the common population (1.8%). Among the pregnant women who received prenatal diagnosis, the positive rates of chromosomal abnormalities in the chromosomal microarray analysis/copy number variation sequencing (CMA/CNV-seq) group and in the karyotyping group were 15.28 and 4.76%, respectively.

Conclusion

Prenatal diagnosis should be strongly recommended in posttest genetic counseling for pregnant women with NIPS failures. Further, high-resolution detection methods should be recommended for additional prenatal diagnoses.

Universal chromosomal microarray analysis reveals high proportion of copy-number variants in low-risk pregnancies

OBJECTIVES

To evaluate the yield and utility of the routine use of chromosomal microarray analysis (CMA) for prenatal genetic diagnosis in a large cohort of pregnancies with normal ultrasound (US) at the time of genetic testing, compared with pregnancies with abnormal US findings.

METHODS

We reviewed all prenatal CMA results in our center between November 2013 and December 2018. The prevalence of different CMA results in pregnancies with normal US at the time of genetic testing ('low-risk pregnancies'), was compared with that in pregnancies with abnormal US findings ('high-risk pregnancies'). Medical records were searched in order to evaluate subsequent US follow-up and the outcome of pregnancies with a clinically relevant copy-number variant (CNV), i.e. a pathogenic or likely pathogenic CNV or a susceptibility locus for disease with > 10% penetrance, related to early-onset disease in the low-risk group.

RESULTS

In a cohort of 6431 low-risk pregnancies that underwent CMA, the prevalence of a clinically significant CNV related to early-onset disease was 1.1% (72/6431), which was significantly lower than the prevalence in high-risk pregnancies (4.9% (65/1326)). Of the low-risk pregnancies, 0.4% (27/6431) had a pathogenic or likely pathogenic CNV, and another 0.7% (45/6431) had a susceptibility locus with more than 10% penetrance. Follow-up of the low-risk pregnancies with a clinically significant early-onset CNV revealed that 31.9% (23/72) were terminated, while outcome data were missing in 26.4% (19/72). In 16.7% (12/72) of low-risk pregnancies, an US abnormality was discovered later on in gestation, after genetic testing had been performed.

CONCLUSION

Although the background risk of identifying a clinically significant early-onset abnormal CMA result in pregnancies with a low a-priori risk is lower than that observed in high-risk pregnancies, the risk is substantial and should be conveyed to all pregnant women. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Procedure-to-delivery interval after late amniocentesis and the need for routine antenatal corticosteroids

OBJECTIVES

The aim of this study is to assess the procedure-to-delivery interval (PDI), the obstetric complications, and the early neonatal outcome in patients that did or did not receive glucocorticosteroids (GCSs) before third-trimester amniocentesis (TTA).

METHODS

A retrospectively analysis of 445 TTA procedures divided into two groups based on the administration (study group = 220 patients) or not (control group = 225 patients) of GCSs before TTA. The PDI was calculated for all patients. Obstetric and neonatal outcomes were compared between the groups.

RESULTS

The rate of procedure-associated complications was similar between the groups. The mean PDI was 47.2 ± 16.8 days. The overall incidence of preterm birth was 11.7%; 9% delivered between 34 and 37 weeks and 2.7% between 28 and 34 weeks. Only nine patients (2%) delivered within seven days following TTA. The incidence of respiratory distress syndrome in the study and control groups was 1.8% and 1.3%, p = .71, respectively. There were no significant differences in other neonatal outcomes in term and preterm deliveries between the study and control groups.

CONCLUSIONS

In the present study, the administration of glucocorticoids prior to TTA did not reduce the rates of neonatal complications, which was similar in both groups and not higher than the general population.

Guideline No. 410: Prevention, Screening, Diagnosis, and Pregnancy Management for Fetal Neural Tube Defects

OBJECTIVE

This revised guideline is intended to provide an update on the genetic aspects, prevention, screening, diagnosis, and management of fetal neural tube defects.

TARGET POPULATION

Women who are pregnant or may become pregnant. Neural tube defect screening should be offered to all pregnant women.

OPTIONS

For prevention: a folate-rich diet, and folic acid and vitamin B₁₂ supplementation, with dosage depending on risk level. For screening: second-trimester anatomical sonography; first-trimester sonographic screening; maternal serum alpha fetoprotein; prenatal magnetic resonance imaging. For genetic testing: diagnostic amniocentesis with chromosomal microarray and amniotic fluid alpha fetoprotein and acetylcholinesterase; fetal exome sequencing. For pregnancy management: prenatal surgical repair; postnatal surgical repair; pregnancy termination with autopsy. For subsequent pregnancies: prevention and screening options and counselling.

OUTCOMES

The research on and implementation of fetal surgery for prenatally diagnosed myelomeningocele has added a significant treatment option to the previous options (postnatal repair or pregnancy termination), but this new option carries an increased risk of maternal morbidity. Significant improvements in health and quality of life, both for the mother and the infant, have been shown to result from the prevention, screening, diagnosis, and treatment of fetal neural tube defects.

BENEFITS, HARMS, AND COSTS

The benefits for patient autonomy and decision-making are provided in the guideline. Harms include an unexpected fetal diagnosis and the subsequent management decisions. Harm can also result if the patient declines routine sonographic scans or if counselling and access to care for neural tube defects are delayed. Cost analysis (personal, family, health care) is not within the scope of this clinical practice guideline.

EVIDENCE

A directed and focused literature review was conducted using the search terms spina bifida, neural tube defect, myelomeningocele, prenatal diagnosis, fetal surgery, neural tube defect prevention, neural tube defect screening, neural tube defect diagnosis, and neural tube defect management in order to update and revise this guideline. A peer review process was used for content validation and clarity, with appropriate ethical considerations.

VALIDATION METHODS

The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. See online Appendix A (Tables A1 for definitions and A2 for interpretations of strong and weak recommendations).

INTENDED AUDIENCE

Maternity care professionals who provide any part of pre-conception, antenatal, delivery, and neonatal care. This guideline is also appropriate for patient education. RECOMMENDATIONS (GRADE RATINGS IN PARENTHESES).

Directive clinique no 410 : Anomalies du tube neural : Prévention, dépistage, diagnostic et prise en charge de la grossesse

OBJECTIF

La présente directive clinique révisée vise à fournir une mise à jour sur les aspects génétiques, la prévention, le dépistage, le diagnostic et la prise en charge des anomalies du tube neural.

POPULATION CIBLE

Les femmes enceintes ou qui pourraient le devenir. Il convient d'offrir le dépistage des anomalies du tube neural à toutes les femmes enceintes.

OPTIONS

Pour la prévention : un régime alimentaire riche en acide folique et des suppléments d'acide folique et de vitamine B₁₂ selon une posologie d'après le niveau de risque. Pour le dépistage : l'échographie obstétricale du deuxième trimestre, le dépistage échographique du premier trimestre, le dosage de l'alphafœtoprotéine sérique maternelle et l'imagerie par résonance magnétique prénatale. Pour les tests génétiques : l'amniocentèse diagnostique avec analyse chromosomique sur micropuce et le dosage de l'alphafœtoprotéine et de l'acétylcholinestérase dans le liquide amniotique et le séquençage de l'exome fœtal. Pour la prise en charge de la grossesse : la réparation chirurgicale prénatale, la réparation chirurgicale postnatale et l'interruption de grossesse avec autopsie. Pour les grossesses subséquentes : les options de prévention et de dépistage et les conseils. RéSULTATS: La recherche et la mise en œuvre du traitement chirurgical fœtal en cas de diagnostic prénatal de myéloméningocèle ont ajouté une option thérapeutique fœtale importante aux options précédentes (réparation postnatale ou interruption de grossesse), mais cette nouvelle option comporte un risque accru de morbidité maternelle. La prévention, le dépistage, le diagnostic et le traitement des anomalies du tube neural se révèlent entraîner des améliorations importantes à la mère et au nourrisson en matière de santé et de qualité de vie. BéNéFICES, RISQUES ET COûTS: Le type et l'ampleur des bénéfices, risques et coûts attendus pour les patientes grâce à la mise en œuvre de la présente directive clinique par un établissement de soins de santé intègrent un canal maternel préconception et prénatal adéquat comprenant l'accès des patientes aux soins, les conseils, les analyses et examens, l'imagerie, le diagnostic et l'interprétation. Les bénéfices relatifs à l'autonomie de la patiente et au processus décisionnel sont énoncés dans la présente directive clinique. Les risques comprennent un diagnostic fœtal inattendu et les décisions de prise en charge subséquentes. Le fait que la patiente refuse les échographies habituelles et le retard du conseil ou d'accès aux soins en cas d'anomalie du tube neural comportent également des risques. L'analyse des coûts (personnels, familiaux, santé publique) ne fait pas partie de la portée de la présente directive clinique. DONNéES PROBANTES: Afin de mettre à jour et réviser la présente directive, une revue de la littérature ciblée et dirigée a été effectuée à l'aide des termes de recherche suivants : spina bifida, neural tube defect, myelomeningocele, prenatal diagnosis, fetal surgery, neural tube defect prevention, neural tube defect screening, neural tube defect diagnosis et neural tube defect management. Un processus d'examen par les pairs a été utilisé pour la validation et la clarté du contenu, avec des considérations appropriées d'ordre éthique. MéTHODES DE VALIDATION: Les auteurs ont évalué la qualité des données probantes et la force des recommandations en utilisant l'approche d'évaluation, de développement et d'évaluation (GRADE). Consulter l'annexe A en ligne (le tableau A1 pour les définitions et le tableau A2 pour les interprétations des recommandations fortes et faibles). PROFESSIONNELS CONCERNéS: Professionnels des soins de maternité qui offrent des soins préconception, prénataux, obstétricaux ou néonataux. La présente directive clinique convient également aux fins d'éducation des patientes. RECOMMANDATIONS (CLASSEMENT GRADE ENTRE PARENTHèSES).

New approach for estimating risk of miscarriage after chorionic villus sampling

OBJECTIVE

To estimate the risk of miscarriage associated with chorionic villus sampling (CVS).

METHODS

This was a retrospective cohort study of women attending for routine ultrasound examination at 11 + 0 to 13 + 6 weeks' gestation at one of eight fetal-medicine units in Spain, Belgium and Bulgaria, between July 2007 and June 2018. Two populations were included: (1) all singleton pregnancies undergoing first-trimester assessment at Hospital Clínico Universitario Virgen de la Arrixaca in Murcia, Spain, that did not have CVS (non-CVS group); and (2) all singleton pregnancies that underwent CVS following first-trimester assessment at one of the eight participating centers (CVS group). We excluded pregnancies diagnosed with genetic anomalies or major fetal defects before or after birth, those that resulted in termination and those that underwent amniocentesis later in pregnancy. We used propensity score (PS) matching analysis to estimate the association between CVS and miscarriage. We compared the risk of miscarriage of the CVS and non-CVS groups after PS matching (1:1 ratio). This procedure creates two comparable groups balancing the maternal and pregnancy characteristics that are associated with CVS, in a similar way to that in which randomization operates in a randomized clinical trial.

RESULTS

The study population consisted of 22 250 pregnancies in the non-CVS group and 3613 in the CVS group. The incidence of miscarriage in the CVS group (2.1%; 77/3613) was significantly higher than that in the non-CVS group (0.9% (207/22 250); P < 0.0001). The PS algorithm matched 2122 CVS with 2122 non-CVS cases, of which 40 (1.9%) and 55 (2.6%) pregnancies in the CVS and non-CVS groups, respectively, resulted in a miscarriage (odds ratio (OR), 0.72 (95% CI, 0.48-1.10); P = 0.146). We found a significant interaction between the risk of miscarriage following CVS and the risk of aneuploidy, suggesting that the effect of CVS on the risk of miscarriage differs depending on background characteristics. Specifically, when the risk of aneuploidy is low, the risk of miscarriage after CVS increases (OR, 2.87 (95% CI, 1.13-7.30)) and when the aneuploidy risk is high, the risk of miscarriage after CVS is paradoxically reduced (OR, 0.47 (95% CI, 0.28-0.76)), presumably owing to prenatal diagnosis and termination of pregnancies with major aneuploidies that would otherwise have resulted in spontaneous miscarriage. For example, in a patient in whom the risk of aneuploidy is 1 in 1000 (0.1%), the risk of miscarriage after CVS will increase to 0.3% (0.2 percentage points higher).

CONCLUSIONS

The risk of miscarriage in women undergoing CVS is about 1% higher than that in women who do not have CVS, although this excess risk is not solely attributed to the invasive procedure but, to some extent, to the demographic and pregnancy characteristics of the patients. After accounting for these risk factors and confining the analysis to low-risk pregnancies, CVS seems to increase the risk of miscarriage by about three times above the patient's background risk. Although this is a substantial increase in relative terms, in pregnancies without risk factors for miscarriage, the risk of miscarriage after CVS remains low and similar to, or slightly higher than, that in the general population. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

What is the meaning of a 'genomic result' in the context of pregnancy?

Prenatal genetic testing and analysis in the past was usually only offered when a particular fetal phenotype was noted or suspected, meaning that filtering and interpretation of genetic variants identified could be anchored in attempts to explain an existing health concern. Advanced genomic testing is now increasingly used in "low-risk" pregnancies, producing information on genotype adrift of the phenotypic data that is necessary to give it meaning, thus increasing the difficulty in predicting whether and how particular genetic variants might affect future development and health. A challenge to healthcare scientists, clinicians, and parents therefore is deciding what qualities prenatal genotypic variation should have in order to be constructed as a 'result.' At the same time, such tests are often re requested in order to make binary decisions about whether to continue a pregnancy or not. As a range of professional organizations develop guidelines on the use of advanced genomic testing during pregnancy, we highlight the particular difficulties of discovering ambiguous findings such as variants with uncertain clinical significance, susceptibility loci for neurodevelopmental problems and susceptibility to adult-onset diseases. We aim to foster international discussions about how decisions around disclosure are made and how uncertainty is communicated.

Comparison of spontaneous fetal loss rates between women with singleton and twin pregnancies after mid-trimester amniocentesis - A historical cohort study

OBJECTIVE

To assess and compare fetal loss rates before 28 weeks of singleton and twin pregnancies after mid-trimester amniocentesis.

METHOD

This historic cohort study included 13 773 women with singletons and 426 women with twins undergoing mid-trimester amniocentesis from 1/2015 to 3/2017. Pregnancies resulting in termination or selective reduction before 28 weeks were excluded, as well as twin gestations undergoing single-puncture amniocentesis. Fetal loss rates were compared between singleton and twins taking into account maternal characteristics, amniocentesis procedure, and fetal chromosomal abnormalities.

RESULTS

The rates of fetal chromosomal abnormalities were similar in singleton and twin gestations (1.13% vs 0.70%, P = .253). No difference was found in maternal or fetal characteristics, or amniocentesis procedure between the two groups. The fetal loss rate was significantly higher in twin compared with singleton pregnancies (1.91% vs 0.24%, P < .001, RR = 8.25 [95% CI: 4.51 to 15.09]). The fetal loss rate between monochorionic twins and dichorionic twins was similar (1.80% vs 1.78%, P = 1.000).

CONCLUSIONS

Twin pregnancies have higher risk of fetal loss after mid-trimester amniocentesis, which cannot be explained by differences in rates of fetal chromosomal abnormalities, maternal characteristic, or amniocentesis technique.

Making the most of the first prenatal visit: The challenge of expanding prenatal genetic testing options and limited clinical encounter time

OBJECTIVE

Advances in prenatal genetics place additional challenges as patients must receive information about a growing array of screening and testing options. This raises concerns about how to achieve a shared decision-making process that prepares patients to make an informed decision about their choices about prenatal genetic screening and testing options, calling for a reconsideration of how healthcare providers approach the first prenatal visit.

METHODS

We conducted interviews with 40 pregnant women to identify components of decision-making regarding prenatal genetic screens and tests at this visit. Analysis was approached using grounded theory.

RESULTS

Participants brought distinct notions of risk to the visit, including skewed perceptions of baseline risk for a fetal genetic condition and the implications of screening and testing. Participants were very concerned about financial considerations associated with these options, ranking out-of-pocket costs on par with medical considerations. Participants noted diverging priorities at the first visit from those of their healthcare provider, leading to barriers to shared decision-making regarding screening and testing during this visit.

CONCLUSION

Research is needed to determine how to restructure the initiation of prenatal care in a way that best positions patients to make informed decisions about prenatal genetic screens and tests.

Chorionic villus sampling: 10 years of experience in a University referral center

OBJECTIVES

The purpose of this study was to estimate our center-specific CVS-related miscarriage rate.

METHODS

This is an observational retrospective study of women submitted to a CVS in our hospital, between January 1^st, 2007 and December 31^st, 2016. Maternal and pregnancy characteristics, procedure details, genetic results and pregnancy outcomes of all patients were collected. The FMF miscarriage risk algorithm was used to estimate our population expected risk of miscarriage. To establish the procedure-related risk of miscarriage, we compared the observed with the expected miscarriage rate.

RESULTS

We had a total number of 1523 women with a singleton pregnancy who did a CVS over the 10-year period. The mean maternal age was 34 years old; the majority of the women was Caucasian, multiparous and had a spontaneous pregnancy. The most common indication for CVS was a high-risk result in the 1^st trimester combined screening test. The karyotype was normal in 72,7% of cases, 11,1% were T21 and 7,2% were T13 or T18. In the study group, 33 women were diagnosed with a fetal demise, 435 had a TOP and there were 4 intrauterine deaths and 34 miscarriages. The rate of miscarriage in our population was 3,2% and the expected patient specific risk for miscarriage was 3,0%. There was no statistical significance between the two miscarriage rates p = 0,705.

CONCLUSION

In our study the risk of miscarriage in the CVS group was not significantly different from that the expected patient specific risk (3.2 % vs 3%, p = 0.7). The procedure-related risk of miscarriage was 0,2%, similar to the rates describe in the literature. An accurate risk of pregnancy loss should be used when counseling women for CVS to allow an informed decision.

Chorionic villus sampling experience of a reference perinatal medicine center

AIM

To share the chorionic villus sampling (CVS) experience of a single surgeon in our institution.

METHODS

This retrospective study consists of CVS cases performed between 2000 and 2018. A total of 66 types of indications were classified under two main categories, the screening group (SG) and the inherited disease group (IDG). The SG and IDG were compared in terms of clinical characteristics of the patients, Beksaç obstetrics index (BOI), timing of CVS in terms of gestational week, and complications and termination of pregnancy (TOP) rate.

RESULTS

CVS was performed at 656 women, 69 and 587 of whom were included in the SG and IDG, respectively. CVS indications of the SG were determined as advanced maternal age, high risk in combined test, fetal anomaly suspicion in ultrasonography, and increased nuchal translucency in 23, 23, 14 and 9 cases, respectively. On the other hand, CVS indications of the IDG were hereditary disorders related to hematological, muscular, and metabolic systems for 233, 179, and 116 cases, respectively. Furthermore, 32 patients had a single-gene disorder and 14 had a neurodegenerative disease. According to the results of CVS, 359 fetuses were found to be normal (54.73%), while 205 (31.25%) and 92 (14.02%) fetuses were found to be disorder-positive or carriers, respectively. Two hundred pregnant women accepted TOP. Eight (1.2%) pregnancies ended with abortion after CVS. Statistically significant differences were observed in BOI and TOP rate between SG and IDG (p: 0.042 and 0.013).

CONCLUSION

Hereditary disorders were the most common CVS indications and the acceptance of TOP was significantly higher in this group.

Risk of miscarriage following amniocentesis or chorionic villus sampling: systematic review of literature and updated meta-analysis

OBJECTIVE

To estimate the procedure-related risk of miscarriage after amniocentesis and chorionic villus sampling (CVS) based on a systematic review of the literature and an updated meta-analysis.

METHODS

A search of MEDLINE, EMBASE and The Cochrane Library was carried out to identify studies reporting complications following CVS or amniocentesis. Eligible for inclusion were large controlled studies reporting data for pregnancy loss prior to 24 weeks' gestation. Study authors were contacted when required to identify additional necessary data. Data for cases that had an invasive procedure and controls were inputted into contingency tables and the risk of miscarriage was estimated for each study. Summary statistics based on a random-effects model were calculated after taking into account the weighting for each study included in the systematic review. Procedure-related risk of miscarriage was estimated as a weighted risk difference from the summary statistics for cases and controls. Subgroup analyses were performed according to the similarity in risk levels for chromosomal abnormality between the invasive-testing and control groups. Heterogeneity was assessed using the I² statistic. Egger's bias was estimated to assess reporting bias in published studies.

RESULTS

The electronic search yielded 2943 potential citations, from which 12 controlled studies for amniocentesis and seven for CVS were selected for inclusion in the systematic review. A total of 580 miscarriages occurred following 63 723 amniocentesis procedures, resulting in a weighted risk of pregnancy loss of 0.91% (95% CI, 0.73-1.09%). In the control group, there were 1726 miscarriages in 330 469 pregnancies with a loss rate of 0.58% (95% CI, 0.47-0.70%). The weighted procedure-related risk of miscarriage following amniocentesis was 0.30% (95% CI, 0.11-0.49%; I²  = 70.1%). A total of 163 miscarriages occurred following 13 011 CVS procedures, resulting in a risk of pregnancy loss of 1.39% (95% CI, 0.76-2.02%). In the control group, there were 1946 miscarriages in 232 680 pregnancies with a loss rate of 1.23% (95% CI, 0.86-1.59%). The weighted procedure-related risk of miscarriage following CVS was 0.20% (95% CI, -0.13 to 0.52%; I²  = 52.7%). However, when studies including only women with similar risk profiles for chromosomal abnormality in the intervention and control groups were considered, the procedure-related risk for amniocentesis was 0.12% (95% CI, -0.05 to 0.30%; I²  = 44.1%) and for CVS it was -0.11% (95% CI, -0.29 to 0.08%; I²  = 0%).

CONCLUSIONS

The procedure-related risks of miscarriage following amniocentesis and CVS are lower than currently quoted to women. The risk appears to be negligible when these interventions were compared to control groups of the same risk profile. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.