Amniocentesis Rate Research Articles

Analysis of the results of non-invasive prenatal testing (NIPT) in 545 pregnant women in advanced maternal age.

This research aimed to explore the value of non-invasive prenatal testing (NIPT) as a prenatal screening method for common aneuploidy in pregnant women in advanced maternal age. A retrospective analysis was conducted on a cohort of 545 mothers with singleton pregnancy who were of advanced age and underwent NIPT testing voluntarily at the Second Affiliated Hospital of Guangxi Medical University between November 2020 and February 2023. In cases where NIPT testing suggested chromosomal abnormalities, amniocentesis was conducted, karyotype analysis or gene copy number variation (CNV) testing was performed, and the pregnancy outcome was tracked. Among 545 pregnant women in advanced maternal age, 11 cases had high risk of NIPT, and the detection rate was 2.02%. Among 11 pregnant women deemed to be at high risk for NIPT, 10 cases underwent amniotic fluid puncture, and one case refused amniocentesis despite a suggestive chromosomal abnormality in NIPT. The overall rate of amniocentesis was 1.83%. Among 11 pregnant women deemed to be at high risk for NIPT, the results suggested that 5 of them had trisomy 21, 1 had trisomy 18, 2 had sex chromosome abnormalities (specifically, 47, XYY), and 3 had other autosomal abnormalities. The positive predictive values of NIPT were 100.00% for the cases of trisomy 21 and trisomy 18, while the values were 0.00% for the cases of sex chromosome abnormalities and other autosomal abnormalities, respectively. After the follow-up, each of the 6 cases that were diagnosed with definite chromosomal abnormalities during prenatal screening opted to induce labor and terminate the pregnancy, including 5 cases that exhibited a high risk of trisomy 21 (47, XN,+21) and 1 case that showed a high risk of trisomy 18 (47, XN,+18). One instance of NIPT indicated a potential abnormality in the sex chromosomes, the individual declined to undergo amniocentesis. Another instance of NIPT suggested a sex chromosome abnormality, amniocentesis revealed a deletion of 0.72 Mb in the 4q22.1 region. They all had normal pregnancies and normal newborns. The remaining three cases had normal prenatal diagnoses (46, XN) and experienced normal pregnancies with healthy neonatal outcomes. NIPT has demonstrated its efficacy as a screening tool in the face of increasing maternal age. As a result, it can substantially decrease the requirement for invasive prenatal diagnosis. Nonetheless, there are instances of erroneous positive outcomes in NIPT testing, and therefore, interventional prenatal diagnosis remains necessary for individuals with high-risk screening outcomes to prevent false positives or unwarranted labor induction.

Neonatal and long-term outcomes of infants with congenital cytomegalovirus infection and negative amniocentesis: systematic review and meta-analysis.

Cytomegalovirus (CMV) DNA is detectable in the amniotic fluid collected by amniocentesis in cases in which the fetus has been infected. However, cases of congenital neonatal CMV infection with a negative amniocentesis result have also been reported in the literature. The aim of the present study was to compare pregnancies with a negative amniocentesis result to those with a positive amniocentesis result in terms of incidence of fetal insult and long-term sequelae. Observational studies that included pregnant women with CMV infection who underwent amniocentesis and that reported their results together with neonatal and/or long-term outcomes of the offspring were included. The risk of bias in included studies was assessed using the Newcastle-Ottawa Scale. The rate of severe symptoms at birth, defined as neurological symptoms or multiorgan involvement at birth, and the rate of severe sensorineural hearing loss (SNHL) and/or neurodevelopmental impairment at follow-up were the main outcomes of the study. The secondary outcome was the rate of pregnancy termination due to the presence of CMV-associated central nervous system (CNS) findings or multiorgan involvement on ultrasound/magnetic resonance imaging (MRI). Seven studies were included in the systematic review and meta-analysis. The pooled false-negative rate of amniocentesis was 8.0% (95% CI, 5.0-13.0%). The pooled rate of severe symptoms at birth was 0.0% (95% CI, 0.0-1.0%; I2 = 0%) in fetuses with a negative amniocentesis result and 22.0% (95% CI, 11.0-38.0%; I2 = 75%) in those with a positive amniocentesis result. The pooled odds ratio (OR) was 0.03 (95% CI, 0.01-0.10; I2 = 0%). The pooled rate of severe SNHL and/or neurodevelopmental impairment at follow-up in fetuses with a negative amniocentesis result was 0.0% (95% CI, 0.0-1.0%; I2 = 0%) and, in those with a positive amniocentesis result, it was 14.0% (95% CI, 7.0-26.0%; I2 = 64%). The pooled OR was 0.04 (95% CI, 0.01-0.14; I2 = 0%). The pooled rate of pregnancy termination due to the presence of CMV-associated CNS findings or multiorgan involvement on ultrasound/MRI was 0.0% (95% CI, 0.0-2.0%; I2 = 0%) in fetuses with a negative amniocentesis result and 20.0% (95% CI, 10.0-36.0%; I2 = 82%) in those with a positive amniocentesis result. The pooled OR was 0.03 (95% CI, 0.01-0.08; I2 = 0%). A subgroup analysis including only pregnancies with primary CMV infection and a sensitivity analysis including only prospective studies were carried out, showing very similar results to those of the main analysis. A negative amniocentesis result in pregnant women with CMV infection ensures lack of fetal insult and long-term sequelae to the child, even if transmission has occurred. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Prenatal characteristics and management of pregnants with fetal cerebellar malformation: 4-year single center experience

Introduction: Fetal cerebellar malformations (FCM) are known as very rare central nervous system malformations that occur as hypoplasia or agenesis of the cerebellum or vermis. In this study, the characteristics, diagnostic methods, risk factors and management of pregnant women diagnosed with FCM in the prenatal period were investigated.
 Material and Method: The patients who diagnosed with prenatal FCM in the perinatology center between March 2017-February 2021 were included, retrospectively. The frequency of fetal magnetic resonance imaging (MRI), amniocentesis and/or karyotype analysis rates, and termination frequency were evaluated. In addition, the factors affecting the amniocentesis and the termination/follow-up decision were investigated. 
 Results: A total of 42 pregnant with FCM were included. The median gestational age was 24.0 years, and the mean gestational week was 25+2 (SD±5+1) weeks. Nearly half (40.5%) of patients were diagnosed before 24 weeks of gestation and 45.2% were primiparous. Cerebellar hypoplasia was observed in 47.6%, while vermis agenesis was observed in almost one third (31.0%); and also 19.0% had multiple FCM. The fetal USG was used in all pregnant women, fetal MRI was performed in only 4.8% for diagnosis of FCM. The rate of amniocentesis and karyotype analysis were 11.9% and 7.1%, retrospectively. No any complications were observed after the amniocentesis. The termination rate was 30.9%. The mean gestational week of those who had live birth was higher than those who were terminated (24+4 vs 20+5) (p=0.019).
 Conclusion: The frequency of FCM diagnosis has increased with the development of modern medicine and technology. There is no relationship between demographic characteristics of pregnant women and FCM. Socio-economic levels and religious belief differences affect the termination and birth rates.

Impact of non - invasive prenatal testing on prenatal diagnosis at Da Nang Hospital for women and children

ABSTRACT Background: Non-invasive prenatal testing (NIPT) is being applied more widely in Vietnam. However, the effects of NIPT on prenatal diagnosis have not been studied much in our country. This study aims to analyze the impact of NIPT on the changes in the number of routine screening tests for chromosomal abnormalities 21, 18, and 13 and the impact of NIPT on invasive prenatal diagnostic procedures and propose strategies to screen for fetal aneuploidy. Results: NIPT did not change the number of routine screening tests for chromosomal abnormalities 21, 18, and 13. The rate of amniocentesis used to confirm the diagnosis of aneuploidy was decreased by 6,32 (p < 0,0001, 95% CI: 3,99 – 10,45). Among the strategies to detect aneuploidy 21, 18, and 13 suitable for socio-economic conditions in Vietnam, a 2-step screening method can be applied. Conclusions: NIPT did not change the number of routine screening tests. NIPT reduced the number of invasive prenatal procedures. The screening strategy for fetal aneuploidy should follow a two-step approach.

Pregnancy Loss After Amniocentesis with Double-Needle Insertions in Twin Pregnancies.

The aim of this study was to determine the pregnancy loss rate of amniocentesis with double-needle insertions in twin pregnancies. This was a retrospective study of twin pregnancies who underwent amniocentesis with double-needle insertion between 2010 and 2019 at a single center. The pregnancy loss rates were recorded as single or double fetal loss before 24 weeks' gestation and within 4 weeks after the procedure. Risk factors for pregnancy loss after amniocentesis were also assessed. A total of 678 twin pregnancies with amniocentesis were finally included. The pregnancy loss rates before 24 weeks' gestation and within 4 weeks after the procedure were 0.9% and 1.9%, respectively. Only one fetal loss was presumed to be a direct result of the procedure. All other cases were complicated by structural or chromosomal anomalies. Twin pregnancies with abnormal ultrasound findings had a significantly higher rate of pregnancy loss with a relative risk of 4.81 (95% CI [1.03, 22.2]). Our study showed a low pregnancy loss rate after amniocentesis in twin pregnancies with double-needle insertions technique of sampling, which can help decision making in prenatal screening and diagnosis for twin pregnancies.

Comparison of indications and results of prenatal invasive diagnostic tests before and after the implementation of the use of cell-free fetal DNA: a tertiary referral center experience.

In this study, we aimed to compare the changes in the number, yield, and the percentage of karyotyping indications of the invasive prenatal diagnostic tests between the periods before and after cell-free fetal DNA was introduced to clinical use. The number of invasive prenatal diagnostic procedures such as amniocentesis and chorionic villus sampling, indication percentages and karyotype results in the periods before (January 1, 2009-December 31, 2010), (n = 1412) and after (January 1, 2016-December 31, 2017), and (n = 593) the introduction of cell-free fetal DNA was retrospectively evaluated. When compared with the period before cell-free fetal DNA came into clinical use, the number of invasive prenatal diagnostic tests decreased by 58% while their yield was found to have increased (4.4% vs. 10.3%) in the period after cell-free DNA began to be used (p < 0.001). While there was a decrease in the indications due to advanced maternal age, an increase was found in ultrasonography indications for structural anomaly and the risk of a single-gene disorder (p < 0.001). Amniocentesis rate was found to have decreased in invasive prenatal diagnostic procedure types, while an increase was reported in CVS rates (p < 0.001). Invasive prenatal diagnosis gradually decreases over the years, but the yield of invasive prenatal diagnostic tests increases. In parallel with the rapid development of modern molecular technologies and cheaper and easier access to the tests, we think that the number of invasive prenatal diagnostic tests will experience a more dramatic decrease in the following years.

The decline of amniocentesis and the increase of chorionic villus sampling in modern perinatal medicine.

Objective The aims of this study were to determine the rate of change by type of diagnosis by transabdominal chorionic villus sampling (TA-CVS) vs. amniocentesis for aneuploidy and to describe a successful and intensive international training program for TA-CVS in ongoing pregnancies. Methods We conducted a retrospective cohort study of all deliveries from 2010 to 2018 in Sardinia. All invasive diagnostic procedures are conducted at a single regional perinatal referral center. Descriptive statistics were used to compare data across groups, and inter-correlations between variables were investigated by Pearson's correlation coefficient. We subsequently describe the international trainee experiences in TA-CVS over a 35-year period. Results A total of 101,025 deliveries occurred over 9 years. The number of deliveries (13,413-9143, P < 0.0001) and total invasive diagnostic procedures (1506-858 per year, P = 0.019) declined over this period. The percentage of deliveries undergoing invasive diagnostic procedures remained steady (mean: 12.2%). In 2010, TA-CVS made up 32.3% of all invasive diagnostic procedures, while amniocentesis made up 67.7%. By 2018, TA-CVS made up 61.3% of the invasive diagnostic procedures, and amniocentesis, only 38.7%. The rate of TA-CVS increased over 9 years, while the rate of amniocentesis declined. A total of 236 trainees from 39 different countries and 5 different continents rotated through this site. The average length of stay was 2.4 weeks. Conclusion We demonstrate an increasing prevalence of TA-CVS vs. amniocentesis in the current era of prenatal testing and underscore the importance of continuing to train specialists skilled in TA-CVS. Our global operative experience is feasible and sustainable and will have a lasting impact on physicians conducting invasive fetal procedures.

Amniocentesis Following Positive First Trimester Combined Screening: A Comparative Study

Abstract- The birth of a neonate with chromosomal abnormalities, e.g. Down syndrome has very serious problems for family, society, and for the neonate itself, and therefore prenatal evaluation is imperative in determining the fate of the fetus. This research aimed to assess the association and accuracy of amniocentesis with first-trimester combined screening. In this study, specimens from 1066 cases were analyzed for free Beta human chorionic gonadotropin, pregnancy-associated plasma protein A, along with nuchal translucency and nasal bone ultrasonography from October 2013 till November 2014. Upon observing positive screening, mothers underwent amniocentesis. Finally the amniocentesis results were compared with that of first-trimester screening. Our results determined a direct relation between the high age of the mother and gravidity with P of 0.001 and 0.020 with positive first-trimester screening. Our study attained a 92% accuracy rate of amniocentesis due to one case of mosaicism of trisomy 21, that was not diagnosed, because it was not requested by physician. Only 12 (17.1%) cases out of 70 (mothers with positive first-trimester screening) showed positive amniocentesis, which had a significant relationship with chromosomal abnormality. First trimester combined screening has very high accuracy (94.6%) in prediction of genetic abnormalities. The probability of positive first-trimester screening is directly influenced by number of factors, including the mother age and gravidity. Amniocentesis is necessary for all of mothers with positive first-trimester screening and will almost always detect chromosomal abnormalities.

The impact of preimplantation genetic testing on prenatal diagnostic procedures

Objective In recent years, cell-free DNA screening has significantly reduced the number of invasive prenatal diagnostic testing in pregnancy. Preimplantation genetic testing for aneuploidies (PGT-A) is a commonly performed screening test in in vitro fertilization (IVF) pregnancies. Therefore, we aimed to determine the impact of PGT-A on subsequent utilization of prenatal diagnostic testing in IVF pregnancies. Methods Retrospective cohort of singleton and twin IVF pregnancies at a single center from January 2014 to December 2017. The rate of invasive diagnostic genetic testing (chorionic villus sampling (CVS) and/or amniocentesis) was compared between patients with pregnancies achieved after transfer of a euploid embryo by PGT-A (n = 71) and those with pregnancies achieved after transfer of an untested embryo (n = 38). Wilcoxon rank sum and Fisher’s exact tests were used for statistical analysis. Results There was no statistically significant difference in the number of prenatal diagnostic procedures (25.4% PGT-A euploid embryo versus 31.6% untested embryo, p = .51 and p = .32 for one-sided and two-sided analyses, respectively) between the two groups. Maternal age, nuchal translucency measurements and the rate of abnormal sonographic findings were similar between the two groups. Patients without PGT-A pregnancies had a higher BMI (mean 29.6, p = .01) and were ethnically different (p = .013) compared to those with PGT-A. Conclusion The implementation of PGT-A in IVF patients did not reduce the number of invasive diagnostic tests performed at our institution.

Obstetrical Outcomes of Amniocentesis or Chorionic Villus Sampling in Dichorionic Twin Pregnancies.

BackgroundUnder certain situations, women with twin pregnancies may be counseled to undergo invasive prenatal diagnostic testing. Chorionic villus sampling and amniocentesis are the two generally performed invasive prenatal diagnostic tests. Studies comparing procedure-related fetal loss between first-trimester chorionic villus sampling and second-trimester amniocentesis in twin pregnancies are limited. This study aimed to evaluate the procedure-related fetal loss and the obstetrical outcomes of these two procedures, chorionic villus sampling and amniocentesis in twin pregnancies.MethodsThe data from dichorionic-diamniotic twin pregnancies on which first-trimester chorionic villus sampling (n = 54) or second-trimester amniocentesis (n = 170) was performed between December 2006 and January 2017 in a single center were retrospectively analyzed. The procedure-related fetal loss was classified as loss of one or all fetuses within 4 weeks of procedure, and overall fetal loss was classified as loss of one or all fetuses during the gestation. The groups were compared with respect to the procedure-related and obstetrical outcomes.ResultsThe difference in proportion of procedure-related fetal loss rate (1.9% for chorionic villus sampling vs. 1.8% for amniocentesis; P = 1.000) and the overall fetal loss rate (7.4% for chorionic villus sampling vs. 4.7% for amniocentesis; P = 0.489) between the two groups was not significant. The mean gestational ages at delivery were not statistically significant.ConclusionBoth the overall fetal loss rate and the procedure-related fetal loss rate of chorionic villus sampling and amniocentesis in dichorionic twin pregnancies had no statistical significance. Both procedures can be safely used individually.

Change in rates of prenatal tests for chromosomal abnormality over a 12-year period in women of advanced maternal age

ObjectiveIn 2007, the American College of Obstetricians and Gynecologists (ACOG) recommended that all pregnant women be offered screening or diagnostic tests for chromosomal abnormalities regardless of their age. Noninvasive prenatal testing (NIPT) for common chromosomal aneuploidies was introduced as a screening test in case of high-risk pregnancies. We assessed the rates of prenatal tests in women aged 35 years and older.MethodsA retrospective study was conducted to compare the rates of amniocentesis, chorionic villus sampling (CVS), serum screening, and NIPT from January 2005 through March 2017 in women aged 35 years and older. We divided the initial 12 months after NIPT introduction into 4-month intervals, beginning in April 2016 through March 2017.ResultsThe rates of amniocentesis were 56% before the ACOG statement, 38% between the ACOG statement and NIPT introduction, and 10% after NIPT introduction (P=0.001). The rates of CVS during the same periods were 0.5%, 2.1%, and 4.3% (P=0.016), respectively. The rates of serum screening were 44.2%, 61.3%, and 55.1% (P=0.049), respectively. During the 3 quarters after NIPT introduction, the rates of amniocentesis were 16.2%, 12.3%, and 7.3% (P=0.002), respectively; the rates of serum screening were 62%, 54%, and 46% (P=0.03), respectively; and the rates of NIPT were 19.9%, 30.3%, and 39.5% (P=0.007), respectively. The rates of CVS over the same periods were not significantly different.ConclusionThe ACOG statement and NIPT introduction significantly decreased the rate of amniocentesis in women of advanced maternal age. NIPT also reduced the rate of serum screening.

Transabdominal Amniocentesis Is a Feasible and Safe Procedure in Preterm Prelabor Rupture of Membranes

Objectives: To determine the feasibility and the complication rate of amniocentesis in a large cohort of women with preterm prelabor rupture of membranes (PPROM). Methods: A retrospective cohort study was conducted in all women with singleton gestation complicated by PPROM at between 24⁺⁰ and 36⁺⁶ weeks admitted to the Department of Obstetrics and Gynecology, University Hospital Hradec Kralove, Czech Republic between May 2008 and July 2016. Amniocentesis was offered as a part of a routine protocol of PPROM for the detection of microbial invasion of the amniotic cavity and intra-amniotic inflammation. Procedure was performed under ultrasound guidance. A successful procedure was defined as obtaining at least 0.5 mL of amniotic fluid. No more than 2 attempts were performed. Results: In total, 590 women with PPROM were included. Amniocentesis was successful in 96% (567/590). Two amniocentesis attempts were necessary in 9% (55/590) and the transplacental approach was used in 13% (76/590). No association between gestational age at sampling and the amniocentesis failure rate was found (Spearman rho -0.12; p = 0.71). The complication rate was 0.7% (4/590). Two umbilical cord punctures and 2 chorionic plate fetal vessel injuries occurred, without fetal morbidity. Conclusion: Based on our study population, so far the largest published, amniocentesis is a feasible and safe procedure carrying a very low risk of failure or complications in PPROM.

How do the trends in the prenatal diagnosis of aneuploidy change after a non-invasive prenatal test becomes available? A Japanese single center study.

To clarify the trends in the use of the prenatal diagnosis of and screening for aneuploidy after a non-invasive prenatal test (NIPT) was made available at a single Japanese hospital. The subjects included consecutive pregnant females who visited our hospital for maternal checkups and delivery between January 2012 and April 2014. After the subjects were divided into those who desired a prenatal diagnosis or screening before the availability of NIPT and those who did after the availability of NIPT, the frequencies of various prenatal diagnosis and screening procedures were compared between the two groups. A total of 544 patients who visited the hospital before NIPT was available and 703 who visited the hospital after NIPT became available were analyzed. While only 16.2 % of pregnant females received a prenatal diagnosis or screening before the NIPT was available, 27.5 % of them considered undergoing a prenatal diagnosis or screening after the NIPT was available before genetic counseling, and 24.0 % ultimately received a prenatal diagnosis or screening following genetic counseling. Of these patients, 7.7 % underwent NIPT. First trimester ultrasound screening for chromosomal abnormalities was unlikely to be selected (from 12.9 to 10.5 %, p = 0.212), although the rate of amniocentesis significantly increased after genetic counseling (from 1.5 to 3.7 %, p = 0.021). Since NIPT became available in 2013, pregnant females have demonstrated a deep interest in obtaining a prenatal diagnosis and screening. Whereas some patients choose to forgo a screening after receiving genetic counseling, others prefer invasive diagnostic tests in contrast to screening.

Prenatal diagnostic testing among women referred for advanced maternal age in Beijing, 2001–2012

ObjectiveTo determine the proportion of women with advanced maternal age (AMA) undergoing amniocentesis and assess the recommended indication of 35years or older in China. MethodsData were retrospectively evaluated from 9641 patients who underwent diagnostic prenatal amniocentesis in Beijing, China, between January 2001 and December 2012. Maternal age, indication for testing, and karyotype data were collected. Patients referred for AMA were stratified in 2 ways: 35–37years, 38–40years, and 41years or older; and indication of AMA alone or combined with other screening. Outcomes and safety performance were compared among the groups. ResultsFrom 2001 to 2012, the annual rate of amniocentesis and the proportion of AMA-related indications increased (P<0.01). Overall, 82 abnormalities were detected. In the AMA group, the spontaneous abortion rate was 0.5% (22/4748). The positive predictive value (PPV) of AMA alone was 0.5% for women aged 35–37years. Only among women aged 41years or older was the PPV of AMA alone better than that of AMA plus other indications (2.3% vs 1.5%, respectively). ConclusionThe PPV of 35years or older did not offset the risk of spontaneous abortion. AMA alone should not be used as an indication for amniocentesis especially among women aged 35–40years.

A new model for providing cell-free DNA and risk assessment for chromosome abnormalities in a public hospital setting.

Objective. Cell-free DNA (cfDNA) offers highly accurate noninvasive screening for Down syndrome. Incorporating it into routine care is complicated. We present our experience implementing a novel program for cfDNA screening, emphasizing patient education, genetic counseling, and resource management. Study Design. Beginning in January 2013, we initiated a new patient care model in which high-risk patients for aneuploidy received genetic counseling at 12 weeks of gestation. Patients were presented with four pathways for aneuploidy risk assessment and diagnosis: (1) cfDNA; (2) integrated screening; (3) direct-to-invasive testing (chorionic villus sampling or amniocentesis); or (4) no first trimester diagnostic testing/screening. Patients underwent follow-up genetic counseling and detailed ultrasound at 18–20 weeks to review first trimester testing and finalize decision for amniocentesis. Results. Counseling and second trimester detailed ultrasound were provided to 163 women. Most selected cfDNA screening (69%) over integrated screening (0.6%), direct-to-invasive testing (14.1%), or no screening (16.6%). Amniocentesis rates decreased following implementation of cfDNA screening (19.0% versus 13.0%, P < 0.05). Conclusion. When counseled about screening options, women often chose cfDNA over integrated screening. This program is a model for patient-directed, efficient delivery of a newly available high-level technology in a public health setting. Genetic counseling is an integral part of patient education and determination of plan of care.

497: Amniocentesis rates and genetic screening initiatives in a single center over a nine year period; is there a correlation?

497: Amniocentesis rates and genetic screening initiatives in a single center over a nine year period; is there a correlation?

Echogenic intracardiac foci: disclosure and the rate of amniocentesis in low-risk patients

Our objective was to determine the impact of disclosure of echogenic intracardiac focus (EIF) on the rate of amniocentesis in women who have undergone sequential testing. This was a retrospective study of women who had sequential testing for Down syndrome from 2009 through 2011. The Down syndrome risk was doubled in pregnancies with EIF, consistent with counseling provided to patients. In the control group Down syndrome risk was based on sequential testing. Within risk categories (1 in <250, 251-1000, 1001-5000, >5000) rates of amniocentesis with and without documented EIF were compared using Fisher exact test. In all, 4429 women at a median maternal age were included, including 229 with EIF (5.2%). In those at highest Down syndrome risk (1 in <250), rates of amniocentesis were similar between the 2 groups. In those at lower levels of risk, the rate of amniocentesis was significantly higher following disclosure of EIF compared to pregnancies without EIF at similar levels of risk. Except for those at highest risk, rates of invasive testing were significantly higher in pregnancies with isolated EIF vs those at comparable risk.

PF.05 Advances in Trisomy 21 Screening in the West Midlands, 1995–2011

BackgroundScreening for trisomy 21 (T21) in the West Midlands has evolved from double screening in 1995 to combined screening in 2011, with the perception of improved detection amongst the public...

Primiparity at Very Advanced Maternal Age (≥45 years)

This study describes maternal and birth outcomes of primiparae aged ≥ 45. High rates of pregnancy complications and poor birth outcomes were found, stressing that the personal risks and ramifications to the health system should be taken into account in establishing obstetric health policy regarding primiparity at advanced maternal age.

An Economic Model of Amniocentesis Choice

Medical practitioners typically utilize the following protocol when advising pregnant women about testing for the possibility of genetic disorders: Pregnant women over the age of 35 should be tested for Down syndrome and other genetic disorders; for younger women, such tests are discouraged since they can cause a miscarriage. The logic appears compelling. The rate at which amniocentesis causes a miscarriage is constant while genetic disorders rise over a woman's reproductive years. Hence the potential benefit from testing - being able to terminate a fetus with a genetic disorder - rises with maternal age. We argue that this logic is incomplete. While the benefits to testing rise with age, so do the costs. While undergoing an amniocentesis always entails the risk of miscarriage of a healthy fetus, these costs are lower at early ages, because there is a higher probability of being able to replace a miscarried fetus with a healthy birth at a later age. We develop and calibrate a dynamic model of amniocentesis choice to explore this tradeoff. For parameters that characterize realistic age patterns of chromosomal abnormalities, fertility rates and miscarriages following amniocentesis, our model implies a falling, rather than rising, rate of amniocentesis as women approach menopause.