Chorionic villus sampling and amniocentesis

Confirmed non-invasive prenatal testing for foetal Rh blood group genotyping along with bi-allelic short insertion/deletion polymorphisms as a positive internal control

BACKGROUND

Determination of foetus rhesus blood group at risk of hemolytic disease has potential application for early non-invasive prenatal testing (NIPT). There are several challenges in developing NIPT rhesus blood group genotyping assays by using cell-free foetal DNA (cff-DNA) in plasma of RhD-negative pregnant women. So, the aim of this study was optimization of Real-time PCR assay for NIPT rhesus genotyping and development of Bi-allelic short insertion/deletion polymorphisms (INDELs) as internal control to optimise and validate rhesus genotyping based on Real-time PCR to avoid false or negative results.

MATERIAL AND METHODS

NIPT Rhesus genotyping including RHD (exon 7), RHCc, and RHEe genes were performed by TaqMan Real-time PCR on 104 maternal samples at different gestation ages (12 to ≥40 weeks) from 51 alloimmunized pregnant women. The sensitivity protocol was confirmed with standard DNA samples. Eight selected INDELs were designed and used to detectable cff-DNA in maternal plasma. INDELs frequency and inheritance were determined on 6 family and 61 unrelated individuals. Finally, multiplex Real-time PCR was performed for each sample with INDELs pairs and Rh probes.

RESULTS

The results showed 100% accuracy rhesus typing for RHD, RHC and RHE assays and 95.7% accuracy for RHc. Also, eight selected INDELs as internal control for NIPT were 100% concordance for typed samples.

CONCLUSION

The Real-time PCR assay is a suitable method with high sensitivity and specificity for rhesus typing as NIPT for prediction of hemolytic disease in foetuses. The INDELs described here are suitable internal control for confirmation of NIPT on cff-DNA.

Chorionic Villus Sampling, Early Amniocentesis, and Termination of Pregnancy Without Diagnostic Testing: Comparison of Fetal Risk Following Positive Non-invasive Prenatal Testing

BACKGROUND

With the increased accuracy of non-invasive prenatal testing (NIPT) based on cell-free DNA (cfDNA) techniques, the likelihood of false-positive screening results has been reduced for high-risk populations. Following a positive screening test, a diagnostic procedure to confirm the result is strongly recommended, although some patients have terminated pregnancies because of a positive NIPT alone. Chorionic villus sampling (CVS), the diagnostic procedure of choice in the first trimester, is not available in all locations. Amniocentesis before 15 weeks, referred to as early amniocentesis (EA), is associated with a 1% rate of talipes and an increased rate of early pregnancy loss compared with CVS. Our objective was to compare the level of risk for euploid pregnancies following a positive NIPT based on the invasive procedure chosen.

METHOD

Using data from a 2003 meta-analysis, we estimated the rates of adverse pregnancy outcome in euploid pregnancies based on the positive predictive value (PPV) of NIPT and the invasive procedure used-that is, CVS, EA, or termination of pregnancy (TOP).

RESULTS

Following NIPT, we found that the rate of adverse fetal outcomes in euploid pregnancies was lower for CVS than for EA at all PPV levels. As the PPV of NIPT increased, the difference in risk between EA and CVS decreased. The risk to euploid pregnancies of TOP was excessive at all PPVs.

CONCLUSION

CVS is the recommended diagnostic test in the first trimester because it is safer than EA for the fetus. However, EA is better than no testing when early TOP is planned. Patients should be strongly counselled against TOP without confirmatory testing.

The human sex ratio from conception to birth

We describe the trajectory of the human sex ratio from conception to birth by analyzing data from (i) 3- to 6-d-old embryos, (ii) induced abortions, (iii) chorionic villus sampling, (iv) amniocentesis, and (v) fetal deaths and live births. Our dataset is the most comprehensive and largest ever assembled to estimate the sex ratio at conception and the sex ratio trajectory and is the first, to our knowledge, to include all of these types of data. Our estimate of the sex ratio at conception is 0.5 (proportion male), which contradicts the common claim that the sex ratio at conception is male-biased. The sex ratio among abnormal embryos is male-biased, and the sex ratio among normal embryos is female-biased. These biases are associated with the abnormal/normal state of the sex chromosomes and of chromosomes 15 and 17. The sex ratio may decrease in the first week or so after conception (due to excess male mortality); it then increases for at least 10-15 wk (due to excess female mortality), levels off after ∼20 wk, and declines slowly from 28 to 35 wk (due to excess male mortality). Total female mortality during pregnancy exceeds total male mortality. The unbiased sex ratio at conception, the increase in the sex ratio during the first trimester, and total mortality during pregnancy being greater for females are fundamental insights into early human development.

Physiological basis for the etiology, diagnosis, and treatment of adrenal disorders: Cushing's syndrome, adrenal insufficiency, and congenital adrenal hyperplasia

The hypothalamic-pituitary-adrenal (HPA) axis is a classic neuroendocrine system. One of the best ways to understand the HPA axis is to appreciate its dynamics in the variety of diseases and syndromes that affect it. Excess glucocorticoid activity can be due to endogenous cortisol overproduction (spontaneous Cushing's syndrome) or exogenous glucocorticoid therapy (iatrogenic Cushing's syndrome). Endogenous Cushing's syndrome can be subdivided into ACTH-dependent and ACTH-independent, the latter of which is usually due to autonomous adrenal overproduction. The former can be due to a pituitary corticotroph tumor (usually benign) or ectopic ACTH production from tumors outside the pituitary; both of these tumor types overexpress the proopiomelanocortin gene. The converse of Cushing's syndrome is the lack of normal cortisol secretion and is usually due to adrenal destruction (primary adrenal insufficiency) or hypopituitarism (secondary adrenal insufficiency). Secondary adrenal insufficiency can also result from a rapid discontinuation of long-term, pharmacological glucocorticoid therapy because of HPA axis suppression and adrenal atrophy. Finally, mutations in the steroidogenic enzymes of the adrenal cortex can lead to congenital adrenal hyperplasia and an increase in precursor steroids, particularly androgens. When present in utero, this can lead to masculinization of a female fetus. An understanding of the dynamics of the HPA axis is necessary to master the diagnosis and differential diagnosis of pituitary-adrenal diseases. Furthermore, understanding the pathophysiology of the HPA axis gives great insight into its normal control.

[Transabdominal chorionic villus sampling using biopsy forceps or needle: pregnancy outcomes by technique used]

OBJECTIVES

To compare pregnancy outcomes after transabdominal chorionic villus sampling using biopsy forceps or needle.

MATERIALS AND METHODS

Retrospective bicentric study including all women who had a transabdominal chorionic villus sampling between 2005 and 2009 (172 using biopsy forceps and 160 using needle). The primary endpoint was the rate of fetal loss, after excluding medical abortion due to the result of the biopsy. The secondary endpoint was the rate of premature rupture of the membrane. All cases were reviewed to try to determine the responsibility of the biopsy.

RESULTS

The pregnancy outcomes were not different between the two groups: 4 (4.4%) fetal losses in the biopsy forceps group and 6 (7.4%) in the needle group (P=0.52). Only one case (1.2%) of fetal loss can be attributed to the biopsy, using a needle, and none (0%) following a forceps biospy (P=0.29). The rate of premature rupture of the membrane was comparable in the two groups.

CONCLUSION

The pregnancy outcomes following chorionic villus sampling using a biopsy forceps or a needle seem comparable.

Transvaginal administration of intraamniotic digoxin prior to dilation and evacuation

BACKGROUND

Transabdominal injection of digoxin into the amniotic fluid or fetus to induce fetal demise before dilation and evacuation (D&E) abortion has become common practice since the passage of the Partial-Birth Abortion Ban Act in 2007.

STUDY DESIGN

We performed a prospective study to assess the feasibility of transvaginal administration of intraamniotic digoxin the day before D&E. All women between 18 0/7 and 23 5/7 weeks of gestation seeking termination from December 2009 to May 2011 were approached for study participation. Women who declined participation were asked to identify their primary rationale. For women declining study participation, transection of the umbilical cord during D&E was performed to meet the requirements of the ban.

RESULTS

Over 18 months, 134 women met study entry criteria and 108 (81%) declined to participate. Of the 26 women who enrolled, 1.0 mg undiluted digoxin was successfully administered transvaginally in 24 (92%, 95% confidence interval 75%-99%). The most common reasons for declining participation were discomfort with preoperatively inducing fetal demise (37%) and desire to avoid a medically unnecessary medication (36%).

CONCLUSIONS

Transvaginal administration of digoxin is a feasible alternative to transabdominal administration to induce preoperative fetal demise. The majority of women decline digoxin administration when an alternative is available.

Korean-specific parameter models for calculating the risk of Down syndrome in the second trimester of pregnancy

The purpose of the current study was to propose a Korean-specific parameter set for calculating the risk of Down syndrome in the second trimester of pregnancy and to determine the screening performances of triple and quadruple tests in Korean women. Using the data on triple or quadruple screening from three hospitals in Korea during 7 yr, we re-converted the concentrations of four serum markers to multiple of median values according to gestational age and maternal weight. After re-calculating the risk of Down syndrome in each pregnancy by multiplying maternal age-specific risk by the likelihood ratio values for the serum markers, screening performances and optimal cut-off values of triple and quadruple tests were analyzed. Among 16,077 pregnancies, 23 cases had Down syndrome (1.4/1,000 deliveries). Compared to the previous program, the tests with new parameters had improved screening performance. The triple and quadruple tests had detection rates of 65.2% and 72.7%, respectively, at a false-positive rate of 5%. The optimal cut-off value for the quadruple and triple tests was 1:250. We have presented a Korean-specific parameter set for Down syndrome screening. The proposed screening test using this parameter set may improve the performance of Down syndrome screening for Korean women.

Canadian Cardiovascular Society 2009 Consensus Conference on the management of adults with congenital heart disease: introduction

With advances in pediatric cardiology and cardiac surgery, the population of adults with congenital heart disease (CHD) has increased. In the current era, there are more adults with CHD than children. This population has many unique issues and needs. Since the 2001 Canadian Cardiovascular Society consensus conference report on the management of adults with CHD, there have been significant advances in the field of adult CHD. Therefore, new clinical guidelines have been written by Canadian adult CHD physicians in collaboration with an international panel of experts in the field. The present introductory section is a summary of the epidemiology and scope of adult CHD in Canada, the structure of the Canadian health care system and adult congenital cardiac health services in Canada. The recommendations for antibiotic prophylaxis and genetic evaluation in this population are included. The complete document consists of four manuscripts, which are published online in the present issue of The Canadian Journal of Cardiology, including sections on genetics, outcomes, diagnostic workups, surgical and interventional options, treatment of arrhythmias, assessment of pregnancy and contraception risks, and follow-up recommendations. The complete document and references can also be found at www.ccs.ca or www.cachnet.org.

Genetic basis for congenital heart defects: current knowledge: a scientific statement from the American Heart Association Congenital Cardiac Defects Committee, Council on Cardiovascular Disease in the Young: endorsed by the American Academy of Pediatrics

The intent of this review is to provide the clinician with a summary of what is currently known about the contribution of genetics to the origin of congenital heart disease. Techniques are discussed to evaluate children with heart disease for genetic alterations. Many of these techniques are now available on a clinical basis. Information on the genetic and clinical evaluation of children with cardiac disease is presented, and several tables have been constructed to aid the clinician in the assessment of children with different types of heart disease. Genetic algorithms for cardiac defects have been constructed and are available in an appendix. It is anticipated that this summary will update a wide range of medical personnel, including pediatric cardiologists and pediatricians, adult cardiologists, internists, obstetricians, nurses, and thoracic surgeons, about the genetic aspects of congenital heart disease and will encourage an interdisciplinary approach to the child and adult with congenital heart disease.

Prenatal diagnosis of haemophilia A by chorionic villus sampling and cordocentesis: all India Institute of Medical Science experience

BACKGROUND AND OBJECTIVE

We looked at the two most commonly used methods for prenatal diagnosis, cordocentesis and chorionic villus sampling for prenatal diagnosis of haemophilia A in an Indian setting.

MATERIAL AND METHODS

The study sample included 16 families which reported to us for prenatal diagnosis of haemophilia A at All India Institute of Medical Science, New Delhi, India. Prenatal tests were done on chorionic villus samples or on cord blood (cordocentesis). Molecular work-up included the use of indirect mutation analysis in the form of linkage markers like CA-13, CA-22, Xba1 and Bcl1 as well as direct mutation analysis in the form of inversion 1 and 22 detection. Non-molecular work-up included primarily factor VIII assays.

RESULT

Chorionic villus sampling was performed in eight mothers. Of the other eight mothers, six underwent cord blood factor VIII assays because these had absence of family history and were negative for linkage and inversion 1 and 22. One patient had a female child and another had a fetus that showed congenital abnormalities.

CONCLUSION

We found that the choice of either technique, chorionic villus or cordocentesis, is not really an alternative, but rather dependent on the gestational age of presentation.

Use of maternal plasma for non-invasive prenatal diagnosis of fetal ABO genotypes

BACKGROUND

Measurement of free fetal DNA in maternal plasma opened a door for non-invasive prenatal diagnosis. Prenatal diagnosis of fetal ABO genotypes can provide a basis for the prevention and therapy of maternal-fetal incompatibility. We identified fetal ABO genotypes using fetal DNA in plasma from pregnant women with blood group O. The aim of the study was to investigate the accuracy and feasibility of this method.

METHODS

A total of 105 blood group O women in middle or late pregnancy were enrolled. Fetal DNA in maternal plasma and genomic DNA in umbilical vein blood from newborns were extracted using a QIAamp DNA Blood Kit. DNA was amplified to identify ABO genotypes by PCR with sequence-specific primers (PCR-SSP). The genotype results were evaluated using serologic tests for ABO phenotyping.

RESULTS

Using DNA from umbilical vein blood, ABO genotypes of 105 newborns were successfully identified by PCR-SSP. Using fetal DNA from maternal plasma, 88.6% (93/105) fetal ABO genotypes was correct; 12 false results were from 66 pregnant women with fetuses of type non-O. The accuracy in middle pregnancy was lower than that in late pregnancy, although the difference was not significant (0.05<p<0.10).

CONCLUSIONS

It is feasible to use measurement of fetal DNA in plasma from pregnant women with blood group O for prenatal diagnosis of fetal ABO genotypes. The method is useful for the diagnosis and therapy of ABO maternal-fetal incompatibility and hemolytic disease of the newborn.