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OBJECTIVE: To study associations of first trimester cell-free fetal DNA levels (in this paper referred to as cell-free placental DNA (cfpDNA) levels) and preeclampsia (PE), pregnancy-induced hypertension (PIH), gestational diabetes (GDM) and spontaneous preterm birth (sPB). METHOD: A nested case-control study was conducted in first trimester samples (gestational age 8(+0) -13(+6) weeks). A total of 226 cases and 301 controls were included. CfpDNA levels were quantified in male-bearing pregnancies using real-time DYS14-PCRs on DNA isolated from maternal serum. CfpDNA multiples of the median (MoMs) were calculated based on associations with patient characteristics (body mass index, parity, ethnicity and smoking). Associations between MoMs and adverse outcomes were studied. RESULTS: Cell-free placental DNA levels were negatively associated with body mass index (β = -0.297, p

Key Clinical Message One of the confounders in noninvasive prenatal testing (NIPT) is the vanishing twin phenomenon. Prolonged contribution to the maternal Cell‐free DNA (cfDNA) pool by cytotrophoblasts representing a demised, aneuploid cotwin may lead to a false‐positive outcome for a normal, viable twin. We show that a vanishing trisomy‐14 twin contributes to cfDNA for more than 2 weeks after demise.

Objectives We aim to elucidate causes of false-positive fetal RHD screening results obtained with cell-free DNA. Methods Fetal RHD screening was performed in 32 222 samples from RhD-negative women by multiplex real-time PCR in triplicate for RHD exons 5 and 7 using cell-free DNA isolated from maternal plasma obtained in the 27th gestational week. PCR results were compared with cord blood serology in 25 789 pregnancies (80.04%). False-positive cases were analyzed. Known biological causes (RHD variant genes), technical causes of discordance, and errors around blood sampling were investigated with leukocyte DNA from maternal and cord blood, and cell-free DNA from stored maternal plasma. Results Not only RHD but also Y-chromosome (DYS14) sequences were present in four plasma samples from RHD-negative women bearing an RHD-negative girl. Sample mix-up and other sampling errors could be excluded in three samples. Conclusions These results indicate that false-positive fetal RHD screening results can be caused by cell-free DNA fragments in maternal plasma derived from a third cell line that is not representative for either the maternal genome or the genome of the vital fetus. We propose that remaining (cyto)trophoblasts of a vanishing twin are the underlying mechanism, and we estimate a frequency of this phenomenon of 0.6%. © 2015 John Wiley & Sons, Ltd.

Objectives The objective of this study is to determine what percentage of fetal chromosomal anomalies remains undetected when first trimester combined testing is replaced by non-invasive prenatal testing for trisomies 13, 18, and 21. We focused on the added clinical value of nuchal translucency (NT) measurement. Methods Data on fetal karyotype, ultrasound findings, and pregnancy outcome of all pregnancies with an NT measurement ≥3.5 mm were retrospectively collected from a cohort of 25 057 singleton pregnancies in which first trimester combined testing was performed. Results Two hundred twenty-five fetuses (0.9 %) had an NT ≥3.5 mm. In 24 of these pregnancies, a chromosomal anomaly other than trisomy 13, 18, or 21 was detected. Eleven resulted in fetal demise, and ten showed fetal ultrasound anomalies. In three fetuses with normal ultrasound findings, a chromosomal anomaly was detected, of which one was a triple X. Conclusions In three out of 25 057 pregnancies (0.01%), non-invasive prenatal testing and fetal ultrasound would have missed a chromosomal anomaly that would have been identified by NT measurement. © 2015 John Wiley & Sons, Ltd.

Please cite this paper as: Scheffer P, Ait Soussan A, Verhagen O, Page-Christiaens G, Oepkes D, de Haas M, van der Schoot C. Noninvasive fetal genotyping of human platelet antigen-1a. BJOG 2011;118:1392–1395. We describe a reliable noninvasive fetal human platelet antigen (HPA)-1a genotyping assay on a real-time polymerase chain reaction (PCR) platform using cell-free fetal DNA isolated from maternal blood. Nonspecific amplification of maternal cell-free DNA is overcome by pre-PCR digestion of the cell-free DNA with the Msp1 restriction enzyme. Noninvasive fetal HPA-1a genotyping offers a safe method for alloimmunised pregnant women to determine whether their fetus is at risk of fetal or neonatal alloimmune thrombocytopenia (FNAIT) and whether interventions to prevent intracranial haemorrhage are required. The availability of this test is relevant to the ongoing debate on screening pregnancies for HPA-1a-mediated FNAIT.

Please cite this paper as: Scheffer P, van der Schoot C, Page-Christiaens G, de Haas M. Noninvasive fetal blood group genotyping of rhesus D, c, E and of K in alloimmunised pregnant women: evaluation of a 7-year clinical experience. BJOG 2011;118:1340–1348. Objective To evaluate the diagnostic performance of noninvasive fetal blood group genotyping. Design Descriptive analysis. Setting Dutch national reference laboratory for pregnancies complicated by alloimmunisation. Population All consecutive alloimmunised pregnant women for whom fetal blood group genotyping of rhesus D, c, E or of K in maternal plasma was performed from 2003 up to 2010. Methods The test results of each individual assay were collected. Real-time polymerase chain reaction was performed for RHD exon 5 and RHD exon 7, or the specific allele of the RHCE or KEL gene. A stringent diagnostic algorithm was applied. In the case of a negative result, the presence of fetal DNA was ascertained by the analysis of the Y chromosome-specific SRY gene or other paternal genetic markers. Results were compared with available serology after birth or genotyping results of amniotic fluid cells. Main outcome measures Percentage of conclusive test results and diagnostic accuracy. Results A total of 362 tests was performed (D: n = 168; c: n = 49; E: n = 85; K: n = 60). The median gestational age was 17 weeks (range 7–38 weeks). In 351 women (97%), a test result was issued: in seven samples, the presence of fetal DNA could not be confirmed; in two samples, non-specific amplification in the K assay led to an inconclusive result; in two samples, a maternal silent RHD gene prevented fetal RHD genotyping. No false-positive or false-negative results were found among those women for whom cord blood serology or genotyping results of amniotic fluid cells were available (n = 212). Conclusions Noninvasive fetal blood group genotyping is accurate and applicable in a clinical diagnostic setting.

Objective To identify short-term factors influencing psychological outcome of termination of pregnancy for fetal anomaly, in order to define those patients most vulnerable to psychopathology.Study Design A prospective cohort of 217 women and 169 men completed standardized questionnaires 4 months after termination. Psychological adjustment was measured by the Inventory of Complicated Grief (ICG), the Impact of Event Scale (IES), the Edinburgh Postnatal Depression Scale (EPDS), and the Symptom Checklist-90 (SCL-90).Results Women and men showed high levels of posttraumatic stress (PTS) symptoms (44 and 22%, respectively) and symptoms of depression (28 and 16%, respectively). Determinants of adverse psychological outcome were the following: high level of doubt in the decision period, inadequate partner support, low selfefficacy, lower parental age, being religious, and advanced gestational age. Whether the condition was Down syndrome or another disability was irrelevant to the outcome. Termination did not have an important effect on future reproductive intentions. Only 2% of women and less than I % of men regretted the decision to terminate.Conclusion Termination of pregnancy (TOP) for fetal anomaly affects parents deeply. Four months after termination a considerable part still suffers from posttraumatic stress symptoms and depressive feelings. Patients who are at high risk could benefit from intensified support. Copyright (c) 2007 John Wiley & Sons, Ltd.

The practice of prenatal screening is undergoing important changes as a result of the introduction of genomic testing technologies at different stages of the screening trajectory. It is expected that eventually it will become possible to routinely obtain a comprehensive 'genome scan' of all fetuses. Although this will still take several years, there are clear continuities between present developments and this future scenario. As this review shows, behind the still limited scope of screening for common aneuploidies, a rapid widening of the range of conditions tested for is already taking shape at the invasive testing stage. But the continuities are not just technical; they are also ethical. If screening for Down's syndrome is a matter of providing autonomous reproductive choice, then why would providing the choice to have a full fetal genome scan be something entirely different? There is a clear need for a sustainable normative framework that will have to answer three challenges: the indeterminateness of the autonomy paradigm, the need to acknowledge the future child as an interested stakeholder, and the prospect of broad-scope genomic prenatal screening with a double purpose: autonomy and prevention.

We aim to elucidate causes of false-positive fetal RHD screening results obtained with cell-free DNA.Fetal RHD screening was performed in 32,222 samples from RhD-negative women by multiplex real-time PCR in triplicate for RHD exons 5 and 7 using cell-free DNA isolated from maternal plasma obtained in the 27th gestational week. PCR results were compared with cord blood serology in 25,789 pregnancies (80.04%). False-positive cases were analyzed. Known biological causes (RHD variant genes), technical causes of discordance, and errors around blood sampling were investigated with leukocyte DNA from maternal and cord blood, and cell-free DNA from stored maternal plasma.Not only RHD but also Y-chromosome (DYS14) sequences were present in four plasma samples from RHD-negative women bearing an RHD-negative girl. Sample mix-up and other sampling errors could be excluded in three samples.These results indicate that false-positive fetal RHD screening results can be caused by cell-free DNA fragments in maternal plasma derived from a third cell line that is not representative for either the maternal genome or the genome of the vital fetus. We propose that remaining (cyto)trophoblasts of a vanishing twin are the underlying mechanism, and we estimate a frequency of this phenomenon of 0.6%.

Noninvasive prenatal testing (NIPT) validation studies show high sensitivity and specificity for detection of trisomies 13, 18, and 21. False negative cases have rarely been reported. We describe a false negative case of trisomy 13 and another of trisomy 18 in which NIPT was commercially marketed directly to the clinician. Both cases came to our attention because a fetal anatomy scan at 20 weeks of gestation revealed multiple anomalies. Karyotyping of cultured amniocytes showed nonmosaic trisomies 13 and 18, respectively. Cytogenetic investigation of cytotrophoblast cells from multiple placental biopsies showed a low proportion of nontrisomic cells in each case, but this was considered too small for explaining the false negative NIPT result. The discordant results also could not be explained by early gestational age, elevated maternal weight, a vanishing twin, or suboptimal storage or transport of samples. The root cause of the discrepancies could, therefore, not be identified. The couples involved experienced difficulties in accepting the unexpected and late-adverse outcome of their pregnancy. We recommend that all parties involved in caring for couples who choose NIPT should collaborate to clarify false negative results in order to unravel possible biological causes and to improve the process of patient care from initial counseling to communication of the result.

The objective of this study is to determine what percentage of fetal chromosomal anomalies remains undetected when first trimester combined testing is replaced by non-invasive prenatal testing for trisomies 13, 18, and 21. We focused on the added clinical value of nuchal translucency (NT) measurement.Data on fetal karyotype, ultrasound findings, and pregnancy outcome of all pregnancies with an NT measurement ≥3.5 mm were retrospectively collected from a cohort of 25,057 singleton pregnancies in which first trimester combined testing was performed.Two hundred twenty-five fetuses (0.9 %) had an NT ≥3.5 mm. In 24 of these pregnancies, a chromosomal anomaly other than trisomy 13, 18, or 21 was detected. Eleven resulted in fetal demise, and ten showed fetal ultrasound anomalies. In three fetuses with normal ultrasound findings, a chromosomal anomaly was detected, of which one was a triple X.In three out of 25,057 pregnancies (0.01%), non-invasive prenatal testing and fetal ultrasound would have missed a chromosomal anomaly that would have been identified by NT measurement. © 2015 John WileySons, Ltd.

Objectives The objective of this study is to determine what percentage of fetal chromosomal anomalies remains undetected when first trimester combined testing is replaced by non-invasive prenatal testing for trisomies 13, 18, and 21. We focused on the added clinical value of nuchal translucency (NT) measurement. Methods Data on fetal karyotype, ultrasound findings, and pregnancy outcome of all pregnancies with an NT measurement ≥3.5 mm were retrospectively collected from a cohort of 25 057 singleton pregnancies in which first trimester combined testing was performed. Results Two hundred twenty-five fetuses (0.9 %) had an NT ≥3.5 mm. In 24 of these pregnancies, a chromosomal anomaly other than trisomy 13, 18, or 21 was detected. Eleven resulted in fetal demise, and ten showed fetal ultrasound anomalies. In three fetuses with normal ultrasound findings, a chromosomal anomaly was detected, of which one was a triple X. Conclusions In three out of 25 057 pregnancies (0.01%), non-invasive prenatal testing and fetal ultrasound would have missed a chromosomal anomaly that would have been identified by NT measurement. © 2015 John Wiley & Sons, Ltd.

We describe a reliable noninvasive fetal human platelet antigen (HPA)-1a genotyping assay on a real-time polymerase chain reaction (PCR) platform using cell-free fetal DNA isolated from maternal blood. Nonspecific amplification of maternal cell-free DNA is overcome by pre-PCR digestion of the cell-free DNA with the Msp1 restriction enzyme. Noninvasive fetal HPA-1a genotyping offers a safe method for alloimmunised pregnant women to determine whether their fetus is at risk of fetal or neonatal alloimmune thrombocytopenia (FNAIT) and whether interventions to prevent intracranial haemorrhage are required. The availability of this test is relevant to the ongoing debate on screening pregnancies for HPA-1a-mediated FNAIT.

To evaluate the diagnostic performance of noninvasive fetal blood group genotyping.Descriptive analysis.Dutch national reference laboratory for pregnancies complicated by alloimmunisation.All consecutive alloimmunised pregnant women for whom fetal blood group genotyping of rhesus D, c, E or of K in maternal plasma was performed from 2003 up to 2010.The test results of each individual assay were collected. Real-time polymerase chain reaction was performed for RHD exon 5 and RHD exon 7, or the specific allele of the RHCE or KEL gene. A stringent diagnostic algorithm was applied. In the case of a negative result, the presence of fetal DNA was ascertained by the analysis of the Y chromosome-specific SRY gene or other paternal genetic markers. Results were compared with available serology after birth or genotyping results of amniotic fluid cells.Percentage of conclusive test results and diagnostic accuracy.A total of 362 tests was performed (D: n = 168; c: n = 49; E: n = 85; K: n = 60). The median gestational age was 17 weeks (range 7-38 weeks). In 351 women (97%), a test result was issued: in seven samples, the presence of fetal DNA could not be confirmed; in two samples, non-specific amplification in the K assay led to an inconclusive result; in two samples, a maternal silent RHD gene prevented fetal RHD genotyping. No false-positive or false-negative results were found among those women for whom cord blood serology or genotyping results of amniotic fluid cells were available (n = 212).Noninvasive fetal blood group genotyping is accurate and applicable in a clinical diagnostic setting.

Genetic cancer syndromes have identical clinical severity, limited therapeutic options, reduced life expectancy, and risks of genetic transmission, as do other genetic or congenital diseases for which prenatal genetic diagnosis or preimplantation genetic diagnosis (PGD) is allowed in the Netherlands. That was implied in the certification of one Dutch PGD centre at Maastricht University Hospital by the Dutch Ministry of Health, Welfare and Sport in 2003. A report by the Health Council of the Netherlands in 2006 confirmed this view with scientific and ethical evaluation. However, in 2006 the State Secretary for Health strongly objected to PGD for cancer, and disease risks of 50-100% for gene carriers, i.e. for highly, but not always fully penetrant genes. In 2006, the Maastricht centre discontinued PGD for cancer and couples were referred to other countries; prenatal genetic diagnosis remained available, however. On 26 May 2008, the present State Secretary proposed to parliament that the Health Council of the Netherlands report from 2006 be followed. This once again clashed with the fears of some Christian parties for a slippery slope and embryo selection for 'only a risk and not certainty of disease'. Yet no firm evidence for the existence of such a slope has been found. The Dutch framework for handling the ethical and medical evaluation of new reproductive and genetic technologies by the Health Council of the Netherlands Advisory Committees, professional and patient organisations, and the Ministry, has functioned for over 30 years without leading to any wrongdoing. There is no actual need for a new government body to license genetic tests on a case-by-case or per disease basis.

Determination of factors related to the need for transfusion in premature infants.Descriptive.The need for transfusion in premature infants was determined in 2 academic centres: University Medical Center Utrecht and Leiden University Medical Center, The Netherlands. The data had been acquired in another study. The factors under study were: hospital, pregnancy duration, birth weight, gender, time of clamping of the umbilical cord, total volume of blood sampled for diagnostic purposes, number of days of mechanical ventilation, total duration of admission and duration of the admission to the Neonatal Intensive care unit. Both hospitals followed the national interdisciplinary practice guideline 'Blood transfusion'.The total volume ofsampled blood for diagnosis, the duration of the mechanical ventilation and the admission period were related to a greater need for transfusion. On the other hand, the chance of transfusions diminished with longer pregnancy duration or increased birth weight. The difference in need for blood transfusion between both centres was significant. The total volume of transfused erythrocytes showed a strong correlation with the volume sampled for diagnostic procedures.Anaemia in neonates is strongly related to the amount of blood taken for diagnostic procedures. Alternatives for blood transfusions in premature infants, and consequently for the reduction of the number of donors per child, are to be sought in delayed clamping of the umbilical cord, use of erythropoietin and use ofautologous umbilical cord blood.

The Health Council of the Netherlands has published an advisory report on neonatal screening in view of developments in diagnostics, therapy and the prevalence of neonatal diseases. Currently it involves screening for phenylketonuria, congenital hypothyroidism and congenital adrenal hyperplasia. Because screening may lead to considerably better outcomes in affected newborns, the council recommends expanding current screening to include medium-chain acyl-CoA dehydrogenase deficiency, sickle-cell disease and 12 other rare disorders: biotinidase deficiency, galactosaemia, glutaricaciduria type I, HMG-CoA lyase deficiency, holocarboxylase-synthetase deficiency, homocystinuria, isovaleric-acidaemia, long-chain hydroxyacyl-CoA dehydrogenase deficiency, maple syrup urine disease, 3-methylcrotonyl-CoA carboxylase deficiency, tyrosinaemia I and very-long-chain acyl-CoA dehydrogenase deficiency. A better detection method for cystic fibrosis must be developed before it is included in screening to restrict the number of sweat-test referrals of unaffected newborns. The council recommends providing information on neonatal screening during pregnancy and gives special attention to the possibility of detecting carriership in the parents.

The existence of cell free fetal DNA, derived from apoptotic syncytiotrophoblasts, in the maternal circulation during pregnancy has opened new possibilities of non-invasive prenatal diagnosis, such as fetal RhD genotyping, prenatal diagnosis of hemoglobinopathies and fetal sexing in X-linked disorders like hemophilia. These diagnostic applications are however hampered by the lack of a generic control marker for circulating fetal DNA, which is especially cumbersome early in pregnancy. Fetal DNA concentration is extremely low and can be less then 5 genome equivalents (geq)/mL in the first trimester. It gradually increases during pregnancy, but greatly varies between women, from 15 to 150 geq/ml at 30th week of pregnancy. A negative test result can therefore be due to lack of fetal DNA in the PCR tube or to absence of the mutation/polymorphism in the fetus. Fetal DNA control assays based on Y-chromosome sequences can be used in only 50% of the pregnancies. We have previously developed a set of RQ-PCRs based on del-ins polymorphisms as fetal identifier, which has been introduced in routine diagnostics. However, in up to 5–10% of cases no suitable paternal marker can be identified and also the workload is considerable. Recently, it has been demonstrated that the promoter of RASSF1A gene is hyper-methylated in the placenta and hypo-methylated in maternal blood cells (Chiu et al., Am J Pathol.2007;170:941). This methylation pattern allows the use of methylation-sensitive restriction enzyme digestion with BSTU1, for detecting the placental, hence fetal-derived hyper-methylated RASSF1A sequences in maternal plasma. We wanted to implement this potential fetal DNA identifier, RASSF1A, in our diagnostic tests. Initial results however showed weak positive results in virtually all male plasmas. This could be due to incomplete digestion of hypo-methylated leukocyte derived DNA or to the presence in plasma of hypermethylated DNA from other sources. To increase the efficiency of digestion we performed a double digestion by adding another enzyme Hha1, which adds two extra restriction sites within the PCR target DNA sequence. Pilot experiments on DNA derived from male plasma showed decreased amplification signals, suggesting that the previously observed weak signals were derived from incompletely digested hypo-methylated DNA. We selected enzymes working in the same buffer. The optimal reaction time and temperature were established (1 hour at 37 °C with 10U of each enzyme). Applying this protocol, no amplification or only spurious amplification with high Ct values (mean Ct value of the positive wells: 43.3) were observed with DNA isolated from 2 ml of plasma obtained from non-pregnant women or male (n=20). In contrast, all samples obtained from pregnant women (n= 20) showed positive amplification signals in all wells tested (n=87, 3 or 5 replicates), with clearly lower Ct values (mean 41.04 ± 1.54) The beta-actin data showed in all samples complete digestion. In conclusion: Our results indicate that a real time PCR assay on RASSF1a sequence can be used as universal fetal identifier for non-invasive fetal genotyping assays, if it is tested after double digestion with BSTU1 and Hha1. It is to be expected that the availability of this control assay will lead to wider implementation of prenatal genotyping assays based on cell-free fetal DNA.