Presence of fetal DNA in maternal plasma and serum

BACKGROUND

The potential use of plasma and serum for molecular diagnosis has generated interest. Tumour DNA has been found in 'the plasma and serum of cancer patients, and molecular analysis has been done on this material. We investigated the equivalent condition in pregnancy-that is, whether fetal DNA is present in maternal plasma and serum.

METHODS

We used a rapid-boiling method to extract DNA from plasma and serum. DNA from plasma, serum, and nucleated blood cells from 43 pregnant women underwent a sensitive Y-PCR assay to detect circulating male fetal DNA from women bearing male fetuses.

FINDINGS

Fetus-derived Y sequences were detected in 24 (80%) of the 30 maternal plasma samples, and in 21 (70%) of the 30 maternal serum samples, from women bearing male fetuses. These results were obtained with only 10 microL of the samples. When DNA from nucleated blood cells extracted from a similar volume of blood was used, only five (17%) of the 30 samples gave a positive Y signal. None of the 13 women bearing female fetuses, and none of the ten non-pregnant control women, had positive results for plasma, serum or nucleated blood cells.

INTERPRETATION

Our finding of circulating fetal DNA in maternal plasma may have implications for non-invasive prenatal diagnosis, and for improving our understanding of the fetomaternal relationship.

Pregnancies from biopsied human preimplantation embryos sexed by Y-specific DNA amplification

Over 200 recessive X chromosome-linked diseases, typically affecting only hemizygous males, have been identified. In many of these, prenatal diagnosis is possible by chorion villus sampling (CVS) or amniocentesis, followed by cytogenetic, biochemical or molecular analysis of the cells recovered from the conceptus. In others, the only alternative is to determine the sex of the fetus. If the fetus is affected by the defect or is male, abortion can be offered. Diagnosis of genetic defects in preimplantation embryos would allow those unaffected to be identified and transferred to the uterus. Here we report the first established pregnancies using this procedure, in two couples known to be at risk of transmitting adrenoleukodystrophy and X-linked mental retardation. Two female embryos were transferred after in vitro fertilization (IVF), biopsy of a single cell at the six- to eight-cell stage, and sexing by DNA amplification of a Y chromosome-specific repeat sequence. Both women are confirmed as carrying normal female twins.

Retinopathy of prematurity

The immature retinas of preterm neonates are susceptible to insults that disrupt neurovascular growth, leading to retinopathy of prematurity. Suppression of growth factors due to hyperoxia and loss of the maternal-fetal interaction result in an arrest of retinal vascularisation (phase 1). Subsequently, the increasingly metabolically active, yet poorly vascularised, retina becomes hypoxic, stimulating growth factor-induced vasoproliferation (phase 2), which can cause retinal detachment. In very premature infants, controlled oxygen administration reduces but does not eliminate retinopathy of prematurity. Identification and control of factors that contribute to development of retinopathy of prematurity is essential to prevent progression to severe sight-threatening disease and to limit comorbidities with which the disease shares modifiable risk factors. Strategies to prevent retinopathy of prematurity will depend on optimisation of oxygen saturation, nutrition, and normalisation of concentrations of essential factors such as insulin-like growth factor 1 and ω-3 polyunsaturated fatty acids, as well as curbing of the effects of infection and inflammation to promote normal growth and limit suppression of neurovascular development.

Maternal serum screening for Down's syndrome in early pregnancy

The possibility of improving the effectiveness of antenatal screening for Down's syndrome by measuring human chorionic gonadotrophin concentrations in maternal serum during the second trimester to select women for diagnostic amniocentesis was examined. The median maternal serum human chorionic gonadotrophin concentration in 77 pregnancies associated with Down's syndrome was twice the median concentration in 385 unaffected pregnancies matched for maternal age, gestational age, and duration of storage of the serum sample. Measuring human chorionic gonadotrophin in maternal serum was an effective screening test, giving a lower false positive rate (3%) at a 30% detection rate than that for maternal age (5%) and the two existing serum screening tests, unconjugated oestriol (7%) and alpha fetoprotein (11%). The most effective screening results were obtained with all four variables combined; at the same 30% detection rate the false positive rate declined to 0.5%. The new screening method would detect over 60% of affected pregnancies, more than double that achievable with the same amniocentesis rate in existing programmes (5%), and could reduce the number of children born with Down's syndrome in the United Kingdom from about 900 a year to about 350 a year.

Care of girls and women with Turner syndrome: a guideline of the Turner Syndrome Study Group

OBJECTIVES

The objective of this work is to provide updated guidelines for the evaluation and treatment of girls and women with Turner syndrome (TS).

PARTICIPANTS

The Turner Syndrome Consensus Study Group is a multidisciplinary panel of experts with relevant clinical and research experience with TS that met in Bethesda, Maryland, April 2006. The meeting was supported by the National Institute of Child Health and unrestricted educational grants from pharmaceutical companies.

EVIDENCE

The study group used peer-reviewed published information to form its principal recommendations. Expert opinion was used where good evidence was lacking.

CONSENSUS

The study group met for 3 d to discuss key issues. Breakout groups focused on genetic, cardiological, auxological, psychological, gynecological, and general medical concerns and drafted recommendations for presentation to the whole group. Draft reports were available for additional comment on the meeting web site. Synthesis of the section reports and final revisions were reviewed by e-mail and approved by whole-group consensus.

CONCLUSIONS

We suggest that parents receiving a prenatal diagnosis of TS be advised of the broad phenotypic spectrum and the good quality of life observed in TS in recent years. We recommend that magnetic resonance angiography be used in addition to echocardiography to evaluate the cardiovascular system and suggest that patients with defined cardiovascular defects be cautioned in regard to pregnancy and certain types of exercise. We recommend that puberty should not be delayed to promote statural growth. We suggest a comprehensive educational evaluation in early childhood to identify potential attention-deficit or nonverbal learning disorders. We suggest that caregivers address the prospect of premature ovarian failure in an open and sensitive manner and emphasize the critical importance of estrogen treatment for feminization and for bone health during the adult years. All individuals with TS require continued monitoring of hearing and thyroid function throughout the lifespan. We suggest that adults with TS be monitored for aortic enlargement, hypertension, diabetes, and dyslipidemia.

Prenatal and postnatal prevalence of Klinefelter syndrome: a national registry study

The objective of this study was to describe the prevalence of Klinefelter syndrome (KS) prenatally and postnatally in Denmark and determine the influence of maternal age. All chromosomal examinations in Denmark are registered in the Danish Cytogenetic Central Registry. Individuals with KS diagnosed prenatally or postnatally were extracted from the registry with information about age at the time of diagnosis and mother's age. In the period 1970-2000, 76,526 prenatal examinations on male fetuses resulted in the diagnosis of 163 fetuses with KS karyotype, corresponding to a prevalence of 213 per 100,000 male fetuses. Standardization according to maternal age resulted in a prevalence of 153 per 100,000 males. Postnatally, 696 males of 2,480,858 live born were diagnosed with KS, corresponding to a prevalence among adult men of approximately 40 per 100,000. Less than 10% of the expected number was diagnosed before puberty. Advanced maternal age had a significant impact on the prevalence. KS is severely underdiagnosed in Denmark. Only approximately one fourth of adult males with KS are diagnosed. There is a marked delay in diagnosis of the syndrome. A delay in treatment with testosterone may lead to decreased muscle and bone mass with subsequent risk of osteoporosis.

Risk factors for antenatal depression, postnatal depression and parenting stress

BACKGROUND

Given that the prevalence of antenatal and postnatal depression is high, with estimates around 13%, and the consequences serious, efforts have been made to identify risk factors to assist in prevention, identification and treatment. Most risk factors associated with postnatal depression have been well researched, whereas predictors of antenatal depression have been less researched. Risk factors associated with early parenting stress have not been widely researched, despite the strong link with depression. The aim of this study was to further elucidate which of some previously identified risk factors are most predictive of three outcome measures: antenatal depression, postnatal depression and parenting stress and to examine the relationship between them.

METHODS

Primipara and multiparae women were recruited antenatally from two major hoitals as part of the beyondblue National Postnatal Depression Program 1. In this subsidiary study, 367 women completed an additional large battery of validated questionnaires to identify risk factors in the antenatal period at 26-32 weeks gestation. A subsample of these women (N = 161) also completed questionnaires at 10-12 weeks postnatally. Depression level was measured by the Beck Depression Inventory (BDI).

RESULTS

Regression analyses identified significant risk factors for the three outcome measures. (1). Significant predictors for antenatal depression: low self-esteem, antenatal anxiety, low social support, negative cognitive style, major life events, low income and history of abuse. (2). Significant predictors for postnatal depression: antenatal depression and a history of depression while also controlling for concurrent parenting stress, which was a significant variable. Antenatal depression was identified as a mediator between seven of the risk factors and postnatal depression. (3). Postnatal depression was the only significant predictor for parenting stress and also acted as a mediator for other risk factors.

CONCLUSION

Risk factor profiles for antenatal depression, postnatal depression and parenting stress differ but are interrelated. Antenatal depression was the strongest predictor of postnatal depression, and in turn postnatal depression was the strongest predictor for parenting stress. These results provide clinical direction suggesting that early identification and treatment of perinatal depression is important.

Carrier testing for severe childhood recessive diseases by next-generation sequencing

Of 7028 disorders with suspected Mendelian inheritance, 1139 are recessive and have an established molecular basis. Although individually uncommon, Mendelian diseases collectively account for ~20% of infant mortality and ~10% of pediatric hospitalizations. Preconception screening, together with genetic counseling of carriers, has resulted in remarkable declines in the incidence of several severe recessive diseases including Tay-Sachs disease and cystic fibrosis. However, extension of preconception screening to most severe disease genes has hitherto been impractical. Here, we report a preconception carrier screen for 448 severe recessive childhood diseases. Rather than costly, complete sequencing of the human genome, 7717 regions from 437 target genes were enriched by hybrid capture or microdroplet polymerase chain reaction, sequenced by next-generation sequencing (NGS) to a depth of up to 2.7 gigabases, and assessed with stringent bioinformatic filters. At a resultant 160x average target coverage, 93% of nucleotides had at least 20x coverage, and mutation detection/genotyping had ~95% sensitivity and ~100% specificity for substitution, insertion/deletion, splicing, and gross deletion mutations and single-nucleotide polymorphisms. In 104 unrelated DNA samples, the average genomic carrier burden for severe pediatric recessive mutations was 2.8 and ranged from 0 to 7. The distribution of mutations among sequenced samples appeared random. Twenty-seven percent of mutations cited in the literature were found to be common polymorphisms or misannotated, underscoring the need for better mutation databases as part of a comprehensive carrier testing strategy. Given the magnitude of carrier burden and the lower cost of testing compared to treating these conditions, carrier screening by NGS made available to the general population may be an economical way to reduce the incidence of and ameliorate suffering associated with severe recessive childhood disorders.

Prenatal diagnosis of fetal RhD status by molecular analysis of maternal plasma

BACKGROUND

The ability to determine fetal RhD Status noninvasively is useful in the treatment of RhD-sensitized pregnant women whose partners are heterozygous for the RhD gene. The recent demonstration of fetal DNA in maternal plasma raises the possibility that fetal RhD genotyping may be possible with the use of maternal plasma.

METHODS

We studied 57 RhD-negative pregnant women and their singleton fetuses. DNA extracted from maternal plasma was analyzed for the RhD gene with a fluorescence-based polymerase-chain-reaction (PCR) test sensitive enough to detect the RhD gene in a single cell. Fetal RhD status was determined directly by serologic analysis of cord blood or PCR analysis of amniotic fluid.

RESULTS

Among the 57 RhD-negative women, 12 were in their first trimester of pregnancy, 30 were in their second trimester, and 15 were in their third trimester. Thirty-nine fetuses were RhD-positive, and 18 were RhD-negative. In the samples obtained from women in their second or third trimester of pregnancy, the results of RhD PCR analysis of maternal plasma DNA were completely concordant with the results of serologic analysis. Among the maternal plasma samples collected in the first trimester, 2 contained no RhD DNA, but the fetuses were RhD-positive; the results in the other 10 samples were concordant (7 were RhD-positive, and 3 RhD-negative).

CONCLUSIONS

Noninvasive fetal RhD genotyping can be performed rapidly and reliably with the use of maternal plasma beginning in the second trimester of pregnancy.

Detection of 98% of DMD/BMD gene deletions by polymerase chain reaction

We describe oligonucleotide primer sequences that can be used to amplify eight exons plus the muscle promoter of the dystrophin gene in a single multiplex polymerase chain reaction (PCR). When used in conjunction with an existing primer set, these two multiplex reactions detect about 98% of deletions in patients with Duchenne or Becker muscular dystrophy (DMD, BMD). Furthermore, these primers amplify most of the exons in the deletion prone "hot spot" region around exons 44 to 53, allowing determination of deletion endpoints and prediction of mutational effects on the translational reading frame. Thus, use of these PCR-based assays will allow deletion detection and prenatal diagnosis for most DMD/BMD patients in a fraction of the time required for Southern blot analysis.

Fetal fibronectin in cervical and vaginal secretions as a predictor of preterm delivery

BACKGROUND

Preterm delivery is the leading cause of neonatal mortality in the United States, but efforts to address the problem are hampered by the inability to predict accurately which pregnancies are at risk. We postulated that damage to the fetal membranes may release fetal fibronectin into the cervix and vagina, giving rise to a biochemical marker for preterm delivery.

METHODS

We measured fetal-fibronectin concentrations in cervical and vaginal secretions, amniotic fluid, and maternal plasma with a sensitive immunoassay using the monoclonal antibody FDC-6. Immunohistochemical studies were used to determine the distribution of fetal fibronectin in the placenta and amniochorionic membranes and to ascertain its cell of origin.

RESULTS

Women with uncomplicated pregnancies (n = 163) who delivered at term rarely had cervicovaginal fetal-fibronectin concentrations above 0.05 micrograms per milliliter between 21 and 37 weeks of gestation (11 of 267 cervical samples [4 percent] and 9 of 267 vaginal samples [3 percent]. High levels of fetal fibronectin were detected in amniotic fluid and in the cervical or vaginal secretions of 93.8 percent of the women with preterm rupture of membranes (n = 65). Cervical or vaginal fetal fibronectin was also present in 50.4 percent of the women with preterm uterine contractions and intact membranes (n = 117), and its presence identified the women who delivered before term (n = 60) with a sensitivity of 81.7 percent and a specificity of 82.5 percent. In the placenta and membranes, fetal fibronectin was found at points of contact with the uterine wall.

CONCLUSIONS

The presence of cervicovaginal fetal fibronectin in the second and third trimesters of pregnancy identifies a subgroup of women who are at high risk for preterm delivery. This phenomenon may reflect the separation of the chorion from the decidual layer of the uterus, with the release of intact or degraded chorionic components of the extracellular matrix into the cervical and vaginal secretions.

Diagnosis and management of human cytomegalovirus infection in the mother, fetus, and newborn infant

Human cytomegalovirus (HCMV) is the leading cause of congenital viral infection and mental retardation. HCMV infection, while causing asymptomatic infections in most immunocompetent subjects, can be transmitted during pregnancy from the mother with primary (and also recurrent) infection to the fetus. Hence, careful diagnosis of primary infection is required in the pregnant woman based on the most sensitive serologic assays (immunoglobulin M [IgM] and IgG avidity assays) and conventional virologic and molecular procedures for virus detection in blood. Maternal prognostic markers of fetal infection are still under investigation. If primary infection is diagnosed in a timely manner, prenatal diagnosis can be offered, including the search for virus and virus components in fetal blood and amniotic fluid, with fetal prognostic markers of HCMV disease still to be defined. However, the final step for definite diagnosis of congenital HCMV infection is detection of virus in the blood or urine in the first 1 to 2 weeks of life. To date, treatment of congenital infection with antiviral drugs is only palliative both prior to and after birth, whereas the only efficacious preventive measure seems to be the development of a safe and immunogenic vaccine, including recombinant, subunit, DNA, and peptide-based vaccines now under investigation. The following controversial issues are discussed in the light of the most recent advances in the field: the actual perception of the problem; universal serologic screening before pregnancy; the impact of correct counseling on decision making by the couple involved; the role of prenatal diagnosis in ascertaining transmission of virus to the fetus; the impact of preconceptional and periconceptional infections on the prevalence of congenital infection; and the prevalence of congenitally infected babies born to mothers who were immune prior to pregnancy compared to the number born to mothers undergoing primary infection during pregnancy.

Prenatal management of 746 pregnancies at risk for congenital toxoplasmosis

When infection with Toxoplasma gondii occurs during pregnancy, there is a risk that the parasite will cause severe congenital toxoplasmosis. We developed a method of diagnosing and treating congenital toxoplasmosis in utero. Diagnosis was based on the identification of maternal acute infection, followed by culture of fetal blood and amniotic fluid, testing of fetal blood for toxoplasma-specific IgM and nonspecific measures of infection, and ultrasound examination of the fetal brain. Treatment included the administration of antibiotics to all mothers with confirmed acute infection during pregnancy, with more intensive antibiotic treatment of those who had infected fetuses and who chose to continue the pregnancy. We report a prospective study of 746 documented cases of maternal toxoplasma infection, in which the infants were followed for at least three months. Infection was diagnosed antenatally in 39 of 42 fetuses. Twenty-four of the 39 pregnancies were terminated, and 15 were continued. All the mothers were treated with spiramycin throughout pregnancy; if fetal infection was demonstrated, pyrimethamine and either sulfadoxine or sulfadiazine were added to the regimen. Of the 15 fetuses with congenital toxoplasmosis who were carried to term, all but 2, who had chorioretinitis, remained clinically well during follow-up. We conclude that prenatal diagnosis of congenital toxoplasmosis is practical and that prenatal therapy in women who wish to continue their pregnancies reduces the severity of the manifestations of the disease.

Gestational weight gain and risk of gestational diabetes mellitus

OBJECTIVE

To estimate the relationship between the rate of gestational weight gain before the 50-g, 1-hour oral glucose challenge test screening for gestational diabetes mellitus (GDM) and subsequent risk of GDM.

METHODS

We conducted a nested case-control study (345 women with GDM and 800 women in the control group) within a multiethnic cohort of women delivering between 1996 and 1998 who were screened for GDM at 24-28 weeks of gestation. GDM was diagnosed according to the National Diabetes Data Group plasma glucose cut-offs for the 100-g, 3-hour oral glucose tolerance test. Women's plasma glucose levels, weights, and covariate data were obtained by medical record chart review.

RESULTS

After adjusting for age at delivery, race/ethnicity, parity, and prepregnancy body mass index, the risk of GDM increased with increasing rates of gestational weight gain. Compared with the lowest tertile of rate of gestational weight gain (less than 0.27 kg/week [less than 0.60 lb/wk]), a rate of weight gain from 0.27-0.40 kg/wk (0.60-0.88 lb/wk) and 0.41 kg/wk (0.89 lb/wk) or more, were associated with increased risks of GDM (odds ratio 1.43, 95% confidence interval 0.96-2.14; and odds ratio 1.74, 95% confidence interval 1.16-2.60, respectively). The association between the rate of gestational weight gain and GDM was primarily attributed to increased weight gain in the first trimester. The association was stronger in overweight [corrected] and nonwhite women.

CONCLUSION

High rates of gestational weight gain, especially early in pregnancy, may increase a woman's risk of GDM. Gestational weight gain during early pregnancy may represent a modifiable risk factor for GDM and needs more attention from health care providers.

Antenatal thyroid screening and childhood cognitive function

BACKGROUND

Children born to women with low thyroid hormone levels have been reported to have decreased cognitive function.

METHODS

We conducted a randomized trial in which pregnant women at a gestation of 15 weeks 6 days or less provided blood samples for measurement of thyrotropin and free thyroxine (T(4)). Women were assigned to a screening group (in which measurements were obtained immediately) or a control group (in which serum was stored and measurements were obtained shortly after delivery). Thyrotropin levels above the 97.5th percentile, free T(4) levels below the 2.5th percentile, or both were considered a positive screening result. Women with positive findings in the screening group were assigned to 150 μg of levothyroxine per day. The primary outcome was IQ at 3 years of age in children of women with positive results, as measured by psychologists who were unaware of the group assignments.

RESULTS

Of 21,846 women who provided blood samples (at a median gestational age of 12 weeks 3 days), 390 women in the screening group and 404 in the control group tested positive. The median gestational age at the start of levothyroxine treatment was 13 weeks 3 days; treatment was adjusted as needed to achieve a target thyrotropin level of 0.1 to 1.0 mIU per liter. Among the children of women with positive results, the mean IQ scores were 99.2 and 100.0 in the screening and control groups, respectively (difference, 0.8; 95% confidence interval [CI], -1.1 to 2.6; P=0.40 by intention-to-treat analysis); the proportions of children with an IQ of less than 85 were 12.1% in the screening group and 14.1% in the control group (difference, 2.1 percentage points; 95% CI, -2.6 to 6.7; P=0.39). An on-treatment analysis showed similar results.

CONCLUSIONS

Antenatal screening (at a median gestational age of 12 weeks 3 days) and maternal treatment for hypothyroidism did not result in improved cognitive function in children at 3 years of age. (Funded by the Wellcome Trust UK and Compagnia di San Paulo, Turin; Current Controlled Trials number, ISRCTN46178175.).

Suggested guidelines for the diagnosis and management of urea cycle disorders

Urea cycle disorders (UCDs) are inborn errors of ammonia detoxification/arginine synthesis due to defects affecting the catalysts of the Krebs-Henseleit cycle (five core enzymes, one activating enzyme and one mitochondrial ornithine/citrulline antiporter) with an estimated incidence of 1:8.000. Patients present with hyperammonemia either shortly after birth (~50%) or, later at any age, leading to death or to severe neurological handicap in many survivors. Despite the existence of effective therapy with alternative pathway therapy and liver transplantation, outcomes remain poor. This may be related to underrecognition and delayed diagnosis due to the nonspecific clinical presentation and insufficient awareness of health care professionals because of disease rarity. These guidelines aim at providing a trans-European consensus to: guide practitioners, set standards of care and help awareness campaigns. To achieve these goals, the guidelines were developed using a Delphi methodology, by having professionals on UCDs across seven European countries to gather all the existing evidence, score it according to the SIGN evidence level system and draw a series of statements supported by an associated level of evidence. The guidelines were revised by external specialist consultants, unrelated authorities in the field of UCDs and practicing pediatricians in training. Although the evidence degree did hardly ever exceed level C (evidence from non-analytical studies like case reports and series), it was sufficient to guide practice on both acute and chronic presentations, address diagnosis, management, monitoring, outcomes, and psychosocial and ethical issues. Also, it identified knowledge voids that must be filled by future research. We believe these guidelines will help to: harmonise practice, set common standards and spread good practices with a positive impact on the outcomes of UCD patients.

A population-based comparison of strategies to prevent early-onset group B streptococcal disease in neonates

BACKGROUND

Guidelines issued in 1996 in the United States recommend either screening of pregnant women for group B streptococcal colonization by means of cultures (screening approach) or assessing clinical risk factors (risk-based approach) to identify candidates for intrapartum antibiotic prophylaxis.

METHODS

In a multistate retrospective cohort study, we compared the effectiveness of the screening and risk-based approaches in preventing early-onset group B streptococcal disease (in infants less than seven days old). We studied a stratified random sample of the 629,912 live births in 1998 and 1999 in eight geographical areas where there was active surveillance for group B streptococcal infection, including all births in which the neonate had early-onset disease. Women with no documented culture for group B streptococcus were considered to have been cared for according to the risk-based approach.

RESULTS

We studied 5144 births, including 312 in which the newborn had early-onset group B streptococcal disease. Antenatal screening was documented for 52 percent of the mothers. The risk of early-onset disease was significantly lower among the infants of screened women than among those in the risk-based group (adjusted relative risk, 0.46; 95 percent confidence interval, 0.36 to 0.60). Because women whose providers had no strategy for prophylaxis may have been misclassified in the risk-based group, we excluded all women with risk factors and adequate time for prophylaxis who did not receive antibiotics. The adjusted relative risk of early-onset disease associated with the screening approach in this secondary analysis was similar--0.48 (95 percent confidence interval, 0.37 to 0.63).

CONCLUSIONS

Routine screening for group B streptococcus during pregnancy prevents more cases of early-onset disease than the risk-based approach. Recommendations that endorse both strategies as equivalent warrant reconsideration.

Tetralogy of Fallot

Tetralogy of Fallot is the most common form of cyanotic congenital heart disease, and one of the first to be successfully repaired by congenital heart surgeons. Since the first procedures in the 1950s, advances in the diagnosis, perioperative and surgical treatment, and postoperative care have been such that almost all those born with tetralogy of Fallot can now expect to survive to adulthood. The startling improvement in outcomes for babies born with congenital heart disease in general-and for those with tetralogy of Fallot in particular-is one of the success stories of modern medicine. Indeed, in many countries adults with tetralogy of Fallot outnumber children. Consequently, new issues have emerged, ranging from hitherto unpredicted medical complications to issues with training for caregivers and resource allocation for this population of survivors. Therefore, evolution of treatment, recognition of late complications, research on disease mechanisms and therapies-with feedback to changes in care of affected children born nowadays-are templates on which the timely discussion of organisation of care of those affected by congenital heart diseases from the fetus to the elderly can be based. Here, we focus on new developments in the understanding of the causes, diagnosis, early treatment, and late outcomes of tetralogy of Fallot, emphasising the continuum of multidisciplinary care that is necessary for best possible lifelong treatment of the 1% of the population born with congenital heart diseases.

The hidden mortality of monochorionic twin pregnancies

In an ultrasound screening study at 10 to 14 weeks of gestation for measurement of fetal nuchal translucency thickness there were 102 monochorionic and 365 dichorionic twin pregnancies. In the monochorionic compared with the dichorionic pregnancies there was a higher rate of fetal loss before 24 weeks of gestation (12.2% versus 1.8%), perinatal mortality (2.8% versus 1.6%), prevalence of delivery before 32 weeks (9.2% versus 5.5%), and prevalence of birthweight below the 5th centile in both twins (7.5% versus 1.7%). However, the proportion of pregnancies with a birthweight discordancy of more than 25% was similar in the two groups (11.3% versus 12.1%).