Spontaneous fetal loss rates in a non-selected population

Abortion Bans and Resource Utilization for Congenital Heart Disease: A Decision Analysis

OBJECTIVE

To investigate the implications of potential national abortion ban scenarios on the incidence of neonatal single-ventricle cardiac defects.

METHODS

A decision tree model was developed to predict the incidence of neonatal single-ventricle cardiac defects and related outcomes in the United States under four theoretical national abortion bans: 1) abortion restrictions in existence immediately before the June 2022 Dobbs v Jackson Women's Health Organization Supreme Court decision, 2) 20 weeks of gestation, 3) 13 weeks of gestation, and 4) a complete abortion ban. The model included incidence of live births of neonates with single-ventricle cardiac defects, neonatal heart surgery (including heart transplant and extracorporeal membrane oxygenation [ECMO]), and neonatal death. Cohort size was based on national pregnancy incidence and different algorithm decision point probabilities were aggregated from the existing literature. Monte Carlo simulations were conducted with 10,000 iterations per model.

RESULTS

In the scenario before the Dobbs decision, an estimated 6,369,000 annual pregnancies in the United States resulted in 1,006 annual cases of single-ventricle cardiac defects. Under a complete abortion ban, the model predicted a 53.7% increase in single-ventricle cardiac defects, or an additional 9 cases per 100,000 live births. This increase would result in an additional 531 neonatal heart surgeries, 16 heart transplants, 77 ECMO utilizations, and 102 neonatal deaths annually. More restrictive gestational age-based bans are predicted to confer increases in cases of neonatal single-ventricle cardiac defects and related adverse outcomes as well.

CONCLUSION

Universal abortion bans are estimated to increase the incidence of neonatal single-ventricle cardiac defects, associated morbidity, and resource utilization. States considering limiting abortion should consider the implications on the resources required to care for increasing number of children that will be born with significant and complex medical needs, including those with congenital heart disease.

Fetal fraction-based risk algorithm for non-invasive prenatal testing: screening for trisomies 13 and 18 and triploidy in women with low cell-free fetal DNA

OBJECTIVE

To identify pregnancies at increased risk for trisomy 13, trisomy 18 or triploidy attributable to low fetal fraction (FF).

METHODS

A FF-based risk (FFBR) model was built using data from more than 165 000 singleton pregnancies referred for single-nucleotide polymorphism (SNP)-based non-invasive prenatal testing (NIPT). Based on maternal weight and gestational age (GA), FF distributions for normal, trisomy 13, trisomy 18 and triploid pregnancies were constructed and used to adjust prior risks for these abnormalities. A risk cut-off of ≥ 1% was chosen to define pregnancies at high risk for trisomy 13, trisomy 18 or triploidy (high FFBR score). The model was evaluated on an independent blinded set of pregnancies for which SNP-based NIPT did not return a result, and for which pregnancy outcome information was gathered retrospectively.

RESULTS

The evaluation cohort comprised 1148 cases, of which approximately half received a high FFBR score. Compared with rates expected based on maternal age (MA) and GA, cases with a high FFBR score had a significantly increased rate of trisomy 13, trisomy 18 or triploidy combined (5.7% vs 0.7%; P < 0.001) and also of unexplained pregnancy loss (14.7% vs 10.4%; P < 0.001). For cases that did not receive a high FFBR score, the incidence of a chromosomal abnormality or pregnancy loss was not significantly different from that expected based on MA and GA. In this study cohort, the sensitivity of the FFBR model for detection of trisomy 13, trisomy 18 or triploidy was 91.4% (95% CI, 76.9-98.2%) with a positive predictive value of 5.7% (32/564; 95% CI, 3.9-7.9%).

CONCLUSIONS

For pregnancies with a FF too low to receive a result on standard NIPT, the FFBR algorithm identified a subset of cases at increased risk for trisomy 13, trisomy 18 or triploidy. For the remainder of cases, the risk of a fetal chromosomal abnormality was unchanged from that expected based on MA and GA. © 2018 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

Early pregnancy angiogenic markers and spontaneous abortion: an Odense Child Cohort study

BACKGROUND

Spontaneous abortion is the most commonly observed adverse pregnancy outcome. The angiogenic factors soluble Fms-like kinase 1 and placental growth factor are critical for normal pregnancy and may be associated to spontaneous abortion.

OBJECTIVE

We investigated the association between maternal serum concentrations of soluble Fms-like kinase 1 and placental growth factor, and subsequent spontaneous abortion.

STUDY DESIGN

In the prospective observational Odense Child Cohort, 1676 pregnant women donated serum in early pregnancy, gestational week <22 (median 83 days of gestation, interquartile range 71-103). Concentrations of soluble Fms-like kinase 1 and placental growth factor were determined with novel automated assays. Spontaneous abortion was defined as complete or incomplete spontaneous abortion, missed abortion, or blighted ovum <22+0 gestational weeks, and the prevalence was 3.52% (59 cases). The time-dependent effect of maternal serum concentrations of soluble Fms-like kinase 1 and placental growth factor on subsequent late first-trimester or second-trimester spontaneous abortion (n = 59) was evaluated using a Cox proportional hazards regression model, adjusting for body mass index, parity, season of blood sampling, and age. Furthermore, receiver operating characteristics were employed to identify predictive values and optimal cut-off values.

RESULTS

In the adjusted Cox regression analysis, increasing continuous concentrations of both soluble Fms-like kinase 1 and placental growth factor were significantly associated with a decreased hazard ratio for spontaneous abortion: soluble Fms-like kinase 1, 0.996 (95% confidence interval, 0.995-0.997), and placental growth factor, 0.89 (95% confidence interval, 0.86-0.93). When analyzed by receiver operating characteristic cut-offs, women with soluble Fms-like kinase 1 <742 pg/mL had an odds ratio for spontaneous abortion of 12.1 (95% confidence interval, 6.64-22.2), positive predictive value of 11.70%, negative predictive value of 98.90%, positive likelihood ratio of 3.64 (3.07-4.32), and negative likelihood ratio of 0.30 (0.19-0.48). For placental growth factor <19.7 pg/mL, odds ratio was 13.2 (7.09-24.4), positive predictive value was 11.80%, negative predictive value was 99.0%, positive likelihood ratio was 3.68 (3.12-4.34), and negative likelihood ratio was 0.28 (0.17-0.45). In the sensitivity analysis of 54 spontaneous abortions matched 1:4 to controls on gestational age at blood sampling, the highest area under the curve was seen for soluble Fms-like kinase 1 in prediction of first-trimester spontaneous abortion, 0.898 (0.834-0.962), and at the optimum cut-off of 725 pg/mL, negative predictive value was 51.4%, positive predictive value was 94.6%, positive likelihood ratio was 4.04 (2.57-6.35), and negative likelihood ratio was 0.22 (0.09-0.54).

CONCLUSION

A strong, novel prospective association was identified between lower concentrations of soluble Fms-like kinase 1 and placental growth factor measured in early pregnancy and spontaneous abortion. A soluble Fms-like kinase 1 cut-off <742 pg/mL in maternal serum was optimal to stratify women at high vs low risk of spontaneous abortion. The cause and effect of angiogenic factor alterations in spontaneous abortions remain to be elucidated.

Vitamin D insufficiency is associated with increased risk of first-trimester miscarriage in the Odense Child Cohort

BACKGROUND

Miscarriage is the most common negative outcome of pregnancy, and identification of modifiable risk factors is potentially of great importance for public health. Low vitamin D concentrations in pregnancy are widespread worldwide, and vitamin D deficiency is implicated in immune cell regulation at the feto-maternal interface and several diseases of pregnancy.

OBJECTIVE

We investigated whether 25-hydroxyvitamin D serum concentration was a modifiable risk factor for early miscarriage.

DESIGN

In a prospective cohort study of 1683 pregnant women donating serum before gestational week 22, we investigated the association between maternal serum concentrations of serum 25-hydroxyvitamin D [25(OH)D] and the risk of subsequent miscarriage (n = 58).

RESULTS

The adjusted hazard of first-trimester miscarriage was lower with higher 25(OH)D concentrations (HR: 0.98; 95% CI: 0.96, 0.99). Concentrations of 25(OH)D <50 nmol/L were associated with a >2-fold increased adjusted HR for miscarriage (HR: 2.50; 95% CI: 1.10, 5.69). Concentrations of 25(OH)D were not associated with an increased risk of second-trimester miscarriage.

CONCLUSIONS

We found an association between 25(OH)D and first-trimester miscarriages, suggesting vitamin D as a modifiable risk factor for miscarriage. To test this hypothesis, randomized controlled trials should investigate the possible effect of vitamin D supplementation to increase 25(OH)D concentrations in early pregnancy, or before conception, to decrease risk of miscarriage. This trial was registered at clinicaltrials.gov as NCT02434900.

[Epidemiology of loss pregnancy]

OBJECTIVES

Study of epidemiology of pregnancy loss.

MATERIALS AND METHOD

A systematic review of the literature was performed using Pubmed and the Cochrane library databases and the guidelines from main international societies.

RESULTS

The occurrence of first trimester miscarriage is 12% of pregnancies and 25% of women. Miscarriage risk factors are ages of woman and man, body mass index greater than or equal to 25kg/m(2), excessive coffee drinking, smoking and alcohol consumption, exposure to magnetic fields and ionizing radiation, history of abortion, some fertility disorders and impaired ovarian reserve. Late miscarriage (LM) complicates less than 1% of pregnancies. Identified risk factors are maternal age, low level of education, living alone, history of previous miscarriage, of premature delivery and of previous termination of pregnancy, any uterine malformation, trachelectomy, existing bacterial vaginosis, amniocentesis, a shortened cervix and a dilated cervical os with prolapsed membranes. Fetal death in utero has a prevalence of 2% in the world and 5/1000 in France. Its main risk factors are detailed in the chapter.

Reproductive Outcome after Hysteroscopic Metroplasty in Patients with Infertility and Recurrent Pregnancy Loss

Introduction: Reproductive outcome can be negatively affected in patients with congenital uterine anomalies (CUA), increasing the number of unsuccessful pregnancies and obstetric complications. Compared with the population with normally formed uterus, patients with CUA have higher abortion rate, higher fetal loss rate and decreased live birth rate. Hysteroscopic metroplasty (HM) is a standard, safe and minimally invasive method for the treatment of correctible types of congenital uterine anomalies.Aim: The aim of the study was to analyze the reproductive outcome in group of patients with infertility and recurrent pregnancy loss and present CUA, before and after hysteroscopic metroplasty.Material and Methods: We analyzed 67 patients to whom 78 interventions hysteroscopic metroplasty were performed at the University Clinic of Obstetrics and Gynecology in Skopje during a two year period, between 01.01.2010 and 31.12.2011. Their reproductive outcome was monitored during a two-year period and the same group served as a control group, taking into account their previous reproductive history. Statistical analysis was performed using Chi-square test and p < 0.05 was considered to be statistically significant.Results: Most common CUA were types 5b and 6 represented by 88 %. In a follow up period of two years, 33 of the patients become pregnant. There was a statistically significant decrease of abortion rate from 92% to 21.2%, as well as an increase in the term delivery rate from 0% to 69.7%.Conclusion: Treatment with hysteroscopic metroplasty is significantly improving the reproductive outcome in patients with CUA and previous fetal loss.

No evidence for an increased risk of adverse pregnancy outcome after paternal low-dose methotrexate: an observational cohort study

OBJECTIVE

There is increasing awareness of the potential impact of paternal exposures on pregnancy outcome. In particular this applies to MTX, which is used in low doses for the treatment of RA and other inflammatory diseases. MTX is associated with a specific pattern of malformations in fetuses of exposed women, but there is uncertainty concerning the risk of paternal low-dose MTX. The aim of this study was to investigate whether paternal low-dose MTX therapy around conception has an unfavourable effect on pregnancy outcome.

METHODS

We performed a prospective observational cohort study involving pregnancies fathered by men who were treated with low-dose MTX around conception. Pregnancies were identified through our Teratology Information Service. Pregnancy outcomes were compared with a cohort neither exposed to MTX nor to other teratogens. Outcomes evaluated were major birth defects, spontaneous abortion (SAB), elective termination of pregnancy, gestational age at delivery, and birth weight.

RESULTS

A total of 113 pregnancies with paternal low-dose MTX treatment were compared with 412 non-exposed pregnancies. Neither the rate of major birth defects [odds ratio (OR) 1.02, 95% CI 0.05, 7.0) nor the risk of SAB (hazard ratio 1.19, 95% CI 0.65, 2.17) was increased. Gestational age at delivery and birth weights did not differ significantly between groups. The rate of electively terminated pregnancies was increased in the MTX-exposed patients compared with controls.

CONCLUSION

Our study does not confirm an increased risk of adverse pregnancy outcome after paternal low-dose MTX therapy. The reassuring findings do not support the necessity of a 3-month MTX-free interval until conception. In the case of unavoidable paternal MTX therapy, it seems reasonable not to postpone family planning.

Evaluating the hazard of foetal death following H1N1 influenza vaccination; a population based cohort study in the UK GPRD

Background

To evaluate the risk of foetal loss associated with pandemic influenza vaccination in pregnancy. Retrospective cohort study. UK General Practice Research Database Pregnancies ending in delivery or spontaneous foetal death after 21 October 2009 and starting before 01 January 2010.

Methodology/Principal Findings

Hazard ratios of foetal death for vaccinated compared to unvaccinated pregnancies were estimated for gestational weeks 9 to 12, 13 to 24 and 25 to 43 using discrete-time survival analysis. Separate models were specified to evaluate whether the potential effect of vaccination on foetal loss might be transient (for ∼4 weeks post vaccination only) or more permanent (for the duration of the pregnancy). 39,863 pregnancies meeting our inclusion criteria contributed a total of 969,322 gestational weeks during the study period. 9,445 of the women were vaccinated before or during pregnancy. When the potential effect of vaccination was assumed to be transient, the hazard of foetal death during gestational weeks 9 through 12 (HR_unadj 0.56; CI₉₅ 0.43 to 0.73) and 13 through 24 (HR_unadj 0.45; CI₉₅ 0.28 to 0.73) was lower in the 4 weeks after vaccination than in other weeks. Where the more permanent exposure definition was specified, vaccinated pregnancies also had a lower hazard of foetal loss than unvaccinated pregnancies in gestational weeks 9 through 12 (HR_unadj 0.74; CI₉₅ 0.62 to 0.88) and 13 through 24 (HR_unadj 0.59; CI₉₅ 0.45 to 0.77). There was no difference in the hazard of foetal loss during weeks 25 to 43 in either model. Sensitivity analyses suggest the strong protective associations observed may be due in part to unmeasured confounding.

Conclusions/Significance

Influenza vaccination during pregnancy does not appear to increase the risk of foetal death. This study therefore supports the continued recommendation of influenza vaccination of pregnant women.

Association between different morphological types and abnormal karyotypes in early pregnancy loss

OBJECTIVES

To identify the abnormal transvaginal ultrasound (TVS) findings typical of aneuploidic pregnancies that end with early pregnancy loss (EPL).

METHODS

This was a prospective clinical trial over a 2½-year period from January 2004 to June 2006 at the University Hospital of Cagliari, Italy. One hundred and fifty-six singleton pregnancies with EPL were evaluated by TVS, both before and at the moment of EPL diagnosis. Fetal karyotyping was performed on products of conception using microsatellite analysis to exclude maternal contamination in 46,XX cases. The proportions of abnormal karyotypes were compared among different groups of EPLs characterized by different morphological features.

RESULTS

Six morphological types were identified in EPLs, one normal and five abnormal (small gestational sac, small embryo/fetus, early symmetrical arrested growth, enlarged yolk sac and empty sac). The highest rate of chromosomal abnormalities was observed in the early symmetrical arrested growth group (100%), followed by small embryo/fetus (94.1%), enlarged yolk sac (93.3%) and empty sac (72.2%) groups. The majority of cases of trisomy 22 (92.3%) were in the enlarged yolk sac group and the majority of cases with a 45,X karyotype were in the small embryo/fetus group (77.8%).

CONCLUSIONS

There is an association in EPLs between some abnormal karyotypes and some morphological types. The demonstration by TVS of abnormalities in the development of early pregnancy structures could be helpful for predicting aneuploidy in EPLs.

Fetal loss rate after chorionic villus sampling and amniocentesis: an 11-year national registry study

OBJECTIVE

To assess the fetal loss rate following amniocentesis and chorionic villus sampling (CVS).

METHODS

This was a national registry-based cohort study, including all singleton pregnant women who had an amniocentesis (n = 32 852) or CVS (n = 31 355) in Denmark between 1996 and 2006. Personal registration numbers of women having had an amniocentesis or a CVS were retrieved from the Danish Central Cytogenetic Registry, and cross-linked with the National Registry of Patients to determine the outcome of each pregnancy. Postprocedural fetal loss rate was defined as miscarriage or intrauterine demise before 24 weeks of gestation.

RESULTS

The miscarriage rates were 1.4% (95% CI, 1.3-1.5) after amniocentesis and 1.9% (95% CI, 1.7-2.0) after CVS. The postprocedural loss rate for both procedures did not change during the 11-year study period, and was not correlated with maternal age. The number of procedures a department performed had a significant effect on the risk of miscarriage. In departments performing fewer than 500 amniocenteses, the odds ratio for fetal loss was 2.2 (95% CI, 1.6-3.1) when compared to departments performing more than 1500 procedures during the 11-year period. For CVS the risk of miscarriage was 40% greater in departments performing 500-1000 and 1001-1500 as compared to those performing more than 1500 procedures.

CONCLUSIONS

The miscarriage rates (i.e. spontaneous loss and procedure-related loss) after amniocentesis and CVS were 1.4% and 1.9%, respectively. This difference may be explained by the difference in gestational age at the time of the procedures. The miscarriage rate was inversely correlated with the number of procedures performed in a department.

Bilineal inheritance of type 1 autosomal dominant polycystic kidney disease (ADPKD) and recurrent fetal loss

We report for the first time a family with type 1 ADPKD in which the marriage between affected non-consanguinous individuals resulted in two live-born heterozygous offspring and two fetuses lost in mid-pregnancy. Given a 25% chance for mutant compound heterozygosity in the offspring of this family, our findings suggest that compound heterozygosity of PKD1 mutations in humans may be embryonically lethal.

Miscarriage after a normal scan at 12-14 gestational weeks in women at low risk of carrying a fetus with chromosomal anomaly according to nuchal translucency screening

OBJECTIVES

To estimate the risk of second-trimester miscarriage in women with low risk of carrying a fetus with chromosomal abnormality, according to nuchal translucency (NT) screening, and to determine whether NT thickness or other factors affect the risk.

METHODS

The study population comprised 14 278 singleton pregnancies with a risk of Down syndrome < 1:250 at NT scan, and where no fetal karyotyping was performed < 25 weeks. Risk factors for miscarriage were investigated by logistic regression.

RESULTS

The median risk of Down syndrome was 1 : 3138 (range 1 : 9651-1 : 251) and median NT was 1.7 (range 0.4-3.0) mm. The miscarriage rate was 0.5% (77/14 278; 95% CI 0.4-0.6). After having controlled for maternal age, we found the number of previous deliveries and miscarriages to independently predict miscarriage: odds ratio (OR) for each previous delivery 1.48, 95% CI 1.22-1.94, P < 0.0001; OR for each previous miscarriage 1.34, 95% CI 1.07-1.68, P = 0.01. Excluding women with any previous miscarriage and adjusting for parity, we found a U-shaped relationship between maternal age and miscarriage (P = 0.04).

CONCLUSION

In singleton pregnancies with estimated risk of Down syndrome < 1:250 according to NT screening at 12-14 weeks, the spontaneous fetal loss rate before 25 weeks is likely to be around 0.5%. NT thickness up to 3 mm does not seem to affect the risk of miscarriage in such pregnancies. Instead, the risk seems to increase with number of previous miscarriages and deliveries, and possibly the risk is highest in the youngest and oldest women.

Miscarriage risk from amniocentesis performed for abnormal maternal serum screening

OBJECTIVE

The purpose of this study was to evaluate miscarriage after mid-trimester amniocentesis for abnormal maternal serum screening.

STUDY DESIGN

An analysis of summary data from the California State maternal serum screening program on 32,050 women with an abnormal serum screen, a singleton fetus, and normal ultrasound was performed. Miscarriage before 24 weeks, days until miscarriage, gestational age at miscarriage, and maternal factors were compared. The power of this study could detect a 50% increase in miscarriage.

RESULTS

The miscarriage rate with amniocentesis, 0.46% (69/15,005), was no different than without, 0.53% (90/17,045), P = .38. There was no difference in maternal age, serum biochemical factors, gestational age at miscarriage (21.1 weeks for both groups), or days until miscarriage (23 after amniocentesis and 20.4 without). Log-rank test revealed no difference for gestational age at miscarriage (P = .61) or number of days until miscarriage (P = .40).

CONCLUSION

The rate and timing of miscarriage was similar with or without amniocentesis in California women with abnormal maternal serum screening.

Age-specific risk of fetal loss post second trimester amniocentesis: analysis of 5043 cases

OBJECTIVES

To assess the risk of fetal loss attributable to second trimester amniocentesis in singleton pregnancies through a cross-sectional study.

METHODS

Records of 5043 consecutive second trimester amniocentesis, performed by a single operator between 1997 and 2003, were analyzed. Fetal loss post amniocentesis was calculated by grouping pregnant women in age classes and assessing observed/expected (O/E) rate.

RESULTS

Total fetal losses were 40 (0.81%): 33 cases (0.67%) occurred before the 24th week, 37 cases (0.76%) before the 28th gestational week, and 3 cases (0.06%) after the 28th week of pregnancy. An age-dependent increase of the rate of fetal loss, not statistically significant (Chi-Square = 0.349, p = 0.505) was observed. The total O/E ratio values did not show any statistically significant risk (O/E ratio = 1.25, CI = 0.86-1.64). The analysis of the single age classes did not detect any statistical significance. The excess fetal loss rate associated with amniocentesis was 0.16%.

CONCLUSIONS

No effect of the 2nd trimester amniocentesis was noted on fetal loss.

Factores de riesgo asociados a los tumores neonatales. Experiencia de una unidad de salud medioambiental pediátrica (PEHSU-Valencia)

BACKGROUND

Neonatal tumors (NT) result from a variable combination of constitutional and environmental determinants. Multiple risk factors (RF) are involved in their development, although most are unknown.

OBJECTIVE

To document the constitutional, environmental, preconceptional and transplacental RF associated with the development of NT with greater or lesser scientific evidence.

PATIENTS AND METHODS

We investigated known RF in NT diagnosed at La Fe University Children's Hospital from January 1990 to December 1999, using a questionnaire completed by parents in a personal interview, either at the Pediatric Environmental Health Specialty Unit (PEHSU-Valencia) or at their home. RF associated with NT and childhood cancer were identified through a literature review of the last 25 years through Medline, Cancerlit, Science Citation Index, and Embase.

RESULTS

The questionnaire was completed in 59 of 74 NT diagnosed during the period studied. All patients were Caucasians born in Spain. Constitutional-genetic factors were identified in 13.6 %: dominant hereditary syndromes in 5 (familial retinoblastoma in 1 and tuberous sclerosis in 4), and non-hereditary chromosomal syndromes in 3 (trisomy 21). Notable environmental factors were: a) ionizing radiation: preconceptional exposure in 32.2 % and in utero exposure in 6.8 %; b) non-ionizing radiation; 54.2 % reported preconceptional exposure and in utero exposure at home; c) pregnancy-related problems: infections in 13.6 % (8 patients) and a prior history of miscarriage in 20.3 %; d) drugs/chemicals administered during pregnancy: capillary dye in 42.4 %, daily facial make-up in 45.8 %, antacids in 30.5 %, acetaminophen in 34 %, hormone therapy in 10 %, cocaine and marijuana consumption in 11.7 %; e) tobacco: exposure to active smoking in 93.2 % of patients; f) alcohol: in utero exposure in 6.8 %; g) occupational exposure in parents: paternal in 49 % of cases (hydrocarbons in 15, metal in 3, chemical in 2, timber in 2, and agriculture in 7). Four were exposed to pesticides, 3 to solvents, and 3 to paints; and maternal in 12 cases (20 %): low frequency non-ionizing radiation in 6 (textile in 5, and railway in 1), 5 in the service sector (2 hairdressers, 3 cleaners), and 1 the in chemical industry. In another 6 there was exposure to solvents and paints (footwear industry).

CONCLUSIONS

The hypotheses formulated in this observational study, which should be analyzed in future case-control and cohort studies, are: a) to scientifically document genetic-constitutional RF in the etiopathogenesis of NT; b) to determine the frequency and etiology of prior miscarriage and its possible association with NT; c) to determine the importance of active smoking before and during pregnancy as a RF for NT; d) to establish the importance of parental occupational exposure in the etiopathogenesis of NT; and e) to define more precisely the role of other physical and chemical RF in the development of NT. To determine and record the RF involved in the etiopathogenesis of NT, the environmental history should be documented in pediatric cancers. The identification of RF is one of the main objectives of Pediatric Environmental Health Specialty Units.

Famine, social disruption, and involuntary fetal loss: evidence from Chinese survey data

Relying on half a million pregnancy histories collected from Chinese women in the late 1980s, we studied nearly a quarter century of self-reported miscarriages and stillbirths in China. Our results suggest that these two forms of involuntary fetal loss are affected not only by biological and demographic factors, such as the mother's age, pregnancy order, and pregnancy history, but also by the mother's social characteristics and the larger social environment. In this article, we focus on how two social and economic crises--the Great Leap Forward famine and the Cultural Revolution--resulted in elevated risks of miscarriage and stillbirth in the Chinese population.

Age-specific risk of fetal loss observed in a second trimester serum screening population

OBJECTIVE

The purpose of this study was to investigate age-specific spontaneous fetal loss rates of pregnancies without known chromosomal or structural abnormalities from mid-second trimester onward.

STUDY DESIGN

The study consisted of 264,653 women screened between October 1995 and September 2000 with available pregnancy outcomes. Pregnancies associated with fetal chromosomal or structural abnormalities, insulin dependent diabetes mellitus, and multiple pregnancies were excluded. Spontaneous fetal losses at or after 15 weeks of gestation were identified. Women were grouped according to maternal age at expected date of delivery. Spontaneous fetal loss rates in each group were evaluated after adjusting fetal losses associated with amniocentesis and identifiable ethnic groups.

RESULTS

Fetal loss rates increased in both younger and older women. The lowest rate was seen in women at mid-20s. Compared with Caucasian and Asian women, black women had higher fetal loss rate at nearly every age group.

CONCLUSION

The results of the study provided a baseline age-specific spontaneous fetal loss rate of pregnancies at a specified gestational window.

Chorionic villus sampling and amniocentesis: what are the risks in current practice?

PURPOSE OF REVIEW

Public demand for genetic counselling and prenatal diagnosis has increased during the past decade. As invasive diagnostic methods, such as chorionic villus sampling and amniocentesis, still have an important role to play in evaluating the fetus, one of the most important questions to address during genetic counselling is the procedure-related risk of these techniques.

RECENT FINDINGS

The possible factors modifying the specific risk of the actual fetus are discussed, together with factors that have an impact on procedure-related fetal loss and other complications. Risk factors regarding twin pregnancies, first and second-trimester chorionic villus sampling, early and mid-trimester amniocentesis are discussed separately. New developments have recently occurred in the laboratory techniques used in prenatal diagnosis. Their impact on genetic counselling and the employment of invasive techniques are also addressed.

SUMMARY

During genetic counselling, an individually tailored risk assessment needs to be established before any invasive procedure. This should take into account all the factors modifying the specific risk for aneuploidy or other disorders of the fetus, as well as the actual procedure-related risks.

Early second trimester (13 to 20 weeks) transabdominal chorionic villus sampling (TA-CVS): a safe and alternative method for both high and low risk populations

OBJECTIVE

To assess feasibility, effectiveness and risk of prenatal diagnosis by TA-CVS at 13-14 and 15-20 weeks' gestation.

METHODS

CVS was performed transabdominally by free-hand single needle insertion technique under continuous ultrasound visualization on 1844 pregnant women, aged 18 to 48, at 13 to 20 weeks' gestation, whose primary indication was chromosomal anomalies and single gene defects in 85% and 15% of cases, respectively Clinical follow-up of women undergoing TA-CVS at 13 to 20 weeks' was prospectively obtained; the population was split in two groups of 13-14 (series B) and 15-20 weeks' (series C) gestation. Statistical evaluation included a group of TA-CVS cases performed at 11-12 weeks (series A).

RESULTS

Sampling was feasible in 98.2%, 99.1% and 95.8% of cases of series A, B and C, respectively. Sampling was successful in all cases of the three series and a second insertion was required in 1.5%, 1.3% and 0.9%, respectively. A trend towards lower fetal loss rate is apparent (1.02%, 0.86%, and 0.46 in series A, B, and C, respectively), although differences were not statistically significant. No post-procedural complications were reported for series B and C, while spotting was present in 1.8% of cases for series A. Karyotyping was totally successful by short term culture and was also available by long term culture in 99% of cases for series A, B and C when the amount of chorionic tissue was more than 15 mg.

CONCLUSION

TA-CVS appears highly effective and safe and might be offered as a valuable alternative to early as well as mid-trimester amniocentesis.

Chorionic villus sampling: a 15-year experience

The authors describe experiences gained over the period of 1984-1999 at two medical centers with chorionic villus sampling (CVS). Altogether 1,149 CVSs had been performed between the 10th and 32nd gestational weeks. Prior to 1993 the transcervical approach (TC-CVS), after 1994 the transabdominal method (TA-CVS) was used. Analysis of data collected within the framework of this study was based on the following factors: indications for sampling, complications and incidence of pregnancy loss. 91.6% of the CVSs were carried out for the purposes of cytogenetic examination of the fetus. Over the past few years an increasing number of procedures had been carried out for molecular-genetic tests (7.6% of the total number of cases). Though the primary indication for cytogenetic tests was the advanced age of the mother, a remarkable increase in the number of samplings had taken place for the purpose of examining "suspicious ultrasound findings", minor anomalies detected by ultrasound. In this group the proportion of pathological cases was significantly higher (14%) than in all the other samplings, carried out for other indications. This data in itself underlines the importance of ultrasound screening performed in the 18-20th weeks of gestation. Over the first half of the period being reviewed (1984-1993, TC-CVS), a fetal loss of 4.8% occurring within 3 weeks from the date of sampling, dropped to 1.7% in the period subsequent to year 1994 (TA-CVS). In cases of TA-CSV, both the complications and spontaneous abortions were fewer. In 74.1% of the cases studied, birth had taken place after the 37th week of gestation. Premature births (6.4%) and stillbirth rate (1.1%) did not exceed normal rates observed in the general population. On the basis of our results, it is safe to say that in prenatal diagnosis, TA-CVS is a real alternative method of mid-trimester amniocentesis and it is recommended for use at any stage of the pregnancy.

Recurrent fetal loss associated with bilineal inheritance of type 1 autosomal dominant polycystic kidney disease

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is a common Mendelian disorder that affects approximately 1 in 500 to 1,000 live births. Mutations in one of two genes, PKD1 and PKD2, account for the disease in most ADPKD families. Despite the relative high frequency of PKD1 mutant alleles, compound heterozygotes or diseased homozygotes have not been described.

METHODS AND RESULTS

We report a family with type 1 ADPKD in which the marriage between affected first-degree cousins resulted in two live-born heterozygous offspring and two fetuses lost in late pregnancy. Genetic analysis with PKD1 and PKD2 flanking markers showed that this family is PKD1 linked (z(max) = 1.66 and -2.54 at thetas = 0.0 for intragenic markers for PKD1 [ie, KG8] and PKD2 [ie, SPP1], respectively).

CONCLUSION

Given a 25% chance for mutant homozygosity in the offspring of this family, our findings suggest that homozygosity of PKD1 mutations in humans is embryonically lethal, as recently documented in Pkd1 knockout mice.