Congenital anomalies in offspring of subfertile couples: a registry-based study in the northern Netherlands

New horizons in human sperm selection for assisted reproduction

Male infertility is a commonly encountered pathology that is estimated to be a contributory factor in approximately 50% of couples seeking recourse to assisted reproductive technologies. Upon clinical presentation, such males are commonly subjected to conventional diagnostic andrological practices that rely on descriptive criteria to define their fertility based on the number of morphologically normal, motile spermatozoa encountered within their ejaculate. Despite the virtual ubiquitous adoption of such diagnostic practices, they are not without their limitations and accordingly, there is now increasing awareness of the importance of assessing sperm quality in order to more accurately predict a male's fertility status. This realization raises the important question of which characteristics signify a high-quality, fertilization competent sperm cell. In this review, we reflect on recent advances in our mechanistic understanding of sperm biology and function, which are contributing to a growing armory of innovative approaches to diagnose and treat male infertility. In particular we review progress toward the implementation of precision medicine; the robust clinical adoption of which in the setting of fertility, currently lags well behind that of other fields of medicine. Despite this, research shows that the application of advanced technology platforms such as whole exome sequencing and proteomic analyses hold considerable promise in optimizing outcomes for the management of male infertility by uncovering and expanding our inventory of candidate infertility biomarkers, as well as those associated with recurrent pregnancy loss. Similarly, the development of advanced imaging technologies in tandem with machine learning artificial intelligence are poised to disrupt the fertility care paradigm by advancing our understanding of the molecular and biological causes of infertility to provide novel avenues for future diagnostics and treatments.

Risk of birth defects in children conceived with assisted reproductive technology: A meta-analysis

BACKGROUND

Although assisted reproductive technology (ART) is extensively used in couples with fertility problems, the risk of birth defects among infants conceived with ART is still a concern. Therefore, to more accurately assess the risk of birth defects after ART treatment, we performed a meta-analysis of all available cohort studies relating to birth defects among infants conceived with ART.

METHODS

We used an established strategy to search the databases of PUBMED, EMBASE, COCHRANE, WEB OF SCIENCE, CNKI, CBM and VIP for studies published between 2008 and 2020. Subgroup analyses and sensitivity analyses were used to examine sources of heterogeneity. Pooled adjusted odds ratios (ORs) were calculated using a fixed effects model. RevMan5.3 was used to draw a forest plot, and Stata14.0 was used to test for publication bias.

RESULTS

We included 14 cohort studies from different countries. The infants conceived with ART had a 1.22-fold higher likelihood of birth defects than children born after natural pregnancy(OR = 1.22, 95% CI [1.17, 1.28], P < .05). The prevalence of birth defects after ART treatment was higher in singleton births than in multiple births. In a meta-analysis of data from 6 studies, we found associations between ART and birth defects related to specifics organs: cardiovascular defects, OR = 1.51, 95% CI [1.34-1.69], P < .05; musculoskeletal defects, OR = 1.09, 95% CI [1.03-1.15], P < .05; urogenital defects, OR = 1.24, 95% CI [1.11-1.38], P < .05; central nervous system defects, OR = 1.33, 95% CI [1.14-1.55], P < .05; and orofacial defects, OR = 1.45, 95% CI [1.15-1.83], P < .05.

CONCLUSIONS

ART treatment does present an increased risk of birth defects. The prevalence of birth defects after ART treatment is lower in multiple births than in singleton births. Further research is required to examine the risks for birth defects after ART treatment.

The longer-term effects of IVF on offspring from childhood to adolescence

It is well established that there are increased pregnancy-related complications for a woman who conceives through assisted reproductive treatment (ART). Furthermore, it is known that the risk to the child born is greater, believed to be related to prematurity and growth restriction. Studies have also reported epigenetic changes in the DNA of offspring conceived through ART. In addition, it is believed that they have a greater risk of congenital malformations, although some of these risks may relate to underlying infertility, rather than the ART treatment per se. As a result, it may be expected that there is a greater risk to the longer-term health of the child who is born from ART; however, evidence about the long-term health of children conceived through ART is reassuring. Even though, it is recognised that many of the studies in this field come with limitations. Low numbers of participants is one of the major limitations, which makes subgroup analyses for diverse types of ART, or diverse types of infertility, not feasible. Furthermore, studies are often limited by short follow-up periods because of the difficulty and costs involved in longitudinal study designs. In addition, the rapid changes over time in ART limit the generalisability and significance of long-term findings. Well-designed studies investigating the long-term health outcomes of ART-conceived offspring and the potential influences of various aspects of the ART procedure, as well as studies of the potential underlying epigenetic mechanisms, are imperative. Furthermore, conclusions from childhood hospitalisation data from the United Kingdom, the long-term follow-up and quality of life study from researchers in Melbourne, and the data published from the Western Australian Growing Up Healthy Study will go a long way to help reassure current and prospective parents who may require ART to conceive.

Prognosis of Congenital Anomalies in Conceptions Following In Vitro Fertilization: A Multicenter Retrospective Cohort Study in China

BACKGROUND

Conceptions following in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) have an increased risk of congenital anomalies. Few studies have explored the prognosis of fetuses with congenital anomalies. This study aimed to investigate the prevalence and prognosis of congenital anomalies in IVF/ICSI pregnancies, and to analyze the influencing factors contributing to poor prognosis.

METHODS

In this multicenter retrospective cohort study, we followed 405,473 embryo transfer cycles at 15 reproductive centers between January 2010 and December 2019 and enrolled 2,006 intrauterine pregnancies with congenital anomalies. The relatively positive prognosis group with one or more live births and neonatal survival for more than 7 days was compared with the poor prognosis group with poorer outcomes.

RESULTS

Among the 168,270 ongoing intrauterine pregnancy cycles, the prevalence of congenital anomalies was 1.19%, wherein the malformation rates of cycles with late abortion and delivery were 2.37% (716/30,202) and 0.93% (1,290/138,068), respectively. Among all IVF/ICSI cycles with congenital anomalies, the relatively positive prognosis rate was 61.39%. Moreover, the fertilization failure rate (2 pro-nuclei rate < 25%) in the poor prognosis group was significantly higher than that in the relatively positive prognosis group (10.89% vs. 5.09%, p < 0.001). Multivariate logistic regression analysis revealed no significant differences in the relatively positive prognosis rate among the various IVF/ICSI protocols. The relatively positive prognosis rate of fertilization failure cycles was 0.180 times that of normal fertilization cycles.

CONCLUSION

Poor fertilization rates during IVF/ICSI treatments are more likely to have poor prognosis in fetuses or neonates with congenital anomalies, and obstetric management should be strengthened in pregnant women, with which pregnant women should be recommended to strengthen obstetric management.

The Risk of Congenital Anomalies by Fertility Treatment Modality

Importance

Up to 4% of all births in developed nations involve assisted reproductive technology (ART), along with other fertility treatment modalities. Thus, ART pregnancies constitute an important epidemiologic population with a known increased risk of congenital anomalies. In this review, we summarize current fertility treatment modalities and their associated risk of congenital anomalies.

Objective

To review the risk of birth defects among pregnancies conceived with ART and other fertility treatments.

Evidence Acquisition

Articles were obtained from PubMed and the American College of Obstetricians and Gynecologists and American Society of Reproductive Medicine committee opinions.

Results

In vitro fertilization has been associated with a 25% to 50% increased risk of birth defects, including abnormalities of these organ systems: cardiovascular (25%-40% of anomalies), genitourinary (10%-60%), gastrointestinal (10%-20%), and musculoskeletal (10%-35%). Although the data are mixed, intracytoplasmic sperm injection has also been found to be associated with an increased risk of defects, particularly hypospadias, when compared with conventional in vitro fertilization. The risk among fresh versus frozen cycles and cleavage stage versus blastocyst transfers remains uncertain. There appears to be no significant added risk with preimplantation genetic testing, although more studies are needed. Ovulation induction with oral agents appears safe and not associated with an increased risk of anomalies. Oocyte cryopreservation also appears safe, but the data are still limited, requiring future investigation.

Conclusions and Relevance

While the relative risk of birth defects among ART pregnancies is increased when compared with spontaneous conceptions, the absolute risk remains low. There are no standard screening recommendations for ART pregnancies. Per the American College of Obstetricians and Gynecologists, patients who have undergone ART should be counseled regarding the risk of birth defects and available antenatal evaluation, including fetal echocardiogram and detailed ultrasound evaluation.

The association between in vitro fertilization and intracytoplasmic sperm injection treatment and the risk of congenital heart defects

OBJECTIVE

Assisted reproductive technology (ART), an effective treatment modality for infertility, is associated with a higher prevalence of congenital anomalies such as congenital heart defects (CHDs). The present study aimed to evaluate data linking CHDs in infants to pregnancies resulting from in vitro fertilization (IVF) and/or intracytoplasmic sperm injection (ICSI).

METHODS

In this study, we conducted a systematic literature search on CHDs in infants following IVF/ICSI in Google Scholar, Embase, Scopus, MEDLINE, and PubMed databases from inception to February 2020. The search strategy used combinations of search keywords that included assisted reproductive technology/ART, in vitro fertilization/IVF, intracytoplasmic sperm injection/ICSI, birth defect, congenital malformation, and congenital heart defects.

RESULTS

Fifty-six studies fulfilled the inclusion criteria and were selected in the current systematic review, which assessed the association between ART and the risk of CHDs.

CONCLUSION

Children conceived by IVF/ICSI manifested an increased risk of CHDs compared with spontaneously conceived children. Further studies are needed to assess the long-term cardiovascular safety of these techniques, which is important for the counseling of patients before the use of ART.

Assisted reproductive technologies and the risk of congenital urogenital tract malformations: A systematic review and meta-analysis

A systematic review was conducted to evaluate the relationship between ART and the risk of urogenital tract malformations, especially hypospadias and cryptorchidism. Thirty-three papers were selected. Meta-analysis showed that ART was correlated with an increased risk of urogenital tract malformation in offspring (odds ratio (OR) = 1.61, 95% confidence interval (CI): 1.41-1.85), hypospadias (OR = 1.87, 95% CI: 1.47-2.40) and cryptorchidism (OR = 1.83, 95% CI: 1.54-2.18). Among offspring conceived by ART, multiple pregnancies appeared to result in a higher risk of urogenital tract malformation than singleton pregnancies (OR = 1.42, 95% CI: 0.99-2.04; P = 0.058). No significant difference in the risk of urogenital tract malformation was found between in vitro fertilization and intracytoplasmic sperm injection technologies. A sensitivity analysis showed that the above conclusions were relatively consistent. Conclusion: ART is correlated with an increased risk of urogenital tract malformations in offspring, especially hypospadias and cryptorchidism. Among ART offspring, multiple pregnancies may lead to a higher risk of urogenital tract malformations than singleton pregnancies, but more studies are needed for confirmation.

The risk of birth defects with conception by ART

STUDY QUESTION

What is the association between ART conception and treatment parameters and the risk of birth defects?

SUMMARY ANSWER

Compared to naturally conceived singleton infants, the risk of a major nonchromosomal defect among ART singletons conceived with autologous oocytes and fresh embryos without use of ICSI was increased by 18%, with increases of 42% and 30% for use of ICSI with and without male factor diagnosis, respectively.

WHAT IS KNOWN ALREADY

Prior studies have indicated that infertility and ART are associated with an increased risk of birth defects but have been limited by small sample size and inadequate statistical power, failure to differentiate results by plurality, differences in birth defect definitions and methods of ascertainment, lack of information on ART treatment parameters or study periods spanning decades resulting in a substantial historical bias as ART techniques have improved.

STUDY DESIGN, SIZE, DURATION

This was a population-based cohort study linking ART cycles reported to the Society for Assisted Reproductive Technology Clinic Outcome Reporting System (SART CORS) from 1 January 2004 to 31 December 2015 that resulted in live births from 1 September 2004 to 31 December 2016 in Massachusetts and North Carolina and from 1 September 2004 to 31 December 2015 for Texas and New York: these were large and ethnically diverse States, with birth defect registries utilizing the same case definitions and data collected, and with high numbers of ART births annually. A 10:1 sample of non-ART births were chosen within the same time period as the ART birth. Naturally conceived ART siblings were identified through the mother's information. Non-ART children were classified as being born to women who conceived with ovulation induction (OI)/IUI when there was an indication of infertility treatment on the birth certificate, but the woman did not link to the SART CORS; all others were classified as being naturally conceived.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The study population included 135 051 ART children (78 362 singletons and 56 689 twins), 23 647 naturally conceived ART siblings (22 301 singletons and 1346 twins) and 9396 children born to women treated with OI/IUI (6597 singletons and 2799 twins) and 1 067 922 naturally conceived children (1 037 757 singletons and 30 165 twins). All study children were linked to their respective State birth defect registries to identify major defects diagnosed within the first year of life. We classified children with major defects as either chromosomal (i.e. presence of a chromosomal defect with or without any other major defect) or nonchromosomal (i.e. presence of a major defect but having no chromosomal defect), or all major defects (chromosomal and nonchromosomal). Logistic regression models were used to generate adjusted odds ratios (AORs) and 95% CI to evaluate the risk of birth defects due to conception with ART (using autologous oocytes and fresh embryos), and with and without the use of ICSI in the absence or presence of male factor infertility, with naturally conceived children as the reference. Analyses within the ART group were stratified by combinations of oocyte source (autologous, donor) and embryo state (fresh, thawed), with births from autologous oocytes and fresh embryos as the reference. Analyses limited to fresh embryos were stratified by oocyte source (autologous, donor) and the use of ICSI. Triplets and higher-order multiples were excluded.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 21 998 singleton children (1.9%) and 3037 twin children (3.3%) had a major birth defect. Compared to naturally conceived children, ART singletons (conceived from autologous oocytes, fresh embryos without the use of ICSI) had increased risks of a major nonchromosomal birth defect (AOR 1.18, 95% 1.05, 1.32), cardiovascular defects (AOR 1.20, 95% CI 1.03, 1.40), and any birth defect (AOR 1.18, 95% CI 1.09, 1.27). Compared to naturally conceived children, ART singletons conceived (from autologous oocytes, fresh embryos) with the use of ICSI, the risks were increased for a major nonchromosomal birth defect (AOR 1.30, 95% CI 1.16, 1.45 without male factor diagnosis; AOR 1.42, 95% CI 1.28, 1.57 with male factor diagnosis); blastogenesis defects (AOR 1.49, 95% CI 1.08, 2.05 without male factor; AOR 1.56, 95% CI 1.17, 2.08 with male factor); cardiovascular defects (AOR 1.28, 95% CI 1.10,1.48 without male factor; AOR 1.45, 95% CI 1.27, 1.66 with male factor); in addition, the risk for musculoskeletal defects was increased (AOR 1.34, 95% CI 1.01, 1.78 without male factor) and the risk for genitourinary defects in male infants was increased (AOR 1.33, 95% CI 1.08, 1.65 with male factor). Comparisons within ART singleton births conceived from autologous oocytes and fresh embryos indicated that the use of ICSI was associated with increased risks of a major nonchromosomal birth defect (AOR 1.18, 95% CI 1.03, 1.35), blastogenesis defects (AOR 1.65, 95% CI 1.08, 2.51), gastrointestinal defects (AOR 2.21, 95% CI 1.28, 3.82) and any defect (AOR 1.11, 95% CI 1.01, 1.22). Compared to naturally conceived children, ART singleton siblings had increased risks of musculoskeletal defects (AOR 1.32, 95% CI 1.04, 1.67) and any defect (AOR 1.15, 95% CI 1.08, 1.23). ART twins (conceived with autologous oocytes, fresh embryos, without ICSI) were at increased risk of chromosomal defects (AOR 1.89, 95% CI 1.10, 3.24) and ART twin siblings were at increased risk of any defect (AOR 1.26, 95% CI 1.01, 1.57). The 18% increased risk of a major nonchromosomal birth defect in singleton infants conceived with ART without ICSI (∼36% of ART births), the 30% increased risk with ICSI without male factor (∼33% of ART births), and the 42% increased risk with ICSI and male factor (∼31% of ART births) translates into an estimated excess of 386 major birth defects among the 68 908 singleton children born by ART in 2017.

LIMITATIONS, REASONS FOR CAUTION

In the SART CORS database, it was not possible to differentiate method of embryo freezing (slow freezing vs vitrification), and data on ICSI was only available in the fresh embryo ART group. In the OI/IUI group, it was not possible to differentiate type of non-ART treatment utilized, and in both the ART and OI/IUI groups, data were unavailable on duration of infertility.

WIDER IMPLICATIONS OF THE FINDINGS

The use of ART is associated with increased risks of a major nonchromosomal birth defect, cardiovascular defect and any defect in singleton children, and chromosomal defects in twins; the use of ICSI further increases this risk, the most with male factor infertility. These findings support the judicious use of ICSI only when medically indicated. The relative contribution of ART treatment parameters versus the biology of the subfertile couple to this increased risk remains unclear and warrants further study.

STUDY FUNDING/COMPETING INTEREST(S)

This project was supported by grant R01 HD084377 from the National Institute of Child Health and Human Development. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute of Child Health and Human Development, or the National Institutes of Health, nor any of the State Departments of Health which contributed data. E.W. is a contract vendor for SART; all other authors report no conflicts.

TRIAL REGISTRATION NUMBER

N/A.

Long-term endocrine disorders in children born from pregnancies conceived following fertility treatments

BACKGROUND

Despite the endocrine basis of several infertility etiologies, data on long-term endocrine consequences in offspring conceived following fertility treatments remain limited.

AIM

To determine the risk of long-term endocrine disorders among children born after in-vitro fertilization (IVF) and ovulation induction (OI) as compared with spontaneous pregnancies.

STUDY DESIGN, SUBJECTS, AND OUTCOME MEASURES

A population-based cohort study including all singleton deliveries occurring between 1991 and 2014 at a single tertiary medical center was performed. Hospitalization rates up to the age of 18 years involving endocrine disorders were compared between children delivered following pregnancies achieved by IVF, OI, and spontaneous pregnancies. A Kaplan-Meier survival curve was used to compare cumulative morbidity incidence. A Cox regression model was used to control for confounders.

RESULTS

During the study period, 242,187 singleton deliveries met the inclusion criteria; 1.0% were following IVF (n = 2603), 0.7% following OI (n = 1721), and the remaining (n = 237,863) were following spontaneous conceptions. Hospitalizations up to the age of 18 years involving endocrine disorders were comparable in children delivered following IVF (0.4%), OI (0.8%) and spontaneous pregnancies (0.5%; p = 0.09). The Kaplan-Meier survival curve demonstrated comparable cumulative incidence of endocrine morbidity following IVF and OI (log-rank p = 0.30). Using the Cox regression model while controlling for confounders, no significant association was noted between IVF (adjusted HR = 0.95, CI 0.51-1.87), or OI (adjusted HR = 1.32, CI 0.78-2.24) conceived pregnancies, and long-term pediatric endocrine morbidity.

CONCLUSIONS

Singletons conceived via fertility treatment do not appear to be at an increased risk for long-term endocrine disorders.

Paternal impacts on development: identification of genomic regions vulnerable to oxidative DNA damage in human spermatozoa

STUDY QUESTION

Do all regions of the paternal genome within the gamete display equivalent vulnerability to oxidative DNA damage?

SUMMARY ANSWER

Oxidative DNA damage is not randomly distributed in mature human spermatozoa but is instead targeted, with particular chromosomes being especially vulnerable to oxidative stress.

WHAT IS KNOWN ALREADY

Oxidative DNA damage is frequently encountered in the spermatozoa of male infertility patients. Such lesions can influence the incidence of de novo mutations in children, yet it remains to be established whether all regions of the sperm genome display equivalent susceptibility to attack by reactive oxygen species.

STUDY DESIGN, SIZE, DURATION

Human spermatozoa obtained from normozoospermic males (n = 8) were split into equivalent samples and subjected to either hydrogen peroxide (H2O2) treatment or vehicle controls before extraction of oxidized DNA using a modified DNA immunoprecipitation (MoDIP) protocol. Specific regions of the genome susceptible to oxidative damage were identified by next-generation sequencing and validated in the spermatozoa of normozoospermic males (n = 18) and in patients undergoing infertility evaluation (n = 14).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Human spermatozoa were obtained from normozoospermic males and divided into two identical samples prior to being incubated with either H2O2 (5 mm, 1 h) to elicit oxidative stress or an equal volume of vehicle (untreated controls). Alternatively, spermatozoa were obtained from fertility patients assessed as having high basal levels of oxidative stress within their spermatozoa. All semen samples were subjected to MoDIP to selectively isolate oxidized DNA, prior to sequencing of the resultant DNA fragments using a next-generation whole-genomic sequencing platform. Bioinformatic analysis was then employed to identify genomic regions vulnerable to oxidative damage, several of which were selected for real-time quantitative PCR (qPCR) validation.

MAIN RESULTS AND THE ROLE OF CHANCE

Approximately 9000 genomic regions, 150–1000 bp in size, were identified as highly vulnerable to oxidative damage in human spermatozoa. Specific chromosomes showed differential susceptibility to damage, with chromosome 15 being particularly sensitive to oxidative attack while the sex chromosomes were protected. Susceptible regions generally lay outside protamine- and histone-packaged domains. Furthermore, we confirmed that these susceptible genomic sites experienced a dramatic (2–15-fold) increase in their burden of oxidative DNA damage in patients undergoing infertility evaluation compared to normal healthy donors.

LIMITATIONS, REASONS FOR CAUTION

The limited number of samples analysed in this study warrants external validation, as do the implications of our findings. Selection of male fertility patients was based on high basal levels of oxidative stress within their spermatozoa as opposed to specific sub-classes of male factor infertility.

WIDER IMPLICATIONS OF THE FINDINGS

The identification of genomic regions susceptible to oxidation in the male germ line will be of value in focusing future analyses into the mutational load carried by children in response to paternal factors such as age, the treatment of male infertility using ART and paternal exposure to environmental toxicants.

STUDY FUNDING/COMPETING INTEREST(S)

Project support was provided by the University of Newcastle’s (UoN) Priority Research Centre for Reproductive Science. M.J.X. was a recipient of a UoN International Postgraduate Research Scholarship. B.N. is the recipient of a National Health and Medical Research Council of Australia Senior Research Fellowship. Authors declare no conflict of interest.

Fertility treatments and the risk of pediatric obstructive sleep apnea in the offspring-Results from a population-based cohort study

OBJECTIVE

While the impact of fertility treatments on the perinatal outcome is well established, the long-term effects on offspring are yet to be determined. The current study aimed to investigate the risk of long-term obstructive sleep apnea (OSA) among children born following in vitro fertilization (IVF) and ovulation induction (OI) as compared with spontaneously conceived pregnancies.

STUDY DESIGN

A retrospective population-based cohort study was performed. Exposure was defined as delivery following pregnancies conceived by IVF or OI. Incidence of OSA related hospitalizations of the offspring, up to the age of 18 years, was evaluated. A Kaplan-Meier survival curve and multivariable Cox regression models were used to assess the association.

RESULTS

During the study period, 242 187 singleton deliveries met the inclusion criteria; 1.1% were conceived following IVF (n = 2603), and 0.7% following OI (n = 1721). Offspring hospitalization rates, involving OSA (n = 1607), were higher among children conceived following IVF and OI pregnancies as compared with the rate in children conceived spontaneously (1.4% vs 1.2% vs 0.7%, respectively; P < .001). The Kaplan-Meier survival curve demonstrated a significantly higher cumulative incidence of OSA related hospitalizations following IVF and OI (log-rank P < .001). Using multiple Cox regression models, controlled for gestational age, maternal age, maternal smoking, maternal obesity, birthweight, offspring gender and obesity, IVF as well as OI exhibited a significant and independent association with pediatric OSA in all models with adjusted hazard ratios of 2.25, (95% confidence interval [CI] = 1.6-3.1) and 1.63 (95% CI = 1.1-2.5), respectively.

CONCLUSION

Both IVF and OI treatments appear to be independently associated with OSA in the offspring.

The risk of birth defects is not associated with semen parameters or mode of conception in offspring of men visiting a reproductive health clinic

STUDY QUESTION

What is the relationship between semen parameters and birth defect (BD) rates in offspring of men evaluated for infertility?

SUMMARY ANSWER

Among men undergoing infertility evaluation, there is no significant relationship between semen parameters and defect rates in live or still births, even when considering mode of conception.

WHAT IS KNOWN ALREADY

Approximately 15% of couples have fertility difficulties, with up to a 50% male factor contribution. An increased risk of BDs exists in couples using ART, particularly IVF and ICSI, but it is unknown if this related to the ART procedures or an underlying male factor.

STUDY DESIGN, SIZE, DURATION

To determine if the severity of male factor infertilty, as assessed via sperm quality and mode of conception, is associated with BD rates, we performed a retrospective cohort study. Fathers with semen analysis data in the Baylor College of Medicine Semen Database (BCMSD) were linked with their offspring using Texas Birth Defects Registry (TBDFR) data between 1999 and 2009. In this 10-year period, a total of 1382 men were identified in linkage between the BCMSD and TBDFR. A total of 109 infants with and 2115 infants without BDs were identified.

PARTICIPANTS/MATERIALS, SETTING, METHODS

To determine the association between BDs and semen parameters, we used hierarchical linear modeling to determine odds ratios between BD rates, semen parameters, and mode of conception before and after adjustment for paternal, maternal and birth covariates. Semen parameters were stratified based on thresholds defined by the WHO fifth edition laboratory manual for the examination and processing of human semen.

MAIN RESULTS AND THE ROLE OF CHANCE

In total 4.9% of 2224 infants were identified with a BD. No statistically significant association was observed between BD rates and semen parameters, before or after adjustment for covariates. The association between sperm concentration and BDs demonstrated an odds ratio (OR) of 1.07 (95% confidence interval: 0.63-1.83); motility: OR 0.91 (0.52-2.22); and total motile count: OR 1.21 (0.70-2.08). Likewise, mode of conception, including infertility treatment and ART, did not affect BD rates (P > 0.05).

LIMITATIONS, REASONS FOR CAUTION

BDs recorded in the TBDFR only include live born infants or still births after 20 weeks, our study did not evaluate the effect of impaired semen parameters on developmental defects prior to 20 weeks of gestation. With 109 BDs, our statistical analysis was powered to detect moderate differences associated with particular semen parameters. Additionally, data about mode of conception was not available for 1053 of 2224 births.

WIDER IMPLICATIONS OF THE FINDINGS

BD rates are not associated with semen quality or mode of conception. The current study suggests that the severity of male factor infertility does not impact the rate of congenital anomalies. This information is important when counseling couples concerned about the relationship between impaired semen quality and BDs.

STUDY FUNDING/COMPETING INTEREST(S)

Supported in part by the NIH Men's Reproductive Health Research (MRHR) K12 HD073917 (D.J.L.), the Multidisciplinary K12 Urologic Research (KURe) Career Development Program (D.J.L.), P01HD36289 from the Eunice Kennedy Shriver National Institute for Child Health and Human Development, NIH (D.J.L.), and by U01DD000494 from the Centers for Disease Control and Prevention and the Title V Block Grant to the Texas Department of State Health Services. A.W.P. is a National Institutes of Health K08 Scholar supported by a Mentored Career Development Award (K08DK115835-01) from the from the National Institute of Diabetes and Digestive and Kidney Diseases. This work is also supported in part through a Urology Care Foundation Rising Stars in Urology Award (to A.W.P.) None of the authors has a conflict of interest.

TRIAL REGISTRATION NUMBER

Not applicable.

Severity of congenital heart defects associated with assisted reproductive technologies: Case series and review of the literature

OBJECTIVE

Assisted reproductive technology (ART) has been associated with a higher incidence of congenital anomalies, including a specific increase in the rate of congenital heart defects (CHD). In this study, the rate of CHD in pregnancies resulting from ART at a single high-risk pregnancy referral center are compared to the published literature.

METHODS

Pregnancies were screened by fetal echocardiography for the indication of ART over a 2-year period. CHD were classified as either mild or severe based on the need for postnatal surgical intervention. Results were compared to findings from a literature review of studies examining CHD in pregnancies resulting from ART since 1980.

RESULTS

Over the course of two years, 363 fetuses in 264 pregnancies from our cohort were screened for CHD. The incidence of mild CHD in fetuses from ART pregnancies was 2.75% (10 out of 363 fetuses). None of the affected fetuses had severe CHD. Review of the literature yielded 20 studies since 1980 that examined CHD in pregnancies resulting from ART. Composite data from the studies was described based on characterization of severity of the CHD anomalies. The incidence of mild CHD in ART pregnancies was 2.2%, compared to 1% in non-ART pregnancies (out of 332,157 infants). The incidence of severe CHD in ART pregnancies and naturally conceived pregnancies was 1.4% and 1.2%, respectively (out of 661,455 infants). The incidence of unspecified CHD in ART pregnancies was 1.8%, compared to 1% in naturally conceived pregnancies (out of 1,593,277 infants).

CONCLUSION

The greatest increase in risk appears to be for mild CHD (nonsurgical), which may inform counseling of patients prior to use of assisted reproductive technologies.

IVF procedures are not, but subfertility is associated with neurological condition of 9-year-old offspring

In vitro fertilization (IVF) is not associated with neurological abnormalities in offspring's early childhood. Yet, it is unclear whether this is also true for school age. Neither do we know the role of parental subfertility in offspring's neurological development. The present study examined neurological condition at 9 years of 57 singletons born after controlled ovarian hyperstimulation IVF (COH-IVF), 46 singletons born after modified natural cycle IVF (MNC-IVF) and 66 singletons born to subfertile parents after natural conception (Sub-NC). To assess the effect of subfertility, the groups were pooled to form a subfertile group, and compared with a prospectively followed fertile reference group (n = 282). The sensitive Minor Neurological Dysfunction (MND) examination was used, resulting in the detailed Neurological Optimality Score (NOS) and the prevalence of the clinically relevant complex MND. Neurological condition of the three subfertile groups did not differ significantly: median NOS was 53 in each subfertile group and the prevalence of complex MND in the three subfertile groups was 30%, 37% and 36%, respectively. However, the NOS was lower and the prevalence of complex MND higher in children born to subfertile couples than in children of fertile couples (adjusted mean difference [95% CI]: -4.48 [-5.53 to -3.42]) and adjusted OR [95% CI]: 5.13 [2.60-10.16], respectively). We conclude that ovarian hyperstimulation, in vitro procedures, and the combination of both were not associated with a less favourable neurological outcome of 9-year-old singletons. However, the presence of parental subfertility was associated with less favourable neurological outcome of offspring at 9 years follow up.

Long-Term Cardiovascular Morbidity in Children Born Following Fertility Treatment

OBJECTIVE

To determine the risk of long-term cardiovascular disease (CVD) among children born following in vitro fertilization (IVF) and compared with spontaneous pregnancies.

STUDY DESIGN

A population-based cohort study including all singleton deliveries occurring between 1991and 2014 at a tertiary medical center was performed. Hospitalizations up to the age of 18 years involving CVD were evaluated in children delivered following IVF, ovulation induction, and spontaneous pregnancies. CVD included valvular disorders, hypertension, arrhythmias, rheumatic disease, cardiomyopathy, ischemic heart disease, and heart failure. Kaplan-Meier survival curves were used to compare cumulative morbidity incidence, and a Cox regression model controlled for confounders.

RESULTS

During the study period, 242 187 singleton deliveries met the inclusion criteria; 1.1% following IVF (n = 2603), and 0.7% following ovulation induction (n = 1721). Hospitalizations up to the age of 18 years involving CVD (n = 1503) were comparable in children delivered following IVF (0.6%), ovulation induction (0.7%), and spontaneous pregnancies (0.6%; P = .884). No significant difference in the cumulative incidence of CVD was noted between the groups (log rank P = .781). Controlling for maternal age, gestational age, birthweight, maternal diabetes, and hypertensive disorders in pregnancy, fertility treatment was not noted as a risk factor for long-term pediatric CVD (IVF adjusted hazard ratio 1.05, 95% CI 0.63-1.74, P = .86; ovulation induction adjusted hazard ratio 0.97, CI 95% 0.55-1.71, P = .92).

CONCLUSIONS

Singletons conceived via fertility treatments do not appear to be at an increased risk of long-term pediatric CVD.

Congenital Malformations in Infants of Mothers Undergoing Assisted Reproductive Technologies: A Systematic Review and Meta-analysis Study

Objectives

This meta-analysis aimed to evaluate congenital malformations in infants conceived by assisted reproductive techniques (ART), compared with infants conceived spontaneously.

Methods

In this study, available resources searched to find relevant articles included PubMed, ScienceDirect, Scopus, Google Scholar, Cochrane, ProQuest, Iranmedex, Magiran, and Scientific Information Database. After extracting the necessary information from evaluated articles, meta-analysis on the articles’ data was performed using Stata version 11.2.

Results

In this study, from a total of 339 articles, extracted from the initial investigation, ultimately 30 articles were selected for meta-analysis that assessed the use of ART on the risk of congenital abnormalities and some birth complications on 5 470 181 infants (315 402 cases and 5 154 779 controls). The odds ratio (95% confidence interval [CI]) for low birth weight was 1.89 (95% CI, 1.36 to 2.62), preterm labor 1.79 (95% CI, 1.21 to 2.63), cardiac abnormalities 1.43 (95% CI, 1.27 to 1.62), central nervous system abnormalities 1.36 (95% CI, 1.10 to 1.70), urogenital system abnormalities 1.58 (95% CI, 1.28 to 1.94), musculoskeletal disorders 1.35 (95% CI, 1.12 to 1.64), and chromosomal abnormalities in infants conceived by ART was 1.14 (95% CI, 0.90 to 1.44), which were all statistically significant, except chromosomal abnormalities.

Conclusions

The risk of congenital abnormalities and some birth complications were significantly higher in ART than normal conception, while chromosomal abnormalities were not; therefore, the application of ART should be selected individually for patients by detailed assessment to reduce such risks in the population.

An epigenetic association of malformations, adverse reproductive outcomes, and fetal origins hypothesis related effects

VACTERL, the prototype for associated congenital anomalies, also has connections with functional issues such as pregnancy losses, prematurity, growth delays, perinatal difficulties, and parental subfertility. This segues into a broader association with similar connections even in the absence of malformations. DNA methylation disturbances in the ovum are a likely cause, with epigenetic links to individual components and to folate effects before conception, explaining diverse fetal and placental findings and providing a link to fetal origin hypothesis-related effects. The association encompasses the following: (1) Pre- and periconceptual effects, with frequent fertility issues and occasional imprinting disorders. (2) Early malformations. (3) Adverse pregnancy outcomes (APOs), as above. (4) Developmental destabilization that resolves soon after birth. This potentiates other causes of association findings, introducing multiple confounders. (5) Long-term fetal origins hypothesis-related risks. The other findings are exceptional when the same malformations have Mendelian origins, supporting a distinct pathogenesis. Expressions are facilitated by one-carbon metabolic issues, maternal and fetal stress, and decreased embryo size. This may be one of the commonest causes of adverse reproductive outcomes, but multifactorial findings, variable onsets and phenotypes, and interactions with multiple confounders make recognition difficult. This association supports VACTERL as a continuum that includes isolated malformations, extends the fetal origins hypothesis, explains adverse effects linked to maternal obesity, and suggests possible interventions.

Beckwith Wiedemann syndrome: A population-based study on prevalence, prenatal diagnosis, associated anomalies and survival in Europe

Beckwith Wiedemann syndrome is a complex developmental disorder characterized by somatic overgrowth, macroglossia, abdominal wall defects, neonatal hypoglycemia, and predisposition to embryonal tumors. We present epidemiological and clinical aspects of patients with Beckwith Wiedemann syndrome diagnosed prenatally or in the early years of life, using data from EUROCAT (European Surveillance of Congenital Anomalies) registries. The study population consisted of 371 cases identified between January 1990 and December 2015 in 34 registries from 16 European countries. There were 15 (4.0%) terminations of pregnancy after prenatal detection of severe anomaly/anomalies, 10 fetal deaths (2.7%), and 346 (93.3%) live-births. Twelve (3.6%) of the 330 live-births with available information on survival died in the first week of life, of those eleven (91.6%) were preterm. First-year survival rate was 90.9%. Prematurity was present in 40.6% of males and 33.9% of females. Macrosomia was found in 49.2% and 43.3% of preterm males and females, respectively. Of term newborns, 41.1% of males and 24% of females were macrosomic. Out of 353 cases with known time of diagnosis, 39.9% were suspected prenatally, 36.3% at birth, 7.6% were diagnosed in the first week of life, and 16.2% in the first year of life. The mean gestational age at prenatal diagnosis by obstetric ultrasound was 19.8 ± 6.2 (11-39) gestational weeks. The mean prenatal diagnosis of cases where parents opted for termination of pregnancy was 15.3 ± 2.4 (11-22) gestational weeks, and the mean gestational age at termination was 19.3 ± 4.1 (13-26) gestational weeks. The prenatal detection rate was 64.1% (141/220) with no significant change over time. There were 12.7% of familial cases. The study confirmed the association of assisted reproductive technologies with Beckwith Wiedemann syndrome, as 7.2% (13/181) of patients were conceived by one of the methods of assisted reproductive technologies, which was three times higher compared to the general population of the countries included in the study. Twin pregnancies of undetermined zygosity were recorded in 5.7% (21/365) cases, and were on average three to four times more common than in European countries that participated in the study. The estimated mean prevalence of classical Beckwith Wiedemann syndrome in Europe was 3.8 per 100,000 births or 1:26,000 births.

Parental health status and infant outcomes: Upstate KIDS Study

OBJECTIVE

To assess parental health status inclusive of infertility and infant outcomes.

DESIGN

Birth cohort with cross-sectional analysis of parental health status and infant outcomes.

SETTING

Not applicable.

PATIENT(S)

Parents (n = 4,886) and infants (n = 5,845) participating in the Upstate KIDS birth cohort.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Infertility was defined as [1] sexually active without contraception for 1+ years without pregnancy, [2] ever requiring ≥12 months to become pregnant, and [3] requiring ≥12 months for index pregnancy. Multivariable linear regression with generalized estimating equations estimated the change (β coefficient and 95% confidence interval [CI]) in infant outcomes (gestation, birthweight, length, head circumference, ponderal index) and relative to each disease, including infertility after adjusting for age, body mass index, and infertility treatment.

RESULT(S)

Prevalence of parental chronic diseases ranged from <1% to 19%, and 21% to 54% for infertility. Maternal hypertension was negatively associated with gestation (β, -0.64; 95% CI, -1.03, -0.25) and birthweight (-151.98; -262.30, -41.67) as was asthma and birthweight (-75.01; -130.40, -19.62). Maternal kidney disease was associated with smaller head circumference (-1.09; -2.17, -0.01), whereas paternal autoimmune disease was associated with larger head circumference (0.87; 0.15, 1.60). Infertility was negatively associated with birthweight (-62.18; -103.78, -20.58), length (-0.33; -0.60, -0.06), and head circumference (-0.35; -0.67, -0.03).

CONCLUSION(S)

Infertility was significantly associated with reduced infant size even after accounting for infertility treatment, although the magnitude of reduction varied by definition of infertility. Absence of pregnancy within a year of being at risk may be informative about health.

Congenital heart defects in IVF/ICSI pregnancy: systematic review and meta-analysis

OBJECTIVE

There is no consensus in current practice guidelines on whether conception by in-vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) techniques is an indication for performing a fetal echocardiogram. The aim of the study was to assess whether congenital heart defects (CHD) occur more often in pregnancies conceived after IVF/ICSI as compared with those conceived spontaneously.

METHODS

A systematic search for studies was conducted of PubMed/MEDLINE, EMBASE and Scopus from inception to September 2017. The search included the following medical subject heading (MeSH) terms alone or in different combinations: 'IVF', 'IVF/ICSI', 'ART pregnancy', 'assisted conception', 'birth defect', 'congenital heart defects' and 'congenital malformation or abnormalities'. Studies comparing neonatal incidence of CHD in pregnancies conceived after IVF/ICSI and those conceived spontaneously were included. Studies reporting on other types of assisted reproductive technology (ART) or lacking information concerning termination of pregnancy were excluded. Chromosomal abnormalities were excluded in all analyzed studies. A meta-analysis of selected cohort studies was conducted to estimate the pooled odds ratio (OR) with 95% CI using a random-effects model. Statistical heterogeneity among the studies was evaluated with the I² statistic and Q-test.

RESULTS

Forty-one studies were identified for review including six case-control and 35 cohort studies. Data of eight selected cohort studies were used for meta-analysis. A total of 25 856 children conceived from IVF/ICSI techniques and 287 995 children conceived spontaneously, involving both singleton and multiple gestations, were included in the analysis. Total CHD events were 337/25 856 (1.30%) and 1952/287 995 (0.68%) in the IVF/ICSI and spontaneous conception groups, respectively. The risk of CHD was significantly increased in the IVF/ICSI group as compared with the spontaneous conception group (pooled OR, 1.45; 95% CI, 1.20-1.76; P = 0.0001; I²  = 44%; P = 0.08). In the subgroup of singleton IVF pregnancies, a significant difference was also obtained (OR, 1.55; 95% CI, 1.21-1.99; P = 0.0005; I²  = 36%; P = 0.18) and also multiple confounding factors adjusted ORs showed statistical significance (pooled OR, 1.29; 95% CI, 1.03-1.60; P = 0.02; I²  = 0%; P = 0.43).

CONCLUSION

Fetuses conceived with IVF/ICSI methods are at an increased risk of developing CHD compared with those conceived spontaneously. However, this finding deserves further investigation due to heterogeneity of both ART procedures and cardiac defects. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Placental imprinting variation associated with assisted reproductive technologies and subfertility

Infertility affects one in 6 couples in developed nations, resulting in an increasing use of assisted reproductive technologies (ART). Both ART and subfertility appear to be linked to lower birth weight outcomes, setting infants up for poor long-term health. Prenatal growth is, in part, regulated via epigenetically-controlled imprinted genes in the placenta. Although differences in DNA methylation between ART and control infants have been found, it remains unclear whether these differences are due to the ART procedures or to the underlying parental subfertility and how these methylation differences affect imprinted gene expression. In this study, we examined the expression of 108 imprinted genes in placental tissues from infants born to subfertile parents (n = 79), matched naturally-conceived controls (n = 158), and infants conceived using in vitro fertilization (IVF, n = 18). Forty-five genes were identified as having significantly different expression between the subfertile infants and controls, whereas no significant differences were identified between the IVF and control groups. The expression of 4 genes-IGF2, NAPIL5, PAX8-AS1, and TUBGCP5-was significantly downregulated in the IVF compared with the subfertile group. Three of the 45 genes significantly dysregulated between subfertile and control placentae-GRB10, NDN, and CD44 -were found to have a significant positive correlation between expression and birth weight. Methylation levels for these 3 genes and 4 others-MKRN3, WRB, DHCR24, and CYR61-were significantly correlated with expression. Our findings indicate that epigenetic differences in placentas resulting from IVF pregnancies may be related to the underlying subfertility in parents using IVF rather than the IVF procedure itself.

No difference in congenital anomalies prevalence irrespective of insemination methods and freezing procedure: cohort study over fourteen years of an ART population in the south of France

PURPOSE

A retrospective cohort study was conducted to evaluate and compare the prevalence of congenital anomalies in babies and fetuses conceived after four procedures of assisted reproduction technologies (ART).

METHODS

The prevalence of congenital anomalies was compared retrospectively between 2750 babies and fetuses conceived between 2001 and 2014 in vitro fertilization with standard insemination (IVF), IVF with intracytoplasmic sperm injection (ICSI), IVF with frozen embryo transfer (FET-IVF), and ICSI with frozen embryo transfer (FET-ICSI). Congenital anomalies were described according to European Surveillance of Congenital Anomalies (EUROCAT) classification. The parental backgrounds, biologic parameters, obstetric parameters, and perinatal outcomes were compared between babies and fetuses with and without congenital anomalies. Data were analyzed by the generalized estimating equation.

RESULTS

Between 2001 and 2014, a total of 2477 evolutionary pregnancies were notified. Among these pregnancies, 2379 were included in the analysis. One hundred thirty-four babies and fetuses had a congenital anomaly (4.9%). The major prevalences found among the recorded anomalies were congenital heart defects, chromosomal anomalies, and urinary defects. However, the risk of congenital anomalies in babies and fetuses conceived after FET was not increased compared with babies and fetuses conceived after fresh embryo transfer, even when adjusted for confounding factors (p = 0.40).

CONCLUSIONS

There is no increased risk of congenital anomalies in babies and fetuses conceived by fresh versus frozen embryo transfer after in vitro fertilization with and without micromanipulation. Indeed, distribution of congenital anomalies found in our population is consistent with the high prevalence of congenital heart defects, chromosomal anomalies, and urinary defects that have been found by other authors in children conceived by infertile couples when compared to children conceived spontaneously.

Epigenetic Influences During the Periconception Period and Assisted Reproduction

The periconception period starts 6 months before conception and lasts until the tenth week of gestation. In this chapter, we will focus on epigenetic modifications to DNA and gene expression within this period and during assisted reproduction. There are two critical times during the periconception window when significant epigenetic 'reprogramming' occur: one during gametogenesis and another during the pre-implantation embryonic stage. Furthermore, assisted conception treatments, laboratory protocols and culture media can affect the embryo development and birth weights in laboratory animals. There is, however, an ongoing debate as to whether epigenetic changes in humans, causing embryo mal-development, placenta dysfunction and birth defects, result from assisted reproductive technologies or are consequences of pre-existing medical and/or genetic conditions in the parents. The periconception period starts from ovarian folliculogenesis, through resumption of oogenesis, fertilisation, peri-implantation embryo development, embryogenesis until the end of organogenesis. In men, it is the period from spermatogenesis to epididymal sperm storage and fertilisation. Gametes and developing embryos are sensitive to environmental factors during this period, and epigenetic modifications can occur in response to adverse lifestyles and environmental factors. We now know that lifestyle factors such as advanced parentage age, obesity or undernutrition, smoking, excessive alcohol and caffeine intake and recreational drugs used during gamete production and embryogenesis could induce epigenetic alterations, which could impact adversely on pregnancy outcomes and health of the offspring. Furthermore, these can also result in a permanent and irreversible effect in a dose-dependent manner, which can be passed on to the future generations.

Client perspectives of midwifery care in the transition from subfertility to parenthood: a qualitative study in the Netherlands

BACKGROUND

Pregnancy, childbirth and the postpartum period after fertility treatment are considered "normal" in the Netherlands, with no indication of an increased obstetric risk, and can therefore be monitored by a primary care midwife. However, there is little evidence on the experiences of couples and women who finally get pregnant after fertility treatment and a lack of training for midwives exists on this subject. The aim of this study was to map the midwifery care needs of the subfertile client with past fertility problems.

METHODS

In 2011, we interviewed two couples and seven women who conceived through fertility treatment and received primary midwifery care at some point during their pregnancies. This explorative, qualitative study was based on the interpretivist/constructivist paradigm.

RESULTS

Although the participants are not representative of all subfertile clients, the findings of our qualitative study highlight the needs of women and their partners who have become pregnant through fertility treatment including help from the primary care midwife in understanding the likely course of their pregnancy, more psychosocial support and acknowledgement of the fertility treatment history, and more consultations and frequent ultrasound scans than usual to confirm pregnancy.

CONCLUSIONS

Our study points out that the women who have become pregnant through fertility treatment and their partners communicate seemingly paradoxical prenatal care needs. It can help maternity care providers to optimally meet the care needs of subfertile clients and empower them during their transition from subfertility to parenthood.

The Ultrasonic Microsurgical Anatomical Comparative Study of the CHD Fetuses and Their Clinical Significance

The aim of our study was to increase the detection rate of fetal cardiac malformations for congenital heart disease (CHD). The ultrasonic and microanatomical methods were combined to study the CHD cases firstly, which could provide the microsurgical anatomical basis to the prenatal ultrasonic diagnosis which was used in suspected CHD and help the sonographer to improve the quality of fetal cardiac diagnosis. We established the ultrasonic standard section of the 175 complex CHD cases and collected the fetal echocardiography image files. The induced/aborted fetuses were fixed by 4% paraformaldehyde and dissected by the ultrasonic microsurgical anatomy. This research could obtain the fetal cardiac anatomic cross-sectional images which was consistent with the ultrasonic standard section and could clearly show the internal structure of the vascular malformation that optimized the ultrasound examination individually. This method could directly display the variation of the CHD fetal heart clearly and comprehensively help us to understand the complex fetal cardiac malformation from the internal structure of the vascular malformation which was consolidated by the anatomical basis of the fetal heart. This study could improve the integrity and accuracy of the prenatal cardiac ultrasound examination tremendously.

Findings from the National Birth Defects Prevention Study: Interpretation and translation for the clinician

BACKGROUND

The National Birth Defects Prevention Study (NBDPS) is a large U.S. multi-site case-control study first established in 1996 to identify potentially preventable environmental causes and genetic risk factors for more than 30 selected categories of major birth defects.

METHODS

Numerous reports with both positive and negative findings have been produced by the NBDPS, and many have influenced clinical practice. Many NBDPS reports have included novel findings, and in some cases these findings could only be considered hypothesis-generating. Other reports have met criteria for causality such as replication of findings in other studies, biological plausibility, and coherence.

RESULTS

However, translation of even strongly supported associations, in some cases, has required clinicians to learn to communicate information to patients about small and uncertain absolute risks in the context of the potential effects of under- or poorly treated maternal conditions.

CONCLUSION

The NBDPS has continued to play an important role as a rich U.S. data source that can advance the understanding of maternal conditions and their treatments in relation to birth defects.