Cerebral palsy among children born after in vitro fertilization: the role of preterm delivery--a population-based, cohort study

Current approach to cerebral palsy

This teaching review aims to provide an overview of the current approach to children with cerebral palsy (CP), retrieving the best available evidence and summarizing existing knowledge in the field of CP in children. We also highlight areas where more research is needed and novel strategies for diagnosing and treating cerebral palsy. CP includes a group of permanent disorders of movement and posture that cause activity limitation. Multiple risk factors, occurring preconceptionally, prenatally, perinatally, or postneonatally, are involved in the pathogenesis of CP, with the prenatal ones accounting for 80-90 % of cases. Due to its heterogeneity, CP has various classifications, but usually is classified based on clinical findings and motor impairment. Standardized function classification systems have been developed to address inconsistencies in previous classifications. The combination of clinical assessment and validated predictive tools is recommended for an early diagnosis, which is important for early intervention and prevention of secondary impairments. The therapeutic regimen in CP involves prevention and management of the motor and associated problems. It includes the enhancement of motor performance, the enrichment of cognition and communication skills, the prevention of secondary impairments, and the support of parents and caregivers. The care of CP children demands a multidisciplinary approach focused on improving motor skills, reducing comorbidities, enhancing the quality of life, and prolonging survival.

Children born to subfertile couples, how are they doing? Evidence from research

More than 10 million children have been born with assisted reproductive technology (ART) as we begin to enter the third generation of individuals conceived by ART. Here we summarise key messages from an enlarging body of literature regarding their health. Earlier research had pointed towards increases in perinatal, neonatal and neurological risks, such as preterm birth, low birth weight, congenital malformations and cerebral palsy. Many of these risks have continued to persist in most recent work but have shown reduction. Newer research proposes long-term cardiometabolic and endocrine concerns. Fortunately, most reports conclude there is little or no risk of increased childhood malignancy or abnormal neurodevelopment. Moving forward, new research may benefit from changes in comparator groups and a better understanding of infertility per se in ART, and the confounding role it probably plays in many of the known risk associations, to reliably scan the horizon for health threats for individuals born after ART.

Association Between Assisted Reproductive Technology and Cerebral Palsy: A Meta-Analysis

BACKGROUND

Since 1978 many children are born thanks to assisted reproductive technology (ART). However, the long-term effects of these therapies are still not fully known. Our objective is to evaluate the risk of cerebral palsy (CP) after ART compared with that in those spontaneously conceived (SC) and to examine this risk in single, multiple, and preterm births and the evolution of the risk over the years.

METHODS

PubMed, Embase, and Web of Science databases were searched until December 2022. Studies were included if they studied CP cases in children born through ART. 16 studies were finally selected. Quality of studies was assessed using Newcastle Ottawa Scale. Pooled OR was estimated by weighting individual OR/RR by the inverse of their variance. A random-effect model was applied. To assess the causes of heterogeneity, we performed meta-regression analyses.

RESULTS

A significantly high risk of CP was found (OR = 1.27; 95% CI 1.12 to 1.43) in children born through ART compared with those SC. This risk increased in singletons (OR = 1.48; 95% CI 1.23 to 1.79) but disappeared in multiple (OR = 1.05; 95% CI 0.93 to 1.18) and preterm births (OR = 1.09; 95% CI 0.87 to 1.37). We found a higher risk of CP in children born before the year 2000 (OR = 3.40; 95% CI 2.49 to 4.63).

CONCLUSIONS

ARTs slightly increase the risk of CP once the effect of multiple gestation is controlled. Further studies are needed to clarify whether the techniques themselves, fertility problems, or associated maternal comorbidities are responsible for this risk.

Cerebral palsy in children born after assisted reproductive technology in Norway: Risk, prevalence, and clinical characteristics

INTRODUCTION

The aim was to investigate the risk, prevalence, and clinical characteristics of cerebral palsy among children born after assisted reproductive technology (ART) in Norway.

MATERIAL AND METHODS

All liveborn children from 2002 to 2015 were included. Information was collected from the Medical Birth Registry of Norway, linked to the Norwegian Quality and Surveillance Registry for Cerebral Palsy as of December 31, 2022. Logistic regression analyses were used to calculate the prevalence of cerebral palsy per 1000 live births after ART and natural conception with birth year as covariate, crude odds ratios (OR) for cerebral palsy among children born after ART using children born after natural conception as reference, and OR adjusted for potential confounders, with 95% confidence intervals (CI). Potential mediators of the association were studied in stratified analyses. Descriptive statistics were used to compare proportions in clinical characteristics among children with cerebral palsy born after ART and natural conception.

RESULTS

Among 833 645 livebirths, 23 645 children were born after ART and of the latter 97 were diagnosed with cerebral palsy. The overall prevalence of cerebral palsy after ART was 4.10 per 1000 live births (95% CI 3.36-5.00), decreasing from 7.79 per 1000 in 2002 to 3.55 in 2015. Compared with children born after natural conception, the OR for cerebral palsy was 2.01 (95% CI 1.63-2.47) adjusted for mother's age at birth, parity, and pre-pregnancy health. When restricted to singletons born at term, the adjusted OR for cerebral palsy was 1.13 (95% CI 0.76-1.69). The distribution of cerebral palsy subtypes and the severity of gross and fine motor function and associated impairments did not differ significantly between children with cerebral palsy born after ART and natural conception.

CONCLUSIONS

Children born after ART had a risk of cerebral palsy that was twice that of children born after natural conception. The increased risk of cerebral palsy after ART is likely attributed to multiple pregnancies and preterm births. The prevalence of cerebral palsy after ART decreased significantly during the study period, despite an increased use of ART in the population. The distribution of clinical characteristics did not differ between children with cerebral palsy born after ART and those born after a natural conception, suggesting that the risk factors for, and causes of cerebral palsy were similar.

Case report: Suspecting guanine nucleotide-binding protein beta 1 mutation in dyskinetic cerebral palsy is important

Herein, we describe the case of a 43-month-old girl who presented with clinical manifestations of dyskinetic cerebral palsy (CP), classified as the Gross Motor Function Classification System (GMFCS) V. The patient had no family history of neurological or perinatal disorders. Despite early rehabilitation, serial assessments using the Gross Motor Function Measure (GMFM) showed no significant improvements in gross motor function. Brain magnetic resonance imaging showed nonspecific findings that could not account for developmental delay or dystonia. Whole-genome sequencing identified a heterozygous NM_002074.5(GNB1):c.239T>C (p.Ile80Thr) mutation in guanine nucleotide-binding protein beta 1 (GNB1) gene. Considering this case and previous studies, genetic testing for the etiology of dyskinetic CP is recommended for children without relevant or with nonspecific brain lesions.

Neurodevelopment at 5 years of age for preterm-born children according to mode of conception: a cohort study

BACKGROUND

Preterm delivery is a risk factor for sub-optimal neurodevelopment. Pregnancies conceived after medically-assisted reproduction - which includes in vitro fertilisation, with or without intracytoplasmic insemination, as well as induction of ovulation followed by intra-uterine insemination or timed intercourse - have a higher risk of preterm delivery. Few studies have evaluated the outcome at more than 2 years of age of such preterm-born children.

OBJECTIVE

To evaluate neurodevelopmental outcome at 5 ½ years of age of children born preterm according to the mode of conception (spontaneous versus medically-assisted reproduction).

STUDY DESIGN

4349 children born between 24 and 34 weeks of gestation who survived to 5 ½ years of age in the 2011 French prospective national cohort study EPIPAGE-2 were included: 814 in the medically-assisted reproduction group (433 by in vitro fertilisation, with or without intracytoplasmic insemination, and 381 by induction of ovulation) and 3535 in the spontaneously conceived group. Neurodevelopmental outcomes studied were sensory (hearing and vision) impairments, cerebral palsy, cognition and developmental coordination disorders. Multivariate analyses were performed with generalised estimating equation models adjusted for gestational age, antenatal steroids and social characteristics. All analyses were performed following multiple imputation. Sensitivity analyses were performed with the populations of singletons and cases with complete data.

RESULTS

No differences in cerebral palsy (adjusted odds ratio =1.00, 95% confidence interval 0.67-1.49), neurodevelopmental impairment (adjusted odds ratio=1.09; 95% confidence interval 0.82-1.45), or developmental coordination disorders (adjusted odds ratio=0.75; 95% confidence interval 0.50-1.12) were found between children born following medically-assisted reproduction and children born following spontaneous conception after adjustment for sociodemographic factors. For proportions of children with an intelligence quotient below one and two standard deviations, there were no differences between those born after medically-assisted reproduction or spontaneous pregnancy (respectively, adjusted odds ratio= 0.99 95% confidence interval 0.80-1.23, and adjusted odds ratio=1.14; 95% confidence interval 0.83-1.56). In subgroup analyses, no differences were seen between children born following induction of ovulation nor among those conceived through in vitro fertilisation when compared to children conceived spontaneously. Sensitivity analyses were consistent with the main results.

CONCLUSION

In this cohort of preterm born children, there was no evidence of an impact of the mode of conception on neurodevelopmental outcomes at 5 ½ years of age.

Cerebral palsy in ART children has declined substantially over time: a Nordic study from the CoNARTaS group

STUDY QUESTION

Are the decreasing multiple birth rates after ART associated with a simultaneous drop in the incidence of cerebral palsy (CP) in ART children over time?

SUMMARY ANSWER

The relative odds of CP in ART children have declined in the Nordic countries over the past two decades concurrently with declining multiple birth rates.

WHAT IS KNOWN ALREADY

In the Nordic countries, the rate of twin pregnancies after ART has decreased from 30% in the early 1990s to 4-13% in 2014, following the implementation of elective single embryo transfer (SET). Consequently, preterm birth rates have declined substantially in ART pregnancies. However, whether the risk of CP, a known consequence of preterm birth, has decreased correspondingly is still unknown.

STUDY DESIGN, SIZE, DURATION

Retrospective register-based cohort study based on data on all singletons, twins, and higher-order multiples born in Denmark (birth year 1994-2010), Finland (1990-2010), and Sweden (1990-2014), corresponding to 111 844 ART children and 4 679 351 spontaneously conceived children.

PARTICIPANTS/MATERIAL, SETTING, METHODS

Data were obtained from a large Nordic cohort of children born after ART and spontaneous conception initiated by the Committee of Nordic ART and Safety-CoNARTaS. The CoNARTaS cohort was established by cross-linking national register data using the unique personal identification number, allocated to every citizen in the Nordic countries. Data from the National Medical Birth Registers, where information on maternal, obstetric, and perinatal outcomes is recorded, were cross-linked to data from the National ART- and Patients Registers to obtain information on fertility treatments and CP diagnoses. Relative risks of CP for ART compared to spontaneous conception were estimated as odds ratios from multivariate logistic regression analyses across all birth years, as well as for the following birth year categories: 1990-1993, 1994-1998, 1999-2002, 2003-2006, 2007-2010, and 2011-2014. Analyses were made for all children and for singletons and twins, separately.

MAIN RESULTS AND THE ROLE OF CHANCE

The main outcome measure was the relative odds of CP in different time periods for ART versus spontaneously conceived children. CP was diagnosed in 661 ART children and 16 478 spontaneously conceived children born between 1990 and 2014. In 1990-1993, the relative odds of CP were substantially higher in all ART children (adjusted odds ratio (aOR) 2.76 (95% CI 2.03-3.67)) compared with all spontaneously conceived children, while in 2011-2014, it was only moderately higher (aOR 1.39 (95% CI 1.01-1.87)). In singletons, the higher relative odds of CP in ART children diminished over time from 1990 to 1993 (aOR 2.02 (95% CI 1.22-3.14)) to 2003-2006 (aOR 1.18 (95% CI 0.91-1. 49)) and was not significantly increased for birth cohorts 2007-2010 and 2011-2014. For ART twins versus spontaneously conceived twins, the relative odds of CP was not statistically significantly increased throughout the study period.

LIMITATIONS, REASONS FOR CAUTION

The main limitation of the study was a shorter follow-up time and younger age at first CP diagnosis for ART children compared with spontaneously conceived children. However, analyses ensuring a minimum of bias from differences in age at CP diagnosis and follow-up time confirmed the results, hence, we do not consider this to cause substantial bias.

WIDER IMPLICATIONS OF THE FINDINGS

A SET policy in ART treatments has the potential to reduce the increased risk of cerebral palsy in the ART population due to lower rates of multiple deliveries. At a time with high survival rates of frozen/thawed embryos, this study provides a strong argument against the continued use of multiple embryo transfer in most ART settings. Larger cohort studies including also the number of gestational sacs in early pregnancy will be preferable to show an effect of vanishing twins on the risk of CP in the ART population.

STUDY FUNDING/COMPETING INTEREST(S)

The study was financed by grants from NordForsk (grant number 71450), Elsass Foundation (19-3-0444), the ALF-agreement (ALFGBG 70940), and The Research Fund of Rigshospitalet, Copenhagen University Hospital. There are no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

ISRCTN11780826.

Cerebral palsy in children born after assisted reproductive technology: a meta-analysis

BACKGROUND

Several studies have assessed the association between cerebral palsy (CP) and assisted reproductive technology (ART), but the results remain controversial. We conducted a meta-analysis to evaluate the risk of CP after ART compared with natural conceptions and to examine CP risk separately in ART singletons, multiples and preterm births.

METHODS

Web-based databases (PubMed, Embase, the Cochrane Library, and Web of Science) were searched until November 22, 2020. Studies which compare CP rates after ART with natural conceptions were included. The Newcastle-Ottawa Scale was used to assess the quality of the included studies. Effect estimates were extracted and combined using the fixed-effects or random-effects model depending on the heterogeneity test.

RESULTS

There were nine studies included in the meta-analysis. The included studies were of moderate or high quality. A significantly higher risk of CP [odds ratio (OR) = 2.17, 95% confidence interval (CI) 1.72-2.74] was found in ART children (n = 89,214) compared with naturally conceived children (n = 4,160,745). The significantly higher risk decreased when data were restricted to singletons (OR = 1.36, 95% CI 1.16-1.59) and disappeared when data were restricted to multiples (OR = 1.05, 95% CI 0.86-1.29) or preterm births (OR = 1.53, 95% CI 0.66-3.56). Subgroup and sensitivity analyses indicated that the overall results were robust.

CONCLUSIONS

The risk of CP is increased more than two-fold after ART. This increased risk is largely due to increased rates of multiple birth and preterm delivery in ART children.

Risk of neurodevelopmental disorders in children born from different ART treatments: a systematic review and meta-analysis

BACKGROUND

Various techniques in assisted reproductive technology (ART) have been developed as solutions for specific infertility problems. It is important to gain consensual conclusions on the actual risks of neurodevelopmental disorders among children who are born from ART. This study aimed to quantify the relative risks of cerebral palsy, intellectual disability, autism spectrum disorder (ASD), and behavioral problems in children from different ART methods by using systematic review and meta-analysis. Healthcare providers could use the results of this study to suggest the suitable ART technique and plan optimum postnatal care.

METHODS

Pubmed, Google Scholar, and Scopus databases were used to search for studies up to January 2020. Of the 181 screened full manuscripts, 17 studies (9.39%) fulfilled the selection criteria. Based on the Newcastle-Ottawa scale ratings, 7 studies were excluded, resulting in 10 studies that were eventually included in the meta-analyses. Mantel-Haenszel risk ratio model was used in the meta-analysis, and the results are described using forest plot with 95% confidence interval. Heterogeneity was assessed using the I² value.

RESULTS

Pooled evaluation of 10 studies showed that the risk of cerebral palsy in children from assisted reproductive technology (ART) is higher than children from natural conceptions (risk ratio [RR] 1.82, [1.41, 2.34]; P = 0.00001). Risk of intellectual disability (RR 1.46, [1.03, 2.08]; P = 0.03) and ASD (RR 1.49 [1.05, 2.11]; P = 0.03) are higher in intracytoplasmic sperm injection (ICSI) children compared to conventional in vitro fertilization (IVF) children. The differences in the risk of neurodevelopmental disorders in children born after frozen and fresh embryo transfers are not significant. Analysis on potential cofounder effects, including multiple birth, preterm birth, and low birth body weight highlight possibilities of significant correlation to the risks of neurodevelopmental disorders.

CONCLUSIONS

Pooled estimates suggest that children born after ART are at higher risk of acquiring cerebral palsy. ICSI treatment causes higher risk of intellectual disability and ASD. These findings suggest the importance of the availability of intensive care unit at the time of delivery and long-term developmental evaluation particularly in children from ICSI.

Epigenetics and Neurological Disorders in ART

About 1–4% of children are currently generated by Assisted Reproductive Technologies (ART) in developed countries. These babies show only a slightly increased risk of neonatal malformations. However, follow-up studies have suggested a higher susceptibility to multifactorial, adult onset disorders like obesity, diabetes and cardiovascular diseases in ART offspring. It has been suggested that these conditions could be the consequence of epigenetic, alterations, due to artificial manipulations of gametes and embryos potentially able to alter epigenetic stability during zygote reprogramming. In the last years, epigenetic alterations have been invoked as a possible cause of increased risk of neurological disorders, but at present the link between epigenetic modifications and long-term effects in terms of neurological diseases in ART children remains unclear, due to the short follow up limiting retrospective studies. In this review, we summarize the current knowledge about neurological disorders promoted by epigenetics alterations in ART. Based on data currently available, it is possible to conclude that little, if any, evidence of an increased risk of neurological disorders in ART conceived children is provided. Most important, the large majority of reports appears to be limited to epidemiological studies, not providing any experimental evidence about epigenetic modifications responsible for an increased risk.

Twins and neurodevelopmental outcomes: the effect of IVF, fetal growth restriction, and preterm birth

This invited review aimed at presenting the evidence concerning neurodevelopmental outcomes, particularly cerebral palsy (CP), motor disability, cognitive impairment, mental retardation, any major disability, blindness and deafness in cases of twins, conceived after in vitro fertilization, presenting fetal/intrauterine growth restriction (FGR/IUGR) or being prematurely born. FGR/IUGR, prematurity and zygosity affect neurodevelopmental outcome; CP is higher in term infants, those presenting with FGR/IUGR, as well as in survivors of intrauterine co-twin death; cognitive ability of twins versus singletons mainly relates to confounding factors, as FGR/IUGR and prematurity, while evidence for differences in behavioral and psychiatric disorders between twins and singletons is limited. The impact of IVF per se has not been documented. Nevertheless, available literature, usually of heterogeneous and retrospective nature, diverges in the criteria for neurodevelopmental delay. Furthermore, differences in selection/exclusion criteria and small mixed cohorts, including the full range of complications, make comparison of the existing studies difficult. Future studies should focus in confirming the lack of IVF impact on twins' neurodevelopment and general health, in comparing long-term outcome of naturally conceived twins with those conceived following assisted reproduction techniques and in including evaluation of individual, longitudinal trajectories of growth, and development. In this respect, worldwide population-based registries will enable more precise description of neurodevelopmental outcomes among twins.

Cerebral palsy after assisted reproductive technology: a cohort study

AIM

To calculate the birth prevalence of cerebral palsy (CP) after assisted reproductive technology (ART) and compare the clinical outcomes of children with CP after ART or natural conception.

METHOD

This cohort study used linked CP and ART register data from live births in Western Australia (1994-2002). Birth prevalence was calculated and data analysed using descriptive statistics and logistic regression. It was adjusted for confounding variables and stratified by plurality and gestational age.

RESULTS

In total, 211 660 live births were included; prevalence of CP was increased in children born after ART (7.2/1000 live births compared with naturally conceived births, 2.5/1000). Odds of CP were doubled for singletons; when stratified by gestational age odds were only increased in the under 32-week group. Prevalence of CP was increased in ART (9.9/1000 live births) and naturally conceived twins (8.4/1000 live births). Clinical outcomes were similar between ART and naturally conceived children.

INTERPRETATION

The birth prevalence of CP is increased two-fold after ART. After stratification for gestational age and plurality, residual risk remains in singletons born very preterm. Birth prevalence of CP will be tracked over time to identify any impact of changes to clinical practice.

WHAT THIS PAPER ADDS

In Western Australia, assisted reproductive technology (ART) increases birth prevalence of cerebral palsy (CP), mediated mostly by preterm and multiple births. Preterm birth alone does not account for the doubled odds of CP for ART singletons born very preterm. Clinical outcomes are similar between ART and naturally conceived children with CP.

The health outcomes of human offspring conceived by assisted reproductive technologies (ART)

Concerns have been raised about the health and development of children conceived by assisted reproductive technologies (ART) since 1978. Controversially, ART has been linked with adverse obstetric and perinatal outcomes, an increased risk of birth defects, cancers, and growth and development disorders. Emerging evidence suggests that ART treatment may also predispose individuals to an increased risk of chronic ageing related diseases such as obesity, type 2 diabetes and cardiovascular disease. This review will summarize the available evidence on the short-term and long-term health outcomes of ART singletons, as multiple pregnancies after multiple embryos transfer, are associated with low birth weight and preterm delivery, which can separately increase risk of adverse postnatal outcomes, and impact long-term health. We will also examine the potential factors that may contribute to these health risks, and discuss underlying mechanisms, including epigenetic changes that may occur during the preimplantation period and reprogram development in utero, and adult health, later in life. Lastly, this review will consider the future directions with the view to optimize the long-term health of ART children.

Accuracy of self-reported survey data on assisted reproductive technology treatment parameters and reproductive history

BACKGROUND

It is unknown whether data obtained from maternal self-report for assisted reproductive technology treatment parameters and reproductive history are accurate for use in research studies.

OBJECTIVES

We evaluated the accuracy of self-reported in assisted reproductive technology treatment and reproductive history from the Upstate KIDS study in comparison with clinical data reported to the Society for Assisted Reproductive Technology Clinic Outcome Reporting System.

STUDY DESIGN

Upstate KIDS maternal questionnaire data from deliveries between 2008 and 2010 were linked to data reported to Society for Assisted Reproductive Technology Clinic Outcome Reporting System. The 617 index deliveries were compared as to treatment type (frozen embryo transfer and donor egg or sperm) and use of intracytoplasmic sperm injection and assisted hatching. Use of injectable medications, self-report for assisted reproductive technology, or frozen embryo transfer prior to the index deliveries were also compared. We report agreement in which both sources had yes or both no and sensitivity of maternal report using Society for Assisted Reproductive Technology Clinic Outcome Reporting System as the gold standard. Significance was determined using χ(2) at P < 0.05.

RESULTS

Universal agreement was not reached on any parameter but was best for treatment type of frozen embryo transfer (agreement, 96%; sensitivity, 93%) and use of donor eggs (agreement, 97%; sensitivity, 82%) or sperm (agreement, 98%; sensitivity, 82%). Use of intracytoplasmic sperm injection (agreement, 78%: sensitivity, 78%) and assisted hatching (agreement, 57%; sensitivity, 38%) agreed less well with self-reported use (P < .0001). In vitro fertilization (agreement, 82%) and frozen embryo transfer (agreement, 90%) prior to the index delivery were more consistently reported than was use of injectable medication (agreement, 76%) (P < .0001).

CONCLUSION

Women accurately report in vitro fertilization treatment but are less accurate about procedures handled in the laboratory (intracytoplasmic sperm injection or assisted hatching). Clinics might better communicate with patients on the use of these procedures, and researchers should use caution when using self-reported treatment data.

Assisted Reproductive Technology and Early Intervention Program Enrollment

OBJECTIVES

We examined the prevalence of Early Intervention (EI) enrollment in Massachusetts comparing singleton children conceived via assisted reproductive technology (ART), children born to mothers with indicators of subfertility but no ART (Subfertile), and children born to mothers who had no indicators of subfertility and conceived naturally (Fertile). We assessed the natural direct effect (NDE), the natural indirect effect (NIE) through preterm birth, and the total effect of ART and subfertility on EI enrollment.

METHODS

We examined maternal and infant characteristics among singleton ART (n = 6447), Subfertile (n = 5515), and Fertile (n = 306,343) groups and characteristics associated with EI enrollment includingpreterm birth using χ(2) statistics (α = 0.05). We estimated the NDE and NIE of the ART-EI enrollment relationship by fitting a model for enrollment, conditional on ART, preterm and the ART-preterm delivery interaction, and covariates. Similar analyses were conducted by using Subfertile as the exposure.

RESULTS

The NDE indicated that the odds of EI enrollment were 27% higher among the ART group (odds ratioNDE = 1.27; 95% confidence interval (CI): 1.19 ̶ 1.36) and 20% higher among the Subfertilegroup (odds ratioNDE = 1.20; 95% CI: 1.12 ̶ 1.29) compared with the Fertile group, even if the rate of preterm birth is held constant.

CONCLUSIONS

Singleton children conceived through ART and children of subfertile mothers both have elevated risks of EI enrollment. These findings have implications for clinical providers as they counsel women about child health outcomes associated with ART or subfertility.

Disabling chronic conditions in childhood and socioeconomic disadvantage: a systematic review and meta-analyses of observational studies

OBJECTIVE

To determine the association of socioeconomic disadvantage with the prevalence of childhood disabling chronic conditions in high-income countries.

STUDY DESIGN

Systematic review and meta-analyses.

DATA SOURCES

6 electronic databases, relevant websites, reference lists and experts in the field.

STUDY SELECTION

160 observational studies conducted in high-income countries with data on socioeconomic status and disabling chronic conditions in childhood, published between 1 January 1991 and 31 December 2013.

DATA EXTRACTION AND SYNTHESIS

Abstracts were reviewed, full papers obtained, and papers identified for inclusion by 2 independent reviewers. Inclusion decisions were checked by a third reviewer. Where reported, ORs were extracted for low versus high socioeconomic status. For studies reporting raw data but not ORs, ORs were calculated. Narrative analysis was undertaken for studies without data suitable for meta-analysis.

RESULTS

126 studies had data suitable for meta-analysis. ORs for risk estimates were: all-cause disabling chronic conditions 1.72 (95% CI 1.48 to 2.01); psychological disorders 1.88 (95% CI 1.68 to 2.10); intellectual disability 2.41 (95% CI 2.03 to 2.86); activity-limiting asthma 2.20 (95% CI 1.87 to 2.85); cerebral palsy 1.42 (95% CI 1.26 to 1.61); congenital abnormalities 1.41 (95% CI 1.24 to 1.61); epilepsy 1.38 (95% CI 1.20 to 1.59); sensory impairment 1.70 (95% CI 1.39 to 2.07). Heterogeneity was high across most estimates (I(2)>75%). Of the 34 studies without data suitable for meta-analysis, 26 reported results consistent with increased risk associated with low socioeconomic status.

CONCLUSIONS

The findings indicate that, in high-income countries, childhood disabling chronic conditions are associated with social disadvantage. Although evidence of an association is consistent across different countries, the review provides limited evidence to explain the association; future research, using longitudinal data, will be required to distinguish low socioeconomic status as the cause or consequence of childhood disabling chronic conditions and the aetiological pathways and mechanisms.

The risk of neurodisability and other long-term outcomes for infants born following ART

Children born after assisted reproductive technologies (ART) have an increased morbidity. The risk of developing cerebral palsy is nearly doubled and the risk of developing epilepsy is also higher. Behavioural problems including attention deficit/hyperactivity disorder may be more common in children born following ART than among naturally conceived children but the finding is uncertain. Data on autism are difficult to interpret. There may exist a small increase in the incidence of childhood cancer and there is greater evidence of an elevated risk of asthma. To some extent, these risks are mediated by neonatal complications including prematurity and low birth weight but some effects such as cerebral palsy are likely to be linked to the increased rate of multiple births after ART. Many of the neonatal complications after ART are most likely linked to parental subfertility and are less an effect of the ART technology. The possibility exists that imprinting errors, associated with subfertility and/or ART, may result in long-term morbidity.

In search of real autonomy for fertility patients

Nearly one in eight infants in the United States is born preterm. A variety of factors are associated with preterm birth, including multiplicity. In the United States fertility treatments are currently associated with high rates of multiplicity, but these rates could be reduced significantly if changes can be made to fertility treatment policy and practice. These include reducing the financial pressure on patients to prioritize pregnancy chances over safety by expanding insurance coverage and altering the way we calculate success rates and insurance benefits so that two consecutive single embryo transfers is equivalent to one double embryo transfer.

Cerebral palsy

The syndrome of cerebral palsy encompasses a large group of childhood movement and posture disorders. Severity, patterns of motor involvement, and associated impairments such as those of communication, intellectual ability, and epilepsy vary widely. Overall prevalence has remained stable in the past 40 years at 2-3·5 cases per 1000 livebirths, despite changes in antenatal and perinatal care. The few studies available from developing countries suggest prevalence of comparable magnitude. Cerebral palsy is a lifelong disorder; approaches to intervention, whether at an individual or environmental level, should recognise that quality of life and social participation throughout life are what individuals with cerebral palsy seek, not improved physical function for its own sake. In the past few years, the cerebral palsy community has learned that the evidence of benefit for the numerous drugs, surgery, and therapies used over previous decades is weak. Improved understanding of the role of multiple gestation in pathogenesis, of gene environment interaction, and how to influence brain plasticity could yield significant advances in treatment of the disorder. Reduction in the prevalence of post-neonatal cerebral palsy, especially in developing countries, should be possible through improved nutrition, infection control, and accident prevention.

Comparative analysis of dynamic proteomic profiles between in vivo and in vitro produced mouse embryos during postimplantation period

Assisted reproductive technology (ART) increasingly is associated with long-term side-effects on postnatal development and behaviors. High-throughput gene expression analysis has been extensively used to explore mechanisms responsible for these disorders. Our study, for the first time, provides a comparative proteomic analysis between embryos after in vivo fertilization and development (IVO, control) and in vitro fertilization and culture (IVP). By comparing the dynamic proteome during the postimplantation period, we identified 300 and 262 differentially expressed proteins (DEPs) between IVO and IVP embryos at embryonic day 7.5 (E7.5) and E10.5, respectively. Bioinformatic analysis showed many DEPs functionally associated with post-transcriptional, translational, and post-translational regulation, and these observations were consistent with correlation analysis between mRNA and protein abundance. In addition to altered gene expression due to IVP procedures, our findings suggest that aberrant processes at these various levels also contributed to proteomic alterations. In addition, numerous DEPs were involved in energy and amino acid metabolism, as well as neural and sensory development. These DEPs are potential candidates for further exploring the mechanism(s) of ART-induced intrauterine growth restriction and neurodevelopmental disorders. Moreover, significant enrichment of DEPs in pathways of neurodegenerative diseases implies the potentially increased susceptibility of ART offspring to these conditions as adults.

Refuting a misguided campaign against the goal of single-embryo transfer and singleton birth in assisted reproduction

Much recent progress has been made by assisted reproductive technology (ART) professionals toward minimizing the incidence of multiple pregnancy following ART treatment. While a healthy singleton birth is widely considered to be the ideal outcome of such treatment, a vocal minority continues a campaign to advocate the benefits of multiple embryo transfer as treatment and twin pregnancy as outcome for most ART patients. Proponents of twinning argue four points: that patients prefer twins, that multiple embryo transfer maximizes success rates, that the costs per infant are lower with twins and that one twin pregnancy and birth is associated with no higher risk than two consecutive singleton pregnancies and births. We find fault with the reasoning and data behind each of these tenets. First, we respect the principle of patient autonomy to choose the number of embryos for transfer but counter that it has been shown that better patient education reduces their desire for twins. In addition, reasonable and evidentially supported limits may be placed on autonomy in exchange for public or private insurance coverage for ART treatment, and counterbalancing ethical principles to autonomy exist, especially beneficence (doing good) and non-maleficence (doing no harm). Second, comparisons between success rates following single-embryo transfer (SET) and double-embryo transfers favor double-embryo transfers only when embryo utilization is not comparable; cumulative pregnancy and birth rates that take into account utilization of cryopreserved embryos (and the additional cryopreserved embryo available with single fresh embryo transfer) consistently demonstrate no advantage to double-embryo transfer. Third, while comparisons of costs are system dependent and not easy to assess, several independent studies all suggest that short-term costs per child (through the neonatal period alone) are lower with transfers of one rather than two embryos. And, finally, abundant evidence conclusively demonstrates that the risks to both mother and especially to children are substantially greater with one twin birth compared with two singleton births. Thus, the arguments used by some to promote multiple embryo transfer and twinning are not supported by the facts. They should not detract from efforts to further promote SET and thus reduce ART-associated multiple pregnancy and its inherent risks.

Long-term follow-up of children conceived through assisted reproductive technology

Children conceived via assisted reproductive technologies (ART) are nowadays a substantial proportion of the population. It is important to follow up these children and evaluate whether they have elevated health risks compared to naturally conceived (NC) children. In recent years there has been a lot of work in this field. This review will summarize what is known about the health of ART-conceived children, encompassing neonatal outcomes, birth defects, growth and gonadal developments, physical health, neurological and neurodevelopmental outcomes, psychosocial developments, risk for cancer, and epigenetic abnormalities. Most of the children conceived after ART are normal. However, there is increasing evidence that ART-conceived children are at higher risk of poor perinatal outcome, birth defects, and epigenetic disorders, and the mechanism(s) leading to these changes have not been elucidated. Continuous follow-up of children after ART is of great importance as they progress through adolescence into adulthood, and new ART techniques are constantly being introduced.

Assisted reproductive technologies and children's neurodevelopmental outcomes

Initial reports suggested that children conceived with assisted reproductive technologies (ART) may be at increased risk for a spectrum of developmental disabilities. Evolving evidence suggests that some of the early risks may have been overstated when not taking plurality of birth or gestational age at delivery into consideration, as both are independent risk factors for neurodevelopmental disabilities arising from alterations in structure and function or limitations in activities. Continued research is needed to overcome lingering data gaps in light of the equivocal literature for many neurodevelopmental disabilities relative to ART, increasing utilization of services, and changes in the clinical management of infecund couples such as the adoption of natural cycles or in vitro maturation treatment options. Population-based cohorts with longitudinal assessment of the multifaceted nature of neurodevelopment across critical and sensitive windows is paramount for the development of empirically based guidance for clinical and population health.

ART and health: clinical outcomes and insights on molecular mechanisms from rodent studies

Since the birth of the first IVF-conceived child in 1978, the use of assisted reproductive technologies (ART) has grown dramatically, contributing to the successful birth of 5 million individuals worldwide. However, there are several reported associations of ART with pregnancy complications, such as low birthweight (LBW), preterm birth, birth defects, epigenetic disorders, cancer and poor metabolic health. Whether this is attributed to ART procedures or to the subset of the population seeking ART remains a controversy, but the most relevant question today concerns the potential long-term implications of assisted conception. Recent evidence has emerged suggesting that ART-conceived children have distinct metabolic profiles that may predispose to cardiovascular pathologies in adulthood. Because the eldest IVF individuals are still too young to exhibit components of chronic middle-aged syndromes, the use of animal models has become particularly useful in describing the effects of unusual or stressful preimplantation experiences on adult fitness. Elucidating the molecular mechanisms by which embryos integrate environmental signals into development and metabolic gene expression programs will be essential for optimizing ART procedures such as in vitro culture conditions, embryo selection and transfer. In the future, additional animal studies to identify mechanisms underlying unfavorable ART outcomes, as well as more epidemiological reviews to monitor the long-term health of ART children are required, given that ART procedures have become routine medical practice.

The paediatric consequences of Assisted Reproductive Technologies, with special emphasis on multiple pregnancies

Paediatricians will encounter many babies and children who are the result of assisted reproductive technologies. Although in most cases, there are no adverse health consequences, assisted reproductive technologies (ART) are associated with some risks that are reviewed in this article.

CONCLUSION

ART has had a major impact on multiple gestation and the incidence of prematurity in many countries. Among singletons, there are also increases in prematurity, small for gestational age, congenital anomalies and perinatal mortality.

Comparison of Growth Parameters of 5-year-old Singleton Children Born in Assisted Versus Natural Conception

Introduction: At present, about 1% of newborns are delivered through assisted reproductive technologies (ART) worldwide. This study aimed to evaluate and compare the growth parameters of children born in assisted and natural conception at 5 years of age. Materials and Methods: In a cross-sectional case control study, weight, height and head circumference of 5-year old children were assessed. The case group consisted of term, singleton babies who were products of ART in the Center for Infertility of Shahid Sadoughi University, Yazd, Iran in 2005. The control group consisted of term, first child, singleton and spontaneously conceived 5-year-old children who were referred for vaccination to primary health care center of Shahid Akbari in 2010. Results: Fifty-eight girls (47.5%) and 64 boys (52.5%) “with equal numbers in each of the 2 groups” were evaluated. Sex distribution, mean ages of fathers and mothers were not statistically significant different in both groups. Children born after ART tend to have lower birth weight, smaller birth head circumference and lower weight at 5 years of age. Having low birth weight (<2500 g), being underweight and having short stature at the age of 5 were more common in babies born through ART. Conclusion: Growth retardation is more prevalent in babies born through ART. Thus, growth assessment, parents’ knowledge about child physical development, and timely and accurate follow-up of these children are necessary for early detection of any growth disorders. Key words: ART, Growth, Height, Natural Conception, Weight

Reproductive outcomes after assisted conception

The last three decades have witnessed a dramatic increase in the use of assisted reproductive technology (ART) so that now, in developed countries, 1.7% to 4.0% of all children are born after ART. Although absolute risks appear small, data from prospective and retrospective studies indicate increased risks of adverse maternal and perinatal outcomes after ART as compared with spontaneous conception. Recent studies suggest that underlying maternal factors and subfertility play an important role in some of these outcomes rather than the ART procedure itself. A significant risk of assisted conception is multiple pregnancies, but even singleton pregnancies achieved by ART are at a higher risk of hypertensive disease, diabetes, prematurity, low birth weight, and perinatal mortality even after adjusting for confounders. Couples undergoing ART procedures should be counseled in advance regarding increased risks of pregnancy complications and higher rates of obstetric interventions. Although conflicting data exist, studies of children born from ART suggest increased rates of congenital malformations, imprinting disorders (Beckwith-Wiedemann syndrome and Angelman syndrome), and marginally increased risk of cancer. However, the current evidence is inadequate, and prospective long-term studies are needed to eliminate the effect of confounders and draw definite conclusions about the long-term outcomes after ART. The absolute risk of imprinting disorders remains small, and routine screening is not recommended at present. The long-term outcomes after ART are difficult to evaluate because of the variability in ART methods and data reporting, and there is a need for standardized methodology for follow-up after ART.

Neonatal mortality and morbidity in preterm infants born from assisted reproductive technologies

AIM

Premature birth is frequent in infants conceived with assisted reproductive technologies (ART). We sought to determine whether neonatal outcome in ART preterm infants differs from that of spontaneously conceived (SC) preterm infants.

METHODS

Data were prospectively collected in infants born ≤ 32 weeks after ART or SC. We calculated a composite index of severe morbidity (based on occurrences of severe necrotizing enterocolitis, severe intraventricular haemorrhage, periventricular leukomalacia or bronchopulmonary dysplasia). Survival rate without severe morbidity was compared between the two groups.

RESULTS

Six hundred and twelve preterm infants were hospitalized in our tertiary care centre: 81 in ART group and 521 in SC group. In the ART group, twin pregnancy (69.1% vs. 15.9%, p < 0.001) and inborn delivery (98.8% vs. 90.0%, p < 0.01) were more frequent. Gestational age (29 vs. 28 weeks, p < 0.05) and birth weight (1100 vs. 1020 g, p < 0.001) were also higher. Survival without severe morbidity was significantly higher in ART infants (76.5% vs. 55.2%, p < 0.001), with the difference mainly observed in infants born ≤ 28 weeks (22.9% vs. 55.7%, p < 0.001).

CONCLUSION

Assisted reproductive technologies was not associated with adverse neonatal outcome. Differences in pregnancy and neonatal characteristics probably explain the increased survival without severe morbidity in ART infants.

Obstetric outcome and long-term follow up of children conceived through assisted reproduction

Most children born after assisted reproduction techniques are healthy. The most important risk associated with in-vitro fertilisation is the higher multiple birth rate, which may result in increased child morbidity because several embryos are transferred at each cycle. Single-embryo transfer reduces this risk dramatically. Large registry studies and meta-analyses have indicated a small but statistically significantly increased risk of congenital malformations among children born after in-vitro fertilisation. Other risks, such as preterm birth and low birth weight seem to be associated more with parental characteristics than the in-vitro fertilisation technique. All knowledge about children conceived through in-vitro fertilisation is based on observational studies, with risks of bias and confounders. It is possible that pregnancies and children resulting from in-vitro fertilisation are more carefully monitored and seek health care more frequently, resulting in more health problems being discovered. Continuous follow up of children after in-vitro fertilisation is of great importance, particularly as new techniques are constantly being introduced.

Neurodevelopmental outcomes of twins

In population-based studies, the prevalence of neurodevelopmental disability is consistently higher in twins than singletons. This is largely because birth weight and gestational age (GA) distributions of twin births are shifted to the left when compared with singleton births, and lower birth weight and lower GA are associated with increased risk of neurodevelopmental disability. From a pathophysiologic perspective, a question of interest is whether neurodevelopmental outcomes of twins differ from singletons after controlling for covariates. If significant differences in outcomes persist, this would suggest that the twining process itself or something intrinsic to shared life in the womb may be responsible for observed differences. From a clinical perspective, when counseling parents at risk for preterm delivery of twins, it is useful to understand how twin outcomes compare relative to singleton outcomes at the same birth weight or GA. The purpose of this review is to examine the long-term neurodevelopmental outcomes of twins compared with singletons with control for important covariates.

In vitro fertilization and risk of childhood leukemia in Greece and Sweden

BACKGROUND

Cancer risk in children born after in vitro fertilization (IVF) remains largely unknown. We aimed to investigate risk of leukemia and lymphoma following IVF using two nationwide datasets.

METHODS

The hospital-based case-control study in Greece derived from the National Registry for Childhood Hematological Malignancies (1996-2008, 814 leukemia and 277 lymphoma incident cases with their 1:1 matched controls). The Swedish case-control study was nested in the Swedish Medical Birth Register (MBR) (1995-2007, 520 leukemia and 71 lymphoma cases with their 5,200 and 710 matched controls) with ascertainment of incident cancer cases in the National Cancer Register. Study-specific and combined odds ratios (OR) were estimated using conditional logistic regression, with adjustment for possible risk factors.

RESULTS

Nationwide studies pointed to similar size excess risk of leukemia following IVF, but to a null association between IVF and lymphoma. The proportion of leukemia cases conceived through IVF was 3% in Greece and 2.7% in Sweden; prevalence of IVF in matched controls was 1.8% and 1.6%, respectively. In combined multivariable analyses, the increased risk of leukemia was confined to age below 3.8 years (OR = 2.21; 95% confidence interval, CI: 1.27-3.85) and to acute lymphoblastic leukemia (ALL) (OR = 1.77; 95% CI: 1.06-2.95) with no sufficient evidence of excess risk for other leukemias (OR = 1.34; 95% CI: 0.38-4.69). Following IVF, OR for ALL was 2.58 (95% CI: 1.37-4.84) before age 3.8 and 4.29 (95% CI: 1.49-12.37) before age 2 years.

CONCLUSIONS

IVF seems to be associated with increased risk of early onset ALL in the offspring.

Cerebral palsy and assisted conception

Assisted reproductive technologies have been widely used over the past 30 years, and 1% to 4% of births worldwide are products of these technologies. However, adverse health outcomes related to assisted reproductive technologies, including cerebral palsy, have been reported. We extracted and reviewed all relevant studies cited by Medline from 1996 to 2010 evaluating the role of assisted reproductive technologies as a causative factor for cerebral palsy and poor long-term neurologic outcome. The research suggests that multiple pregnancy, preterm delivery, and babies small for gestational age are factors in the development of cerebral palsy. The vanishing embryo syndrome may also play a role. We review the evidence for these potentially causative factors, as well as their implications for embryo transfer policies.

The effects of multiple pre- and perinatal risk factors on the occurrence of cerebral palsy. A Norwegian register based study

AIMS

To examine the effects of multiple risk factors on cerebral palsy (CP).

MATERIALS/METHODS

For 176,591 Norwegian infants born 1996-98 and surviving the early neonatal period, data on a number of potential pre- and perinatal risk factors (RFs) for CP were available in the Medical Birth Registry of Norway. For 241 children with CP detailed clinical data were available in the Norwegian CP registry.

RESULTS

In children born at term, 31% had no RF, and none had five or more, while in children born preterm, 9% had no RF in addition to prematurity (p < 0.001 vs. term), and 5% had five or more (p < 0.02 vs. term). In both groups, few children shared the same combination of RFs. Interdependent sequences were more often observed among children born preterm than at term (p < 0.001 vs. term). The most detrimental effect was observed for the combination of maternal disease and low 5-min Apgar score, registered in 11.2% of children with CP. The combination of maternal disease and premature birth had an interaction contrast ratio of 9.25 (CI: 3.56; 14.94), which may be consistent with biological interaction.

CONCLUSIONS

The majority of children with CP born at term most likely had an antenatal or single cause, suggesting individual susceptibility to an injury. The majority of children born preterm, had combinations or sequences of antenatal and perinatal risk factors as the most likely cause of CP.

Preterm deliveries that result from multiple pregnancies associated with assisted reproductive technologies in the USA: a cost analysis

PURPOSE OF REVIEW

Simultaneous transfer of multiple embryos in an assisted reproductive technology (ART) cycle results in a high rate of multiple pregnancy. Besides the medical complications associated with multiple pregnancy, the financial burden of the resultant preterm infants is also substantial. The current review evaluates the costs associated with the care of preterm infants that are born as a result of ART-associated multiple pregnancies.

RECENT FINDINGS

In 2006, 30% of all ART live births were multiple infant deliveries in the USA. This resulted in 48% of all ART neonates being the product of a multiple infant delivery. In the same year, 62% of ART twins and 97% of ART triplets were delivered preterm, corresponding to approximately 17 000 infants. The Board of Health Sciences Policy has estimated the mean cost of each preterm infant to be US$ 51 600. Therefore, the financial burden of ART-associated preterm deliveries is estimated to be approximately US$ 1 billion annually. This figure has remained essentially unchanged between 2001 and 2006, despite decreasing number of embryos transferred, due to increasing total number of ART cycles performed.

SUMMARY

Preterm deliveries that result from ART-associated multiple pregnancies add a substantial burden to overall US healthcare expenditure annually. Policies limiting the number of embryos transferred should be considered with a perspective to increase elective single embryo transfers.

Childhood outcomes of assisted reproductive technology

There is a large population of children conceived via assisted reproductive technology (ART), which continues to increase worldwide, without a clear understanding of associated long-term outcomes. ART children are more likely to be the result of multiple pregnancies, and thus to be born prematurely or low birthweight. There is growing evidence that ART children are phenotypically and biochemically different from naturally conceived children, but the mechanism(s) leading to these changes have not been elucidated. There is a possible increased risk of rare imprinted gene disorders in these children. However, it remains unclear whether more subtle changes in DNA methylation occur commonly, leading to differences in gene expression and phenotype in ART children. Although an increased risk of cancer among ART children has been reported, the role of ART in the development of cancer has not been demonstrated. Further research and ongoing surveillance of ART children is essential to better understand the possible effects of ART on the long-term health of this population.

Maternal risk factors for small-for-gestational age newborns in Japanese dichorionic twins

AIM

To investigate the maternal risk factors for small-for-gestational age (SGA) newborns in Japanese dichorionic (DC) twins.

METHODS

A retrospective study was conducted from 2003 to 2008 on 340 DC twin pregnancies resulting in two live births. Newborns were classified as SGA if their birth weight was below the 10th percentile according to Japanese singleton norms. Statistical differences were evaluated between pregnancies resulting in appropriate-for-gestational age (AGA) pairs and those resulting in at least one SGA neonate.

RESULTS

The study population consisted of AGA/AGA (50.8%), AGA/SGA (37.0%) and SGA/SGA pairs (12.0%). Logistic regression analysis identified significant interrelations for SGA with maternal nulliparity (odds ratio [OR] 0.52, 95% confidence interval [CI] 0.30-0.91), smoking (OR 3.25, 95% CI 1.09-9.66), assisted reproductive technology (OR 0.52, 95% CI 0.30-0.89), pregnancy-induced hypertension (OR 2.00, 95% CI 1.01-4.31), pregravid weight (kg) (unitary OR 0.94, 95% CI 0.91-0.97) and monthly weight gain (kg/month) (unitary OR 0.25, 95% CI 0.14-0.44). Bivariable receiver operating characteristic curves were generated for monthly weight gain (area under the curve [AUC] 0.626, cutoff 1.41 kg/month, P<0.001) and total weight gain (AUC 0.615, cutoff 14.0 kg, P<0.001).

CONCLUSION

Cigarette smoking and weight gain control are relatively modifiable factors for which interventional management is necessary to avoid perinatal problems arising from SGA pregnancy. Further studies are needed to investigate optimal nutrition, health guidance and subsequent weight gain control that lead to concrete improvement in maternal and infant prognoses.

Parental infertility and cerebral palsy in children

BACKGROUND

Children born after in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) have been reported to have a higher risk of cerebral palsy (CP), perhaps due to the higher frequency of preterm birth, multiple births or vanishing embryo in the pregnancies. However, it has been suggested that the underlying infertility may be part of the pathway. In this study, we examined whether untreated subfecundity (measured by time to pregnancy) or infertility treatment was associated with an increased risk of CP in the offspring.

METHODS

Using the Danish National Birth Cohort (1997-2003), we compared children born after 0-2 months of waiting time to pregnancy (n = 35 848) with those born after a time to pregnancy of 3-5 months (n = 15 361), 6-12 months (n = 11 528) and >12 months (n = 7387), as well as those born after IVF/ICSI (n = 3617), ovulation induction with or without intrauterine insemination (n = 3000), and unplanned pregnancies (n = 13 462). CP cases were identified through the Danish CP Register.

RESULTS

In total, 165 (0.18%) children were diagnosed with CP in the entire cohort. We found no significant association between time to pregnancy and the risk of CP in children conceived spontaneously. Children born after IVF/ICSI had an increased risk of CP, even after adjustment for preterm birth and multiplicity (hazard ratio 2.30, 95% confidence interval 1.12-4.73).

CONCLUSIONS

Subfecundity per se did not appear to be associated with the risk of CP in children, whereas being born after IVF/ICSI conferred an increased risk.

Cerebral palsy in children born after in vitro fertilization. Is the risk decreasing?

BACKGROUND

Infants born after in vitro fertilization (IVF) differ from spontaneously conceived infants in a number of aspects which could increase the risk for future cerebral palsy (CP), e.g., multiple births, preterm births, neonatal complications.

AIMS

To follow up children conceived by IVF with respect to risk for CP.

METHODS

Infants born after IVF were identified from all IVF clinics in Sweden 1982-2007. Perinatal characteristics were obtained by linkage with the Medical Birth Register. The presence of CP in children born after IVF and in other children was identified from the Patient Register which contains diagnoses given at hospitalizations or specialist outpatient clinics. The risk for CP after IVF was studied after adjustment for year of birth, maternal age, parity, and smoking, all factors which co-vary both with IVF and with CP. Stratification was made for singletons and multiple births and for various neonatal outcomes.

RESULTS

The adjusted odds ratio for CP after IVF was 1.81 (95% confidence interval, 95% CI 1.52-2.13), lower and not statistically significant when singletons or when unlike-sexed twins were analyzed. Stratification for various neonatal characteristics also reduced odds ratios to non-significant levels. For the last few years of the study (2004-2007) when the twinning rate after IVF was <10%, the odds ratio for CP was 0.97 (95% CI 0.57-1.66).

CONCLUSIONS

The moderately increased risk for CP was most likely a consequence of an increased risk of neonatal morbidity, notably associated with multiple births.

Cerebral palsy and assisted reproductive technologies: a case-control study

AIM

To determine whether assisted reproductive technologies (ART) were more likely to be the method of conception in singletons with cerebral palsy (CP) than in those without CP.

METHOD

Singletons with CP born between 1991 and 2004 were selected from the Victorian Cerebral Palsy Register and matched for birth year to two singletons randomly selected from the Victorian Perinatal Data Collection Unit. Data from both sources were linked to records from three ART centres. Conditional logistic regression was used to assess the association between CP and aspects of conception using ART. Multivariate models were adjusted for parity, previous miscarriages, sex, gestational age, birthweight, and weight for gestational age.

RESULTS

We identified 1241 singletons with CP (males n=721 [58%], females n=420 [42/100]; motor type: spastic [87%; unilateral 37%; bilateral 63%], ataxic n=60 [5/100], dyskinetic n=46 [4/100], hypotonic n=29 [2/100], unknown n=25 [2/100]. Gross Motor Function Classification System levels were I n=363 [29/100], II n=297 [24/100], III n=137 [11/100], IV n=160 [13/100], V n=192 [15/100], and unknown n=92 [7/100]). Sixteen (1.3/100) of the children with CP and 25 (1.0/100) of 2482 children without CP were conceived using ART. There was no significant increase in the odds of children with CP being conceived using ART (adjusted odds ratio 1.19, 95% confidence interval (CI) 0.63, 2.24) nor in the odds of them being conceived by a subfertile couple without ART (adjusted odds ratio 2.7, 95% CI 0.87, 8.36).

INTERPRETATION

Singleton conception using ART is not strongly associated with an increased risk of CP.

Multiplicity and early gestational age contribute to an increased risk of cerebral palsy from assisted conception: a population-based cohort study

BACKGROUND

This paper assesses the risk of cerebral palsy (CP) in children born after assisted conception compared with children born after natural conception (NC).

METHODS

This population based follow-up study included all 588,967 children born in Denmark from 1995 to 2003. Assisted conception was defined as IVF, with or without ICSI, and ovulation induction (OI), with or without subsequent insemination.

RESULTS

There were 33 139 (5.6%) children born in Denmark from 1995 to 2003 as a result of assisted conception and through to June 2009, 1146 (0.19%) children received a CP diagnosis. Children born after assisted conception had an increased risk of a CP diagnosis, crude hazard rate ratio (HRR) 1.90 (95% CI: 1.57-2.31) compared with NC children. Divided into IVF and OI children compared with NC children, the risk was HRR 2.34 (95% CI: 1.81-3.01) and HRR 1.55 (95% CI: 1.17-2.06), respectively. When we included the intermediate factors multiplicity and gestational age in multivariate models, the risk of CP in assisted conception disappeared. In general, children with CP born after assisted conception had similar CP subtypes and co-morbidities as children with CP born after NC.

CONCLUSION

The risk of CP is increased after both IVF and OI. The increased risk of CP in children born after assisted conception, and in particular IVF, is strongly associated with the high proportion of multiplicity and preterm delivery in these pregnancies. A more widespread use of single embryo transfer warrants consideration to enhance the long-term health of children born after IVF.