Trends in perinatal health after assisted reproduction: a Nordic study from the CoNARTaS group

Assessing the impact of medically assisted reproduction on autism spectrum disorder risk

PURPOSE

Techniques of medically assisted reproduction interact with the embryo at crucial developmental stages, yet their impact on the fetus and subsequent child's health remains unclear. Given rising infertility rates and more frequent use of fertility treatments, we aimed to investigate if these methods heighten the risk of autism spectrum disorder (ASD) in children.

METHODS

A population-based cohort study was conducted at Soroka University Medical Center, a tertiary referral hospital, encompassing singleton births. The incidence of ASD in offspring, incorporating either hospital or community-based diagnoses, was compared in relation to the conception method. To examine the cumulative incidence of ASD, a Kaplan-Meier survival curve was utilized. Cox proportional hazards model was employed to adjust for confounders.

RESULTS

Among 115,081 pregnancies, 0.5% involved ovulation induction (OI) and 1.7% in vitro fertilization (IVF), with the rest conceived naturally. Fertility treatments were more common in older patients and linked to more diabetes, hypertensive disorders, preterm, and cesarean deliveries. Out of 767 ASD diagnoses, offspring from OI and IVF had higher initial ASD rates (2.1% and 1.3%) than natural conceptions (0.6%). In a Cox model accounting for maternal age, ethnicity, and gender, neither OI nor IVF was significantly associated with ASD. The adjusted hazard ratios were 0.83 (95% CI 0.48-1.43) for OI and 1.34 (95% CI 0.91-1.99) for IVF. When considering fertility treatments combined, the association with ASD remained non-significant (aHR 1.11, 95% CI 0.80-1.54, p = 0.52).

CONCLUSION

Fertility treatments, including OI and IVF, do not exhibit a significant association with heightened ASD risk in offspring.

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.

Long-Term Effects of ART on the Health of the Offspring

Assisted reproductive technologies (ART) significantly increase the chance of successful pregnancy and live birth in infertile couples. The different procedures for ART, including in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), intrauterine insemination (IUI), and gamete intrafallopian tube transfer (GIFT), are widely used to overcome infertility-related problems. In spite of its inarguable usefulness, concerns about the health consequences of ART-conceived babies have been raised. There are reports about the association of ART with birth defects and health complications, e.g., malignancies, high blood pressure, generalized vascular functional disorders, asthma and metabolic disorders in later life. It has been suggested that hormonal treatment of the mother, and the artificial environment during the manipulation of gametes and embryos may cause genomic and epigenetic alterations and subsequent complications in the health status of ART-conceived babies. In the current study, we aimed to review the possible long-term consequences of different ART procedures on the subsequent health status of ART-conceived offspring, considering the confounding factors that might account for/contribute to the long-term consequences.

Fetal growth disorders following medically assisted reproduction: due to maternal context or techniques? A national French cohort study

RESEARCH QUESTION

What part do maternal context and medically assisted reproduction (MAR) techniques play in the risk of fetal growth disorders?

DESIGN

This retrospective nationwide cohort study uses data available in the French National Health System database and focuses on the period from 2013 to 2017. Fetal growth disorders were divided into four groups according to the origin of pregnancy: fresh embryo transfer (n = 45,201), frozen embryo transfer (FET, n = 18,845), intrauterine insemination (IUI, n = 20,179) and natural conceptions (n = 3,412,868). Fetal growth disorders were defined from the percentiles of the weight distribution according to gestational age and sex: small and large for gestational age (SGA and LGA) if <10th and >90th percentiles, respectively. Analyses were performed using univariate and multivariate logistic models.

RESULTS

Compared with births following natural conception, multivariate analysis showed that the risk of SGA was higher for births following fresh embryo transfer and IUI (adjusted odds ratio [aOR] 1.26 [1.22-1.29] and 1.08 [1.03-1.12], respectively) and significantly lower following FET (aOR 0.79 [0.75-0.83]). The risk of LGA was higher for births following FET (aOR 1.32 [1.27-1.38]), especially in artificial cycles when compared with ovulatory cycles (aOR 1.25 [1.15-1.36]). In the subgroup of births without any obstetrical or neonatal morbidity, the same increased risk of SGA and LGA were observed following fresh embryo transfer or IUI and FET (aOR 1.23 [1.19-1.27] or 1.06 [1.01-1.11] and aOR 1.36 [1.30-1.43], respectively).

CONCLUSIONS

An effect of MAR techniques on the risks for SGA and LGA is suggested independently from maternal context and obstetrical or neonatal morbidities. Pathophysiological mechanisms remain poorly understood and should be further evaluated, as well as the influence of embryonic stage and freezing techniques.

Subjects Conceived through Assisted Reproductive Technologies Display Normal Arterial Stiffness

Multiple studies reported signs of vascular dysfunction in subjects conceived through assisted reproductive technologies (ART). The assessment of arterial stiffness in this cohort seems beneficial for risk stratification. Regional arterial stiffness of the abdominal aorta (AAO) and the common carotid arteries (CCA) was evaluated sonographically using two-dimensional speckle tracking in subjects conceived through ART and spontaneously conceived peers. Global arterial stiffness was assessed utilizing an oscillometric blood pressure device. The cohorts of 67 ART subjects and 86 spontaneously conceived peers (11.31 (8.10-18.20) years vs. 11.85 (8.72-18.27) years, p = 0.43) did not differ significantly in parameters of regional and global arterial stiffness. In the sub-analysis of study participants ≥10 years of age, markers of arterial stiffness did not display significant differences between both groups. However, a higher tendency of brachial systolic blood pressure was demonstrated in the ART cohort compared to the control group (120.18 ± 9.57 mmHg vs. 116.55 ± 8.05 mmHg, p = 0.050). The present study displayed no significant differences in arterial stiffness between ART subjects and spontaneously conceived peers. Moreover, this study suggests that arterial stiffness does not elevate more profoundly in ART subjects with increasing age. Further studies are required for a more detailed cardiovascular risk stratification of the ART cohort.

Single-embryo transfer implies quality of care in reproductive medicine

This review appraises evidence on the difference between single- and double-embryo transfer (SET, DET) in assisted reproductive technology (ART) regarding the four healthcare quality dimensions most important to fertility patients and doctors. Regarding safety, not only does DET create the uncontested perinatal risks of twin pregnancies, but compelling evidence has added that singleton pregnancies after a vanishing twin also have poorer perinatal outcomes. SET is as effective as DET, as shown by meta-analyses of randomized controlled trials, comparing two cycles of SET versus DET and shown by cumulative live birth rates of entire ART trajectories of up to six cycles. Proposing SET, which is safer than DET and as effective, as the gold standard is not irreconcilable with patient-centred care if patients are thoroughly informed on the reasoning behind the proposition and welcomed to challenge whether it fits their personal values. The cost-efficiency of SET is clearly higher, which has even induced certain countries to start reimbursing ART on the condition that SET is used. In conclusion, SET should be the gold standard offered to all patients. The question is not whether to apply SET but how to apply it in terms of patient selection, patient-centred counselling and coverage of treatment.

Obstetric Outcomes and Successful Reduction of Twin Pregnancies Achieved by In Vitro Fertilization

The use of in vitro fertilization methods around the world is constantly increasing. In some developed countries, up to 5% of newborns are as a result of pregnancies after IVF procedures. In vitro fertilization as one of the main and widespread methods for treatment of infertility is the main reason for the high frequency of multiple pregnancies, which, in many countries, is still too high. Most of the multiple pregnancies are in fact twin pregnancies. Twin pregnancies, regardless of how they are achieved, are associated with large number of complications compared with singleton ones. More often these pregnancies can lead to maternal complications and adverse pregnancy outcomes. Maternal complications include development of preeclampsia, gestational diabetes, placenta previa, placental abruption, premature rupture of membranes, antepartum and postpartum hemorrhage, and delivery by cesarean sections. Adverse pregnancy outcomes mostly include preterm birth (PTB), low birth weight (LBW), small for gestational age newborn (SGA), intrauterine growth restriction (IUGR), neonatal respiratory distress syndrome (RDS), and admission to neonatal intensive care unit (NICU). A number of studies have found differences in the course of twin pregnancies according to their mode of occurrence – spontaneous or after IVF. Some of them have found that twin pregnancies after IVF are associated with poorer obstetric and perinatal outcomes, others do not find such a difference, and there are even studies that find a better outcome in IVF twin pregnancies. Twin pregnancy is a common occurrence after IVF procedure, because multiple-embryo transfer is commonly regarded as an effective strategy to improve the likelihood of a successful pregnancy. Understanding the risks of these pregnancies should be a strong motive for the transfer of fewer embryos during IVF procedures. The most effective way to do this is to transfer a single-embryo into the uterus in cases, where this is justified and the chances of getting pregnant are high. An important element in achieving this goal is the use of methods for vitrification of embryos, which leads to a sufficiently high rate of clinical pregnancies after freezing of embryos obtained by IVF and their subsequent transfer after thawing in case of failure of fresh ET.

Medically Assisted Reproduction Treatment Types and Birth Outcomes

Medically assisted reproduction treatments are associated with adverse birth outcomes; however, those risks are unlikely to be associated with the infertility treatments themselves.

OBJECTIVE:

To compare risks of adverse birth outcomes among pregnancies conceived with and without medically assisted reproduction treatments.

METHODS:

Birth certificates were used to study birth outcomes of all neonates born in Utah from 2009 through 2017. Of the 469,919 deliveries, 52.8% (N=248,013) were included in the sample, with 5.2% of the neonates conceived through medically assisted reproduction. The outcome measures included birth weight, gestational age, low birth weight (LBW, less than 2,500 g), preterm birth (less than 37 weeks of gestation), and small for gestational age (SGA, birth weight less than the 10th percentile). Linear models were estimated for the continuous outcomes (birth weight, gestational age), and linear probability models were used for the binary outcomes (LBW, preterm birth, SGA). First, we compared the birth outcomes of neonates born after medically assisted reproduction and natural conception in the overall sample (between-family analyses), before and after adjustment for parental background and neonatal characteristics. Second, we employed family fixed effect models to investigate whether the birth outcomes of neonates conceived through medically assisted reproduction differed from those of their naturally conceived siblings (within-family comparisons).

RESULTS:

Neonates conceived through medically assisted reproduction weighed less, were born earlier, and were more likely to be LBW, preterm, and SGA than neonates conceived naturally. More invasive treatments (assisted reproductive technology [ART] and artificial insemination [AI] or intrauterine insemination) were associated with worse birth outcomes; for example, the proportion of LBW and preterm birth was 6.1% and 7.9% among neonates conceived naturally and 25.5% and 29.8% among neonates conceived through ART, respectively. After adjustments for various neonatal and parental characteristics, the differences in birth outcomes between neonates conceived through medically assisted reproduction and naturally were attenuated yet remained statistically significant; for example, neonates conceived through ART were at 3.2 percentage points higher risk for LBW (95% CI 2.4–4.1) and 4.8 percentage points higher risk for preterm birth (95% CI 3.9–5.7). Among siblings, the differences in the frequency of adverse outcomes between neonates conceived through medically assisted reproduction and neonates conceived naturally were small and statistically insignificant for all types of treatments.

CONCLUSION:

Medically assisted reproduction treatments are associated with adverse birth outcomes; however, those risks are unlikely to be associated with the infertility treatments itself.

Risk of mayor and minor birth defects in children conceived by assisted reproductive technology (IVF/ICSI): A prospective controlled cohort study

INTRODUCTION

About 0.2-6.1% of newborns in the developed world have been conceived by assisted reproductive techniques (ART). Higher rate of major and minor malformations have been described in this population, but the multiple possible confounders associated make it difficult to establish a direct causal relationship and the specific factors involved.

MATERIAL AND METHODS

To determine the risk of these malformations in our population, a collaborative prospective controlled cohort study was designed. We collected the specific ART-data related to the clinical gestation of women treated in a period of 2 years in the Reproduction Unit from a Spanish public tertiary-level hospital. 231 out of 267 newborns of these gestation (88%) participated in the study and were assessed by a pediatrician with expertise in Clinical Genetics and Dysmorphology at 12-20 and 26-40 months of age. At the same time a controlled group of children naturally conceived (NC) was selected according to the following criteria: the next NC newborn belonging to the same group of maternal and gestational age, and type of gestation (single or multiple). 230 controls were chosen and 208 participated in the study (90%).

RESULTS

Major malformations were presented in 7.8% of the ART-children and 7.2% of the controls, without founding statistically differences between groups. However, differences were found in the risk of some minor malformations such as capillary malformations and pigmentary lesions, higher in the ART-group. A recurrent pattern of craneofacial anomalies was also unexpectedly detected.

CONCLUSIONS

In spite of the high rate of major congenital malformations detected, there were no differences between groups. Thus, our results suggest that ART may affect the normal embryonic development but in a milder way than other confounding factors do. The facial phenotype identified has not previously been described, either the higher risk of capillary malformations and pigmentary lesions. More studies are needed to confirm this association.

Asthma and allergies in offspring conceived by ART: a systematic review and meta-analysis

BACKGROUND

Currently, 1 in 25 children born in Australia are conceived through ARTs such as IVF and ICSI. Worldwide over 8 million children have been born after ART. There is evidence that these children are at an increased risk of congenital malformations, preterm birth, low birth weight and neonatal morbidity. However, studies on long-term health outcomes of offspring conceived after ART are lacking. Atopic disorders, such as asthma, atopic dermatitis and various allergies are increasingly common within society, and concerns have been raised that ART increases the risk of atopy amongst offspring.

OBJECTIVE AND RATIONALE

The aim of this study was to systematically summarise and quantify the risk of atopic disorders in offspring conceived with ART compared to those conceived without ART.

SEARCH METHODS

A systematic review was conducted according to the PRISMA guidelines. Several systematic searches were performed in the following international databases: Medline, Embase, Cinahl, PsychINFO, AMED, Global Health and ISI Web of Science. Search terms utilised were all terms pertaining to ART, IVF, ICSI, asthma, atopic dermatitis and allergies. The search period was 1978-2021. Included observational studies stated a primary outcome of asthma or allergies in offspring conceived after ART, with a comparison group conceived without ART. Individual studies were scored on quality and risk of bias, using the Newcastle-Ottawa scale (NOS).

OUTCOMES

There were 26 studies which met the inclusion criteria; of these, 24 studies investigated asthma in offspring conceived after ART. While 10 studies, including the two largest population-based studies, reported a significantly increased risk of asthma in offspring conceived after ART (adjusted odds ratio (aOR) range: 1.20-2.38), 14 smaller cohort studies found no difference (aOR range 0.70-1.27). In the meta-analysis of the 14 highest-quality studies (NOS ≥ 7), a modest yet significantly increased risk of asthma was demonstrated in offspring conceived after ART [risk ratio (RR) 1.28 (1.08-1.51)]. Although heterogeneity in these 14 studies was high (I2 = 85%), the removal of outliers and high weight studies significantly reduced heterogeneity (I2 = 0% and I2 = 34% respectively) while still demonstrating a significantly increased risk [RR 1.19 (1.10-1.28) and RR 1.31 (1.03-1.65), respectively]. The increased asthma risk was also observed in most subgroup and sensitivity analyses. The allergy rates were not increased in offspring conceived after ART in 9 of 12 studies (aOR range 0.60-1.30). In summary, the findings of this systematic review and meta-analysis suggest a trend towards a significantly increased risk of asthma, but not allergies, in offspring conceived after ART. There was no evidence of publication bias in the asthma studies and minimal evidence of publication bias in the allergy studies (both P > 0.05).

WIDER IMPLICATIONS

Asthma brings considerable burden to the quality of life of individuals and to society. Hence, it is of great importance to untangle potential causal pathways. Although ART use is common, knowledge about its long-term health effects is required to provide evidence-based advice to couples considering ART, and to be vigilant for any potential adverse health effects on offspring conceived after ART.

Childhood growth of term singletons born after frozen compared with fresh embryo transfer

RESEARCH QUESTION

Is the growth of term singletons born after frozen embryo transfer (FET) comparable to those born after fresh embryo transfer and natural conception up to 5 years of age?

DESIGN

Observational cohort study in an academic medical centre and municipal child health clinics with repeated measurements carried out by medical professionals. Term singletons born after FET (n = 110) and fresh embryo transfer (n = 181) and their matched natural conception controls (n = 543) born in Oulu, Northern Finland, were included. Mean weights, lengths, heights and head circumferences at the ages of 4, 8 and 18 months and 3 and 5 years were compared. At 3 and 5 years, body mass indices were compared.

RESULTS

Childhood growth did not differ between term singletons born after FET, fresh embryo transfer and natural conception, correcting for exact age at measurement and adjusting for maternal body mass index and paternal height.

CONCLUSIONS

Similar growth between children born after FET, fresh embryo transfer and natural conception offers reassurance of the safety and feasibility of the steadily increasing use of embryo cryopreservation in assisted reproduction.

Changes in maternal risk factors and their association with changes in cesarean sections in Norway between 1999 and 2016: A descriptive population-based registry study

BACKGROUND

Increases in the proportion of the population with increased likelihood of cesarean section (CS) have been postulated as a driving force behind the rise in CS rates worldwide. The aim of the study was to assess if changes in selected maternal risk factors for CS are associated with changes in CS births from 1999 to 2016 in Norway.

METHODS AND FINDINGS

This national population-based registry study utilizes data from 1,055,006 births registered in the Norwegian Medical Birth Registry from 1999 to 2016. The following maternal risk factors for CS were included: nulliparous/≥35 years, multiparous/≥35 years, pregestational diabetes, gestational diabetes, hypertensive disorders, previous CS, assisted reproductive technology, and multiple births. The proportion of CS births in 1999 was used to predict the number of CS births in 2016. The observed and predicted numbers of CS births were compared to determine the number of excess CS births, before and after considering the selected risk factors, for all births, and for births stratified by 0, 1, or >1 of the selected risk factors. The proportion of CS births increased from 12.9% to 16.1% (+24.8%) during the study period. The proportion of births with 1 selected risk factor increased from 21.3% to 26.3% (+23.5%), while the proportion with >1 risk factor increased from 4.5% to 8.8% (+95.6%). Stratification by the presence of selected risk factors reduced the number of excess CS births observed in 2016 compared to 1999 by 67.9%. Study limitations include lack of access to other important maternal risk factors and only comparing the first and the last year of the study period.

CONCLUSIONS

In this study, we observed that after an initial increase, proportions of CS births remained stable from 2005 to 2016. Instead, both the size of the risk population and the mean number of risk factors per birth continued to increase. We observed a possible association between the increase in size of risk population and the additional CS births observed in 2016 compared to 1999. The increase in size of risk population and the stable CS rate from 2005 and onward may indicate consistent adherence to obstetric evidence-based practice in Norway.

Multiple births and low birth weight: Evidence from South Korea

OBJECTIVE

The proportion of multiple births has risen rapidly worldwide. Multiple births are likely to affect birth weight, which results in low birth weight (LBW) of less than 2500 g, possibly, because multiples are more likely to be born prematurely or less than 37 weeks into pregnancy. Using data from South Korea, this study aims to estimate the contribution of the rise in multiples to the rise in LBW incidence.

METHODS

Based on data from 2000 to 2017, we estimated the effect of multiples on LBW rates using linear regression analysis. Based on the regression analysis and the change in the proportion of multiples during this period, we calculated the contribution of the rise in multiples to the rise in LBW incidence using the total differential. In other words, we divided the change in LBW during the period due to the change in multiples by the total change during the period. The data are from the birth registry of the National Statistical Office, which contains information on the 8.4 million live births during the period 2000-2017.

RESULTS

We found that a 1 percentage point increase in multiples increases the proportion of LBWs by 0.495 percentage points. In addition, because the changes in the proportion of multiples and LBWs from 2000 to 2017 are 2.2 and 2.4 percentage points, respectively, 1.1 percentage points or 45.8% of the increase in LBWs over the period is due to the increase in multiples.

CONCLUSION

Since the Korean government introduced a measure to reduce the number of transferred embryos recently, one may expect that multiples in Korea would reduce in the near future, as it did in other countries. Subsequently, the incidence of LBW children is also likely to reduce, which is desirable in terms of the children's health outcomes.

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.

[Risk of mayor and minor birth defects in children conceived by assisted reproductive technology (IVF/ICSI): A prospective controlled cohort study]

INTRODUCTION

About 0.2-6.1% of newborns in the developed world have been conceived by assisted reproductive techniques (ART). Higher rate of major and minor malformations have been described in this population, but the multiple possible confounders associated, make it difficult to establish a direct causal relationship, and the specific factors involved.

MATERIAL AND METHODS

To determine the risk of these malformations in our population, a collaborative prospective controlled cohort study was designed. We collected the specific ART-data related to the clinical gestation of women treated in a period of 2 years in the Reproduction Unit from a Spanish public tertiary-level hospital. 231 out of 267 newborns of these gestation (88%) were exhausted assessed by a Clinical Geneticist expertise in Dysmorphology at 12-20 and 26-40 months of age. At the same time a controlled group of children naturally conceived (NC) was selected according to the following criteria: the next NC newborn belonging to the same group of maternal and gestational age, and type of gestation (single or multiple). 230 controls were chosen and 208 participated in the study (90%).

RESULTS

Major malformations were presented in 7.8% of the ART-children and 7.2% of the controls, without founding statistically differences between groups. However, differences were found in the risk of some minor malformations such as capillary malformations and pigmentary lesions, higher in the ART-group. A recurrent pattern of craneofacial anomalies was also unexpectedly detected.

CONCLUSIONS

In spite of the high rate of major congenital malformations detected, there were no differences between groups. Thus, our results suggest that ART may affect the normal embryonic development but in a milder way than other confounding factors do. The facial phenotype identified has not previously, either the higher risk of capillary malformations and pigmentary lesions. More studies are needed to confirm this association.

The Efficacy of Assisted Reproduction in Women with a Wide Spectrum of Chronic Diseases - A Review

Assisted reproductive technology (ART) treatments in women with underlying chronic diseases have become increasingly frequent. The objective of this review is to provide an overview of the literature examining the chance of having a live born child after ART in women with chronic diseases, compared to other women receiving ART. We focused on some of the most prevalent chronic diseases in women during their reproductive years, ie ulcerative colitis, Crohn's disease, rheumatoid arthritis, multiple sclerosis, epilepsy, hyperthyroidism, hypothyroidism, and diabetes mellitus. Secondly, we studied the chance of successful implantation. The literature search was performed in the database Pubmed.gov. including all studies published before October 2020. Title and abstracts of 58 papers were reviewed, 37 papers were excluded and other 8 studies were excluded after full-text evaluation. Only 13 papers were eligible for review. Results indicate that women with ulcerative colitis, Crohn's disease, rheumatoid arthritis, hyperthyroidism, and diabetes mellitus type 2 might have problems with low implantation rate or early embryo development during ART. On the contrary, the few studies on women with hypothyroidism, diabetes mellitus type 1, and epilepsy suggest an equivalent chance of a live birth compared to other women undergoing ART. A possible explanation behind these differences could reside in the disease-specific dysregulation of the innate or adaptive immune system. To our knowledge, this is the first review on ART in women with chronic diseases, and it has disclosed that the evidence in this area is indeed sparse. We encourage others to examine live birth after ART in women with chronic diseases.

High birth weight and large-for-gestational-age in singletons born after frozen compared to fresh embryo transfer, by gestational week: a Nordic register study from the CoNARTaS group

STUDY QUESTION

When do the differences in birth weights become apparent between singletons born after frozen embryo transfer (FET) and fresh embryo transfer (fresh ET)?

SUMMARY ANSWER

Mean birth weights after FET become significantly higher starting from gestational week (GW) 33 among boys and from GW 34 among girls.

WHAT IS KNOWN ALREADY

In recent years, there has been a steep rise in recorded FET treatments, enabling widespread use of elective single embryo transfer, thus reducing the risks associated with multiple gestations. However, singletons born after FET are heavier and there is a higher risk of large-for-gestational-age (LGA) (birth weight > 90 percentiles) compared to fresh ET. In contrast, risk of small-for-gestational-age (SGA, birth weight < 10 percentiles) is lower in singletons born after FET compared to fresh ET. The reasons, timing and consequences of these differences remain largely unclear. There is limited evidence about whether this difference in growth develops before the last trimester of pregnancy.

STUDY DESIGN, SIZE, DURATION

This retrospective Nordic register-based cohort study compared singletons born after FET (n = 17 500) to singletons born after fresh ET (n = 69 510) and natural conception (NC, n = 3 311 588). All live born singletons born between the years 2000 and 2015 in Denmark, Norway and Sweden at gestational age ≥22 weeks were included from the population-based Committee of Nordic ART and Safety (CoNARTaS) study population.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Children born after FET were compared to those born after fresh ET and NC for mean birth weight and proportion of LGA and SGA for each GW at birth. Chi-square test and tests for relative proportions were used to compare categorical variables and Student's t-test was used to compare continuous variables. Adjusted odds ratios (aORs) for LGA and SGA were calculated using logistic regressions, adjusting for year of birth, maternal age, parity, BMI, chronic hypertension, diabetes, smoking and offspring sex.

MAIN RESULTS AND THE ROLE OF CHANCE

Mean birth weights were significantly higher after FET compared to fresh ET starting from GW 33 (range from 75 g to 228 g by week) for boys and starting from GW 34 (range from 90 g to 236 g by week) for girls. Boys born after FET had a significantly higher proportion of LGA (11.0-15.1%) at birth between GW 36 and 42, compared to those born after fresh ET (7.1-9.4%) (range from P < 0.001 to P = 0.048 by week). For girls born after FET, the difference was seen between GW 37 and 42 (10.6-13.4%) compared to those born after fresh ET (6.6-8.0%) (range from P < 0.001 to P = 0.009 by week).The proportion of SGA was significantly lower among boys born after FET (7.6-8.7%) compared to fresh ET (11.9-13.6%) between GW 36 and 42 (range from P < 0.001 to P = 0.016 by week). For girls born after FET, the difference was seen between GW 38 and 42 (7.0-9.3%) compared to those born after fresh ET (13.0-14.6%) (P < 0.001). The proportion of LGA (12.3-15.1%) was significantly higher for boys born after FET between GW 38 and 41 (P < 0.001) and for girls born after FET (12.6-13.4%) between GW 37 and 40 (range from P < 0.001 to P = 0.018 by week), compared to naturally conceived boys (9.7-9.9%) and girls (9.0-10.0%). All singletons born after FET had a higher risk of LGA compared to singletons born after fresh ET (aOR 1.87, 95% CI 1.76-1.98) and singletons born after NC (aOR 1.28, 95% CI 1.22-1.35).

LIMITATIONS, REASONS FOR CAUTION

There may be residual confounding factors that we were not able to control for, most importantly the causes of preterm birth, which may also influence foetal growth. A further limitation is that we have no knowledge on growth patterns between implantation and GW 22. Finally, the number of children born extremely preterm or post-term was limited even in this large study population.

WIDER IMPLICATIONS OF THE FINDINGS

This is, to date, the largest study on birth weights among preterm and term ART singletons with a population-based design and NC control group. The results suggest that the freeze-thaw process is associated with higher birthweights and greater risk of LGA at least in the last trimester of pregnancy. This is an important aspect of the safety profile of ART. More research is needed on the long-term outcome of these children.

STUDY FUNDING/COMPETING INTEREST(S)

The CoNARTaS collaboration has received the following funding: the Nordic Trial Alliance: a pilot project jointly funded by the Nordic Council of Ministers and NordForsk [71450], the Central Norway Regional Health Authorities [46045000], the Norwegian Cancer Society [182356-2016], the Nordic Federation of Obstetrics and Gynaecology [NF13041, NF15058, NF16026 and NF17043], the Interreg Öresund-Kattegat-Skagerrak European Regional Development Fund (ReproUnion project) and the Research Council of Norway's Centre of Excellence funding scheme [262700]. None of the authors have any competing interests to declare.

TRIAL REGISTRATION NUMBER

ISRCTN11780826.

Fetal fraction of cell-free DNA in pregnancies after fresh or frozen embryo transfer following assisted reproductive technologies

STUDY QUESTION

Is the fetal fraction (FF) of circulating cell-free DNA (cfDNA) affected in pregnancies following ART treatment with either fresh or frozen embryo transfer (ET) compared with natural conception?

SUMMARY ANSWER

This study shows a significant reduction in the FF in ART patients compared with naturally conceived pregnancies, which seems to be more pronounced after fresh ET compared with frozen ET.

WHAT IS KNOWN ALREADY

Non-invasive prenatal testing (NIPT) is based on cfDNA in maternal blood, of which about 10% is of placental origin and thus represents the fetal karyotype. Validation studies have demonstrated a high sensitivity, specificity and positive predictive value of NIPT for the detection of fetal trisomy 21, 18 and 13. Nevertheless, the FF of cfDNA is an important factor for NIPT test accuracy. Several studies have found a reduction in FF for pregnancies following ART in comparison with natural conception. However, knowledge on how the FF is affected in ART pregnancies after fresh ET compared with frozen ET is very limited.

STUDY DESIGN, SIZE, DURATION

The study was designed as a case-control study. A total of 54 women with an ongoing pregnancy following ART treatment were included. After exclusion for different reasons, statistical analyses were based on 23 NIPT samples from pregnant women treated with fresh ET and 26 NIPT samples from pregnant women treated with frozen-thawed ET in a modified natural cycle. Women were included between February 2018 and November 2018. The results were compared with a control group of 238 naturally conceived pregnancies with a high-risk result from the combined first trimester screening (cFTS).

PARTICIPANTS/MATERIALS, SETTING, METHODS

The study included women from the Fertility Clinics at Copenhagen University Hospital Hvidovre and Copenhagen University Hospital Rigshospitalet. Blood samples for NIPT analysis were drawn between 11 + 0 and 14 + 2 weeks of gestation and were all analyzed at the NIPT Center at Copenhagen University Hospital Hvidovre. The NIPT-test was performed by massive-parallel whole-genome sequencing. The FF was determined using the SeqFF algorithm.

MAIN RESULTS AND THE ROLE OF CHANCE

We found a reduction in FF in ART patients compared with naturally conceived pregnancies, and the reduction was more pronounced for ART pregnancies after fresh ET (mean FF = 0.049) compared with frozen ET (mean FF = 0.063) (multivariate analysis adjusted for maternal BMI, P = 0.02). Another multivariate analysis, adjusted for BMI and multiples of median (MoM) values for pregnancy-associated plasma protein-A (PAPP-A), demonstrated a significantly reduced FF for ART pregnancies (mean FF = 0.056) compared with naturally conceived pregnancies (mean FF = 0.072) (P < 0.0001). We found that FF was significantly reduced with increasing maternal BMI (P < 0.0001) and with decreasing MoM values of PAPP-A (P = 0.003).

LIMITATIONS, REASONS FOR CAUTION

A limitation of our study design was the relatively small sample size. Another limitation was that the control group was not matched with the ART-treated women. The majority of the women from the control group had a high risk from cFTS, thereby their biochemical markers were diverging. However, the biochemical markers for the ART-treated women with fresh or frozen ET were not divergent within the subgroups.

WIDER IMPLICATIONS OF THE FINDINGS

Concurrent with other studies demonstrating a reduced FF for singleton pregnancies after ART treatment compared with naturally conceived pregnancies, we found a reduction in FF between the two groups. This is one of the first studies to examine FF in ART pregnancies after fresh ET compared with frozen ET, hence the existing knowledge is limited. We find that FF is even more reduced in pregnancies following fresh ET compared with frozen ET, which might possibly reflect the predisposition of being small for gestational age after fresh ET compared with natural cycle frozen ET.

STUDY FUNDING/COMPETING INTEREST(S)

The study was supported by the A.P. Møller og Hustru Chastine Mc-Kinney Møllers Fond til almene Formaal (the A.P. Møller Foundation for General Purposes). All authors declare no conflicts of interest.

TRIAL REGISTRATION NUMBER

NA.

Ninth-grade school achievement in Danish children conceived following fertility treatment: a population-based cohort study

OBJECTIVE

To assess whether academic achievement among children conceived following fertility treatment is different from that of children born to fertile women while also considering the underlying infertility.

DESIGN

Population-based cohort study.

SETTING

Denmark.

PATIENT(S)

The study population consisted of all 154,536 firstborn, live-born, singleton children in Denmark between 1995 and 2000 who completed their ninth grade with an examination.

INTERVENTION(S)

The Danish Infertility Cohort was used to identify children conceived after fertility treatment (n = 10,099), and information on mean school marks was obtained from Statistics Denmark.

MAIN OUTCOME MEASURE(S)

Linear regression models were used to estimate mean differences (MDs) and 95% confidence intervals (CIs). Multiple logistic regression models were used to estimate odds ratios (OR) and 95% CI of not passing the ninth-grade examination.

RESULTS

The crude overall mean marks for children conceived after the various fertility treatment procedures were in general higher than in children born to fertile women. However, after adjustment for potential confounders, the overall mean marks were statistically significantly lower for children conceived after the various fertility treatment procedures (e.g., any fertility treatment: MD -0.13; 95% CI -0.18, -0.08) compared with children born to fertile women. Further, children conceived after any fertility treatment had a statistically significant lower crude likelihood of not passing the ninth-grade examination (OR 0.66; 95% CI 0.53, 0.81) compared with children born to fertile women, whereas no difference was observed in the confounder adjusted analyses (OR 1.15; 95% CI 0.89, 1.49). When children born to women requiring fertility assistance but without fertility treatment in the index pregnancy were used as a reference group, no differences in the adjusted overall mean marks and the likelihood of not passing the ninth grade with an examination were observed.

CONCLUSION

Our findings indicate that fertility treatment per se is not associated with lower school marks and the likelihood of not passing the ninth grade with an examination. Hence, we suggest that factors related to both fertility problems and cognitive development may more likely explain the slightly lower academic performance (i.e., modest lower mean marks) among children conceived after fertility treatment.

The efficacy of assisted reproductive treatment in women with epilepsy

RESEARCH QUESTION

The question of interest for this study was to examine the chance of a live birth following assisted reproductive technology (ART) treatment in women with epilepsy compared with women without epilepsy. In sub-analyses, the chance of biochemical and clinical pregnancies, and the impact of antiepileptic drugs (AED) treatment prior to embryo transfer, was analysed.

DESIGN

This register-based cohort study was based on the Danish ART register comprising all women who underwent embryo transfer during 2006 to 2017, which included 730 ART treatments in 264 women with a history of epilepsy, and 128,387 ART treatments in 42,938 women without epilepsy. Adjustments were made for comorbidity, women's age, calendar year, type of infertility treatment and cause of infertility. A possible impact of AED use at the time of embryo transfer was studied in a sub-analysis. The primary outcome was live birth within a period of 140-308 days after the date of embryo transfer.

RESULTS

The adjusted odds ratio for a live birth per embryo transfer in women with epilepsy, relative to women without epilepsy, was 1.06 (95% confidence interval [CI] 0.88-1.28). The adjusted odds ratio for a live birth among users of an AED was 1.22 (95% CI 0.77-1.92) relative to women who had stopped the use of AED prior to embryo transfer.

CONCLUSIONS

The chances of a live birth per embryo transfer were similar in women with and without epilepsy. These are novel and reassuring findings on the efficacy of infertility treatment in women with epilepsy.

Defining critical factors in multi-country studies of assisted reproductive technologies (ART): data from the US and UK health systems

As the worldwide use of assisted reproductive technologies (ART) continues to grow, there is a critical need to assess the safety of these treatment parameters and the potential adverse health effects of their use in adults and their offspring. While key elements remain similar across nations, geographic variations both in treatments and populations make generalizability challenging. We describe and compare the demographic factors between the USA and the UK related to ART use and discuss implications for research. The USA and the UK share some common elements of ART practice and in how data are collected regarding long-term outcomes. However, the monitoring of ART in these two countries each brings strengths that complement each other's limitations.

Time trends in placenta-mediated pregnancy complications after assisted reproductive technology in the Nordic countries

BACKGROUND

The use of assisted reproductive technology is increasing worldwide and conception after assisted reproduction currently comprises 3%-6% of birth cohorts in the Nordic countries. The risk of placenta-mediated pregnancy complications is greater after assisted reproductive technology compared with spontaneously conceived pregnancies. Whether the excess risk of placenta-mediated pregnancy complications in pregnancies following assisted reproduction has changed over time, is unknown.

OBJECTIVES

To investigate whether time trends in risk of pregnancy complications (hypertensive disorders in pregnancy, placental abruption and placenta previa) differ for pregnancies after assisted reproductive technology compared with spontaneously conceived pregnancies during 3 decades of assisted reproduction treatment in the Nordic countries.

STUDY DESIGN

In a population-based cohort study, with data from national health registries in Denmark (1994-2014), Finland (1990-2014), Norway (1988-2015) and Sweden (1988-2015), we included 6,830,578 pregnancies resulting in delivery. Among these, 146,998 (2.2%) were pregnancies after assisted reproduction (125,708 singleton pregnancies, 20,668 twin pregnancies and 622 of higher order plurality) and 6,683,132 (97.8%) pregnancies were conceived spontaneously (6,595,185 singleton pregnancies, 87,106 twin pregnancies and 1,289 of higher order plurality). We used logistic regression with post-estimation to estimate absolute risks and risk differences for each complication. We repeated analyses for singleton and twin pregnancies, separately. In subsamples with available information, we also adjusted for maternal body mass index, smoking during pregnancy, previous cesarean delivery, culture duration, and cryopreservation.

RESULTS

The risk of each placental complication was consistently greater in pregnancies following assisted reproductive technology compared with spontaneously conceived pregnancies across the study period, except for hypertensive disorders in twin pregnancies, where risks were similar. Risk of hypertensive disorders increased over time in twin pregnancies for both conception methods, but more strongly for pregnancies following assisted reproductive technology (risk difference, 1.73 percentage points per 5 years; 95% confidence interval, 1.35-2.11) than for spontaneously conceived twins (risk difference, 0.75 percentage points; 95% confidence interval, 0.61-0.89). No clear time trends were found for hypertensive disorders in singleton pregnancies. Risk of placental abruption decreased over time in all groups. Risk differences were -0.16 percentage points (95% confidence interval, -0.19 to -0.12) and -0.06 percentage points (95% confidence interval, -0.06 to -0.05) for pregnancies after assisted reproduction and spontaneously conceived pregnancies, respectively, for singletons and multiple pregnancies combined. Over time, the risk of placenta previa increased in pregnancies after assisted reproduction among both singletons (risk difference, 0.21 percentage points; 95% confidence interval, 0.14-0.27) and twins (risk difference, 0.30 percentage points; 95% confidence interval, 0.16-0.43), but remained stable in spontaneously conceived pregnancies. When adjusting for culture duration, the temporal increase in placenta previa became weaker in all groups of assisted reproductive technology pregnancies, whereas adjustment for cryopreservation moderately attenuated trends in assisted reproductive technology twin pregnancies.

CONCLUSIONS

The risk of placenta-mediated pregnancy complications following assisted reproductive technology remains higher compared to spontaneously conceived pregnancies, despite declining rates of multiple pregnancies. For hypertensive disorders in pregnancy and placental abruption, pregnancies after assisted reproduction follow the same time trends as the background population, whereas for placenta previa, risk has increased over time in pregnancies after assisted reproductive technology.

The impact of IVF on birthweight from 1991 to 2015: a cross-sectional study

STUDY QUESTION

Has birthweight (BW) changed over time among IVF-conceived singletons?

SUMMARY ANSWER

Singleton BW has increased markedly over the past 25 years.

WHAT IS KNOWN ALREADY

IVF conceived singletons have had a higher incidence of low BW compared to spontaneously conceived singletons, and this has raised concerns over long-term increased risks of cardio-metabolic disease. However, few causal links between IVF procedures and BW have been robustly established, and few studies have examined whether BW has changed over time as IVF techniques have developed.

STUDY DESIGN, SIZE, DURATION

A total of 2780 live born singletons conceived via IVF or ICSI treated in the reproductive medicine department of a single publicly funded tertiary care centre between 1991 and 2015 were included in this retrospective study. The primary outcome measure was singleton BW adjusted for gestational age, maternal parity and child gender. Multivariable linear regression models were used to estimate the associations between patient prognostic factors and IVF treatment procedures with adjusted BW.

PARTICIPANTS/MATERIALS, SETTING, METHODS

All singletons conceived at the centre following IVF/ICSI using the mother's own oocytes, and non-donated fresh or frozen/thawed embryos with complete electronic data records, were investigated. Available electronic records were retrieved from the Human Fertilization and Embryology Authority for dataset collation. Multiple linear regression analysis was used to evaluate associations between IVF treatment parameters and BW, after adjusting for the year of treatment and patient characteristics and pregnancy factors.

MAIN RESULTS AND THE ROLE OF CHANCE

In the primary multivariable model, singleton BW increased by 7.4 g per year (95% CI: 3.2-11.6 g, P = 0.001), an increase of close to 180 g throughout the 25-year period after accounting for gestational age, maternal parity, child gender, IVF treatment parameters, patient prognostic characteristics and pregnancy factors. Fresh and frozen embryo transfer-conceived singletons showed a similar increase in BW. Frozen/thawed embryo transfer conceived singletons were on average 53 g heavier than their fresh embryo conceived counterparts (95% CI: 3.7-103.3 g, P = 0.035).

LIMITATIONS, REASONS FOR CAUTION

The independent variables included in the study were limited to those that have been consistently recorded and stored electronically over the past two decades.

WIDER IMPLICATIONS OF THE FINDINGS

There has been a progressive BW increase in IVF singletons over time in one large centre with consistent treatment eligibility criteria. Such a change is not seen in the general population of live born singletons in the UK or other developed countries, and seems to be specific to this IVF population. This may be a reflection of changes in practice such as undisturbed extended embryo culture to the blastocyst stage, optimized commercial culture media composition, single embryo transfer and ICSI. Moreover, singletons conceived from frozen/thawed embryos had higher birth weights when compared to their fresh embryo transfer counterparts. The causal pathway is unknown; however, it could be due to the impact on embryos of the freeze/thaw process, self-selection of embryos from couples who produce a surplus of embryos, and/or embryo replacement into a more receptive maternal environment.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the EU FP7 project grant, EpiHealthNet (FP7-PEOPLE-2012-ITN-317146). The authors have no competing interests to declare.

TRIAL REGISTRATION NUMBER

N/A.

Perinatal outcome in children born after assisted reproductive technologies

Over the past 40 years access and effectiveness of assisted reproductive technologies (ART) have increased, and to date more than 8 million children have been conceived after ART globally. Most pregnancies resulting from ART are uncomplicated and result in the birth of healthy children. Yet, it is well known that pregnancies following ART are more likely to be affected by obstetric complications such as hypertensive disorders in pregnancy, preterm birth, and low birth weight compared with spontaneously conceived pregnancies. ART children are also at increased risk of birth defects. The majority of the problems arise as a result of multiple pregnancies and can be reduced by transferring a single embryo, thereby avoiding multiple pregnancies. New ART technologies are constantly introduced, and monitoring of the health of ART children is crucial.

In Vitro Fertilization Technology and Child Health

BACKGROUND

Just under 3% of children in Germany, and approximately 6% of children in some other countries, such as Denmark, are now being conceived with the aid of in vitro fertilization (IVF) technology. Alongside the increased risk of organ malformation, there is now evidence for functional abnormalities due to epigenetic modifications.

METHODS

This review is based on pertinent publications retrieved by a literature search on currently known associations of IVF therapy with malformations and functional abnormalities. The potential implications for the treatment of infertility are discussed.

RESULTS

The risk of congenital malformations is approximately one-third higher in children conceived with the aid of IVF technology than in other children; specifically, there is an odds ratio (OR) of 1.29 (95% confidence interval, [1.03; 1.60]) for cardiac malformations, and there is a relative risk (RR) of 1.35 ([1.12; 1.64]) for musculo- skeletal malformations and 1.58 ([1.28; 1.94]) for genitourinary malformations. The risks of preterm birth and low birth weight are, respectively, 1.7 and 1.5 times higher in IVF singleton pregnancies than in non-IVF pregnancies. Cardiovascular changes are the main type of functional disturbance. Some of the risks associated with IVF have decreased in recent years. An association has been revealed between cardiovascular abnormalities and epigenetic modifications; the causes are thought to include not only maternal and paternal factors, but also the IVF techniques that are used. A modification of IVF therapies might lower the risks, but might also lower the success rate.

CONCLUSION

For the well-being of the children to be conceived, IVF therapy should hat cannot be treated by any other means, as the precise causes of the risks of IVF to child health are unclear.

Mortality from infancy to adolescence in singleton children conceived from assisted reproductive techniques versus naturally conceived singletons in Sweden

OBJECTIVE

To assess infant (<1 year) and childhood (1-18 years) mortality in singletons conceived through assisted reproductive techniques (ART) versus naturally conceived singletons.

DESIGN

Nationwide prospective study.

SETTING

Sweden.

PATIENT(S)

All singleton liveborn infants born from 1983 to 2012 in Sweden identified using the Medical Birth Register (N = 2,847,108), of whom 43,506 were conceived through ART treatments including in vitro fertilization with and without intracytoplasmic sperm injection.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURES(S)

Infant (<1 year) and childhood (1-18 years) mortality.

RESULT(S)

Data on ART treatment and covariates were retrieved from population-based registers using the unique personal identity number assigned to all permanent residents in Sweden. Cox proportional hazards models estimated the hazard ratios (HRs) with 95% confidence intervals (CIs) as measures of association between ART treatments and death. The analyses were adjusted for maternal characteristics, infertility, child sex, and birth cohort and were restricted to individuals with complete information on covariates for fully adjusted analysis. Compared with naturally conceived singletons, higher infant mortality risks were seen in infants conceived through ART (adjusted HR 1.45; 95% CI, 1.19-1.77), especially after transfer of cryopreserved embryos (adjusted HR 2.30; 95% CI, 1.46-3.64). Early neonatal mortality risk (deaths during the first week) was increased in children born after transfer of blastocysts (HR 2.40; 95% CI, 1.05-5.48). No increased mortality risk was observed between the ages of 1 and 18 years.

CONCLUSION(S)

Singletons conceived through ART had an increased risk of infant mortality from birth up to 1 year of life, predominantly in the early neonatal period and in pregnancies after transfer of frozen and thawed embryos.

Evaluation, Treatment, and Insurance Coverage for Couples With Male Factor Infertility in the US: A Cross-Sectional Analysis of Survey Data

OBJECTIVE

To characterize the evaluation, treatment, and insurance coverage among couples with male factor infertility in the United States.

MATERIALS AND METHODS

A cohort of 969 couples undergoing fertility treatment with a diagnosis of male factor infertility were identified from an online survey. The proportion of men that were seen/not seen by a male were compared. Insurance coverage related to male factor was also assessed.

RESULTS

Overall, 98.0% of the men reported at least one abnormal semen parameter. Of these, 72.0% were referred to a male fertility specialist with the majority being referred by the gynecologist of their female partner. As part of the male evaluation, 72.2% had blood hormone testing. Of the 248 men who were not recommended to see a male fertility specialist, 96.0% had an abnormal semen analysis including 7.6% who had azoospermia. Referral to a male fertility specialist was largely driven by severity of male factor infertility rather than socioeconomic status. Insurance coverage related to male factor infertility was poor with low coverage for sperm extractions (72.9% reported 0-25% coverage) and sperm freezing (83.7% reported 0-25% coverage).

CONCLUSION

Although this cohort includes couples with abnormal semen parameters, 28% of the men were not evaluated by a male fertility specialist. In addition, insurance coverage for services related to male factor was low. These findings may be of concern as insufficient evaluation and coverage of the infertile man could lead to missed opportunities for identifying reversible causes of infertility/medical comorbidities and places an unfair burden on the female partner.

Effect of Maternal Age on Pregnancy or Neonatal Outcomes Among 4,958 Infertile Women Using a Freeze-All Strategy

The freeze-all strategy has been increasingly employed in the context of in vitro fertilization (IVF) cycles globally, but the relative advantages of this approach are not entirely understood. Herein we sought to assess how maternal age affected pregnancy and neonatal outcomes in women who had undergone frozen–thawed embryo transfer (FET). In this retrospective analysis, we assessed outcomes for 4,958 total women at the University-affiliated Tertiary Centre from January—December 2017. We compared pregnancy and neonatal outcomes between a control group (<30 years old) and groups of more advanced maternal age (30–34, 35–37, 38–40, 41–43, and 44–50 years). We found that live birth rates (LBR) for the first FET cycle following a freeze-all strategy significantly declined with increasing maternal age, with the most pronounced declines in the 35–37 and 38–40 age groups (LBR: 51.12% at <30 years, 43.86% at 30–34 years, 41.64% at 35–37 years, 25.67% at 38–40 years, 15.58% at 40–43 years, and 4.78% at 44–50 years, respectively). Rates of preterm delivery (PTD), very PTD, low birth weight (LBW), very LBW, term LBW, preterm LBW, and macrosomia were comparable across study groups. Together these results thus suggest that increasing maternal age has an adverse impact on pregnancy outcomes without affecting PTD or LBW risk in the context of a freeze-all strategy.

Effect of exogenous human chorionic gonadotropin on ovulation in mice

The implementation of assisted reproductive technologies (ART), hormonal stimulation in particular, may change the quality of ovulated oocytes. The purpose of our work was to study ovulation in CD1 mice after their stimulation with human chorionic gonadotropin (hCG) and to investigate the effects of such hormonal stimulation on the pregnancy duration, fetal losses and the weight of the offspring. No significant differences were found in the total number of ovulated oocytes or in the number of immature (without a polar body) ovulated oocytes; nor were there differences between the groups in the number of oocytes with a developing polar body. However, the number of matured oocytes with a distinct polar body was significantly higher (p < 0.05) in mice stimulated with hCG (experimental group) as compared with the controls (6.2 ± 0.86 and 2.2 ± 0.97, respectively). No significant differences were observed between the experimental and control mice in the duration of pregnancy or in the numbers of term offspring, including the percentage of live and stillborn pups. However, the body weight of the offspring in the experimental group was significantly lower (p < 0.001) as compared with the controls on the fifth day after birth (3.16 ± 0.09 and 3.76 ± 0.07, respectively). Thus, exogenous hCG facilitates the development of mouse oocytes in vivo, which leads to the larger number of their mature forms at ovulation, however, the offspring born after hCG-stimulated pregnancy was characterized by a lower body weight on the fifth day after birth.

Single embryo transfer: Why and how to identify the embryo with the best developmental potential

Multiple pregnancies with higher risk of preterm birth and the associated higher morbidity have been a major obstacle from the early days of in vitro fertilization. A good strategy to avoid multiple pregnancies is elective single embryo transfer and cryopreservation of spare embryos. Important factors in adopting this strategy are good counselling of the patients and the selection of embryos with high implantation potential. Technical advances in embryo selection have been described during recent years, time lapse monitoring and genetic assessment of the embryos being the most important achievements. With these studies we have gained new information on early embryos. However, at present, there is insufficient evidence to recommend the routine use of these new techniques. The ultimate goal of infertility treatment is a healthy baby.

Singleton pregnancies after in vitro fertilization in Estonia: a register-based study of complications and adverse outcomes in relation to the maternal socio-demographic background

Background

An increased risk of adverse conditions related to in vitro fertilization (IVF) pregnancies has been repeatedly reported. Our study aimed to summarize outcome differences between pregnancies after IVF and after spontaneous conception (SC) in Estonia.

Methods

Data on all liveborn singletons to primiparas women aged 25–40 years during the period 2005–2014 were obtained from the Estonian Medical Birth Registry. There were 1778 and 33,555 newborns in the IVF and SC cohort, respectively. The relative risk of pregnancy-related complications and adverse pregnancy outcomes in the IVF cohort in comparison with the SC cohort was quantified by prevalence proportion ratios (RR) with 95% confidence intervals (CI) using modified Poisson regression models adjusted for maternal age, education, ethnicity, marital status and study period.

Results

The cohort of IVF singletons experienced a higher risk of preterm birth (RR 1.51; 95% CI 1.28–1.78), iatrogenic preterm birth (RR 1.62; 95% CI 1.32–1.98), very preterm birth (RR 1.49; 95% CI 1.00–2.23), low birthweight (RR 1.47; 95% CI 1.20–1.80), congenital anomalies (RR 1.51; 95% CI 1.08–2.11), and admission to a neonatal intensive care unit (RR 1.13; 95% CI 1.01–1.26). Somewhat elevated risk of spontaneous preterm birth did not reach statistical significance (RR 1.32; 95% CI 0.97–1.80). IVF mothers were at increased risk of placenta previa (RR 7.15; 95% CI 4.04–12.66), placental abruption (RR 2.12; 1.43–3.14) and cesarean section (RR 1.28; 95% CI 1.20–1.37). The risk of pre-eclampsia was borderline (RR 1.25; 95% CI 0.98–1.59). Adjustment for maternal age attenuated the associations between IVF and adverse outcomes. Maternal education, ethnicity and marital status had no effect on the magnitude of the risk estimates.

Conclusions

The increased risk of pregnancy-related complications and adverse pregnancy outcomes was observed in the Estonian cohort of IVF singletons in comparison with the cohort of SC singletons. The relative risk estimates grew with maternal age but were not influenced by the maternal education, ethnicity and marital status. To monitor the efficacy and safety of the used assisted reproductive technology, a specialized country-wide register should be created in Estonia.

Decreased chance of a live born child in women with rheumatoid arthritis after assisted reproduction treatment: a nationwide cohort study

OBJECTIVES

No studies have examined the efficacy of assisted reproductive technology (ART) treatment in women with rheumatoid arthritis. Therefore, we examined the chance of live birth after ART treatment in women with rheumatoid arthritis compared with women without rheumatoid arthritis.

METHODS

Our cohort study is based on nationwide Danish health registries, comprising all women with an embryo transfer during 1 January 1994 through 30 June 2017. The cohorts comprised 1149 embryo transfers in women with rheumatoid arthritis, and 198 941 embryo transfers in women without rheumatoid arthritis. Our outcome was live birth per embryo transfer, and we controlled for multiple covariates in the analyses. In subanalyses, we examined a chance of biochemical/clinical pregnancy after ART and a possible impact of corticosteroid use prior to embryo transfer.

RESULTS

The adjusted OR (aOR) for a live birth per embryo transfer in women with rheumatoid arthritis, relative to women without rheumatoid arthritis, was 0.78 (95% CI 0.65 to 0.92). The aORs for biochemical and clinical pregnancies were 0.81 (95% CI 0.68 to 0.95) and 0.82 (95% CI 0.59 to 1.15), respectively. Corticosteroid prescription prior to embryo transfer increased the OR for live birth (aOR=1.32 (95% CI 0.85 to 2.05)).

CONCLUSIONS

The chance of a live birth was significantly reduced in women with rheumatoid arthritis receiving ART treatment, relative to women without rheumatoid arthritis, and our result suggested that the problem was related to an impaired chance of embryo implantation. The role of corticosteroid use prior to embryo transfer must be a subject for further research.

The impact of specific fertility treatments on cognitive development in childhood and adolescence: a systematic review

STUDY QUESTION

Does fertility treatment influence cognitive ability in school aged children, and does the impact vary with the type of treatment?

SUMMARY ANSWER

The available high-quality evidence indicates that specific treatments may give rise to different effects on cognitive development, with certain treatments, including ICSI, associated with cognitive impairment.

WHAT IS KNOWN ALREADY

Previous reviews of the literature concerning cognitive outcomes among children conceived with medical assistance have concluded that study findings are generally 'reassuring', but limited attention has been paid to the quality of this research. In addition, no review has separately assessed the range of treatment modalities available, which vary in invasiveness, and thus, potentially, in their effects on developmental outcomes.

STUDY DESIGN, SIZE, DURATION

A systematic review was undertaken. We searched PubMed, PsycINFO and the Educational Resources Information Centre database to identify English-language studies published up until 21 November 2016.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Two authors independently reviewed identified articles, extracted data and assessed study quality. Studies were eligible if they assessed cognitive development from age 4 years or more, among children conceived with fertility treatment compared with either children conceived naturally or children born from a different type of fertility treatment. Where available, data were extracted and reported separately according to the various components of treatment (e.g. mode of fertilization, embryo freezing, etc.). Risk of bias was assessed using the Newcastle-Ottawa Scale, with a score ≥7/9 indicative of high quality.

MAIN RESULTS AND THE ROLE OF CHANCE

The search identified 861 articles, of which 35 were included. Of these, seven were rated high quality. Most studies (n = 22) were subject to selection bias, due to the exclusion of children at increased risk of cognitive impairment. Among high-quality studies, there was no difference in cognitive outcomes among children conceived with conventional IVF and those conceived naturally. Findings among high-quality studies of children conceived with ICSI were inconsistent: when compared with children conceived naturally, one study reported lower intelligence quotient (IQ; 5-7 points, on average) among ICSI children whereas the remaining two high-quality studies reported no difference between groups. Furthermore, among the three high-quality studies comparing children conceived with ICSI compared with conventional IVF, one reported a significant increase in the risk of mental retardation, one reported a small difference in IQ (3 points lower, on average) and one no difference at all. There were scant studies examining exposure to embryo freezing, or less invasive treatments such as ovulation induction without IVF/ICSI.

LIMITATION, REASONS FOR CAUTION

Most existing studies had methodological limitations including selection bias and/or failure to address confounding by family background. In addition, a meta-analysis could not be performed due to heterogeneity in the assessment of cognitive outcomes. These factors impeded our ability to synthesize the evidence and draw reliable conclusions.

WIDER IMPLICATIONS OF THE FINDINGS

The conflicting findings among studies of children conceived with ICSI require clarification, in light of the increasing use of this technique for reasons other than male-factor infertility. Further population-based studies are needed that utilize contemporary data to examine specific aspects of treatment and combinations of techniques (e.g. ICSI with frozen embryo cycles). Importantly, studies should include the complete group of children exposed to treatment.

STUDY FUNDING/COMPETING INTEREST(S)

A.R.R. is supported by a Career Development Fellowship from the National Health and Medical Research Council of Australia. L.J.M. is funded by a fellowship from the Heart Foundation of Australia. The authors declare there are no competing interests.

TRIAL REGISTRATION NUMBER

Not applicable.

Association of assisted reproductive technology and multiple pregnancies with the risks of birth defects and stillbirth: A retrospective cohort study

Assisted reproductive technology (ART) has been widely used among women with infertility. However, the association of ART with birth defects and stillbirth remains controversial and has rarely been reported in China. A retrospective cohort study of 112,043 pregnant women and 114,522 newborns from 2006 to 2016 was performed. Compared to spontaneously conceived infants, ART-conceived infants had a higher likelihood of any birth defect, with an adjusted odds ratio (OR) of 2.10 (95% confidence interval, 1.63–2.69). ART-conceived infants also had a significantly increased risk for subcategories of cardiovascular, musculoskeletal, urogenital, gastrointestinal, and respiratory defects. Most (62.25%) of the effect of ART on birth defects was a direct effect, whereas 37.75% of the effect of ART on birth defects was due to multiple pregnancies (i.e., an indirect effect). Compared with naturally conceived singletons, the combined effect of ART and twins on the risk of birth defects was lower than that of the sum of the individual effects of ART and twins on the risk of birth defects, with an adjusted OR of 0.54 (0.32–0.92). These findings clearly show that ART is associated with an increased risk of birth defects in China and may provide guidance to couples and obstetricians in selecting numbers of pregnancies and in identifying organs at a high risk of birth defects.

Trends over time in congenital malformations in live-born children conceived after assisted reproductive technology

INTRODUCTION

Children born after assisted reproductive technology, particularly singletons, have been shown to have an increased risk of congenital malformations compared with children born after spontaneous conception. We wished to study whether there has been a change in the past 20 years in the risk of major congenital malformations in children conceived after assisted reproductive technology compared with children spontaneously conceived.

MATERIAL AND METHODS

Population-based cohort study including 90 201 assisted reproductive technology children and 482 552 children spontaneously conceived, born in Denmark, Finland, Norway and Sweden. Both singletons and twins born after in vitro fertilization, intracytoplasmatic sperm injection and frozen embryo transfer were included. Data on children were taken from when the national Nordic assisted reproductive technology registries were established until 2007. Multiple logistic regression analyses were used to estimate the risks and adjusted odds ratios for congenital malformations in four time periods: 1988-1992, 1993-1997, 1998-2002 and 2003-2007. Only major malformations were included.

RESULTS

The absolute risk for singletons of being born with a major malformation was 3.4% among assisted reproductive technology children vs. 2.9% among children spontaneously conceived during the study period. The relative risk of being born with a major congenital malformation between all assisted reproductive technology children and children spontaneously conceived remained similar through all four time periods (p = 0.39). However, we found that over time the number of children diagnosed with a major malformation increased in both groups across all four time periods.

CONCLUSION

When comparing children conceived after assisted reproductive technology and spontaneously conceived, the relative risk of being born with a major congenital malformation did not change during the study period.

Assisted reproductive technologies: a hierarchy of risks for conception, pregnancy outcomes and treatment decisions

The use of assisted reproductive technologies (ART) for the treatment of infertility has grown exponentially over the last 20 years, and now accounts for 4% of all births in Australia, and over 1 m births annually around the globe. There is consistent reporting of increased risk of adverse perinatal outcomes and birth defects following infertility treatment. However, change in practice has been stymied by critical knowledge gaps with regards to (a) the relative contribution of patient and treatment factors to adverse outcomes, (b) the independent contribution of specific contemporary treatments and treatment combinations to outcomes, (c) the impact of innovations in laboratory and clinical practice on treatment success and observed risk and (d) changes over time in patient characteristics. Here we summarize key findings from the South Australian Birth Cohort, which is a whole-of-population cohort of over 300,000 births from 1986 to 2002. Relative to spontaneous conceptions, singletons from assisted conception were more likely to be stillborn [odds ratio (OR)=1.82; 95% confidence interval (CI) 1.34-2.48], while survivors as a group were comprehensively disadvantaged at birth, including lower birth weight (OR=2109 g; 95% CI 2129-289), very low birth weight (OR=2.74; 95% CI 2.19-3.43), very preterm birth (OR=2.30; 95% CI 1.82-2.90) and neonatal death (OR=2.04; 95% CI 1.27-3.26). Major birth defects, including cardiac, urogenital and musculoskeletal defects are doubled after fresh ICSI cycles, which is a particular concern as ICSI now accounts for 70% of all treatment cycles globally. Future study is needed to provide contemporary, precise evidence to inform patient and clinic decision making, and generate knowledge for future innovation in ART laboratory methods and clinical practice, thereby optimizing treatment and health outcomes while reducing adverse events.

Lack of association between receiving ART treatment and parental psychological distress during pregnancy: Preliminary findings of the Japan Environment and Children's Study

In a nationwide population-based birth cohort study in Japan, pregnant women and their partners were evaluated for psychological distress as part of the first and second/third trimester health checks. Participants were divided into three groups: an infertility group receiving assisted reproductive technology (ART) treatment (239 mothers and 151 fathers); an infertility group receiving non-ART treatment (350 mothers and 215 fathers); and a spontaneous pregnancy group (8514 mothers and 5110 fathers). Data on maternal and child health as well as basic characteristics were collected via medical records and self-administered questionnaires. The Kessler Six-item Psychological Distress Scale was employed for eligible women and their partners. Multivariate logistic regression analysis was used to evaluate the association between psychological distress experienced during pregnancy and ART treatment, with adjustment for potential confounders such as basic health status and socio-economic status. The mothers who received ART treatment suffered less psychological distress than the mothers in the other two groups. In multivariate analysis adjusted for background characteristics, no significant association was observed between persistent maternal distress and ART treatment (adjusted odds ratio 0.79, 95% confidence interval 0.49-1.26). Higher socio-economic status among couples receiving ART treatment may explain, in part, the lack of association between ART treatment and parental distress during pregnancy.

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.

A universal freeze all strategy: why it is not warranted

PURPOSE OF REVIEW

There's some preclinical evidence of an adverse effect of multifollicular growth on endometrial function in assisted reproductive technology cycles. Universal elective frozen embryo transfer (eFET) in an unstimulated cycle is being promoted as a panacea, regardless of patient, and cycle characteristics. We review the clinical evidence on the effectiveness and safety of eFETs.

RECENT FINDINGS

Randomized controlled trials (RCTs) comparing fresh and eFET yield contradictory results in terms of live birth rates. RCTs mainly involve women with an excessive response to ovarian stimulation. Studies including women with a normal or low ovarian response are either patient/physician preference or retrospective studies, prone to bias. Yet, they yield contradictory results as well. Overall, eFET seems to have limited potential to improve effectiveness of assisted reproductive technology, which could be limited to hyper-responders. Other suggested advantages of eFET include better obstetric and perinatal outcome. However, recent studies show that frozen embryo transfers can be associated with serious complications including hypertensive disorders during pregnancy, placenta accreta, or increased perinatal mortality.

SUMMARY

The evidence behind advantages of eFET is of low quality. As such, switching to a universal eFET strategy does not seem justified. New RCTs including women from different strata of ovarian response are needed.

Utility of Population Attributable Fraction Assessment in Guiding Interventions to Reduce Low Birthweight in the High-Altitude State of Colorado

Objectives We evaluated the ability of population attributable fraction (PAF) assessments to alter significant modifiable risks for low birthweight (LBW) and the impact of high altitude as a risk for LBW in Colorado. Methods Logistic regression analysis of birth certificate parameters in 1995-1997 identified risk factors for PAF assessment. PAF for birth at high altitude, multiple births, and LBW in singleton births were determined. Subsequent analysis of singleton LBW risks, using number needed to treat (NNT) analysis, estimated how elimination of major modifiable risk factors could reduce LBW in the study population. Public health interventions were initiated and PAF analysis conducted 12 years afterward to determine the effect of interventions. Results PAF in singleton births revealed low maternal weight gain in pregnancy and maternal smoking as the greatest modifiable attributable risk factors for LBW (12.7/12.5 %, respectively, in 1995-1997 and 12.9/7.1 % in 2007-2009). Significant interaction between these variables resulted in PAF of 34.4 % when the two occurred together in 1995-1997, decreasing to 19.4 % in 2007-2009. NNT analysis of singleton births in 1995-1997 revealed that eliminating low maternal weight gain, smoking, late prenatal care in all women and interpregnancy intervals <1 year in multiparous women reduced LBW by 46.5 %. The respective proportional reductions in PAF of 40.3 and 46.3 % for maternal smoking and weight gain/smoking interaction were associated with a 1.4 % LBW reduction in singleton births between the two study periods. Conclusions for Practice PAF and NNT analyses are valuable tools to predict intervention targets to lower LBW.

Literature review on cancer risk in children born after fertility treatment suggests increased risk of haematological cancers

Medically assisted fertility treatment, including assisted reproductive technology (ART), is increasingly being used and the subsequent child health outcomes are of interest. Some studies have suggested an elevated risk of somatic morbidity, while others have reported an elevated cancer risk. This review summarises the literature on fertility treatments and childhood cancer, based on 23 cohort and case-control studies.

CONCLUSION

The findings varied, but reassuring results on overall childhood cancer and fertility treatment were observed. However, some studies suggested an elevated risk of haematological cancers. More large population-based studies are needed, and the growing population of ART children should be monitored.