Hypertensive disorders in pregnancy and intellectual abilities in the offspring in young adulthood: the Helsinki Birth Cohort Study

Brain Vascular Dysfunction in Mothers and Their Children Exposed to Preeclampsia

Preeclampsia is a maternal syndrome characterized by the new onset of hypertension and proteinuria after 20 weeks of gestation associated with multisystemic complications, including brain alterations. Indeed, brain complications associated with preeclampsia are the leading direct causes of fetal and maternal morbidity and mortality, especially in low- and middle-income countries. In addition to the well-recognized long-term adverse cardiovascular effects of preeclampsia, women who have had preeclampsia have higher risk of stroke, dementia, intracerebral white matter lesions, epilepsy, and perhaps also cognitive decline postpartum. Furthermore, increasing evidence has also associated preeclampsia with similar cognitive and cerebral disorders in the offspring. However, the mechanistic links between these associations remain unresolved. This article summarizes the current knowledge about the cerebrovascular complications elicited by preeclampsia and the potential pathophysiological mechanisms involved, emphasizing the impaired brain vascular function in the mother and their offspring.

The Global Pregnancy Collaboration (CoLab) symposium on short- and long-term outcomes in offspring whose mothers had preeclampsia: A scoping review of clinical evidence

Preeclampsia is a maternal syndrome characterized by the new onset of hypertension after 20 weeks of gestation associated with multisystemic complications leading to high maternal and fetal/neonatal morbidity and mortality. However, sequelae of preeclampsia may extend years after pregnancy in both mothers and their children. In addition to the long-term adverse cardiovascular effects of preeclampsia in the mother, observational studies have reported elevated risk of cardiovascular, metabolic, cerebral and cognitive complications in children born from women with preeclampsia. Less clear is whether the association between maternal preeclampsia and offspring sequelae are causal, or to what degree the associations might be driven by fetal factors including impaired growth and the health of its placenta. Our discussion of these complexities in the 2018 Global Pregnancy Collaboration annual meeting prompted us to write this review. We aimed to summarize the evidence of an association between maternal preeclampsia and neurobehavioral developmental disorders in offspring in hopes of generating greater research interest in this important topic.

Dexamethasone on absent end-diastolic flow in umbilical artery, in growth restricted fetuses from early-onset preeclamptic pregnancies and the perinatal outcome

BACKGROUND

Absent end-diastolic flow (AEDF) in the umbilical artery (UA) worsens the already poor prognosis of growth-restricted fetuses (GRFs) in pregnancies complicated by early-onset preeclampsia with severe features (ESP).

METHOD

We assessed the correlation between the effect of maternal dexamethasone (Dex) on AEDF in the UA and perinatal outcomes, in 59 GRFs from EPS-complicated pregnancies. The maternal outcome was also evaluated.

RESULTS

The mean maternal age at inclusion was 22.4 ± 5.9 years. Dex transiently restored EDF in the UA in 38 (64.4%) cases (trAEDF group), but in 21 (35.6%) patients, the flow was persistently absent (prAEDF group). The effect lasted up to the 4th day.The gestational age at diagnosis, number of days from admission until delivery, and fetal weight were significantly lower in the prAEDF group than in the trAEDF group (p < .05). The same group had a significantly increased rate of fetal proximal deterioration, low APGAR scores, neonatal hypoxia, assisted ventilation, mild intraventricular haemorrhage (I/II), and respiratory distress syndrome, as well as maternal deterioration, especially in cases of resistant hypertension (p < .05). Although the rates of fetal acidemia and perinatal mortality in the prAEDF group were respectively three times and two times higher, the differences were not significant (p > .05).

CONCLUSIONS

The Dex no-effect on UA Doppler in GRFs with AEDF in the UA, in EPS-complicated pregnancies, can be a useful marker for a higher risk of proximal fetal deterioration, poor state at delivery, neonatal hypoxic complications, and worsening maternal condition, but not for perinatal mortality. The findings also highlight the alarmingly younger age of patients with EPS. Finally, all these pregnancies should be monitored in a complex multidisciplinary manner in tertiary referral units.Key messageThe effect of dexamethasone on absent end-diastolic flow in the umbilical artery in growth-restricted fetuses from pregnancies complicated by early-onset preeclampsia with severe features can be a useful prognostic factor for perinatal outcomes.

Association between maternal hypertensive disorders, fetal growth and childhood learning outcomes

OBJECTIVE

Both small for gestational age (SGA) birthweight and pregnancies complicated by maternal hypertension (HTN) are independently associated with poorer childhood learning outcomes, however the relative contribution of each remains unknown.

STUDY DESIGN

A retrospective cohort was created in which 2014-2017 third grade Rhode Island Department of Education data were linked to Rhode Island Department of Health birth certificate data. The study population was composed of non-anomalous, singleton births between 22- and 42-weeks' gestation. Reading and math proficiency were compared among four groups: 1) appropriate for gestational age (AGA) and no maternal HTN (referent), 2) AGA with HTN, 3) SGA without HTN and 4) SGA with HTN.

MAIN OUTCOME MEASURES

Bivariable and multivariable log-binomial regression were used to examine the association between subject proficiency and pregnancy complication, adjusting for potential confounders.

RESULTS

Of the 23,097 who met inclusion criteria, 1004 (4%) were AGA with HTN, 1575 (7%) were SGA without HTN and 176 (1%) were SGA with HTN. Overall, when adjusted for maternal age, gestational age, sex and socioeconomic factors, only children born SGA without HTN had reduced reading proficiency (relative risk (RR) 0.86 95% confidence interval (CI) 0.78, 0.92) and math proficiency (RR 0.88 95% CI 0.82, 0.94) compared to children born AGA without HTN.

CONCLUSION

In a diverse, statewide cohort, only SGA without HTN was associated with lower reading and math proficiency compared to uncomplicated pregnancies. This suggests that only decreased fetal growth from causes other than HTN is associated with risk of poorer school-age outcomes, and has implications for early resource allocation.

Association Between Hypertensive Disorders of Pregnancy and Neurodevelopmental Outcomes Among Offspring

IMPORTANCE

Hypertensive disorders of pregnancy (HDP) have been associated with poorer neurodevelopmental outcomes in offspring, but the role of familial confounding in these associations is unclear.

OBJECTIVE

To investigate associations of maternal HDP with risks in offspring of autism spectrum disorders (ASDs), attention-deficit/hyperactivity disorder (ADHD), and intellectual disability (ID), as well as variation in overall cognitive performance in offspring.

DESIGN, SETTING, AND PARTICIPANTS

This Swedish register-based study used data from a birth cohort divided into 1 085 024 individuals born between 1987 and 1996 and followed up until December 31, 2014, and 285 901 men born between 1982 and 1992 who attended assessments for military conscription, including a cognitive function test. Statistical analysis was performed from April 1, 2019, to June 1, 2020.

EXPOSURES

Diagnoses of HDP, which were provided by the Medical Birth Register.

MAIN OUTCOMES AND MEASURES

Diagnoses of ASDs, ADHD, and ID were extracted from the National Patient Register. Cognitive function was assessed using written tests and summarized as a single 9-point score. Whole-cohort and within-sibship analyses were performed; the latter accounted for unmeasured familial confounding factors shared by siblings.

RESULTS

The study included 1 085 024 individuals (556 912 male participants [51.3%]) born between 1987 and 1996 and 285 901 men born between 1982 and 1992 who attended assessments for military conscription. The prevalence of maternal HDP was 4.0% in the 1987-1996 birth cohort (n = 42 980) and 5.1% in the military conscription cohort (n = 14 515). A total of 15 858 participants received a diagnosis of ASD, 36 852 received a diagnosis of ADHD, and 8454 received a diagnosis of ID. The mean (SD) cognitive score among the men in the conscription cohort was 5.1 (1.9). In whole-cohort analyses with multivariable adjustment, HDP were associated with offspring ASDs (hazard ratio [HR], 1.22; 95% CI, 1.13-1.31), ADHD (HR, 1.10; 95% CI, 1.05-1.16), and ID (HR, 1.39; 95% CI, 1.27-1.53). Analyses comparing siblings discordant for HDP were less statistically powered but indicated estimates of similar magnitude for ASDs (HR, 1.19; 95% CI, 1.00-1.42) and possibly ADHD (HR, 1.09; 95% CI, 0.95-1.24), but not for ID (HR, 1.04; 95% CI, 0.83-1.29). Hypertensive disorders of pregnancy were associated with somewhat lower cognitive scores in whole-cohort analysis (mean difference comparing offspring exposed with those unexposed, -0.10; 95% CI, -0.13 to -0.07), but in within-sibship analysis, the association was null (mean difference, 0.00; 95% CI, -0.09 to 0.08).

CONCLUSIONS AND RELEVANCE

The study results suggest that HDP are associated with small increased risks of ASDs and possibly ADHD in offspring, whereas associations with ID and cognitive performance are likely confounded by shared familial (environmental or genetic) factors.

Preeclampsia and Neurodevelopmental Outcomes: Potential Pathogenic Roles for Inflammation and Oxidative Stress?

Preeclampsia (PE) is a common and serious hypertensive disorder of pregnancy that occurs in approximately 3-5% of first-time pregnancies and is a well-known leading cause of maternal and neonatal mortality and morbidity. In recent years, there has been accumulating evidence that in utero exposure to PE acts as an environmental risk factor for various neurodevelopmental disorders, particularly autism spectrum disorder and ADHD. At present, the mechanism(s) mediating this relationship are uncertain. In this review, we outline the most recent evidence implicating a causal role for PE exposure in the aetiology of various neurodevelopmental disorders and provide a novel interpretation of neuroanatomical alterations in PE-exposed offspring and how these relate to their sub-optimal neurodevelopmental trajectory. We then postulate that inflammation and oxidative stress, two prominent features of the pathophysiology of PE, are likely to play a major role in mediating this association. The increased inflammation in the maternal circulation, placenta and fetal circulation in PE expose the offspring to both prenatal maternal immune activation-a risk factor for neurodevelopmental disorders, which has been well-characterised in animal models-and directly higher concentrations of pro-inflammatory cytokines, which adversely affect neuronal development. Similarly, the exaggerated oxidative stress in the mother, placenta and foetus induces the placenta to secrete factors deleterious to neurons, and exposes the fetal brain to directly elevated oxidative stress and thus adversely affects neurodevelopmental processes. Finally, we describe the interplay between inflammation and oxidative stress in PE, and how both systems interact to potentially alter neurodevelopmental trajectory in exposed offspring.

Preeclampsia may influence offspring neuroanatomy and cognitive function: a role for placental growth factor†

Preeclampsia (PE) is a common pregnancy complication affecting 3-5% of women. Preeclampsia is diagnosed clinically as new-onset hypertension with associated end organ damage after 20 weeks of gestation. Despite being diagnosed as a maternal syndrome, fetal experience of PE is a developmental insult with lifelong cognitive consequences. These cognitive alterations are associated with distorted neuroanatomy and cerebrovasculature, including a higher risk of stroke. The pathophysiology of a PE pregnancy is complex, with many factors potentially able to affect fetal development. Deficient pro-angiogenic factor expression is one aspect that may impair fetal vascularization, alter brain structure, and affect future cognition. Of the pro-angiogenic growth factors, placental growth factor (PGF) is strongly linked to PE. Concentrations of PGF are inappropriately low in maternal blood both before and during a PE gestation. Fetal concentrations of PGF appear to mirror maternal circulating concentrations. Using Pgf-/- mice that may model effects of PE on offspring, we demonstrated altered central nervous system vascularization, neuroanatomy, and behavior. Overall, we propose that development of the fetal brain is impaired in PE, making the offspring of preeclamptic pregnancies a unique cohort with greater risk of altered cognition and cerebrovasculature. These individuals may benefit from early interventions, either pharmacological or environmental. The early neonatal period may be a promising window for intervention while the developing brain retains plasticity.

Chronic hypertension in pregnancy

Chronic hypertension and associated cardiovascular disease are among the leading causes of maternal and perinatal morbidity and death in the United States. Chronic hypertension in pregnancy is associated with a host of adverse outcomes that include preeclampsia, cesarean delivery, cerebrovascular accidents, fetal growth restriction, preterm birth, and maternal and perinatal death. There are several key issues related to the diagnosis and management of chronic hypertension in pregnancy where data are limited and further research is needed. These challenges and recent guidelines for the management of chronic hypertension are reviewed. Well-timed pregnancies are of utmost importance to reduce the risks of chronic hypertension; long-acting reversible contraceptive options are preferred. Research to determine optimal blood pressure thresholds for diagnosis and treatment to optimize short- and long-term maternal and perinatal outcomes should be prioritized along with interventions to reduce extant racial and ethnic disparities.

Neonatal developmental and behavioral outcomes of immediate delivery versus expectant monitoring in mild hypertensive disorders of pregnancy: 5-year outcomes of the HYPITAT II trial

OBJECTIVE

To compare effects of immediate delivery vs expectant monitoring on neurodevelopmental and behavioral outcomes at 5 years of age in offspring of women with mild late preterm hypertensive disorders.

STUDY DESIGN

We studied children born during the HYPITAT-II trial, in which 704 women with a hypertensive disorder between 34 and 37 weeks of gestation were randomized to immediate delivery or expectant monitoring. Participating women were asked to complete the Ages and Stages Questionnaire (ASQ) for developmental outcome and the Child Behavior Checklist (CBCL) for behavioral problems when their child was 5 years old. Outcomes were dichotomized and analyzed by logistic regression analysis. We also assessed factors influencing development and behavior at both 2 and 5 years after a hypertensive pregnancy.

RESULTS

Five years after the original study 322(46%) women were contacted for follow-up, of whom 148 (46%) responded. In the delivery group 22%(n = 14/65) of the children had an abnormal ASQ score compared to 21% (n = 13/62) in the expectant monitoring group (p = 0.9). Abnormal CBCL-scores were found in 19% (n = 14/72) of the children in the delivery group versus in 27% (n = 20/75) in the expectant monitoring group (p = 0.3). The main predictor of development and behavior at 2 and 5 years was fetal growth restriction (for abnormal development OR 2.1, CI 1.0-4.4; for behavior problems OR 2.2, CI 1.1-5.5). Higher maternal education decreased abnormal behavior outcomes (OR 0.5, CI 0.2-0.9) and a similar tendency was observed for developmental problems (OR 0.6, CI 0.3 - 1.1).

CONCLUSION

We did not find different developmental and behavior outcomes at 5 years of age between a management policy of immediate delivery and expectant management in preterm hypertensive disorders. The increased risk of developmental delay at 2 years of age after immediate delivery, we found in the 2 year follow up study, did not persist at 5 years of age.

Neonatal developmental and behavioral outcomes of immediate delivery versus expectant monitoring in mild hypertensive disorders of pregnancy: 2-year outcomes of the HYPITAT-II trial

BACKGROUND

Management of preterm hypertensive disorders remains a clinical dilemma. The maternal benefits of delivery need to be weighed against the adverse neonatal consequences of preterm birth. Long-term consequences of obstetric management in offspring of women with hypertensive disorders in preterm pregnancy are largely unknown. We report child neurodevelopmental and behavioral outcomes at 2 years after the Hypertension and Preeclampsia Intervention Trial at near Term (HYPITAT-II) trial, which compared immediate delivery versus expectant monitoring in mild late preterm hypertensive disorders of pregnancy.

OBJECTIVE

To compare effects of immediate delivery vs expectant monitoring on neurodevelopmental and behavioral outcomes at 2 years of age in offspring of women with mild late preterm hypertensive disorders.

MATERIALS AND METHODS

We studied children born in the HYPITAT-II trial, a study in which women (n = 704) with hypertensive disorders of pregnancy who were between 34 and 37 weeks' gestation were randomized to immediate delivery or expectant monitoring. Participating women were asked to complete the Ages and Stages Questionnaire for developmental outcome and the Child Behavior Checklist for behavioral problems when their toddlers were 2 years old.

RESULTS

We approached 545 of 704 randomized women (77%); 330 of 545 (61%) returned the questionnaires. In the immediate delivery group, 45 of 162 infants (28%) had an abnormal Ages and Stages Questionnaire score compared to 27 of 148 (18%) in the expectant monitoring group (risk difference, 9.6%; 95% CI, 0.3-18.0%); P = .045. In the pregnancies (n = 94) that delivered before reaching 36 weeks, 27% (n = 25) had an abnormal Ages and Stages Questionnaire score compared to 22% (n = 47) when delivered after 36 weeks (odds ratio, 0.77; confidence interval, 0.44-1.34). An abnormal Child Behavior Checklist outcome was found in 31 of 175 (18%) in the delivery group vs 24 of 166 (15%) in the expectant monitoring group (risk difference, 3.2%; 95% CI, -4.6% to 11.0%). After correction for maternal education, management strategy remained an independent predictor of abnormal Ages and Stages Questionnaire score (odds ratio, 0.48; confidence interval, 0.24 to -0.96, P = .03). In multivariable analyses, low birth weight, low maternal education, and immediate delivery policy were all significantly associated with an abnormal Ages and Stages Questionnaire score.

CONCLUSION

In this study, we found that early delivery in women with late preterm hypertensive disorders is associated with poorer neurodevelopmental outcomes in their children at 2 years of age. These findings indicate an increased risk of developmental delay after early delivery compared to expectant monitoring. This follow-up study underlines the conclusion of the original HYPITAT-II study that, until the clinical situation deteriorates, expectant monitoring remains the most appropriate management strategy in the light of short- and long-term neonatal outcomes in women with preterm hypertensive disorders.

Adult Pgf-/- mice behaviour and neuroanatomy are altered by neonatal treatment with recombinant placental growth factor

Offspring of preeclamptic pregnancies have cognitive alterations. Placental growth factor (PGF), is low in preeclampsia; reduced levels may affect brain development. PGF-null mice differ from normal congenic controls in cerebrovasculature, neuroanatomy and behavior. Using brain imaging and behavioral testing, we asked whether developmentally asynchronous (i.e. neonatal) PGF supplementation alters the vascular, neuroanatomic and/or behavioral status of Pgf^−/− mice at adulthood. C57BL/6-Pgf^−/− pups were treated intraperitoneally on postnatal days 1–10 with vehicle or PGF at 10 pg/g, 70 pg/g or 700 pg/g. These mice underwent behavioral testing and perfusion for MRI and analysis of retinal vasculature. A second cohort of vehicle- or PGF-treated mice was perfused for micro-CT imaging. 10 pg/g PGF-treated mice exhibited less locomotor activity and greater anxiety-like behavior relative to vehicle-treated mice. Depressive-like behavior showed a sex-specific, dose-dependent decrease and was lowest in 700 pg/g PGF-treated females relative to vehicle-treated females. Spatial learning did not differ. MRI revealed smaller volume of three structures in the 10 pg/g group, larger volume of seven structures in the 70 pg/g group and smaller volume of one structure in the 700 pg/g group. No cerebral or retinal vascular differences were detected. Overall, neonatal PGF replacement altered behavior and neuroanatomy of adult Pgf^−/− mice.

Effects of placental growth factor deficiency on behavior, neuroanatomy, and cerebrovasculature of mice

Preeclampsia, a hypertensive syndrome occurring in 3-5% of human pregnancies, has lifelong health consequences for fetuses. Cognitive ability throughout life is altered, and adult stroke risk is increased. One potential etiological factor for altered brain development is low concentrations of proangiogenic placental growth factor (PGF). Impaired PGF production may promote an antiangiogenic fetal environment during neural and cerebrovascular development. We previously reported delayed vascularization of the hindbrain, altered retinal vascular organization, and less connectivity in the circle of Willis in Pgf^-/- mice. We hypothesized Pgf^-/- mice would have impaired cognition and altered brain neuroanatomy in addition to compromised cerebrovasculature. Cognitive behavior was assessed in adult Pgf^-/- and Pgf^+/+ mice by four paradigms followed by postmortem high-resolution MRI of neuroanatomy. X-ray microcomputed tomography imaging investigated the three-dimensional cerebrovascular geometry in another cohort. Pgf^-/- mice exhibited poorer spatial memory, less depressive-like behavior, and superior recognition of novel objects. Significantly smaller volumes of 10 structures were detected in the Pgf^-/- compared with Pgf^+/+ brain. Pgf^-/- brain had more total blood vessel segments in the small-diameter range. Lack of PGF altered cognitive functions, brain neuroanatomy, and cerebrovasculature in mice. Pgf^-/- mice may be a preclinical model for the offspring effects of low-PGF preeclampsia gestation.

Association of Hypertensive Disorders of Pregnancy With Risk of Neurodevelopmental Disorders in Offspring: A Systematic Review and Meta-analysis

Importance

Although research suggests an association between hypertensive disorders of pregnancy (HDP) and autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), and other neurodevelopmental disorders in offspring, consensus is lacking. Given the increasing prevalence of hypertension in pregnancy, it is important to examine the association of HDP with neurodevelopmental outcome.

Objective

To synthesize the published literature on the association between HDP and risk of neurodevelopmental disorders in offspring in a systematic review and meta-analysis.

Data Sources

On the basis of a preprepared protocol, a systematic search of PubMed, CINAHL, Embase, PsycINFO, and Web of Science was performed from inception through June 7, 2017, supplemented by hand searching of reference lists.

Study Selection

Two investigators independently reviewed titles, abstracts, and full-text articles. English-language cohort and case-control studies were included in which HDP and neurodevelopmental disorders were reported.

Data Extraction and Synthesis

Data extraction and quality appraisal were performed independently by 2 reviewers. Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines were followed throughout.

Main Outcomes and Measures

Random-effects meta-analyses of estimated pooled odds ratios (ORs) for HDP and ASD and for HDP and ADHD. Stand-alone estimates were reported for all other neurodevelopmental disorders.

Results

Of 1166 studies identified, 61 unique articles met inclusion criteria. Twenty studies reported estimates for ASD. Eleven of these (including 777 518 participants) reported adjusted estimates, with a pooled adjusted OR of 1.35 (95% CI, 1.11-1.64). Ten studies reported estimates for ADHD. Six of these (including 1 395 605 participants) reported adjusted estimates, with a pooled adjusted OR of 1.29 (95% CI, 1.22-1.36). Subgroup analyses according to type of exposure (ie, preeclampsia or other HDP) showed no statistically significant differences for ASD or ADHD. Thirty-one studies met inclusion criteria for all other neurodevelopmental disorders. Individual estimates reported for these were largely inconsistent, with few patterns of association observed.

Conclusions and Relevance

Exposure to HDP may be associated with an increase in the risk of ASD and ADHD. These findings highlight the need for greater pediatric surveillance of infants exposed to HDP to allow early intervention that may improve neurodevelopmental outcome.

Maternal early pregnancy obesity and related pregnancy and pre-pregnancy disorders: associations with child developmental milestones in the prospective PREDO Study

BACKGROUND/OBJECTIVES

Previous studies have linked maternal pre-pregnancy obesity (BMI ≥30 kg/m²) with suboptimal neurodevelopment in her offspring; however, the literature is not entirely consistent. Whether these effects are muddled by maternal self-reports of pre-pregnancy weight and height, or are driven or amplified by the well often comorbid hypertensive and diabetic pregnancy and pre-pregnancy disorders, remains unclear. We examined whether maternal early pregnancy obesity is associated with developmental delay in her offspring, and if the associations are driven or amplified by diabetic and hypertensive pregnancy and pre-pregnancy disorders.

SUBJECTS/METHODS

A total of 2504 mother-child dyads participated in the Prediction and Prevention of Pre-eclampsia and Intrauterine Growth Restriction (PREDO) study. Data on maternal early pregnancy obesity, pre-pregnancy, and gestational hypertension, pre-eclampsia, type 1 and gestational diabetes were derived from the Finnish Medical Birth Register. At the child's mean age of 42.1 (SD = 8.2) months the mothers completed the Ages and Stages Questionnaire (ASQ) Third edition for developmental milestones.

RESULTS

Children of obese mothers had 1.81-2.74 (p-values <0.02) higher odds of failing to meet the development that is typical for a child's age (developmental domain score ≤-2SD below the child's age) on the communication, fine and gross motor, problem solving and personal/social skills and children of overweight mothers had 2.14 (p = 0.002) higher odds of failing to meet the development that is typical for the child's age on communication skills. Odds of developmental delay were also higher for children of mothers with pre-eclampsia and gestational diabetes. The associations were robust to covariates and confounders, the effects of overweight/obesity and pre-eclampsia were not driven by the other disorders, and overweight/obesity and hypertensive and diabetic disorders did not show additive effects.

CONCLUSIONS

Maternal early pregnancy overweight, obesity, and pre-eclampsia are independently associated with neurodevelopmental delay in her offspring. Further studies unraveling the underlying mechanisms are warranted.

Heritable Variation, With Little or No Maternal Effect, Accounts for Recurrence Risk to Autism Spectrum Disorder in Sweden

BACKGROUND

Autism spectrum disorder (ASD) has both genetic and environmental origins, including potentially maternal effects. Maternal effects describe the association of one or more maternal phenotypes with liability to ASD in progeny that are independent of maternally transmitted risk alleles. While maternal effects could play an important role, consistent with association to maternal traits such as immune status, no study has estimated maternal, additive genetic, and environmental effects in ASD.

METHODS

Using a population-based sample consisting of all children born in Sweden from 1998 to 2007 and their relatives, we fitted statistical models to family data to estimate the variance in ASD liability originating from maternal, additive genetic, and shared environmental effects. We calculated sibling and cousin family recurrence risk ratio as a direct measure of familial, genetic, and environmental risk factors and repeated the calculations on diagnostic subgroups, specifically autistic disorder (AD) and spectrum disorder (SD), which included Asperger's syndrome and/or pervasive developmental disorder not otherwise specified.

RESULTS

The sample consisted of 776,212 children of whom 11,231 had a diagnosis of ASD: 4554 with AD, 6677 with SD. We found support for large additive genetic contribution to liability; heritability (95% confidence interval [CI]) was estimated to 84.8% (95% CI: 73.1-87.3) for ASD, 79.6% (95% CI: 61.2-85.1) for AD, and 76.4% (95% CI: 63.0-82.5) for SD.

CONCLUSIONS

There was modest, if any, contribution of maternal effects to liability for ASD, including subtypes AD and SD, and there was no support for shared environmental effects. These results show liability to ASD arises largely from additive genetic variation.

Resting-state functional connectivity in children born from gestations complicated by preeclampsia: A pilot study cohort

BACKGROUND

Individuals (PE-F1s) born from preeclampsia (PE)-complicated pregnancies have elevated risks for cognitive impairment. Intervals of disturbed maternal plasma angiokines precede clinical signs of PE. We hypothesized pan-blastocyst dysregulation of angiokines underlies altered PE-F1 brain vascular and neurological development. This could alter brain functional connectivity (FC) patterns at rest.

MATERIALS AND METHODS

Resting-state functional MRI datasets of ten, matched child pairs (5 boys and 5 girls aged 7-10 years of age) from PE or control pregnancies were available for study. Seed-based analysis and independent component analysis (ICA) methodologies were used to assess whether differences in resting-state functional connectivity (rs-FC) were present between PE-F1s and controls. Bilateral amygdala, bilateral hippocampus, and medial prefrontal cortex (MPFC) were selected as regions of interest (ROI) for the seed-based analysis based on previous imaging differences that we reported in this set of children.

RESULTS

Compared to controls, PE-F1 children had increased rs-FC between the right amygdala and left frontal pole, the left amygdala and bilateral frontal pole, and the MPFC and precuneus. PE-F1 children additionally had decreased rs-FC between the MPFC and the left occipital fusiform gyrus compared to controls.

CONCLUSION

These are the first reported rs-FC data for PE-F1s of any age. Theysuggest that PE alters FC during human fetal brain development. Altered FC may contribute to the behavioural and neurological alterations reported in PE-F1s. Longitudinal MRI studies with larger sample sizes are required to confirm these novel findings.

Profiling of smokers and snuffers among young Finnish men - cross-sectional epidemiological study. Acta Odontol Scand 2017;75:577-583. [PMID: 28789581 DOI: 10.1080/00016357.2017.1361548]

OBJECTIVE

The purpose of this study was to get new information from several sources about the background factors of Finnish smokers, snuffers, and dual users. Profiles of young smokers and snuffers were investigated in association with restorative treatment need, oral hygiene, eating habits, physical activity, body mass index (BMI), psychological and socioeconomic factors.

MATERIAL AND METHODS

The study group comprised 3420 conscripts. The data were collected from four different sources: a health examination including an oral health screening, a computer-based questionnaire for investigating individual background factors, a psychological test assessing cognitive skills, and the Cooper test. Statistical analyses comprised cross tabulation and binary logistic regression modelling.

RESULTS

The odds for smoking were the greatest among those who had DT (Decayed teeth) > 0, used energy drinks or alcohol regularly, or whose parents were divorced. A score of ≥2900 m in the Cooper test, a higher physical exercise level, a higher own education level, and using sports drinks decreased the odds for smoking. The odds for snuffing were higher among those who ran >2500 m in the Cooper test, had a BMI of ≥25, used sports/energy drinks, or exercised regularly, and lower among those who achieved good results in the cognitive test. Using energy/sports drinks or alcohol was positively and a higher education level was negatively associated with dual use.

CONCLUSIONS

Along with increasing prevalence of snuffing, heterogeneity is likely among snuffers. Good cognitive skills may prevent from smoking and snuffing.

Diffusion Tensor Imaging of White Matter in Children Born from Preeclamptic Gestations

BACKGROUND AND PURPOSE

Individuals born from pregnancies complicated by preeclampsia have an elevated risk for cognitive impairment. Deviations in maternal plasma angiokines occur for prolonged intervals before clinical signs of preeclampsia. We hypothesized that fetal brain vascular and nervous tissue development become deviated during maternal progression toward preeclampsia and that such deviations would be detectable by MR imaging.

MATERIALS AND METHODS

In this pilot study, 10 matched (gestational and current ages) pairs (5 boys/5 girls, 7-10 years of age) from preeclampsia or control pregnancies were examined by using diffusion tensor MR imaging. An unbiased voxel-based analysis was conducted on fractional anisotropy and mean diffusivity parametric maps. Six brain ROIs were identified for subsequent analysis by tractography (middle occipital gyrus, caudate nucleus and precuneus, cerebellum, superior longitudinal fasciculus, and cingulate gyrus).

RESULTS

Statistical differences were present between groups for fractional anisotropy in the caudate nucleus (offspring from preeclamptic gestation > controls), volume of the tract for the superior longitudinal fasciculus (offspring from preeclamptic gestation > controls) and the caudate nucleus (offspring from preeclamptic gestation > controls), and for parallel diffusivity of the cingulate gyrus (offspring from preeclamptic gestation > controls).

CONCLUSIONS

These novel preliminary results along with previous results from the same children that identified altered cerebral vessel calibers and increased regional brain volumes justify fully powered MR imaging studies to address the impact of preeclampsia on human fetal brain development.

Prospective assessment of neurodevelopment in children following a pregnancy complicated by severe pre-eclampsia

OBJECTIVE

To prospectively examine whether children of women with a pregnancy affected by severe pre-eclampsia (PE), compared to children of women without a PE-affected pregnancy, have differences in neurodevelopmental performance up to 5 years of age.

DESIGN

Prospective cohort study.

SETTING

Tertiary care centre.

PARTICIPANTS

Women were recruited following a PE-affected pregnancy. After each PE participant was recruited, the next normotensive woman without a prior history of PE and matched by parity, maternal age and race was invited to participate. Women with a history of chronic hypertension, diabetes or renal disease were excluded. Total enrolment included 129 PE-affected and 140 normotensive mothers.

OUTCOME MEASURES

The primary outcome measure was failure of the Ages and Stages Questionnaire (ASQ). The ASQ was completed yearly, until age 5.

RESULTS

A significant difference was found in the proportion of ASQ categories failed in year 3 (p<0.05), and this approached significance in years 1 and 4 (p<0.10 and p<0.15, respectively). At year 1, the number of ASQ categories failed was significantly greater among children born to PE mothers. A subgroup analysis revealed that a significant proportion of PE children born preterm (<37 weeks) failed the ASQ in years 3 and 4 (p<0.05), and when failed, those who were preterm failed significantly more categories (p<0.05). A trend towards increased failure in the gross motor category was found. There was a significant positive correlation between maternal lifetime CVD risk score and number of ASQ categories failed at years 1 and 3 (p<0.05).

CONCLUSIONS

Severe PE is associated with other adverse pregnancy outcomes, including intrauterine growth restriction and preterm birth, all of which are associated with increased neurodevelopment delays. Thus, PE indicates a need for early screening and intervention at the neurodevelopmental level to improve children's long-term health, with larger studies required to tease out contributing factors.

Hypertensive disorders during pregnancy and health outcomes in the offspring: a systematic review

The hypertensive disorders of pregnancy complicate up to 10% of pregnancies worldwide and are a leading cause of maternal, foetal, and neonatal morbidity and mortality. The aim of this study was to present an overview of recent studies addressing offspring's medium and long-term health outcomes after intrauterine exposure to maternal hypertension. A search on PubMed/MEDLINE and Bireme databases was conducted to identify observational studies that reported any offspring outcome measured after the 6th month of life. The search was limited to studies published after May 2008. Forty-five articles were included and categorized into four groups of outcomes: cardiovascular, immune, metabolic and behavioural/neurological effects. According to our findings, hypertensive disorders of pregnancy had an overall negative impact on offspring's cardiovascular, immune and neurological health, although not all parameters analysed in each group had consistent results among studies. The most prominent and reliable associations were verified between gestational hypertension and higher offspring's blood pressure and between preeclampsia and offspring's lower cognitive functioning. In the metabolic outcomes, body composition had conflicting results among papers, while all studies that examined blood biomarkers showed no evidence that preeclampsia or gestational hypertension could be associated with an alteration of this metabolic outcomes. Most included studies were highly heterogeneous regarding the measure of outcomes and covariables used for adjustments. Future studies should consider using the same protocols and cut-off points already published so that results can be better compared and summarized. This review was registered in PROSPERO.

REGISTRATION NUMBER

CRD42015020838.

Analysis of gene expression and preliminary study of methylation about 11β-HSD2 gene in placentas of Chinese pre-eclampsia patients of Han ethnicity

AIMS

The aim of this study was to determine the promoter methylation status of type 2 isoform of 11β-hydroxysteroid dehydrogenase (11β-HSD2) and its regulatory correlation with 11β-HSD2 gene expression in placentas of pre-eclampsia (PE) patients of Chinese Han ethnicity.

MATERIAL AND METHODS

The pathological features of placental tissues were studied using hematoxylin-eosin staining and immunohistochemical staining. The 11β-HSD2 mRNA and protein expressions were detected by real-time polymerase chain reaction and Western blotting. The methylation of the 11β-HSD2 promoter sequence was examined by bisulfite sequencing polymerase chain reaction.

RESULTS

Trophoblast hyperplasia and discontinuous syncytial layer were observed in the PE group, and the 11β-HSD2 was distributed irregularly and its immunoreactivity was weakened distinctly. The expressions of 11β-HSD2 mRNA and protein decreased significantly in the PE group compared with the control group. Unexpectedly, almost no 11β-HSD2 methylation was detected in PE placental tissue (two fragments, 0.6% vs 0%) or normal placental tissue (1% vs 0.6%). No significant difference in 11β-HSD2 promoter methylation was found between the two groups.

CONCLUSIONS

The 11β-HSD2 expression decreased in PE women of Chinese Han ethnicity, but was not interrelated with the promoter methylation status.

Does vitamin C deficiency affect cognitive development and function?

Vitamin C is a pivotal antioxidant in the brain and has been reported to have numerous functions, including reactive oxygen species scavenging, neuromodulation, and involvement in angiogenesis. Absence of vitamin C in the brain has been shown to be detrimental to survival in newborn SVCT2(−/−) mice and perinatal deficiency have shown to reduce hippocampal volume and neuron number and cause decreased spatial cognition in guinea pigs, suggesting that maternal vitamin C deficiency could have severe consequences for the offspring. Furthermore, vitamin C deficiency has been proposed to play a role in age-related cognitive decline and in stroke risk and severity. The present review discusses the available literature on effects of vitamin C deficiency on the developing and aging brain with particular focus on in vivo experimentation and clinical studies.

Maternal hypertensive pregnancy disorders and cognitive functioning of the offspring: a systematic review

Hypertensive pregnancy disorders may affect the fetal developmental milieu and thus hint at mechanisms that link prenatal conditions with later developmental outcomes of the offspring. Here, we systematically review studies that have tested whether maternal pre-eclampsia, gestational hypertension, and hypertensive pregnancy disorders as a single diagnostic entity are associated with cognitive functioning of the offspring. Twenty-six studies were eligible for this review. Of them, 19 provided detailed methodological information deemed necessary to be included for a more detailed review. An overall conclusion is that, in the general population, maternal hypertensive disorders may be associated with lower cognitive ability of the offspring. Studies that extend to adulthood show the most consistent pattern of findings. It is possible that the associations arise during the lifetime or that the findings reflect improvements in management of these disorders. Evidence is, however, insufficient to conclude whether these associations are dissimilar in the offspring exposed to maternal pre-eclampsia and gestational hypertension, due to the varied criteria used across the different studies to distinguish between these conditions. The existing studies also vary in the definition of control groups, and very few have taken into account important confounding factors, including maternal pre-pregnancy obesity and lifestyle behaviors. Given the mixed pattern of findings and limitations related to internal and external validity, further studies are clearly warranted to clarify the associations.

Transmitting biological effects of stress in utero: implications for mother and offspring

The developing foetus makes adaptations to an adverse in utero environment which may lead to permanent changes in structure and physiology, thus 'programming' the foetus to risk of ill health in later life. Epidemiological studies have shown associations between low birth weight, a surrogate marker of an adverse intrauterine environment, and a range of diseases in adult life including cardiometabolic and psychiatric disease. These associations do not apply exclusively to low birth weight babies but also to newborns within the normal birth weight range. Early life stress, including stressors in the prenatal and early postnatal period, is a key factor that can have long-term effects on offspring health. Animal studies show this is mediated through changes in the maternal and foetal hypothalamic-pituitary-adrenal axes resulting in foetal exposure to excess glucocorticoids. Data in humans are more limited but support that the biological effects of stress in utero may be transmitted through changes in glucocorticoid action or metabolism. Common contemporary physical and social stressors of maternal obesity and socio-economic deprivation impact on the maternal response to pregnancy and the prevailing hormonal milieu that the developing foetus will be exposed to. Prenatal stress may also be compounded by early postnatal stresses such as childhood maltreatment with resultant adverse effects for the offspring. Understanding of the mechanisms whereby these stressors are transmitted from mother to foetus will not only improve our knowledge of normal foetal development but will also help identify novel pathways for early intervention either in the periconceptional, pregnancy or the early postpartum period.

Hypertensive diseases of pregnancy predict parent-reported difficult temperament in infancy

OBJECTIVE

Recent research has linked hypertensive diseases of pregnancy with adverse neurodevelopmental outcomes in childhood and adulthood. This study aimed to establish whether such effects are observed in infancy.

METHODS

This was a prospective pregnancy cohort study of 2,785 pregnancies with complete data on hypertensive diseases of pregnancy. Mothers completed a validated Australian adaptation of the Toddler Temperament Scale when the children were 1 year of age (n = 2,384). Algorithms were used to classify children as difficult, slow to warm up, intermediate high, intermediate low, or easy, on the basis of their temperament scores. We then grouped difficult and intermediate-high infants together and compared them with easy, intermediate-low, and slow-to-warm-up infants. We used a multivariable logistic regression model and adjusted for known biomedical, sociodemographic, and psychological factors from the pre- and postnatal period that may influence child behavioral development.

RESULTS

After adjusting for confounders, mothers who were diagnosed with gestational hypertension (odds ratio [OR], 1.36; 95% confidence interval [CI], 1.06-1.75) or preeclampsia (OR, 2.23; 95% CI, 1.18-4.23) were more likely to report that their infants were in the difficult or intermediate-high classifications in the first year of life compared with infants born to mothers without gestational hypertension or preeclampsia.

CONCLUSION

These data suggest that the link between maternal hypertensive diseases of pregnancy and child behavioral development begins in the first year of life.

Maternal hypertensive disorders in pregnancy and self-reported cognitive impairment of the offspring 70 years later: the Helsinki Birth Cohort Study

OBJECTIVE

We tested whether maternal hypertensive disorders during pregnancy predict self-reported cognitive impairment, which is one of the earliest behavioral markers of dementia, of the offspring 70 years later.

STUDY DESIGN

We included 876 participants of the Helsinki Birth Cohort Study 1934-44 who were born after normotensive, preeclamptic, or hypertensive pregnancies that were defined by the use of the mother's blood pressure and urinary protein measurements at maternity clinics and birth hospitals. The participants completed a psychological questionnaire that included questions on cognitive failures and dysexecutive functioning at an average age of 69.3 ± 3.1 (SD) years.

RESULTS

In comparison with the offspring who were born after normotensive pregnancies, the offspring who were born after preeclamptic pregnancies reported more frequent complaints of cognitive failures, distractibility, and false triggering. Further, among women we found maternal hypertension without proteinuria that was associated with more frequent complaints of cognitive failures, forgetfulness, and false triggering.

CONCLUSION

Hypertensive disorders during pregnancy are associated with more frequent subjective complaints of cognitive failures of the offspring in old age.

Early life origins cognitive decline: findings in elderly men in the Helsinki Birth Cohort Study

OBJECTIVES

To examine whether the adverse effects of slow prenatal and postnatal growth on cognitive function persist to old age and predict age related cognitive decline.

DESIGN AND SETTING

A longitudinal birth cohort study of men born in Helsinki, Finland 1934-44.

PARTICIPANTS

Nine-hundred-thirty-one men of the Helsinki Birth Cohort Study, with detailed data on growth from birth to adulthood, aged 20.1 (SD = 1.4) at the first and 67.9 (SD = 2.5) years at the second cognitive testing.

MAIN OUTCOME MEASURES

The Finnish Defense Forces Basic Intellectual Ability Test assessed twice over nearly five decades apart.

RESULTS

Lower weight, length and head circumference at birth were associated with lower cognitive ability at 67.9 years (1.04-1.55 points lower ability per each standard deviation [SD] unit decrease in body size, 95% Confidence Interval [95%CI]: 0.05 to 2.72) and with cognitive decline after 20.1 years (0.07-0.11 SD decline over time per each SD decrease in body size, 95%CI:0.00 to 0.19). Men who were born larger were more likely to perform better in the cognitive ability test over time (1.22-1.43 increase in odds to remain in the top relative to the lower two thirds in ability over time per each SD increase in body size, 95%CI:1.04 to 1.79) and were more resilient to cognitive decline after 20.1 years (0.69 to 0.76 decrease in odds to decline from than remain in the top third of ability over time per each SD increase in body size, 95%CI:0.49 to 0.99). Slower growth between birth and two years in weight, height and body mass index was associated with lower cognitive ability at 67.9 years, but not with cognitive decline.

CONCLUSIONS

Poorer lifetime cognitive ability is predicted by slower growth before and after birth. In predicting resilience to age related cognitive decline, the period before birth seems to be more critical.

Maternal conditions and perinatal characteristics associated with autism spectrum disorder and intellectual disability

Background

As well as being highly comorbid conditions, autism spectrum disorders (ASD) and intellectual disability (ID) share a number of clinically-relevant phenomena. This raises questions about similarities and overlap in diagnosis and aetiological pathways that may exist for both conditions.

Aims

To examine maternal conditions and perinatal factors for children diagnosed with an ASD, with or without ID, and children with ID of unknown cause, compared with unaffected children.

Methods

The study population comprised all live singleton births in Western Australia (WA) between January 1984 and December 1999 (N = 383,153). Univariate and multivariate multinomial logistic regression models were applied using a blocked modelling approach to assess the effect of maternal conditions, sociodemographic factors, labour and delivery characteristics and neonatal outcomes.

Results

In univariate analyses mild-moderate ID was associated with pregnancy hypertension, asthma, urinary tract infection, some types of ante-partum haemorrhage, any type of preterm birth, elective C-sections, breech presentation, poor fetal growth and need for resuscitation at birth, with all factors showing an increased risk. Severe ID was positively associated with poor fetal growth and need for resuscitation, as well as any labour or delivery complication. In the multivariate analysis no maternal conditions or perinatal factors were associated with an increased risk of ASD without ID. However, pregnancy hypertension and small head circumference were associated with a reduced risk (OR = 0.64, 95% CI: 0.43, 0.94; OR = 0.58, 95% CI: 0.34, 0.96, respectively). For ASD with ID, threatened abortion before 20 weeks gestation and poor fetal growth were associated with an increased risk.

Conclusion

Findings show that indicators of a poor intrauterine environment are associated with an elevated risk of ID, while for ASD, and particularly ASD without ID, the associations are much weaker. As such, these findings highlight the importance of accounting for the absence or presence of ID when examining ASD, if we are to improve our understanding of the causal pathways associated with these conditions.

Stroke is predicted by low visuospatial in relation to other intellectual abilities and coronary heart disease by low general intelligence

Background

Low intellectual ability is associated with an increased risk of coronary heart disease and stroke. Most studies have used a general intelligence score. We studied whether three different subscores of intellectual ability predict these disorders.

Methods

We studied 2,786 men, born between 1934 and 1944 in Helsinki, Finland, who as conscripts at age 20 underwent an intellectual ability test comprising verbal, visuospatial (analogous to Raven's progressive matrices) and arithmetic reasoning subtests. We ascertained the later occurrence of coronary heart disease and stroke from validated national hospital discharge and death registers.

Results

281 men (10.1%) had experienced a coronary heart disease event and 131 (4.7%) a stroke event. Coronary heart disease was predicted by low scores in all subtests, hazard ratios for each standard deviation (SD) lower score ranging from 1.21 to 1.30 (confidence intervals 1.08 to 1.46). Stroke was predicted by a low visuospatial reasoning score, the corresponding hazard ratio being 1.23 (95% confidence interval 1.04 to 1.46), adjusted for year and age at testing. Adjusted in addition for the two other scores, the hazard ratio was 1.40 (1.10 to 1.79). This hazard ratio was little affected by adjustment for socioeconomic status in childhood and adult life, whereas the same adjustments attenuated the associations between intellectual ability and coronary heart disease. The associations with stroke were also unchanged when adjusted for systolic blood pressure at 20 years and reimbursement for adult antihypertensive medication.

Conclusions

Stroke is predicted by low visuospatial reasoning scores in relation to scores in the two other subtests. This association may be mediated by common underlying causes such as impaired brain development, rather than by mechanisms associated with risk factors shared by stroke and coronary heart disease, such as socio-economic status, hypertension and atherosclerosis.

Hypertensive disorders in pregnancy and cognitive decline in the offspring up to old age

OBJECTIVE

We tested whether maternal hypertensive disorders in pregnancy predict age-related change in cognitive ability in the offspring up to old age.

METHODS

Using mothers' blood pressure and urinary protein measurements from the maternity clinics and birth hospitals, we defined normotensive or hypertensive pregnancies in mothers of 398 men, who participated in the Helsinki Birth Cohort 1934-1944 Study. The men underwent the Finnish Defence Forces basic ability test twice: first during compulsory military service at age 20.1 (SD = 1.4) years and then in a retest at age 68.5 (SD = 2.9) years. The test yields a total score and subscores for tests measuring verbal, arithmetic, and visuospatial reasoning.

RESULTS

Men born after pregnancies complicated by a hypertensive disorder, compared with men born after normotensive pregnancies, scored 4.36 (95% confidence interval, 1.17-7.55) points lower on total cognitive ability at 68.5 years and displayed a greater decline in total cognitive ability (2.88; 95% confidence interval, 0.07-5.06) after 20.1 years. Of the subscores, associations were strongest for arithmetic reasoning.

CONCLUSION

Maternal hypertensive disorders in pregnancy predict lower cognitive ability and greater cognitive decline up to old age. A propensity to lower cognitive ability and decline up to old age may have prenatal origins.