Ali S. Khashan

Higher risk of offspring schizophrenia following antenatal maternal exposure to severe adverse life events.

CONTEXT Most societies believe that a mothers psychological state can influence her unborn baby. Severe adverse life events during pregnancy have been consistently associated with an elevated risk of low birth weight and prematurity. Such events during the first trimester have also been associated with risk of congenital malformations. OBJECTIVE To assess the effect in offspring of antenatal maternal exposure to an objective measure of stress on risk of adverse neurodevelopment, specifically schizophrenia. We hypothesized that the strongest relationship would be to maternal exposures during the first trimester. DESIGN Population-based study. SETTING Denmark. PARTICIPANTS In a cohort of 1.38 million Danish births from 1973 to 1995, mothers were considered exposed if 1 (or more) of their close relatives died or was diagnosed with cancer, acute myocardial infarction, or stroke syndrome up to 6 months before conception or during pregnancy. Offspring were followed up from their 10th birthday until their death, migration, onset of schizophrenia, or June 30, 2005; admissions were identified by linkage to the Central Psychiatric Register. Main Outcome Measure Schizophrenia. RESULTS The risk of schizophrenia and related disorders was raised in offspring whose mothers were exposed to death of a relative during the first trimester (adjusted relative risk, 1.67 [95% confidence interval, 1.02-2.73]). Death of a relative during other trimesters or up to 6 months before pregnancy were not linked with a higher risk of schizophrenia. CONCLUSIONS Our population-based study suggests that severe stress to a mother during the first trimester may alter the risk of schizophrenia in offspring. This finding is consistent with ecological evidence from whole populations exposed to severe stressors and suggests that environment may influence neurodevelopment at the feto-placental-maternal interface.

Advanced maternal age and adverse pregnancy outcome: evidence from a large contemporary cohort.

Background Recent decades have witnessed an increase in mean maternal age at childbirth in most high-resourced countries. Advanced maternal age has been associated with several adverse maternal and perinatal outcomes. Although there are many studies on this topic, data from large contemporary population-based cohorts that controls for demographic variables known to influence perinatal outcomes is limited. Methods We performed a population-based cohort study using data on all singleton births in 2004–2008 from the North Western Perinatal Survey based at The University of Manchester, UK. We compared pregnancy outcomes in women aged 30–34, 35–39 and ≥40 years with women aged 20–29 years using log-linear binomial regression. Models were adjusted for parity, ethnicity, social deprivation score and body mass index. Results The final study cohort consisted of 215,344 births; 122,307 mothers (54.19%) were aged 20–29 years, 62,371(27.63%) were aged 30–34 years, 33,966(15.05%) were aged 35–39 years and 7,066(3.13%) were aged ≥40 years. Women aged 40+ at delivery were at increased risk of stillbirth (RR = 1.83, [95% CI 1.37–2.43]), pre-term (RR = 1.25, [95% CI: 1.14–1.36]) and very pre-term birth (RR = 1.29, [95% CI:1.08–1.55]), Macrosomia (RR = 1.31, [95% CI: 1.12–1.54]), extremely large for gestational age (RR = 1.40, [95% CI: 1.25–1.58]) and Caesarean delivery (RR = 1.83, [95% CI: 1.77–1.90]). Conclusions Advanced maternal age is associated with a range of adverse pregnancy outcomes. These risks are independent of parity and remain after adjusting for the ameliorating effects of higher socioeconomic status. The data from this large contemporary cohort will be of interest to healthcare providers and women and will facilitate evidence based counselling of older expectant mothers.

Reduced infant birthweight consequent upon maternal exposure to severe life events.

Objective: To investigate the association between maternal exposure to severe life events and fetal growth (birthweight and small for gestational age). Stress has been associated with adverse pregnancy outcome. Methods: Mothers of 1.38 million singleton live births in Denmark between January 1, 1979 and December 31, 2002 were linked to information on their spouses, parents, siblings, and older children. Exposure was defined as death or serious illness in a relative during pregnancy or in the 6 months before conception. Linear regression was used to examine the effect of exposure on birthweight. Log-linear binomial regression was used to assess the effect of exposure on small for gestational age. Results: Death of a relative during pregnancy or in the 6 months before conception reduced birthweight by 27 g (adjusted estimate −27 g, 95% Confidence Interval (CI) = −33, −22). There was a significant association between maternal exposure to death of a relative and risk of a baby weighing below the 10th percentile (adjusted relative risk (RR) = 1.17, 95% CI = 1.13, 1.22) and 5th percentile (adjusted RR = 1.22, 95% CI = 1.15, 1.29). Conclusions: Mothers exposed to severe life events before conception or during pregnancy have babies with significantly lower birthweight. If this association is causal, the potential mechanisms of stress-related effects on birthweight include changes in lifestyle due to the exposure and stress-related dysregulation of the hypothalamic-pituitary-adrenal axis during pregnancy. IUGR = intrauterine growth restriction; CVA = cerebrovascular accident; AMI = acute myocardial infarction; SGA = small for gestational age; VSGA = very small for gestational age; GHQ = general health questionnaire; SES = socioeconomic status.

Rates of preterm birth following antenatal maternal exposure to severe life events: a population-based cohort study

BACKGROUND Preterm birth and other pregnancy complications have been linked to maternal stress during pregnancy. We investigated the association between maternal exposure to severe life events and risk of preterm birth. METHODS Mothers of all singleton live births (n = 1.35 million births) in Denmark between 1 January 1979 and 31 December 2002 were linked to data on their children, parents, siblings and partners. We defined exposure as death or serious illness in close relatives in the first or second trimesters or in the 6 months before conception. Log-linear binomial regression was used to estimate the effect of exposure on preterm birth, very preterm birth and extremely preterm birth. RESULTS There were 58 626 (4.34%) preterm births (<37 weeks), 11 732 (0.87%) very preterm births and 3288 (0.24%) extremely preterm births in the study cohort. Severe life events in close relatives in the 6 months before conception increased the risk of preterm birth by 16% (relative risk, RR = 1.16, [95% CI: 1.08-1.23]). Severe life events in older children in the 6 months before conception increased the risk of preterm birth by 23% (RR = 1.23, [95% CI: 1.02-1.49]) and the risk of very preterm birth by 59% (RR = 1.59, [95% CI: 1.08-2.35]). CONCLUSIONS Our population-based cohort study suggests that maternal exposure to severe life events, particularly in the 6 months before pregnancy, may increase the risk of preterm and very preterm birth.

Offspring psychopathology following preconception, prenatal and postnatal maternal bereavement stress

BACKGROUND Preconception, prenatal and postnatal maternal stress is associated with increased offspring psychopathology, but findings are inconsistent and need replication. We estimated associations between maternal bereavement stress and offspring autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), bipolar disorder, schizophrenia, suicide attempt and completed suicide. METHOD Using Swedish registers, we conducted the largest population-based study to date examining associations between stress exposure in 738,144 offspring born 1992-2000 for childhood outcomes and 2,155,221 offspring born 1973-1997 for adult outcomes with follow-up to 2009. Maternal stress was defined as death of a first-degree relative during (a) the 6 months before conception, (b) pregnancy or (c) the first two postnatal years. Cox proportional survival analyses were used to obtain hazard ratios (HRs) in unadjusted and adjusted analyses. RESULTS Marginal increased risk of bipolar disorder and schizophrenia following preconception bereavement stress was not significant. Third-trimester prenatal stress increased the risk of ASD [adjusted HR (aHR) 1.58, 95% confidence interval (CI) 1.15-2.17] and ADHD (aHR 1.31, 95% CI 1.04-1.66). First postnatal year stress increased the risk of offspring suicide attempt (aHR 1.13, 95% CI 1.02-1.25) and completed suicide (aHR 1.51, 95% CI 1.08-2.11). Bereavement stress during the second postnatal year increased the risk of ASD (aHR 1.30, 95% CI 1.09-1.55). CONCLUSIONS Further research is needed regarding associations between preconception stress and psychopathological outcomes. Prenatal bereavement stress increases the risk of offspring ASD and ADHD. Postnatal bereavement stress moderately increases the risk of offspring suicide attempt, completed suicide and ASD. Smaller previous studies may have overestimated associations between early stress and psychopathological outcomes.

The impact of maternal celiac disease on birthweight and preterm birth: a Danish population-based cohort study

BACKGROUND Adverse pregnancy outcomes have been associated with maternal celiac disease (CD). In this study, we investigate the effect of treated and untreated maternal CD on infant birthweight and preterm birth. METHODS A population-based cohort study consisted of all singleton live births in Denmark between 1 January 1979 and 31 December 2004 was used. A total of 1,504,342 babies were born to 836,241 mothers during the study period. Of those, 1105 babies were born to women with diagnosed CD and 346 were born to women with undiagnosed CD. Women with diagnosed CD were considered as treated with a gluten free diet while women with undiagnosed CD were considered as untreated. The outcome measures were: birthweight, small for gestational age (SGA: birthweight <10th centile), very small for gestational age (VSGA: birthweight <5th centile) and preterm birth. We compared these measures in treated and untreated women with those of a reference group (no history of CD). RESULTS Women with untreated CD delivered smaller babies [difference = -98 g (95% CI: -130, -67)], with a higher risk of SGA infants [OR = 1.31 (95% CI: 1.06, 1.63)], VSGA infants [OR = 1.54 (95% CI: 1.17, 2.03)] and preterm birth [OR = 1.33 (95% CI: 1.02, 1.72)] compared with women without CD. Women with treated CD had no increased risk of reduced mean birthweight, risk of delivering SGA and VSGA infants or preterm birth compared with women without CD. CONCLUSION Untreated maternal CD increases the risk of reduced birthweight, the risk of delivering SGA and VSGA infants and preterm birth. Diagnosis and presumed treatment of maternal CD with a gluten-free diet appeared to result in a birthweight and preterm birth rate similar to those in women without CD.

Research review: Birth by caesarean section and development of autism spectrum disorder and attention-deficit/hyperactivity disorder: a systematic review and meta-analysis.

BACKGROUND Given the growing prevalence of birth by Caesarean section (CS) worldwide, it is important to understand any long-term effects CS delivery may have on a childs development. We assessed the impact of mode of delivery on autism spectrum disorders (ASD) and attention-deficit/hyperactivity disorder (ADHD). METHODS We conducted a systematic review of the literature in PubMed, Embase, CINAHL, PsycINFO and Web of Science up to 28 February 2014. No publication date, language, location or age restrictions were employed. RESULTS Thirteen studies reported an adjusted estimate for CS-ASD, producing a pooled odds ratio (OR) of 1.23 (95% CI: 1.07, 1.40). Two studies reported an adjusted estimate for CS-ADHD, producing a pooled OR of 1.07 (95% CI: 0.86, 1.33). CONCLUSIONS Delivery by CS is associated with a modest increased odds of ASD, and possibly ADHD, when compared to vaginal delivery. Although the effect may be due to residual confounding, the current and accelerating rate of CS implies that even a small increase in the odds of disorders, such as ASD or ADHD, may have a large impact on the society as a whole. This warrants further investigation.

Prevalence and predictors of alcohol use during pregnancy: findings from international multicentre cohort studies

Objectives To compare the prevalence and predictors of alcohol use in multiple cohorts. Design Cross-cohort comparison of retrospective and prospective studies. Setting Population-based studies in Ireland, the UK, Australia and New Zealand. Participants 17 244 women of predominantly Caucasian origin from two Irish retrospective studies (Growing up in Ireland (GUI) and Pregnancy Risk Assessment Monitoring System Ireland (PRAMS Ireland)), and one multicentre prospective international cohort, Screening for Pregnancy Endpoints (SCOPE) study. Primary and secondary outcome measures Prevalence of alcohol use pre-pregnancy and during pregnancy across cohorts. Sociodemographic factors associated with alcohol consumption in each cohort. Results Alcohol consumption during pregnancy in Ireland ranged from 20% in GUI to 80% in SCOPE, and from 40% to 80% in Australia, New Zealand and the UK. Levels of exposure also varied substantially among drinkers in each cohort ranging from 70% consuming more than 1–2 units/week in the first trimester in SCOPE Ireland, to 46% and 15% in the retrospective studies. Smoking during pregnancy was the most consistent predictor of gestational alcohol use in all three cohorts, and smokers were 17% more likely to drink during pregnancy in SCOPE, relative risk (RR)=1.17 (95% CI 1.12 to 1.22), 50% more likely to drink during pregnancy in GUI, RR=1.50 (95% CI 1.36 to 1.65), and 42% more likely to drink in PRAMS, RR=1.42 (95% CI 1.18 to 1.70). Conclusions Our data suggest that alcohol use during pregnancy is prevalent and socially pervasive in the UK, Ireland, New Zealand and Australia. New policy and interventions are required to reduce alcohol prevalence both prior to and during pregnancy. Further research on biological markers and conventions for measuring alcohol use in pregnancy is required to improve the validity and reliability of prevalence estimates.

Prenatal Stress and Risk of Asthma Hospitalization in the Offspring: A Swedish Population-based Study

Objective Recent research suggested that maternal stress and anxiety increase the risk of asthma and eczema in the offspring. In this study, we aimed to study whether maternal exposure to death of a spouse or a child is associated with risk of asthma hospitalization in the offspring using a very large population-based cohort. Methods In a cohort of 3.2 million births in Sweden between January 1, 1973, and December 31, 2004, mothers were considered exposed if their spouse or child died up to 6 months before or during pregnancy. Offspring were followed up from birth to their death, migration, first hospitalization with asthma, or December 31, 2006, whichever came first; hospital admissions were identified by linkage of several national Swedish registers. Log-linear Poisson regression was used for data analysis. Results Overall, the risk of offspring asthma was increased with any prenatal exposure to bereavement in any exposure period (adjusted relative risk [RR] = 1.20 [95% confidence interval {CI} = 1.03–1.39]). The risk was higher when the exposure period was restricted to pregnancy only (adjusted RR = 1.43 [95% CI = 1.06–1.92]). Furthermore, the risk of asthma was increased in relation to death of a spouse during pregnancy (adjusted RR = 1.59 [95% CI = 1.10–2.30]). Conclusions These findings suggest that prenatal exposure to severe life events increases the risk of hospitalization for asthma in the offspring. Fetal programming may be a plausible explanation for the association. Abbreviations HPA = hypothalamic-pituitary-adrenal ICD = International Classification of Disease RR = relative risk

Association between maternal alcohol consumption in early pregnancy and pregnancy outcomes.

OBJECTIVE: To investigate the association between alcohol consumption and binge drinking before and during early pregnancy and adverse pregnancy outcomes. METHODS: We used data from 5,628 nulliparous pregnant participants recruited to the Screening for Pregnancy Endpoints (SCOPE) study, a prospective cohort study. Participants were interviewed at 15 weeks of gestation and information on alcohol intake before pregnancy and until the time of interview was obtained using a standardized questionnaire. Alcohol intake was classified as occasional (1–2 units per week), low (3–7 units per week), moderate (8–14 units per week), and heavy (greater than 14 units per week). Binge alcohol consumption was defined as consumption of 6 or more alcohol units in one session. RESULTS: Of the 5,628 participants, 1,090 (19%) reported occasional alcohol consumption, 1,383 (25%) low alcohol consumption, 625 (11%) moderate alcohol consumption, and 300 (5%) heavy alcohol consumption. Overall, 1,905 (34%) participants reported binge alcohol consumption in the 3 months before pregnancy, and 1,288 (23%) of these participants reported binge alcohol consumption during the first 15 weeks of pregnancy. Participants who consumed occasional to heavy amounts of alcohol in early pregnancy did not have altered odds of a small-for-gestational-age neonate, reduced birth weight, preeclampsia, or spontaneous preterm birth. Similarly, those who binge drank in early pregnancy did not have altered odds of these adverse pregnancy outcomes. CONCLUSION: Alcohol consumption in early pregnancy was prevalent in this nulliparous cohort. There was no association between alcohol consumption before 15 weeks of gestation and small for gestational age, reduced birth weight, preeclampsia, or spontaneous preterm birth. LEVEL OF EVIDENCE: II