Sven Cnattingius | Karolinska Institutet (original) (raw)

Papers by Sven Cnattingius

Research paper thumbnail of Who continues to smoke while pregnant?

Journal of Epidemiology and Community Health, 1992

STUDY OBJECTIVE--The aim was to study changes in smoking habits during pregnancy and differences ... more STUDY OBJECTIVE--The aim was to study changes in smoking habits during pregnancy and differences in characteristics between women who stop smoking and those who continue to smoke during pregnancy. DESIGN--The study was a population based prospective study. Self administered questionnaires were completed on three occasions. SETTING--The study area was Uppsala county, Sweden, in 1987. PARTICIPANTS--The participants were women registered with

Research paper thumbnail of The Risk of Gestational Diabetes Mellitus Following Bereavement: A Cohort Study from Denmark and Sweden

Paediatric and perinatal epidemiology, Jan 5, 2015

We investigated whether bereavement of a close family member - a source of severe psychological s... more We investigated whether bereavement of a close family member - a source of severe psychological stress exposure - the year before pregnancy is associated with gestational diabetes mellitus (GDM). We studied pregnant women with livebirths in Denmark during 1994-2008 and with births in Sweden during 1987-2006 (n = 2 569 446). We obtained data on death of women's parents, siblings, and older children, and on demographic and health- and pregnancy-related factors through linkage between nationwide registers. In multivariable models, death of a close relative the year before pregnancy was associated with a 14% increased odds of GDM [95% confidence intervals (CIs) 1.03, 1.26]. The odds ratios corresponding to the loss of a child, parent, and sibling were 1.51 (95% CI: 1.17, 1.95), 1.12 (95% CI: 1.00, 1.25), and 0.68 (95% CI: 0.40, 1.25), respectively. Deaths due to cardiovascular diseases or diabetes were more closely related to the risk of GDM than other types of deaths. We found no a...

Research paper thumbnail of An international contrast of rates of placental abruption: an age-period-cohort analysis

PloS one, 2015

Although rare, placental abruption is implicated in disproportionately high rates of perinatal mo... more Although rare, placental abruption is implicated in disproportionately high rates of perinatal morbidity and mortality. Understanding geographic and temporal variations may provide insights into possible amenable factors of abruption. We examined abruption frequencies by maternal age, delivery year, and maternal birth cohorts over three decades across seven countries. Women that delivered in the US (n = 863,879; 1979-10), Canada (4 provinces, n = 5,407,463; 1982-11), Sweden (n = 3,266,742; 1978-10), Denmark (n = 1,773,895; 1978-08), Norway (n = 1,780,271, 1978-09), Finland (n = 1,411,867; 1987-10), and Spain (n = 6,151,508; 1999-12) were analyzed. Abruption diagnosis was based on ICD coding. Rates were modeled using Poisson regression within the framework of an age-period-cohort analysis, and multi-level models to examine the contribution of smoking in four countries. Abruption rates varied across the seven countries (3-10 per 1000), Maternal age showed a consistent J-shaped pattern...

Research paper thumbnail of Maternal overweight and obesity in early pregnancy and risk of infant mortality: a population based cohort study in Sweden

BMJ (Clinical research ed.), 2014

To investigate associations between maternal overweight and obesity and infant mortality outcomes... more To investigate associations between maternal overweight and obesity and infant mortality outcomes, including cause-specific mortality. Population based cohort study. 1,857,822 live single births in Sweden 1992-2010. Associations between maternal body mass index (BMI) in early pregnancy and risks of infant, neonatal, and postneonatal mortality, overall and stratified by gestational length and by causes of infant death. Odds ratios were adjusted for maternal age, parity, smoking, education, height, country of birth, and year of delivery. Infant mortality rates increased from 2.4/1000 among normal weight women (BMI 18.5-24.9) to 5.8/1000 among women with obesity grade 3 (BMI ≥ 40.0). Compared with normal weight, overweight (BMI 25.0-29.9) and obesity grade 1 (BMI 30.0-34.9) were associated with modestly increased risks of infant mortality (adjusted odds ratios 1.25 (95% confidence interval 1.16 to 1.35) and 1.37 (1.22 to 1.53), respectively), and obesity grade 2 (BMI 35.0-39.9) and gra...

Research paper thumbnail of Will an adverse pregnancy outcome influence the risk of continued smoking in the next pregnancy?

American journal of obstetrics and gynecology, 2006

The purpose of this study was to study the effect of pregnancy outcomes on risks of continued smo... more The purpose of this study was to study the effect of pregnancy outcomes on risks of continued smoking in subsequent pregnancy. Cohort study of first and second single births among 98,778 Swedish women who were daily smokers in first pregnancy. In all, 70.2% of women continued to smoke in second pregnancy. Compared with women with a previous normal pregnancy outcome, risk of smoking in second pregnancy was increased among women with a previous small-for-gestational-age birth (adjusted odds ratio [OR], 95% CI 1.28 [95% CI 1.19-1.37]), and reduced among women who had experienced a stillbirth (OR 0.76 [95% CI 0.63-0.93]) or an infant death because of congenital malformations (OR 0.67 [95% CI 0.49-0.92]. A previous preterm birth, Sudden Infant Death Syndrome, and other causes of infant death did not influence risk. A previous adverse pregnancy outcome has only a modest influence on smoking habits in the successive pregnancy.

Research paper thumbnail of Caffeine intake and the risk of first-trimester spontaneous abortion

The New England journal of medicine, Jan 21, 2000

Some epidemiologic studies have suggested that the ingestion of caffeine increases the risk of sp... more Some epidemiologic studies have suggested that the ingestion of caffeine increases the risk of spontaneous abortion, but the results have been inconsistent. We performed a population-based, case-control study of early spontaneous abortion in Uppsala County, Sweden. The subjects were 562 women who had spontaneous abortion at 6 to 12 completed weeks of gestation (the case patients) and 953 women who did not have spontaneous abortion and were matched to the case patients according to the week of gestation (controls). Information on the ingestion of caffeine was obtained from in-person interviews. Plasma cotinine was measured as an indicator of cigarette smoking, and fetal karyotypes were determined from tissue samples. Multivariate analysis was used to estimate the relative risks associated with caffeine ingestion after adjustment for smoking and symptoms of pregnancy such as nausea, vomiting, and tiredness. Among nonsmokers, more spontaneous abortions occurred in women who ingested at...

Research paper thumbnail of Pregnancy outcomes by mode of delivery among term breech births: Swedish experience 1987-1993

Obstetrics and gynecology, 1998

To study the influence of mode of delivery on infant mortality, neonatal morbidity, and maternal ... more To study the influence of mode of delivery on infant mortality, neonatal morbidity, and maternal morbidity in pregnancies with nonmalformed term singleton infants presented in breech. We studied all nonmalformed live-born singleton infants, delivered at term (at 37 weeks or later) in breech position in Sweden between 1987 and 1993 (n = 15,818). The pregnancy outcomes analyzed were neonatal and infant mortality, low Apgar score (less than 7) at 5 minutes, birth injury, and neonatal convulsions. Severe perineal or vaginal lacerations, wound rupture, infections, and thrombosis were used as measures of maternal morbidity. Logistic regression analysis was used to determine risks of infant mortality and morbidity, after adjusting for a number of potential confounders. Compared with infants delivered by elective cesarean, infants delivered vaginally were at significantly higher risk for infant mortality (odds ratio [OR] 2.5). Infants delivered vaginally were at increased risk for birth inj...

Research paper thumbnail of Mortality after Parental Death in Childhood: A Nationwide Cohort Study from Three Nordic Countries

PLoS Medicine, 2014

Bereavement by spousal death and child death in adulthood has been shown to lead to an increased ... more Bereavement by spousal death and child death in adulthood has been shown to lead to an increased risk of mortality. Maternal death in infancy or parental death in early childhood may have an impact on mortality but evidence has been limited to short-term or selected causes of death. Little is known about long-term or cause-specific mortality after parental death in childhood. This cohort study included all persons born in Denmark from 1968 to 2008 (n = 2,789,807) and in Sweden from 1973 to 2006 (n = 3,380,301), and a random sample of 89.3% of all born in Finland from 1987 to 2007 (n = 1,131,905). A total of 189,094 persons were included in the exposed cohort when they lost a parent before 18 years old. Log-linear Poisson regression was used to estimate mortality rate ratio (MRR). Parental death was associated with a 50% increased all-cause mortality (MRR = 1.50, 95% CI 1.43-1.58). The risks were increased for most specific cause groups and the highest MRRs were observed when the cause of child death and the cause of parental death were in the same category. Parental unnatural death was associated with a higher mortality risk (MRR = 1.84, 95% CI 1.71-2.00) than parental natural death (MRR = 1.33, 95% CI 1.24-1.41). The magnitude of the associations varied according to type of death and age at bereavement over different follow-up periods. The main limitation of the study is the lack of data on post-bereavement information on the quality of the parent-child relationship, lifestyles, and common physical environment. Parental death in childhood or adolescence is associated with increased all-cause mortality into early adulthood. Since an increased mortality reflects both genetic susceptibility and long-term impacts of parental death on health and social well-being, our findings have implications in clinical responses and public health strategies. Please see later in the article for the Editors' Summary.

Research paper thumbnail of Prenatal Exposure to Maternal Bereavement and Childbirths in the Offspring: A Population-Based Cohort Study

PLoS ONE, 2014

The decline in birth rates is a concern in public health. Fertility is partly determined before b... more The decline in birth rates is a concern in public health. Fertility is partly determined before birth by the intrauterine environment and prenatal exposure to maternal stress could, through hormonal disturbance, play a role. There has been such evidence from animal studies but not from humans. We aimed to examine the association between prenatal stress due to maternal bereavement following the death of a relative and childbirths in the offspring.

Research paper thumbnail of Fetal Growth Restriction and Schizophrenia: A Swedish Twin Study

Twin Research and Human Genetics, 2005

Research paper thumbnail of Maternal Overweight and Obesity and Risks of Severe Birth-Asphyxia-Related Complications in Term Infants: A Population-Based Cohort Study in Sweden

PLoS Medicine, 2014

Background: Maternal overweight and obesity increase risks of pregnancy and delivery complication... more Background: Maternal overweight and obesity increase risks of pregnancy and delivery complications and neonatal mortality, but the mechanisms are unclear. The objective of the study was to investigate associations between maternal body mass index (BMI) in early pregnancy and severe asphyxia-related outcomes in infants delivered at term ($37 weeks).

Research paper thumbnail of The Swedish Twin Registry in the Third Millennium: An Update

Twin Research and Human Genetics, 2006

The Swedish Twin Registry was first established in the late 1950s. Today it includes more than 17... more The Swedish Twin Registry was first established in the late 1950s. Today it includes more than 170,000 twins -in principle all twins born in Sweden since 1886. In this paper we describe some ongoing and recently completed projects based on the registry. In particular, we describe recent efforts to screen all twins born between 1959 and 1985, and young twin pairs when they turn 9 and 12 years of age. For these studies, we present initial frequencies of common conditions and exposures.

Research paper thumbnail of Estimation of genetic and environmental factors for binary traits using family data by Y. Pawitan, M. Reilly, E. Nilsson, S. Cnattingius and P. Lichtenstein,Statistics in Medicine 2004;23:449–465

Statistics in Medicine, 2005

Research paper thumbnail of Human fertility does not decline: evidence from Sweden

Fertility and Sterility, 1999

Objective: To assess changes in human fertility over time.Design: Time-trend analyses and age-per... more Objective: To assess changes in human fertility over time.Design: Time-trend analyses and age-period-cohort modeling.Setting: Sweden, 1983–1993.Patient(s): All primiparous women aged ≥20 years during the study period. There were 401,653 women who were identified through the nationwide Medical Birth Register.Intervention(s): None.Main Outcome Measure(s): Risk of subfertility, defined as ≥1 year of involuntary childlessness.Result(s): Subfertility problems decreased dramatically over successive maternal birth

Research paper thumbnail of Women with schizophrenia: pregnancy outcome and infant death among their offspring

Schizophrenia Research, 2002

Schizophrenia in the mother may imply an increased risk of adverse pregnancy outcome. However, in... more Schizophrenia in the mother may imply an increased risk of adverse pregnancy outcome. However, inconclusive findings, unknown pathological mechanisms and possible confounding by social factors and smoking requests further explorations. The aim of this study were to (1) examine non-optimal pregnancy outcome using data from a population-based cohort, controlling for covariates known to influence fetal growth; and (2) perform separate analyses of women diagnosed before childbirth and women hospitalized for schizophrenia during pregnancy. The study sample comprised 2096 births by 1438 mothers diagnosed with schizophrenia (of whom 696 mothers were antenatal diagnosed and 188 admitted during pregnancy) and 1,555,975 births in the general population. We found significantly increased risks for stillbirth, infant death, preterm delivery, low birth weight, and small-for-gestational-age among the offspring of women with schizophrenia. Women with an episode of schizophrenia during pregnancy had the highest risks (e.g., low birth weight; OR 4.3, 95% CI 2.9-6.6 and stillbirth; OR 4.4, 95% CI 1.4-13.8). Controlling for a high incidence of smoking during pregnancy among schizophrenic women (51% vs. 24% in the normal population) and other maternal factors (single motherhood, maternal age, parity, maternal education, mothers' country of birth and pregnancy-induced hypertensive diseases) in a multiple regression model, reduced the risk estimates markedly. However, the risks for adverse pregnancy outcomes were even after adjustments generally doubled for women with an episode of schizophrenia during pregnancy compared to women in the control group (e.g., low birth weight; OR 2.3, 95% CI 1.5-3.5, preterm delivery; OR 2.4, 95% CI 1.5-3.8 and stillbirth; OR 2.5, 95% CI 0.8-7.9). The risks for preterm delivery and low birth weight were significantly elevated throughout the analyses. We conclude that schizophrenia in the mother implies an increased risk for poor perinatal outcome, not fully explained by maternal factors, and a need to consider a common familial (probably genetic) vulnerability for pre- and perinatal stress and schizophrenia.

Research paper thumbnail of Maternal Snuff Use and Smoking and the Risk of Oral Cleft Malformations - A Population-Based Cohort Study

PLoS ONE, 2014

Objective: To determine if maternal use of snuff (containing high levels of nicotine, low levels ... more Objective: To determine if maternal use of snuff (containing high levels of nicotine, low levels of nitrosamines and no combustion products) is associated with an increased risk of oral cleft malformations in the infant and whether cessation of snuff use or smoking before the antenatal booking influences the risk.

Research paper thumbnail of Psychotic Illness in First-Time Mothers with No Previous Psychiatric Hospitalizations: A Population-Based Study

Research paper thumbnail of Parental Psychiatric Disorders Associated With Autism Spectrum Disorders in the Offspring

Research paper thumbnail of Intellectual and Psychological Performance in Males Born Small for Gestational Age With and Without Catch-Up Growth

Pediatric Research, 2001

Infants born small for gestational age (SGA) have an increased risk of neurologic and intellectua... more Infants born small for gestational age (SGA) have an increased risk of neurologic and intellectual dysfunction. Most of these infants catch up in growth and attain normal height, although some do not. Whether catch-up growth influences intellectual function is not known. To analyze whether intellectual and psychological performance of males in early adulthood are associated with body size at birth or by catch-up growth in height among boys, a population-based cohort was studied. This cohort included all male singletons born without congenital malformations in Sweden from 1973 to 1978 and alive at 18 y (n = 276,033). Information from the Swedish Birth Register was individually linked to the Swedish Conscript Register. Of 254,426 conscripted males, information on intellectual and psychological performance was available for 97% and 91%, respectively. Low birth weight, short birth length, small head circumference at birth, and preterm birth increased the risk of subnormal intellectual and psychological performance. Among SGA-born males, the most important predictor was the absence of catch-up growth. Being born SGA is associated with increased risk of subnormal intellectual and psychological performance. The data strongly support the view that, for males born SGA, it is an advantage to have catch-up growth in length.

Research paper thumbnail of Maternal smoking during pregnancy and intellectual performance in young adult Swedish male offspring

Paediatric and Perinatal Epidemiology, 2010

Maternal smoking during pregnancy and intellectual performance in young adult Swedish male offspr... more Maternal smoking during pregnancy and intellectual performance in young adult Swedish male offspring. Paediatric and Perinatal Epidemiology 2010; 24: 79-87.

Research paper thumbnail of Who continues to smoke while pregnant?

Journal of Epidemiology and Community Health, 1992

STUDY OBJECTIVE--The aim was to study changes in smoking habits during pregnancy and differences ... more STUDY OBJECTIVE--The aim was to study changes in smoking habits during pregnancy and differences in characteristics between women who stop smoking and those who continue to smoke during pregnancy. DESIGN--The study was a population based prospective study. Self administered questionnaires were completed on three occasions. SETTING--The study area was Uppsala county, Sweden, in 1987. PARTICIPANTS--The participants were women registered with

Research paper thumbnail of The Risk of Gestational Diabetes Mellitus Following Bereavement: A Cohort Study from Denmark and Sweden

Paediatric and perinatal epidemiology, Jan 5, 2015

We investigated whether bereavement of a close family member - a source of severe psychological s... more We investigated whether bereavement of a close family member - a source of severe psychological stress exposure - the year before pregnancy is associated with gestational diabetes mellitus (GDM). We studied pregnant women with livebirths in Denmark during 1994-2008 and with births in Sweden during 1987-2006 (n = 2 569 446). We obtained data on death of women's parents, siblings, and older children, and on demographic and health- and pregnancy-related factors through linkage between nationwide registers. In multivariable models, death of a close relative the year before pregnancy was associated with a 14% increased odds of GDM [95% confidence intervals (CIs) 1.03, 1.26]. The odds ratios corresponding to the loss of a child, parent, and sibling were 1.51 (95% CI: 1.17, 1.95), 1.12 (95% CI: 1.00, 1.25), and 0.68 (95% CI: 0.40, 1.25), respectively. Deaths due to cardiovascular diseases or diabetes were more closely related to the risk of GDM than other types of deaths. We found no a...

Research paper thumbnail of An international contrast of rates of placental abruption: an age-period-cohort analysis

PloS one, 2015

Although rare, placental abruption is implicated in disproportionately high rates of perinatal mo... more Although rare, placental abruption is implicated in disproportionately high rates of perinatal morbidity and mortality. Understanding geographic and temporal variations may provide insights into possible amenable factors of abruption. We examined abruption frequencies by maternal age, delivery year, and maternal birth cohorts over three decades across seven countries. Women that delivered in the US (n = 863,879; 1979-10), Canada (4 provinces, n = 5,407,463; 1982-11), Sweden (n = 3,266,742; 1978-10), Denmark (n = 1,773,895; 1978-08), Norway (n = 1,780,271, 1978-09), Finland (n = 1,411,867; 1987-10), and Spain (n = 6,151,508; 1999-12) were analyzed. Abruption diagnosis was based on ICD coding. Rates were modeled using Poisson regression within the framework of an age-period-cohort analysis, and multi-level models to examine the contribution of smoking in four countries. Abruption rates varied across the seven countries (3-10 per 1000), Maternal age showed a consistent J-shaped pattern...

Research paper thumbnail of Maternal overweight and obesity in early pregnancy and risk of infant mortality: a population based cohort study in Sweden

BMJ (Clinical research ed.), 2014

To investigate associations between maternal overweight and obesity and infant mortality outcomes... more To investigate associations between maternal overweight and obesity and infant mortality outcomes, including cause-specific mortality. Population based cohort study. 1,857,822 live single births in Sweden 1992-2010. Associations between maternal body mass index (BMI) in early pregnancy and risks of infant, neonatal, and postneonatal mortality, overall and stratified by gestational length and by causes of infant death. Odds ratios were adjusted for maternal age, parity, smoking, education, height, country of birth, and year of delivery. Infant mortality rates increased from 2.4/1000 among normal weight women (BMI 18.5-24.9) to 5.8/1000 among women with obesity grade 3 (BMI ≥ 40.0). Compared with normal weight, overweight (BMI 25.0-29.9) and obesity grade 1 (BMI 30.0-34.9) were associated with modestly increased risks of infant mortality (adjusted odds ratios 1.25 (95% confidence interval 1.16 to 1.35) and 1.37 (1.22 to 1.53), respectively), and obesity grade 2 (BMI 35.0-39.9) and gra...

Research paper thumbnail of Will an adverse pregnancy outcome influence the risk of continued smoking in the next pregnancy?

American journal of obstetrics and gynecology, 2006

The purpose of this study was to study the effect of pregnancy outcomes on risks of continued smo... more The purpose of this study was to study the effect of pregnancy outcomes on risks of continued smoking in subsequent pregnancy. Cohort study of first and second single births among 98,778 Swedish women who were daily smokers in first pregnancy. In all, 70.2% of women continued to smoke in second pregnancy. Compared with women with a previous normal pregnancy outcome, risk of smoking in second pregnancy was increased among women with a previous small-for-gestational-age birth (adjusted odds ratio [OR], 95% CI 1.28 [95% CI 1.19-1.37]), and reduced among women who had experienced a stillbirth (OR 0.76 [95% CI 0.63-0.93]) or an infant death because of congenital malformations (OR 0.67 [95% CI 0.49-0.92]. A previous preterm birth, Sudden Infant Death Syndrome, and other causes of infant death did not influence risk. A previous adverse pregnancy outcome has only a modest influence on smoking habits in the successive pregnancy.

Research paper thumbnail of Caffeine intake and the risk of first-trimester spontaneous abortion

The New England journal of medicine, Jan 21, 2000

Some epidemiologic studies have suggested that the ingestion of caffeine increases the risk of sp... more Some epidemiologic studies have suggested that the ingestion of caffeine increases the risk of spontaneous abortion, but the results have been inconsistent. We performed a population-based, case-control study of early spontaneous abortion in Uppsala County, Sweden. The subjects were 562 women who had spontaneous abortion at 6 to 12 completed weeks of gestation (the case patients) and 953 women who did not have spontaneous abortion and were matched to the case patients according to the week of gestation (controls). Information on the ingestion of caffeine was obtained from in-person interviews. Plasma cotinine was measured as an indicator of cigarette smoking, and fetal karyotypes were determined from tissue samples. Multivariate analysis was used to estimate the relative risks associated with caffeine ingestion after adjustment for smoking and symptoms of pregnancy such as nausea, vomiting, and tiredness. Among nonsmokers, more spontaneous abortions occurred in women who ingested at...

Research paper thumbnail of Pregnancy outcomes by mode of delivery among term breech births: Swedish experience 1987-1993

Obstetrics and gynecology, 1998

To study the influence of mode of delivery on infant mortality, neonatal morbidity, and maternal ... more To study the influence of mode of delivery on infant mortality, neonatal morbidity, and maternal morbidity in pregnancies with nonmalformed term singleton infants presented in breech. We studied all nonmalformed live-born singleton infants, delivered at term (at 37 weeks or later) in breech position in Sweden between 1987 and 1993 (n = 15,818). The pregnancy outcomes analyzed were neonatal and infant mortality, low Apgar score (less than 7) at 5 minutes, birth injury, and neonatal convulsions. Severe perineal or vaginal lacerations, wound rupture, infections, and thrombosis were used as measures of maternal morbidity. Logistic regression analysis was used to determine risks of infant mortality and morbidity, after adjusting for a number of potential confounders. Compared with infants delivered by elective cesarean, infants delivered vaginally were at significantly higher risk for infant mortality (odds ratio [OR] 2.5). Infants delivered vaginally were at increased risk for birth inj...

Research paper thumbnail of Mortality after Parental Death in Childhood: A Nationwide Cohort Study from Three Nordic Countries

PLoS Medicine, 2014

Bereavement by spousal death and child death in adulthood has been shown to lead to an increased ... more Bereavement by spousal death and child death in adulthood has been shown to lead to an increased risk of mortality. Maternal death in infancy or parental death in early childhood may have an impact on mortality but evidence has been limited to short-term or selected causes of death. Little is known about long-term or cause-specific mortality after parental death in childhood. This cohort study included all persons born in Denmark from 1968 to 2008 (n = 2,789,807) and in Sweden from 1973 to 2006 (n = 3,380,301), and a random sample of 89.3% of all born in Finland from 1987 to 2007 (n = 1,131,905). A total of 189,094 persons were included in the exposed cohort when they lost a parent before 18 years old. Log-linear Poisson regression was used to estimate mortality rate ratio (MRR). Parental death was associated with a 50% increased all-cause mortality (MRR = 1.50, 95% CI 1.43-1.58). The risks were increased for most specific cause groups and the highest MRRs were observed when the cause of child death and the cause of parental death were in the same category. Parental unnatural death was associated with a higher mortality risk (MRR = 1.84, 95% CI 1.71-2.00) than parental natural death (MRR = 1.33, 95% CI 1.24-1.41). The magnitude of the associations varied according to type of death and age at bereavement over different follow-up periods. The main limitation of the study is the lack of data on post-bereavement information on the quality of the parent-child relationship, lifestyles, and common physical environment. Parental death in childhood or adolescence is associated with increased all-cause mortality into early adulthood. Since an increased mortality reflects both genetic susceptibility and long-term impacts of parental death on health and social well-being, our findings have implications in clinical responses and public health strategies. Please see later in the article for the Editors' Summary.

Research paper thumbnail of Prenatal Exposure to Maternal Bereavement and Childbirths in the Offspring: A Population-Based Cohort Study

PLoS ONE, 2014

The decline in birth rates is a concern in public health. Fertility is partly determined before b... more The decline in birth rates is a concern in public health. Fertility is partly determined before birth by the intrauterine environment and prenatal exposure to maternal stress could, through hormonal disturbance, play a role. There has been such evidence from animal studies but not from humans. We aimed to examine the association between prenatal stress due to maternal bereavement following the death of a relative and childbirths in the offspring.

Research paper thumbnail of Fetal Growth Restriction and Schizophrenia: A Swedish Twin Study

Twin Research and Human Genetics, 2005

Research paper thumbnail of Maternal Overweight and Obesity and Risks of Severe Birth-Asphyxia-Related Complications in Term Infants: A Population-Based Cohort Study in Sweden

PLoS Medicine, 2014

Background: Maternal overweight and obesity increase risks of pregnancy and delivery complication... more Background: Maternal overweight and obesity increase risks of pregnancy and delivery complications and neonatal mortality, but the mechanisms are unclear. The objective of the study was to investigate associations between maternal body mass index (BMI) in early pregnancy and severe asphyxia-related outcomes in infants delivered at term ($37 weeks).

Research paper thumbnail of The Swedish Twin Registry in the Third Millennium: An Update

Twin Research and Human Genetics, 2006

The Swedish Twin Registry was first established in the late 1950s. Today it includes more than 17... more The Swedish Twin Registry was first established in the late 1950s. Today it includes more than 170,000 twins -in principle all twins born in Sweden since 1886. In this paper we describe some ongoing and recently completed projects based on the registry. In particular, we describe recent efforts to screen all twins born between 1959 and 1985, and young twin pairs when they turn 9 and 12 years of age. For these studies, we present initial frequencies of common conditions and exposures.

Research paper thumbnail of Estimation of genetic and environmental factors for binary traits using family data by Y. Pawitan, M. Reilly, E. Nilsson, S. Cnattingius and P. Lichtenstein,Statistics in Medicine 2004;23:449–465

Statistics in Medicine, 2005

Research paper thumbnail of Human fertility does not decline: evidence from Sweden

Fertility and Sterility, 1999

Objective: To assess changes in human fertility over time.Design: Time-trend analyses and age-per... more Objective: To assess changes in human fertility over time.Design: Time-trend analyses and age-period-cohort modeling.Setting: Sweden, 1983–1993.Patient(s): All primiparous women aged ≥20 years during the study period. There were 401,653 women who were identified through the nationwide Medical Birth Register.Intervention(s): None.Main Outcome Measure(s): Risk of subfertility, defined as ≥1 year of involuntary childlessness.Result(s): Subfertility problems decreased dramatically over successive maternal birth

Research paper thumbnail of Women with schizophrenia: pregnancy outcome and infant death among their offspring

Schizophrenia Research, 2002

Schizophrenia in the mother may imply an increased risk of adverse pregnancy outcome. However, in... more Schizophrenia in the mother may imply an increased risk of adverse pregnancy outcome. However, inconclusive findings, unknown pathological mechanisms and possible confounding by social factors and smoking requests further explorations. The aim of this study were to (1) examine non-optimal pregnancy outcome using data from a population-based cohort, controlling for covariates known to influence fetal growth; and (2) perform separate analyses of women diagnosed before childbirth and women hospitalized for schizophrenia during pregnancy. The study sample comprised 2096 births by 1438 mothers diagnosed with schizophrenia (of whom 696 mothers were antenatal diagnosed and 188 admitted during pregnancy) and 1,555,975 births in the general population. We found significantly increased risks for stillbirth, infant death, preterm delivery, low birth weight, and small-for-gestational-age among the offspring of women with schizophrenia. Women with an episode of schizophrenia during pregnancy had the highest risks (e.g., low birth weight; OR 4.3, 95% CI 2.9-6.6 and stillbirth; OR 4.4, 95% CI 1.4-13.8). Controlling for a high incidence of smoking during pregnancy among schizophrenic women (51% vs. 24% in the normal population) and other maternal factors (single motherhood, maternal age, parity, maternal education, mothers' country of birth and pregnancy-induced hypertensive diseases) in a multiple regression model, reduced the risk estimates markedly. However, the risks for adverse pregnancy outcomes were even after adjustments generally doubled for women with an episode of schizophrenia during pregnancy compared to women in the control group (e.g., low birth weight; OR 2.3, 95% CI 1.5-3.5, preterm delivery; OR 2.4, 95% CI 1.5-3.8 and stillbirth; OR 2.5, 95% CI 0.8-7.9). The risks for preterm delivery and low birth weight were significantly elevated throughout the analyses. We conclude that schizophrenia in the mother implies an increased risk for poor perinatal outcome, not fully explained by maternal factors, and a need to consider a common familial (probably genetic) vulnerability for pre- and perinatal stress and schizophrenia.

Research paper thumbnail of Maternal Snuff Use and Smoking and the Risk of Oral Cleft Malformations - A Population-Based Cohort Study

PLoS ONE, 2014

Objective: To determine if maternal use of snuff (containing high levels of nicotine, low levels ... more Objective: To determine if maternal use of snuff (containing high levels of nicotine, low levels of nitrosamines and no combustion products) is associated with an increased risk of oral cleft malformations in the infant and whether cessation of snuff use or smoking before the antenatal booking influences the risk.

Research paper thumbnail of Psychotic Illness in First-Time Mothers with No Previous Psychiatric Hospitalizations: A Population-Based Study

Research paper thumbnail of Parental Psychiatric Disorders Associated With Autism Spectrum Disorders in the Offspring

Research paper thumbnail of Intellectual and Psychological Performance in Males Born Small for Gestational Age With and Without Catch-Up Growth

Pediatric Research, 2001

Infants born small for gestational age (SGA) have an increased risk of neurologic and intellectua... more Infants born small for gestational age (SGA) have an increased risk of neurologic and intellectual dysfunction. Most of these infants catch up in growth and attain normal height, although some do not. Whether catch-up growth influences intellectual function is not known. To analyze whether intellectual and psychological performance of males in early adulthood are associated with body size at birth or by catch-up growth in height among boys, a population-based cohort was studied. This cohort included all male singletons born without congenital malformations in Sweden from 1973 to 1978 and alive at 18 y (n = 276,033). Information from the Swedish Birth Register was individually linked to the Swedish Conscript Register. Of 254,426 conscripted males, information on intellectual and psychological performance was available for 97% and 91%, respectively. Low birth weight, short birth length, small head circumference at birth, and preterm birth increased the risk of subnormal intellectual and psychological performance. Among SGA-born males, the most important predictor was the absence of catch-up growth. Being born SGA is associated with increased risk of subnormal intellectual and psychological performance. The data strongly support the view that, for males born SGA, it is an advantage to have catch-up growth in length.

Research paper thumbnail of Maternal smoking during pregnancy and intellectual performance in young adult Swedish male offspring

Paediatric and Perinatal Epidemiology, 2010

Maternal smoking during pregnancy and intellectual performance in young adult Swedish male offspr... more Maternal smoking during pregnancy and intellectual performance in young adult Swedish male offspring. Paediatric and Perinatal Epidemiology 2010; 24: 79-87.