| 1. |
- Carr, Hanna, et al.
(författare)
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Preterm Birth and Risk of Heart Failure Up to Early Adulthood
- 2017
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Ingår i: Journal of the American College of Cardiology. - : Elsevier. - 0735-1097 .- 1558-3597. ; 69:21, s. 2634-2642
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: In small clinical studies, preterm birth was associated with altered cardiac structure and increased cardiovascular mortality in the young.OBJECTIVES: The goal of this study was to determine the association between preterm birth and risk of incident heart failure (HF) in children and young adults.METHODS: This register-based cohort study included 2,665,542 individuals born in Sweden from 1987 to 2012 who were followed up from 1 year of age to December 31, 2013. The main study outcome was diagnosis of HF in the National Patient Register or the Cause of Death Register. The association between preterm birth and risk of incident HF was analyzed by using a Poisson regression model. Estimates were adjusted for maternal and pregnancy characteristics, socioeconomic status, and maternal and paternal cardiovascular disease.RESULTS: During 34.8 million person-years of follow-up (median 13.1 years), there were 501 cases of HF. After exclusion of 52,512 individuals with malformations (n = 196 cases), 305 cases of HF remained (0.88 per 100,000 person-years). Gestational age was inversely associated with the risk of HF. Compared with individuals born at term (>= 37 weeks' gestation), adjusted incidence relative risks for HF were 17.0 (95% confidence interval [CI]: 7.96 to 36.3) after extremely preterm birth (<28 weeks) and 3.58 (95% CI: 1.57 to 8.14) after very preterm birth (28 to 31 weeks). There was no risk increase after moderately preterm birth (32 to 36 weeks) (relative risk: 1.36; 95% CI: 0.87 to 2.13).CONCLUSIONS: There was a strong association between preterm birth before 32 weeks of gestation and HF in childhood and young adulthood. Although the absolute risk of HF is low in young age, our findings indicate that preterm birth may be a previously unknown risk factor for HF. (J Am Coll Cardiol 2017;69:2634-42) (C) 2017 by the American College of Cardiology Foundation.
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| 2. |
- Cnattingius, Sven, et al.
(författare)
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Keep it in the family : comparing perinatal risks in small-for-gestational-age infants based on population vs within-sibling designs
- 2019
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Ingår i: International Journal of Epidemiology. - : Oxford University Press. - 0300-5771 .- 1464-3685. ; 48:1, s. 297-306
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Tidskriftsartikel (refereegranskat)abstract
- Background: Small-for-gestational-age (SGA) birth is commonly used as a proxy for fetal growth restriction, but also includes constitutionally small infants. Genetic factors account for almost half of the risk of SGA birth. We estimated perinatal risks of SGA birth using both population-based and within-sibling analyses, where the latter by design controls for shared genetic factors and maternal environmental factors that are constant across pregnancies.Methods: This was a prospective nationwide cohort study of 2 616 974 singleton infants born in Sweden between January 1987 and December 2012, of whom 1 885 924 were full siblings. We estimated associations between severe or moderate SGA (<3rd percentile and 3rd to <10th percentiles, respectively) and risks of stillbirth, neonatal mortality and morbidity, using both population-based and within-sibling analyses. Hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated in stillbirth analyses, whereas relative risks (RRs) were used for analyses of neonatal outcomes.Results: Compared with non-SGA births (>10th percentile), the HR (95% CI) of stillbirth was 18.5 (95% CI 17.4-19.5) among severe SGA births in the population analysis and 22.5 (95% CI 18.7-27.1) in the within-sibling analysis. In non-malformed infants, RRs for neonatal mortality in moderate and severe SGA infants were similarly increased in both population and within-sibling analyses. In term non-malformed infants (>= 37 weeks), SGA-related RRs of several neonatal morbidities were higher in within-sibling than in population analyses.Conclusions: Perinatal risks associated with fetal growth restriction are more accurately estimated from analyses of SGA in which genetic factors are accounted for.
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| 3. |
- Cnattingius, Sven, et al.
(författare)
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The Swedish medical birth register during five decades : documentation of the content and quality of the register
- 2023
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Ingår i: European Journal of Epidemiology. - : Springer. - 0393-2990 .- 1573-7284. ; 38:1, s. 109-120
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Tidskriftsartikel (refereegranskat)abstract
- Pregnancy-related factors are important for short- and long-term health in mothers and offspring. The nationwide population-based Swedish Medical Birth Register (MBR) was established in 1973. The present study describes the content and quality of the MBR, using original MBR data, Swedish-language and international publications based on the MBR. The MBR includes around 98% of all births in Sweden. From 1982 onwards, the MBR is based on prospectively recorded information in standardized antenatal, obstetric, and neonatal records. When the mother and infant are discharged from hospital, this information is forwarded to the MBR, which is updated annually. Maternal data include information from first antenatal visit on self-reported obstetric history, infertility, diseases, medication use, cohabitation status, smoking and snuff use, self-reported height and measured weight, allowing calculation of body mass index. Birth and neonatal data include date and time of birth, mode of delivery, singleton or multiple birth, gestational age, stillbirth, birth weight, birth length, head circumference, infant sex, Apgar scores, and maternal and infant diagnoses/procedures, including neonatal care. The overall quality of the MBR is very high, owing to the semi-automated data extraction from the standardized regional electronic health records, Sweden's universal access to antenatal care, and the possibility to compare mothers and offspring to the Total Population Register in order to identify missing records. Through the unique personal identity numbers of mothers and live-born offspring, the MBR can be linked to other health registers. The Swedish MBR contains high-quality pregnancy-related information on more than 5 million births during five decades.
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| 4. |
- Lü, Donghao, et al.
(författare)
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Maternal Cancer During Pregnancy and Risks of Stillbirth and Infant Mortality
- 2017
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Ingår i: Journal of Clinical Oncology. - : American Society of Clinical Oncology. - 0732-183X .- 1527-7755. ; 35:14, s. 1522-1529
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To examine whether maternal cancer during pregnancy is associated with increased risks of stillbirth and infant mortality.Methods: On the basis of nationwide health registers, we conducted a study of 3,947,215 singleton births in Sweden from 1973 through 2012. Exposure was defined as maternal cancer diagnosed during pregnancy (number of births = 984) or during the year after pregnancy (number of births = 2,723). We calculated incidence rate ratios (IRRs) for stillbirth and infant mortality, comparing exposed births to unexposed births. Small-for-gestational-age (SGA) and preterm births were examined as secondary outcomes.Results: Maternal cancer diagnosed during pregnancy was positively associated with stillbirth (IRR, 2.5; 95% CI, 1.2 to 5.0), mainly stillbirths assessed as SGA (IRR, 4.9; 95% CI, 2.2 to 11.0), and with preterm SGA births (relative risk 3.0; 95% CI, 2.1 to 4.4). Positive associations of maternal cancer diagnosed during pregnancy or the year after pregnancy were noted for both neonatal mortality (deaths within 0 to 27 days; IRR, 2.7; 95% CI, 1.3 to 5.6 and IRR, 2.0; 95% CI, 1.2 to 3.2, respectively) and preterm birth (IRR, 5.8; 95% CI, 5.3 to 6.5 and IRR, 1.6; 95% CI, 1.4 to 1.8, respectively). The positive association with preterm birth was due to iatrogenic instead of spontaneous preterm birth. Preterm birth explained 89% of the association of maternal cancer during pregnancy with neonatal mortality.Conclusion: Maternal cancer during pregnancy is associated with increased risks of rare but fatal outcomes, including stillbirth and neonatal mortality. This may be due to conditions associated with fetal growth restriction and iatrogenic preterm birth. Careful monitoring of fetal growth and cautious decision making on preterm delivery should therefore be reinforced.
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| 5. |
- Ludvigsson, Jonas F., 1969-, et al.
(författare)
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Maternal Influenza A(H1N1) Immunization During Pregnancy and Risk for Autism Spectrum Disorder in Offspring
- 2020
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Ingår i: Annals of Internal Medicine. - : American College of Physicians. - 0003-4819 .- 1539-3704. ; 173:8, s. 597-604
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Tidskriftsartikel (refereegranskat)abstract
- Background: There are concerns that influenza vaccine exposure during pregnancy may be associated with increased risk for autism spectrum disorder (ASD).Objective: To examine the risk for ASD in offspring of mothers who were vaccinated against influenza A(H1N1)pdm09 ("swine flu") during pregnancy.Design: Population-based cohort study using nationwide registers.Setting: Seven health care regions in Sweden.Participants: Live births between October 2009 and September 2010, with follow-up through December 2016. In total, 39 726 infants were prenatally exposed to H1N1 vaccine (13 845 during the first trimester) and 29 293 infants were unexposed.Measurements: Cox regression was used to estimate hazard ratios (HRs) for the primary outcome, ASD, before and after adjustment for potential confounders. The secondary outcome was autistic disorder (AD).Results: Mean follow up was 6.7 years in both unexposed and exposed children. During follow-up, 394 (1.0%) vaccine-exposed and 330 (1.1%) unexposed children had a diagnosis of ASD. In adjusted analyses, prenatal exposure to H1N1 vaccination was not associated with a later diagnosis of ASD (adjusted HR [aHR], 0.95 [95% CI, 0.81 to 1.12]) or AD (aHR, 0.96 [CI, 0.80 to 1.16]). The 6-year standardized cumulative incidence difference between the unexposed and exposed children was 0.04% (CI, -0.09% to 0.17%) for ASD and 0.02% (CI, -0.09% to 0.14%) for AD. Restricting the analysis to vaccination in the first trimester of pregnancy did not influence risk estimates (aHR, 0.92 [CI, 0.74 to 1.16] for ASD and 0.91 [Cl, 0.70 to 1.18] for AD).Limitation: Data on H1N1 influenza infection are lacking.Conclusion: This large cohort study found no association between maternal H1N1 vaccination during pregnancy and risk for ASD in the offspring. Primary Funding Source: Swedish Research Council.
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| 6. |
- Ludvigsson, Jonas F., 1969-, et al.
(författare)
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Maternal vaccination against H1N1 influenza and offspring mortality : population based cohort study and sibling design
- 2015
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Ingår i: BMJ. British Medical Journal. - London, United Kingdom : BMJ Publishing Group Ltd. - 0959-8146 .- 0959-535X. ; 351
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Tidskriftsartikel (refereegranskat)abstract
- Study question: What is the mortality in offspring of mothers who hadinfluenza A(H1N1)pdm09 vaccination during pregnancy?Methods: This was a prospective population based cohort study in seven healthcare regions in Sweden based on vaccinations taking place between 2 October 2009 and 26 November 2010. H1N1 vaccination data were linked with pregnancy and birth characteristics and offspring mortality data in 275 500 births (of which 1203 were stillbirths) from 137 886 mothers. Of these offspring, 41 183 had been exposed to vaccination with Pandemrix, a monovalent AS03 adjuvanted H1N1 influenza vaccine, during fetal life. A primary comparison group consisted of pregnancies of women who were not vaccinated during the same calendar period. In a second comparison, non-exposed siblings of infants prenatally exposed to vaccination were used as controls. Cox regression was used to estimate hazard ratios for stillbirth, early neonatal mortality (days 0-6 after birth), and subsequent mortality (beginning on day 7) in vaccinated versus nonvaccinated women, adjusting for mother’s age at delivery, body mass index, parity, smoking, country of birth, and disposable income and for sex of offspring.Study answer and limitations: The results of this study suggest that AS03 adjuvanted H1N1 vaccination during pregnancy does not affect the risk of stillbirth, early neonatal death, or later mortality in the offspring. During follow-up, 1172 stillbirths, 380 early neonatal deaths, and 706 deaths thereafter occurred. Compared with general population controls, this corresponded to adjusted hazard ratios of 0.83 (95% confidence interval 0.65 to 1.04) for stillbirth, 0.71 (0.44 to 1.14) for early neonatal death, and 0.97 (0.69 to 1.36) for later death. When siblings were used as controls, adjusted hazard ratios were 0.88 (0.59 to 1.30) for stillbirth, 0.82 (0.46 to 1.49) for early neonatal death, and 0.78 (0.52 to 1.19) for later death. Limitations of the study include lack of data on miscarriage before gestational week 22, inability to ascertain which mothers had pandemic flu during pregnancy, and lack of data on factors influencing the decision to vaccinate during pregnancy.What this study adds: H1N1 vaccination during pregnancy is not associated with adverse fetal outcome or offspring mortality, including when familial factors are taken into account.
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| 7. |
- Ludvigsson, Jonas F., 1969-, et al.
(författare)
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Risk for Congenital Malformation With H1N1 Influenza Vaccine : A Cohort Study With Sibling Analysis
- 2016
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Ingår i: Annals of Internal Medicine. - Philadelphia, USA : American College of Physicians. - 0003-4819 .- 1539-3704. ; 165:12, s. 848-855
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Tidskriftsartikel (refereegranskat)abstract
- Background: Earlier studies reporting varying risk estimates for congenital malformation in offspring of mothers undergoing vaccination against H1N1 influenza during pregnancy did not consider the potential role of confounding by familial (genetic and shared environmental) factors.Objective: To evaluate an association between maternal H1N1 vaccination during pregnancy and offspring malformation, with familial factors taken into account.Design: Population-based prospective study.Setting: Sweden.Participants: Liveborn offspring born between 1 October 2009 and 1 October 2011 to mothers receiving monovalent AS03-adjuvanted H1N1 influenza vaccine (Pandemrix [GlaxoSmithKline]) during pregnancy. A total of 40 983 offspring were prenatally exposed to the vaccine, 14 385 were exposed within the first trimester (14 weeks), and 7502 were exposed during the first 8 weeks of pregnancy. Exposed offspring were compared with 197 588 unexposed offspring. Corresponding risks in exposed versus unexposed siblings were also estimated.Measurements: Congenital malformation, with subanalyses for congenital heart disease, oral cleft, and limb deficiency.Results: Congenital malformation was observed in 2037 (4.97%) exposed offspring and 9443 (4.78%) unexposed offspring. Adjusted risk for congenital malformation was 4.98% in exposed offspring versus 4.96% in unexposed offspring (risk difference, 0.02% [95% CI, -0.26% to 0.30%]). The corresponding risk differences were 0.16% (CI, -0.23% to 0.56%) for vaccination during the first trimester and 0.10% (CI, -0.41% to 0.62%) for vaccination in the first 8 weeks. Using siblings as comparators yielded no statistically significant risk differences.Limitations: The study was based on live births, and the possibility that data on miscarriage or induced abortion could have influenced the findings cannot be ruled out. Study power was limited in analyses of specific malformations.Conclusion: When intrafamilial factors were taken into consideration, H1N1 vaccination during pregnancy did not seem to be linked to overall congenital malformation in offspring, although risk increases for specific malformations could not be ruled out completely.
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| 8. |
- Ludvigsson, Jonas F., 1969-, et al.
(författare)
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Small for gestational age and risk of childhood mortality : A Swedish population study
- 2018
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Ingår i: PLoS Medicine. - : Public Library of Science. - 1549-1277 .- 1549-1676. ; 15:12
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Tidskriftsartikel (refereegranskat)abstract
- Background: Small for gestational age (SGA) has been associated with increased risks of stillbirth and neonatal mortality, but data on long-term childhood mortality are scarce. Maternal antenatal care, including globally reducing the risk of SGA birth, may be key to achieving the Millennium Development Goal of reducing under-5 mortality. We therefore aimed to examine the association between SGA and mortality from 28 days to <18 years using a population-based and a sibling control design.Methods and findings: In a Swedish population study, we identified 3,795,603 non-malformed singleton live births and 2,781,464 full siblings born from January 1, 1973, to December 31, 2012. We examined the associations of severe (<3rd percentile) and moderate (3rd to <10th percentile) SGA with risks of death from 28 days to <18 years after birth. Children born SGA were first compared to non-SGA children from the population, and then to non-SGA siblings. The sibling-based analysis, by design, features a better control for unmeasured factors that are shared between siblings (e.g., socioeconomic status, lifestyle, and genetic factors). Hazard ratios (HRs) were calculated using Cox proportional hazards and flexible parametric survival models. During follow-up (1973-2013), there were 10,838 deaths in the population-based analysis and 1,572 deaths in sibling pairs with discordant SGA and mortality status. The crude mortality rate per 10,000 person-years was 5.32 in children born with severe SGA, 2.76 in children born with moderate SGA, and 1.93 in non-SGA children. Compared with non-SGA children, children born with severe SGA had an increased risk of death in both the population-based (HR = 2.58, 95% CI = 2.38-2.80) and sibling-based (HR = 2.61, 95% CI = 2.19-3.10) analyses. Similar but weaker associations were found for moderate SGA in the population-based (HR = 1.37, 95% CI = 1.28-1.47) and sibling-based (HR = 1.38, 95% CI = 1.22-1.56) analyses. The excess risk was most pronounced between 28 days and <1 year of age but remained throughout childhood. The greatest risk increase associated with severe SGA was noted for deaths due to infection and neurologic disease. Although we have, to our knowledge, the largest study sample so far addressing the research question, some subgroup analyses, especially the analysis of cause-specific mortality, had limited statistical power using the sibling-based approach.Conclusions: We found that SGA, especially severe SGA, was associated with an increased risk of childhood death beyond the neonatal period, with the highest risk estimates for death from infection and neurologic disease. The similar results obtained between the population- and sibling-based analyses argue against strong confounding by factors shared within families.
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| 9. |
- Parikh, Nisha I., et al.
(författare)
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Subfertility and risk of later life maternal cardiovascular disease
- 2012
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Ingår i: Human Reproduction. - : Oxford University Press. - 0268-1161 .- 1460-2350. ; 27:2, s. 568-575
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Subfertility shares common pathways with cardiovascular disease (CVD), including polycystic ovarian syndrome, obesity and thyroid disorders. Women with prior 0-1 pregnancies are at an increased risk of incident CVD when compared with women with two pregnancies. It is uncertain whether history of subfertility among women eventually giving birth is a risk factor for CVD.METHODS: Among Swedish women with self-reported data on subfertility in the Swedish Medical Birth Register (n = 863 324), we used Cox proportional hazards models to relate a history of subfertility to CVD risk after adjustment for age, birth year, highest income, education, birth country, hypertension, diabetes, preterm birth, small for gestational age (SGA), smoking and for BMI in separate models. In additional analyses, we excluded women with: (i) pregnancy-related or non-pregnancy-related hypertension and/or diabetes; and (ii) preterm births and/or SGA babies.RESULTS: Among nulliparous women eventually having a childbirth (between 1983 and 2005, the median follow-up time 11.9; 0-23 years and 9 906 621 person-years of follow-up), there was an increased risk of CVD among women reporting >= 5 years of subfertility versus 0 years (hazard ratio 1.19, 95% confidence interval 1.02-1.39). There were not significantly elevated CVD risks for women with 1-2 or 3-4 years of subfertility versus 0 years. Accounting for BMI did not change results. Excluding women with hypertension and/or diabetes attenuated associations, whereas exclusion of women with preterm and/or SGA births did not change findings.CONCLUSIONS: Subfertility among women eventually having a childbirth is a risk factor for CVD even upon accounting for cardiovascular risk factors and adverse pregnancy outcomes. Future studies should explore the mechanisms underlying this association.
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| 10. |
- Rodriguez-Wallberg, Kenny A., et al.
(författare)
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Mortality from infancy to adolescence in singleton children conceived from assisted reproductive techniques versus naturally conceived singletons in Sweden
- 2020
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Ingår i: Fertility and Sterility. - : Elsevier. - 0015-0282 .- 1556-5653. ; 113:3, s. 524-532
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To assess infant (<1 year) and childhood (1-18 years) mortality in singletons conceived through assisted reproductive techniques (ART) versus naturally conceived singletons.Design: Nationwide prospective study.Setting: Sweden.Patient(s): All singleton liveborn infants born from 1983 to 2012 in Sweden identified using the Medical Birth Register (N = 2,847,108), of whom 43,506 were conceived through ART treatments including in vitro fertilization with and without intracytoplasmic sperm injection.Intervention(s): None.Main Outcome Measures(s): Infant (<1 year) and childhood (1-18 years) mortality.Result(s): Data on ART treatment and covariates were retrieved from population-based registers using the unique personal identity number assigned to all permanent residents in Sweden. Cox proportional hazards models estimated the hazard ratios (HRs) with 95% confidence intervals (CIs) as measures of association between ART treatments and death. The analyses were adjusted for maternal characteristics, infertility, child sex, and birth cohort and were restricted to individuals with complete information on covariates for fully adjusted analysis. Compared with naturally conceived singletons, higher infant mortality risks were seen in infants conceived through ART (adjusted HR 1.45; 95% CI, 1.19-1.77), especially after transfer of cryopreserved embryos (adjusted HR 2.30; 95% CI, 1.46-3.64). Early neonatal mortality risk (deaths during the first week) was increased in children born after transfer of blastocysts (HR 2.40; 95% CI, 1.05-5.48). No increased mortality risk was observed between the ages of 1 and 18 years.Conclusion(s): Singletons conceived through ART had an increased risk of infant mortality from birth up to 1 year of life, predominantly in the early neonatal period and in pregnancies after transfer of frozen and thawed embryos. (C) 2019 by American Society for Reproductive Medicine.
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