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Abstract High maternal body mass index (BMI) and smoking during pregnancy are risk factors for child overweight. Maternal smoking tends to reduce her BMI and the association of smoking with child overweight may be confounded by or interacting with maternal genetic predisposition to adiposity. In the Danish National Birth Cohort, we investigated whether smoking during pregnancy is associated with child BMI/overweight independent of pre-pregnancy BMI and maternal genetic predisposition to adiposity estimated as total, transmitted and non-transmitted genetic risk scores (GRSs) based on 941 common genetic variants associated with BMI. Smoking during pregnancy was associated with higher child BMI and higher odds of child overweight in a dose–response relationship. The odds ratio (95% CI) for smoking 11 + cigarettes in third trimester versus no smoking was 2.42 (1.30; 4.50), irrespective of maternal BMI and maternal GRSs (total, transmitted or non-transmitted). There were no statistically significant interactions between maternal GRSs and smoking (all p-values for interactions > 0.05). In conclusion, in this study, smoking during pregnancy exhibits a dose–response association with increased child BMI/overweight, independent of maternal pre-pregnancy BMI, maternal transmitted, and non-transmitted genetic predisposition to adiposity. Avoidance of smoking during pregnancy may help prevent childhood obesity irrespective of the mother–child genetic predisposition.

Objectives Our aim was to investigate the association between early environmental factors and the development of coeliac disease (CeD) in adolescents, recruited from a cohort nested in the Danish National Birth Cohort (DNBC).Design The study was designed as a prospective cohort study, nested in DNBCParticipants The Glutenfunen cohort comprises 1266 participants, nested in DNBC. All participants were screened for CeD, and in total, 28 cases of biopsy proven CeD were identified. Data about breastfeeding, timing of introduction to solid food in infancy, use of antibiotics, infections and symptoms were parentally reported prospectively at 6 months and 18 months, respectively. We estimated ORs and 95% CIs of CeD in adolescents using logistic regression analysis.Results Viral croup reported at 18 months of age was associated with CeD in adolescents with an OR of 3.2 (95% CI: 1.2 to 8.7). Furthermore, otitis media also reported at 18 months of age was linked with CeD with an OR of 3.2 (95% CI: 1.5 to 7.3). We were not able to find any statistical associations between CeD and breastfeeding, frequency of infections, parentally reported use of antibiotic and timing of solid foods.Conclusion In this study, we present an overview of the relationship between early environmental factors and occurrence of CeD in adolescents. Our findings, despite limitations due to a limited number of cases of CeD, suggest a role of viral infections in the pathogenesis of CeD

Abstract Background Gestational diabetes mellitus (GDM) is associated with adverse pregnancy outcomes and has maternal health implications reaching beyond the perinatal period. We aimed to investigate the incidence and severity of cardiovascular and metabolic morbidity in women with previous GDM in a Danish population and to study whether proxies of impaired beta cell function—insulin treatment during GDM pregnancy and development of subsequent manifest diabetes mellitus—influence incident risk of cardiovascular and metabolic morbidity. Methods A nationwide register-based cohort study was conducted on the complete cohort of 700,648 women delivering in Denmark during 1997–2018. The exposure variable was GDM and primary outcome was overall cardiovascular and metabolic morbidity. Secondary outcomes were major cardiovascular disease (ischemic heart disease, heart failure, and/or stroke/transient cerebral ischemia), hypertension, dyslipidemia, and venous thrombosis. Severity of morbidity was assessed using number of hospital contacts with diagnosis codes related to cardiovascular and metabolic morbidity and number of redemptions of prescribed medication related to cardiovascular and metabolic morbidity in women who developed cardiovascular and metabolic morbidity after pregnancy. Results The median follow-up period was 10.2–11.9 years with a total range of 0–21.9 years. GDM was associated with increased risk of any cardiovascular and metabolic morbidity (adjusted HR 2.13 [95% CI 2.07–2.20]), major cardiovascular disease (adjusted HR 1.69 [95% CI 1.55–1.84]), hypertension (adjusted HR 1.89 [95% CI 1.82–1.96], dyslipidemia (adjusted HR 4.48 [95% CI 4.28–4.69]), and venous thrombosis (adjusted HR 1.32 [95% CI 1.16–1.50]). Insulin treatment during pregnancy and subsequent development of manifest diabetes exacerbated the risk estimates. Previous GDM was associated with more hospital contacts and more redeemed prescriptions in women developing cardiovascular and metabolic morbidity (p

Abstract Background Inequality in health can have profound short- and long-term effects on a child’s life. Infants develop in a responsive environment, and the relationship between mother and infant begins to develop during pregnancy. The mother’s ability to bond with the fetus and newborn child may be challenged by mental health issues which can cause impaired functioning and poorer health outcomes. Families with complex problems need interdisciplinary interventions starting in early pregnancy to be prepared for motherhood and to ensure healthy child development. This study aims to examine the effects of an early and coordinated intervention (the Family Clinic and Municipality (FACAM) intervention) offered to vulnerable pregnant women during pregnancy and the child’s first year of life on the mother-child relationship, maternal social functioning, mental health, reflective functioning, well-being, parental stress, and the development and well-being of the child. Methods The study is a prospective randomized controlled trial where we will randomize 320 pregnant women enrolled to receive antenatal care at the family clinic at Odense University Hospital, to either FACAM intervention or usual care. The FACAM intervention consists of extra support by a health nurse or family therapist during pregnancy and until the child starts school. The intervention is most intensive in the first 12 months and also includes attachment-based support provided either individually or in groups. The participants are assessed at baseline, and when the infant is 3 and 12 months old. The primary outcome is maternal sensitivity measured by the Coding Interactive Behavior (CIB) instrument. Secondary outcomes include prenatal parental reflective functioning, mental well-being, depressive symptoms, breastfeeding duration, maternal satisfaction, child development, parent competence, parental stress, and activities with the child. Discussion The trial is expected to contribute knowledge about the effect of early coordinated support in antenatal and postnatal care for vulnerable pregnant women and their families. Trial registration ClinicalTrials.gov NCT03659721 . Registered on September 6, 2018

OBJECTIVE: Birth cohorts collect valuable and under-utilized information on employment and health of parents before and during pregnancy, at birth, and sometimes after birth. In this discussion paper, we examine how these data could be exploited to study the complex relationships and interactions between parenthood, work, and health among parents themselves. METHODS: Using a web-based database of birth cohorts, we summarize information on maternal employment and health conditions and other potentially related variables in cohorts spread throughout Europe. This provided information on what data are available and could be used in future studies, and what was missing if specific questions are to be addressed, exploiting the opportunity to explore work–health associations across heterogenous geographical and social contexts. RESULTS: We highlight the many potentialities provided by birth cohorts and identify gaps that need to be addressed to adopt a life-course approach and investigate topics specific to the peri-pregnancy period, such as psychosocial aspects. We address the technical difficulties implied by data harmonization and the ethical challenges related to the repurposing of data, and provide scientific, ecological and economic arguments in favor of improving the value of data already available as a result of a serious investment in human and material resources. CONCLUSIONS: There is a hidden treasure in birth cohorts that deserves to be brought out to study the relationships between employment and health among working parents in a time when the boundaries between work and life are being stretched more than ever before.

Abstract Background The outbreak of the COVID-19 pandemic caused great uncertainty about causes, treatment and mortality of the new virus. Constant updates of recommendations and restrictions from national authorities may have caused great concern for pregnant women. Reports suggested an increased number of pregnant women choosing to give birth at home, some even unassisted (‘freebirth’) due to concerns of transmission in hospital or reduction in birthplace options. During April and May 2020, we aimed to investigate i) the level of concern about coronavirus transmission in Danish pregnant women, ii) the level of concern related to changes in maternity services due to the pandemic, and iii) implications for choice of place of birth. Methods We conducted a nationwide cross-sectional online survey study, inviting all registered pregnant women in Denmark (n = 30,009) in April and May 2020. Results The response rate was 60% (n = 17,995). Concerns of transmission during pregnancy and birth were considerable; 63% worried about getting severely ill whilst pregnant, and 55% worried that virus would be transmitted to their child. Thirtyeight percent worried about contracting the virus at the hospital. The most predominant concern related to changes in maternity services during the pandemic was restrictions on partners’ attendance at birth (81%). Especially nulliparous women were concerned about whether cancelled antenatal classes or fewer physical midwifery consultations would affect their ability to give birth or care for their child postpartum.. The proportion of women who considered a home birth was equivalent to pre-pandemic home birth rates in Denmark (3%). During the temporary discontinue of public home birth services, 18% of this group considered a home birth assisted by a private midwife (n = 125), and 6% considered a home birth with no midwifery assistance at all (n = 41). Conclusion Danish pregnant womens’ concerns about virus transmission to the unborn child and worries about contracting the virus during hospital appointments were considerable during the early pandemic. Home birth rates may not be affected by the pandemic, but restrictions in home birth services may impose decisions to freebirth for a small proportion of the population.

Abstract. Objective:. This article aimed to compare the peripheral blood flow intensity (BFI) in the maternal right and left kidney in uncomplicated third trimester pregnancies and to study possible associations between parenchymal BFI in the kidneys and maternal, labor and new-born characteristics. Methods:. We conducted a prospective cohort study in third trimester pregnancies at Trondheim University Hospital, Norway, from January to April 2018. The BFI in the maternal kidneys was examined with color Doppler ultrasound and the peripheral BFI was calculated using the Pixel Flux-method which is a method based on pixel wise calculation of color in an image. Velocity was coded by the color bar in the ultrasound device. The peripheral BFI was calculated as the product of velocity and area encoded by all colored pixels divided by all pixels within the cortical layer by a software examining the color in each pixel of a standardized region of interest of the renal parenchyma in video-clips through a complete heart cycle. BFI (cm/s) was thus calculated as follows: The primary outcome measure was peripheral BFI in the renal cortex. We also examined associations between BFI in the entire cortex with maternal age, body mass index, blood pressure, pH in the umbilical artery, Apgar score after 5 minutes and birthweight. Results:. In all, 51 pregnant women were included in the study, but 17 were excluded, mainly due to movement artifacts from the pulsating aorta, leaving 34 women in the final study population. We found significantly lower BFI in the cortex of the left kidney compared with the right kidney, 0.37 cm/s versus 0.69 cm/s, respectively (P = 0.04). Dividing into regions, the BFI was significantly lower in the proximal 25% of the left renal cortex compared to the corresponding right side (P = 0.01), and in the proximal 50% cortex (P = 0.02), but the differences were not significantly different in the distal 25% (P = 0.06) or in the distal 50% (P = 0.20) of the renal cortex. We observed a significant negative correlation between peripheral BFI in the left kidney and both systolic blood pressure (r = −0.38; P = 0.03) and diastolic blood pressure (r = −0.36; P = 0.04), and no significant correlations between BFI with maternal age, body mass index, blood pressure, pH in the umbilical artery, Apgar score after 5 minutes and birthweight in the left kidney (P > 0.05). We did not observe any significant correlations between BFI in the right kidney and maternal or new-born characteristics (P > 0.05). Conclusion:. The BFI in the left renal cortex was lower compared with the right renal cortex, and BFI in the left renal cortex was negatively correlated with blood pressure, but not significantly correlated with maternal age, body mass index or newborn characteristics. We did not observe any significant correlations between BFI in the right kidney and maternal or new-born characteristics.

Abstract Background Preterm birth and shorter duration of pregnancy are associated with increased morbidity in neonatal and later life. As the epigenome is known to have an important role during fetal development, we investigated associations between gestational age and blood DNA methylation in children. Methods We performed meta-analysis of Illumina’s HumanMethylation450-array associations between gestational age and cord blood DNA methylation in 3648 newborns from 17 cohorts without common pregnancy complications, induced delivery or caesarean section. We also explored associations of gestational age with DNA methylation measured at 4–18 years in additional pediatric cohorts. Follow-up analyses of DNA methylation and gene expression correlations were performed in cord blood. DNA methylation profiles were also explored in tissues relevant for gestational age health effects: fetal brain and lung. Results We identified 8899 CpGs in cord blood that were associated with gestational age (range 27–42 weeks), at Bonferroni significance, P

Abstract Background Chronic stress in childhood may increase the risk of overweight and obesity in young people. Erik Hemmingsson has suggested a new obesity causation model which focuses on psychosocial stress. The aim was to examine the associations between socioeconomic disadvantage and overweight and obesity and examine if these associations attenuate, when the effect of the different domains from Eric Hemmingsson’s obesity causation model were taken into account. Methods A longitudinal study using data from The West Jutland Cohort Study (N = 2879). Outcome was overweight and obesity combined derived from self-reported weight and height at age 15, 18, 21 and 28 years. Exposure variables were equivalised household income, educational level and labour market participation of the mother derived from registers and psychosocial variables derived from questionnaires. A three-step adjustment model using logistic regression and stratified by gender was applied. Results Mother’s low educational level was associated with a 3-fold increased odds of obesity in 18 year-old-girls, which attenuated when adjusting for the domains adult distress, disharmonious family environment and offspring distress. In 28 year-old girls, a 2.5-fold increased odds of obesity was observed, which attenuated when mutual adjusted for other socioeconomic variables and attenuated even further when adjusting for all the domains. In 18-year-old boys, a 3-fold increased odds of obesity was observed which attenuated after adjustments for adult distress, disharmonious family environment and offspring distress. In 21-year old boys, a four-fold increased odds of obesity was observed that attenuated after adjustments. At age 28 years, a three-fold increased odds of obesity was observed, which vanished in the fully adjusted model. Conclusions Our study confirms to some extent that the associations between socioeconomic disadvantage and overweight and obesity can be explained by the domains included in Erik Hemmingsson’s model, although our results should be interpreted with caution. Adult distress, disharmonious family environment and offspring distress accounted for some of the association in girls, whereas in boys it was primarily offspring distress, which had the greatest impact. Young people’s educational attainment can act as a buffer in the relationship between mother’s lower educational level and obesity at age 28 years.

Abstract Background Research on caseload midwifery in a Danish setting is missing. This cohort study aimed to compare labour outcomes in caseload midwifery and standard midwifery care. Methods A historical register-based cohort study was carried out using routinely collected data about all singleton births 2013–2016 in two maternity units in the North Denmark Region. In this region, women are geographically allocated to caseload midwifery or standard care, as caseload midwifery is only available in some towns in the peripheral part of the uptake areas of the maternity units, and it is the only model of care offered here. Labour outcomes of 2679 all-risk women in caseload midwifery were compared with those of 10,436 all-risk women in standard midwifery care using multivariate linear and logistic regression analyses. Results Compared to women in standard care, augmentation was more frequent in caseload women (adjusted odds ratio (aOR) 1.20; 95% CI 1.06–1.35) as was labour duration of less than 10 h (aOR 1.26; 95% CI 1.13–1.42). More emergency caesarean sections were observed in caseload women (aOR 1.17; 95% CI 1.03–1.34), but this might partly be explained by longer distance to the maternity unit in caseload women. When caseload women were compared to women in standard care with a similar long distance to the hospital, no difference in emergency caesarean sections was observed (aOR 1.04; 95% CI 0.84–1.28). Compared to standard care, infants of caseload women more often had Apgar ≤7 after 5 min. (aOR 1.57; 95% CI 1.11–2.23) and this difference remained when caseload women were compared to women with similar distance to the hospital. For elective caesarean sections, preterm birth, induction of labour, dilatation of cervix on admission, amniotomy, epidural analgesia, and instrumental deliveries, we did not obseve any differences between the two groups. After birth, caseload women more often experienced no laceration (aOR 1.17; 95% CI 1.06–1.29). Conclusions For most labour outcomes, there were no differences across the two models of midwifery-led care but unexpectedly, we observed slightly more augmentation and adverse neonatal outcomes in caseload midwifery. These findings should be interpreted in the context of the overall low intervention and complication rates in this Danish setting and in the context of research that supports the benefits of caseload midwifery. Although the observational design of the study allows only cautious conclusions, this study highlights the importance of monitoring and evaluating new practices contextually.

Objective: In the last decade, there has been an increased interest in exploring the impact of the physical birth environment on midwifery practice and women’s birth experiences. This study is based on the hypothesis that the environment for birth needs greater attention to improve some of the existing challenges in modern obstetric practice, for example the increasing use of augmentation and number of interventions during delivery. Study design: A randomized controlled trial was carried out to study the effect of giving birth in a specially designed “birth environment room” on the use of augmentation during labor. The study took place at the Department of Obstetrics and Gynecology, Herning Hospital, Denmark and included 680 nulliparous women in spontaneous labor at term with a fetus in cephalic presentation. Women were randomly allocated to either the “birth environment room” or a standard birth room. The primary outcome was augmentation of labor by use of oxytocin. Secondary outcomes were duration of labor, use of pharmacological pain relief, and mode of birth. Differences were estimated as relative risks (RR) and presented with 95% confidence intervals. Results: No difference was found on the primary outcome, augmentation of labor (29.1% in the “birth environment room” versus 30.6% in the standard room, RR 0.97; 0.89–1.08). More women in the “birth environment room” used the bathtub (60.6% versus 52.4%, RR 1.18; 1.02–1.37), whereas a tendency to lower use of epidural analgesia (22.6% versus 28.2%) did not reach statistical significance (RR 0.87; 0.74–1.02). The chance of an uncomplicated birth was almost similar in the two groups (70.6% in the “birth environment room” versus 72.6% in the standard room, RR 0.97; 0.88–1.07) as were duration of labor (mean 7.9 hours in both groups). Conclusions: Birthing in a specially designed physical birth environment did not lower use of oxytocin for augmentation of labor. Neither did it have any effect on duration of labor, use of pharmacological pain relief, and chance of birthing without complications. We recommend that future trials are conducted in birth units with greater improvement potentials.

IntroductionEducational attainment and employment are essential for young people to develop the skills needed to participate in society and maintain a stable connection to the labour market in adult life. The objective of this study was to examine associations between engagement in society, measured by leisure time activities and part-time work in mid and late adolescence and educational attainment and employment in early adulthood.MethodA cohort of Danish young people born in 1989 was followed in a prospective study with questionnaires in 2004 (n = 3,054) and 2007 (n = 2,400) where information on leisure time activities and part-time work was collected. Information on connection to education and work was collected from a register of social benefits when participants were 25-29 years old and divided into high and low connection. The associations were examined using logistic regression and stratified by gender and childhood socioeconomic groups.ResultsPart-time work was, both in mid (OR: 1.7 [95% CI 1.3; 2.2]) and late (1.9 [1.4;2.6]) adolescence, positively associated with connection to education and work. Leisure time activities in mid adolescence were associated with connection to education and work (OR:1.6 [1.2;2.1]). Among men engagement in society showed strongest associations with later connection to education or work in mid adolescence (ORs up to 2.2), whereas the associations for women seemed strongest in late adolescence (ORs up to 2.8).ConclusionThe study showed that adolescent engagement in society had positive associations with later educational attainment and employment, with stronger impact of part-time work compared to leisure time activities. The study identified differences between genders and the timing of engagement. Associations were consistent across socioeconomic groups.

Maternal obesity is associated with impaired fetal and neonatal survival, but underlying mechanisms are poorly understood. We examined how prepregnancy BMI and early gestational weight gain (GWG) were associated with cause-specific stillbirth and neonatal death. In 85,822 pregnancies in the Danish National Birth Cohort (1996–2002), we identified causes of death from medical records for 272 late stillbirths and 228 neonatal deaths. Prepregnancy BMI and early GWG derived from an early pregnancy interview and Cox regression were used to estimate associations with stillbirth or neonatal death as a combined outcome and nine specific cause-of-death categories. Compared to women with normal weight, risk of stillbirth or neonatal death was increased by 66% with overweight and 78% with obesity. Especially deaths due to placental dysfunction, umbilical cord complications, intrapartum events, and infections were increased in women with obesity. More stillbirths and neonatal deaths were observed in women with BMI < 25 and low GWG. Additionally, unexplained intrauterine death was increased with low GWG, while more early stillbirths were seen with both low and high GWG. In conclusion, causes of death that relate to vascular and metabolic disturbances were increased in women with obesity. Low early GWG in women of normal weight deserves more clinical attention.

Introduction: In the last decade, there has been an increased interest in exploring the impact of the physical birth environment on birth outcomes. The birth environment might have an important role in facilitating the production of the hormone oxytocin that causes contractions during labour. Oxytocin is released in a safe, secure and confidence-inducing environment, and environments focused on technology and medical interventions to achieve birth may disrupt the production of oxytocin and slow down the progress of labour. An experimental “birth environment room” was designed, inspired by knowledge from evidence-based healthcare design, which advocates bringing nature into the room to reduce stress. The purpose is to examine whether the ‘birth environment room’, with its design and decor to minimise stress, has an impact on birth outcomes and the birth experience of the woman and her partner. Materials and methods: A randomised controlled trial will recruit 680 nulliparous women at term who will be randomly allocated to either the “birth environment room” or a standard room. The study will take place at the Department of Obstetrics and Gynecology at Herning Hospital, with recruitment from May 2015. Randomisation to either the “birth environment room” or standard room takes place just before admission to a birth room during labour. The primary outcome is augmentation of labour, and the study has 80% power to detect a 10% difference between the two groups (two-sided α = 0.05). Secondary outcomes are duration of labour, use of pharmacological pain relief, mode of birth, and rating of the birth experience by women and their partners. Trial registration: NCT02478385(10/08/2016).

BackgroundIntermittent auscultation (IA) is the technique of listening to and counting the fetal heart rate (FHR) for short periods during active labour and continuous cardiotocography (CTC) implies FHR monitoring for longer periods. Although the evidence suggests that IA is the best way to monitor healthy women at low risk of complications, there is no scientific evidence for the ideal device, timing, frequency and duration for IA. We aimed to give an overview of the field, identify and describe methods and practices for performing IA, map the evidence and accuracy for different methods of IA, and identify research gaps.MethodsWe conducted a systematic scoping review following the Joanna Briggs methodology. Medline, EMBASE, Cinahl, Maternity & Infant Care, Cochrane Library, SveMed+, Web of Science, Scopus, Lilacs and African Journals Online were searched for publications up to January 2019. We did hand searches in relevant articles and databases. Studies from all countries, international guidelines and national guidelines from Denmark, United Kingdom, United States, New Zealand, Australia, The Netherlands, Sweden, Denmark, and Norway were included. We did quality assessment of the guidelines according to the AGREEMENT tool. We performed a meta-analysis assessing the effects of IA with a Doppler device vs. Pinard device using methods described in The Cochrane Handbook, and we performed an overall assessment of the summary of evidence using the GRADE approach.ResultsThe searches generated 6408 hits of which 26 studies and 11 guidelines were included in the review. The studies described slightly different techniques for performing IA, and some did not provide detailed descriptions. Few of the studies provided details of normal and abnormal IA findings. All 11 guidelines recommended IA for low risk women, although they had slightly different recommendations on the frequency, timing, and duration for IA, and the FHR characteristics that should be observed. Four of the included studies, comprising 8436 women and their babies, were randomised controlled trials that evaluated the effect of IA with a Doppler device vs. a Pinard device. Abnormal FHRs were detected more often using the Doppler device than in those using the Pinard device (risk ratio 1.77; 95% confidence interval 1.29-2.43). There were no significant differences in any of the other maternal or neonatal outcomes. Four studies assessed the accuracy of IA findings. Normal FHR was easiest to identify correctly, whereas identifying periodic FHR patterns such as decelerations and saltatory patterns were more difficult.ConclusionAlthough IA is the recommended method, no trials have been published that evaluate protocols on how to perform it. Nor has any study assessed interrater agreements regarding interpretations of IA findings, and few have assessed to what degree clinicians can describe FHR patterns detected by IA. We found no evidence to recommend Doppler device instead of the Pinard for IA, or vice versa.

Maternal emotional stress during pregnancy has previously been associated with congenital neural malformations, but most studies are based on data collected retrospectively. The objective of our study was to investigate associations between antenatal maternal bereavement due to death of a close relative and neural tube defects (NTDs) in the offspring.We performed a register-based cohort study including all live-born children (N = 1,734,190) from 1978-2008. Exposure was bereavement due to loss of a close relative from one year before conception to the end of the first trimester of pregnancy. The outcome was NTDs in the offspring according to the International Classification of Disease. We used multivariate logistic regression to estimate prevalence odds ratios (ORs).A total of 2% children were born to mothers who lost a close relative prenatally. During 30 years of follow-up, 1,115 children were diagnosed with any NTDs: spina bifida (n = 889), anencephaly (n = 85) and encephalocele (n = 164). And 23 children were diagnosed with two types of NTDs. Overall, when comparing bereaved mothers to non-bereaved mothers, no significant increased prevalence of NTDs in the offspring was seen (OR = 0.84; 95% confidence interval: 0.52-1.33).Overall maternal bereavement in the antenatal period was not related to NTDs in liveborn offspring.

BackgroundMaternal gestational weight gain (GWG) is associated with birth weight, obesity, and possibly blood pressure (BP) and hypertension in the offspring. These associations may however be confounded by genetic and/or shared environmental factors. In contrast to previous studies based on non-siblings and self-reported data, we investigated whether GWG is associated with offspring BP and hypertension, in a register-based cohort of full brothers while controlling for fixed shared effects.MethodsBy using Swedish nation-wide record-linkage data, we identified women with at least two male children (full brothers) born 1982-1989. Their BP was obtained from the mandatory military conscription induction tests. We adopted linear and Poisson regression models with robust variance, using generalized estimating equations to analyze associations between GWG and BP, as well as with hypertension, within and between offspring sibling-pairs.ResultsComplete data on the mothers' GWG and offspring BP was obtained for 9,816 brothers (4,908 brother-pairs). Adjusted regression models showed no significant associations between GWG and SBP (β = 0.03 mmHg per 1-kg GWG difference, [95% CI -0.08, 0.14], or DBP (β = -0.03 mmHg per 1-kg GWG difference [95% CI -0.11, 0.05]), or between GWG and offspring's risk of hypertension (relative risk = 1.0 [95% CI 0.99, 1.02], neither within nor between siblings.ConclusionsIn this large sibling-pair study, we did not find any significant association between GWG and offspring BP or the risk of hypertension at 18y, when taking genetic and environmental factors shared within sibling pairs into account. Further large sibling studies are required to confirm a null association between GWG and other cardiovascular risk factors.

BACKGROUND:Term birth is a gestational age from 259 days to 293 days. However trends in mortality according to gestational ages in days have not yet been described in this time period. METHODS AND FINDINGS:Based on nation-wide registries, we conducted a population-based cohort study among all children born at term in Denmark from 1997 to 2004 to estimate differences in mortality across gestational ages in days among singletons born at term. We studied early-neonatal mortality, neonatal mortality, infant mortality, and five-year mortality. Children were followed from birth up to the last day of the defined mortality period or December 31, 2009. A total of 360,375 singletons born between 259 and 293 days of gestation were included in the study. Mortality decreased with increasing gestational age in days and the highest mortality was observed among children born at 37 week of gestation. A similar pattern was observed when analyses were restricted to children born to by mothers without pregnancy complications. CONCLUSIONS:This study demonstrates heterogeneity in mortality rates even among singletons born at term. The highest mortality was observed among children born 37 weeks of gestation, which call for cautions when inducing labor in term pregnancies just reaching 37 weeks of gestation. The findings support that 37 weeks of gestation should be defined as early term.

In studies of perfluoroalkyl acids, the validity and comparability of measured concentrations may be affected by differences in the handling of biospecimens. We aimed to investigate whether measured plasma levels of perfluoroalkyl acids differed between blood samples subjected to delay and transportation prior to processing and samples with immediate processing and freezing.Pregnant women recruited at Aarhus University Hospital, Denmark, (n = 88) provided paired blood samples. For each pair of samples, one was immediately processed and plasma was frozen, and the other was delayed and transported as whole blood before processing and freezing of plasma (similar to the Danish National Birth Cohort). We measured 12 perfluoroalkyl acids and present results for compounds with more than 50% of samples above the lower limit of quantification.For samples taken in the winter, relative differences between the paired samples ranged between -77 and +38% for individual perfluoroalkyl acids. In most cases concentrations were lower in the delayed and transported samples, e.g. the relative difference was -29% (95% confidence interval -30; -27) for perfluorooctane sulfonate. For perfluorooctanoate there was no difference between the two setups [corresponding estimate 1% (0, 3)]. Differences were negligible in the summer for all compounds.Transport of blood samples and processing delay, similar to conditions applied in some large, population-based studies, may affect measured perfluoroalkyl acid concentrations, mainly when outdoor temperatures are low. Attention to processing conditions is needed in studies of perfluoroalkyl acid exposure in humans.

Exposures during fetal life may have long-term health consequences including risk of childhood overweight. We investigated the associations between maternal recreational exercise during early and late pregnancy and the children’s body mass index (BMI) and risk of overweight at 7 years. Data on 40,280 mother-child pairs from the Danish National Birth Cohort was used. Self-reported information about exercise was obtained from telephone interviews around gestational weeks 16 and 30. Children’s weight and height were reported in a 7-year follow-up and used to calculate BMI and overweight status. Data was analyzed using multiple linear and logistic regression models. Recreational exercise across pregnancy was inversely related to children’s BMI and risk of overweight, but all associations were mainly explained by smoking habits, socioeconomic status, and maternal pre-pregnancy BMI. Additionally, we did not find exercise intensity or changes in exercise habits in pregnancy related to the children’s BMI or risk of overweight.

Thirty-two common variants associated with body mass index (BMI) have been identified in genome-wide association studies, explaining ∼1.45% of BMI variation in general population cohorts. We performed a genome-wide association study in a sample of young adults enriched for extremely overweight individuals. We aimed to identify new loci associated with BMI and to ascertain whether using an extreme sampling design would identify the variants known to be associated with BMI in general populations.From two large Danish cohorts we selected all extremely overweight young men and women (n = 2,633), and equal numbers of population-based controls (n = 2,740, drawn randomly from the same populations as the extremes, representing ∼212,000 individuals). We followed up novel (at the time of the study) association signals (p

According to many national recommendations, women should be physically active during pregnancy, but empirical evidence to support this recommendation is sparse. The authors aim in this study was to examine the relation between physical exercise during pregnancy and the risk of preterm birth. Self-reported data on physical exercise during pregnancy were collected prospectively for 87,232 singleton pregnancies included in the Danish National Birth Cohort between 1996 and 2002. Hazard ratios for preterm birth according to hours of exercise per week, type of exercise, and metabolic equivalent-hours per week, respectively, were calculated using Cox regression analysis. Results showed a reduced risk of preterm birth among the almost 40% of women who engaged in some kind of exercise during pregnancy in comparison with nonexercisers (hazard ratio = 0.82, 95% confidence interval: 0.76, 0.88), but no dose-response relation was seen. The association was not affected by the type of exercise, and the results were not altered when the degree of preterm birth was taken into account. These findings do not indicate any adverse effects of exercise on the risk of preterm birth and therefore do not contradict current recommendations. [ABSTRACT FROM AUTHOR]