Lipopolysaccharide induced systemic inflammation and heart rate variability in a term newborn piglet model.

BACKGROUND: Early biomarkers are needed to improve diagnosis and support antibiotic stewardship in neonatal sepsis. Heart rate variability (HRV) is proposed as such a biomarker. However, there is a lack of studies in term newborns. Infusion of lipopolysaccharide (LPS) from Escherichia coli induces systemic inflammation comparable to sepsis in newborns. We aimed to study the effect of systemic LPS induced inflammation on HRV in term newborn piglets. METHODS: Baseline HRV was recorded for 1 h. This control period was compared to the hourly HRV for each piglet (n = 9) during 4 h of LPS infusion. For comparison, we used a mixed-effects regression model. RESULTS: Systemic inflammation induced by LPS was found to reduce HRV. Compared to baseline, most measures of HRV decreased to lower values compared to baseline at 2 h, 3 h, and 4 h after initiation of LPS infusion. Heart rate (HR) was increased at 2 h, 3 h, and 4 h. When adjusting for HR in the mixed-effects regression model all reductions in HRV were explained by the increase in HR. CONCLUSIONS: Reduced HRV may be an early biomarker of neonatal sepsis. However, an increase in HR alone could be an already available, more accessible, and interpretable biomarker of sepsis in term neonates. IMPACT: In a term newborn piglet model, systemic inflammation induced by lipopolysaccharide from Escherichia coli reduced heart rate variability measures and increased heart rate. All reductions in heart rate variability were mediated by heart rate. While heart rate variability may be a biomarker of sepsis in term newborns, changes in heart rate alone could be a more readily available biomarker.

NON-pharmacological Approach Less Invasive Surfactant Administration (NONA-LISA) trial: protocol for a randomised controlled trial.

INTRODUCTION: Using pre-procedure analgesia with the risk of apnoea may complicate the Less Invasive Surfactant Administration (LISA) procedure or reduce the effect of LISA. METHODS: The NONA-LISA trial (ClinicalTrials.gov, NCT05609877) is a multicentre, blinded, randomised controlled trial aiming at including 324 infants born before 30 gestational weeks, meeting the criteria for surfactant treatment by LISA. Infants will be randomised to LISA after administration of fentanyl 0.5-1 mcg/kg intravenously (fentanyl group) or isotonic saline solution intravenously (saline group). All infants will receive standardised non-pharmacological comfort care before and during the LISA procedure. Additional analgesics will be provided at the clinician's discretion. The primary outcome is the need for invasive ventilation, meaning mechanical or manual ventilation via an endotracheal tube, for at least 30 min (cumulated) within 24 h of the procedure. Secondary outcomes include the modified COMFORTneo score during the procedure, bronchopulmonary dysplasia at 36 weeks, and mortality at 36 weeks. DISCUSSION: The NONA-LISA trial has the potential to provide evidence for a standardised approach to relief from discomfort in preterm infants during LISA and to reduce invasive ventilation. The results may affect future clinical practice. IMPACT: Pre-procedure analgesia is associated with apnoea and may complicate procedures that rely on regular spontaneous breathing, such as Less Invasive Surfactant Administration (LISA). This randomised controlled trial addresses the effect of analgesic premedication in LISA by comparing fentanyl with a placebo (isotonic saline) in infants undergoing the LISA procedure. All infants will receive standardised non-pharmacological comfort. The NONA-LISA trial has the potential to provide evidence for a standardised approach to relief from discomfort or pain in preterm infants during LISA and to reduce invasive ventilation. The results may affect future clinical practice regarding analgesic treatment associated with the LISA procedure.

Neonatal phototherapy and risk of epilepsy-A Danish population based study.

To evaluate the risk of epilepsy in children who received neonatal phototherapy. A cohort of live singletons born at a Danish hospital (2002-2016) with a gestational age ≥ 35 weeks. We used Cox regression to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) of epilepsy in children treated with neonatal phototherapy compared to children not treated with neonatal phototherapy in the general population, and in a subpopulation of children who had serum bilirubin measurement. Adjusted HRs (aHR) were computed using multivariable and propensity score matching models to take maternal and neonatal factors into consideration. Children were followed from day 29 after birth to diagnosis of epilepsy, death, emigration, or December 31, 2016. Among 65,365 children, 958 (1.5%) received neonatal phototherapy. Seven children (incidence rates (IRs): 10.8 /10,000 person-years) who received neonatal phototherapy and 354 children (IR: 7.7) who did not receive neonatal phototherapy were diagnosed with epilepsy. Neonatal phototherapy was not associated with an increased risk of epilepsy using the multivariable (aHR 0.95, 95% CI: 0.43-2.09) and propensity score matched (aHR 0.94, 95% CI: 0.39-2.28) models. In the subpopulation of 9,378 children with bilirubin measurement, 928 (9.9%) received neonatal phototherapy. In the analysis of the subpopulation in which bilirubin level and age at the time of bilirubin measurement were further taking into consideration, neonatal phototherapy was not associated with an increased risk of epilepsy using the multivariable (aHR 1.26, 95% CI: 0.54-2.97) and propensity score matched (aHR 1.24, 95% CI: 0.47-3.25) models,Conclusions: Neonatal phototherapy was not associated with an increased risk of epilepsy after taking maternal and neonatal factors into consideration. What is known: • A few studies have suggested that neonatal phototherapy for hyperbilirubinemia may increase the risk of childhood epilepsy. • Whether the observed associations contribute to hyperbilirubinemia, phototherapy, or underlying factors requires further investigation. What is new: • This study revealed no increased risk of epilepsy in children treated with neonatal phototherapy compared to children not treated with phototherapy after taking maternal and neonatal factors into consideration. • After further taking bilirubin level and age at the time of bilirubin measurement into consideration, neonatal phototherapy was not associated with an increased risk of epilepsy.

Selection bias in a male-offspring cohort investigating fecundity: is there reason for concern?

STUDY QUESTION: Is there risk of selection bias in etiological studies investigating prenatal risk factors of poor male fecundity in a cohort of young men? SUMMARY ANSWER: The risk of selection bias is considered limited despite a low participation rate. WHAT IS KNOWN ALREADY: Participation rates in studies relying on volunteers to provide a semen sample are often very low. Many risk factors for poor male fecundity are associated with participation status, and as men with low fecundity may be more inclined to participate in studies of semen quality, a risk of selection bias exists. STUDY DESIGN, SIZE, DURATION: A population-based follow-up study of 5697 young men invited to the Fetal Programming of Semen Quality (FEPOS) cohort nested within the Danish National Birth Cohort (DNBC), 1998-2019. PARTICIPANTS/MATERIALS, SETTING, METHODS: Young men (age range: 18 years, 9 months to 21 years, 4 months) born 1998-2000 by mothers included in the DNBC were invited to participate in FEPOS. In total, 1173 men answered a survey in FEPOS (n = 115 participated partly); of those, 1058 men participated fully by also providing a semen and a blood sample at a clinical visit. Differential selection according to parental baseline characteristics in the first trimester, the sons' own characteristics from the FEPOS survey, and urogenital malformations and diseases in reproductive organs from the Danish registers were investigated using logistic regression. The influence of inverse probability of selection weights (IPSWs) to investigate potential selection bias was examined using a predefined exposure-outcome association of maternal smoking in the first trimester (yes, no) and total sperm count analysed using adjusted negative binomial regression. A multidimensional bias analysis on the same association was performed using a variety of bias parameters to assess different scenarios of differential selection. MAIN RESULTS AND THE ROLE OF CHANCE: Participation differed according to most parental characteristics in first trimester but did not differ according to the prevalence of a urogenital malformation or disease in the reproductive organs. Associations between maternal smoking in the first trimester and male fecundity were similar when the regression models were fitted without and with IPSWs. Adjusting for other potential risk factors for poor male fecundity, maternal smoking was associated with 21% (95% CI: -32% to -9%) lower total sperm count. In the bias analysis, this estimate changed only slightly under realistic scenarios. This may be extrapolated to other exposure-outcome associations. LIMITATIONS, REASONS FOR CAUTION: We were unable to directly assess markers of male fecundity for non-participants from, for example an external source and therefore relied on potential proxies of fecundity. We did not have sufficient power to analyse associations between prenatal exposures and urogenital malformations. WIDER IMPLICATIONS OF THE FINDINGS: The results are reassuring when using this cohort to identify causes of poor male fecundity. The results may be generalized to other similar cohorts. As the young men grow older, they can be followed in the Danish registers, as an external source, to examine, whether participation is associated with the risk of having an infertility diagnosis. STUDY FUNDING/COMPETING INTEREST(S): The project was funded by the Lundbeck Foundation (R170-2014-855), the Capital Region of Denmark, Medical doctor Sofus Carl Emil Friis and spouse Olga Doris Friis's Grant, Axel Muusfeldt's Foundation (2016-491), AP Møller Foundation (16-37), the Health Foundation, Dagmar Marshall's Fond, Aarhus University and Independent Research Fund Denmark (9039-00128B). The authors declare that they have no conflict of interest. TRIAL REGISTRATION NUMBER: N/A.

Transplacental transfer of SARS-CoV-2 antibodies: a cohort study.

The purpose of this study was to examine the transfer rate of SARS-CoV-2 IgG antibodies in pregnancy and newborns. Two Danish labor wards screened all women for SARS-CoV-2 by PCR upon arrival. Women (n = 99) with a SARS-CoV-2 PCR-positive nasopharyngeal (NP) swab or with a household member with a positive swab at labor or any time during pregnancy, or COVID-19 symptoms upon admission (November 2020 through August 2021), were included. Mother and infant were tested by NP swabs at delivery, and maternal and infant (umbilical cord) venous blood samples were collected. We obtained clinical information including previous PCR test results from the medical records. SARS-Cov-2 IgM and quantified IgG antibodies were measured by enzyme-linked immunosorbent assay and transfer ratios of IgG. We detected IgG antibodies in 73 women and 65 cord blood sera and found a strong correlation between SARS-CoV-2 IgG concentrations in maternal and umbilical cord sera (r = 0.9; p < 0.05). Transfer ratio was > 1.0 in 51 out of 73 (69%) infants and > 1.5 in 26 (35%). We found that transfer was proportional to time from a positive SARS-CoV-2 PCR NP swab to delivery (r = 0.5; p < 0.05). Transfer ratios of SARS-CoV-2 antibodies were associated with time from infection to delivery with transfer ratios of more than 1.0 in the majority of seropositive mother-infant dyads.

Maternal intake of folate and folic acid during pregnancy and pubertal timing in girls and boys: A population-based cohort study.

BACKGROUND: Folate is essential for normal foetal development as it plays an important role for gene expression during different periods of foetal development. Thus, prenatal exposure to folate may have a programming effect on pubertal timing. OBJECTIVES: To study the association between maternal intake of folate during pregnancy and pubertal timing in girls and boys. METHODS: We studied 6585 girls and 6326 boys from a Danish population-based Puberty Cohort, 2000-2021. Information on maternal intake of folate from diet and folic acid from supplements was obtained from a food-frequency questionnaire in mid-pregnancy, and total folate was calculated as dietary folate equivalents. Information on age at menarche in girls, age at first ejaculation and voice break in boys, and Tanner stages, acne and axillary hair in both girls and boys was obtained every 6 months throughout puberty. We estimated mean monthly differences according to exposure groups for each pubertal milestone in addition to a combined estimate for the average age at attaining all pubertal milestones using multivariable interval-censored regression models. Total folate was analysed in quintiles, continuous and as restricted cubic splines. RESULTS: Maternal intake of total folate in mid-pregnancy was not associated with pubertal timing in girls (combined estimate for overall pubertal timing per standard deviation (SD 325 µg/day) decrease in maternal intake of total folate: -0.14 months (95% confidence interval [CI] -0.51, 0.22)). Boys had slightly later overall pubertal timing per standard deviation (SD 325 µg/day) decrease in maternal intake of total folate (combined estimate: 0.40 months, 95% CI 0.01, 0.72). Spline plots supported these findings. CONCLUSIONS: Prenatal exposure to low maternal intake of total folate in mid-pregnancy was not associated with pubertal timing in girls but associated with slightly later pubertal timing in boys. This minor delay is likely not of clinical importance.

Maternal vitamin D levels and male reproductive health: a population-based follow-up study.

Maternal vitamin D levels during pregnancy may be important for reproductive health in male offspring by regulating cell proliferation and differentiation during development. We conducted a follow-up study of 827 young men from the Fetal Programming of Semen Quality (FEPOS) cohort, nested in the Danish National Birth Cohort to investigate if maternal vitamin D levels were associated with measures of reproductive health in adult sons. These included semen characteristics, testes volume, and reproductive hormone levels and were analysed according to maternal vitamin D (25(OH)D3) levels during pregnancy. In addition, an instrumental variable analysis using seasonality in sun exposure as an instrument for maternal vitamin D levels was conducted. We found that sons of mothers with vitamin D levels < 25 nmol/L had 11% (95% CI - 19 to - 2) lower testes volume and a 1.4 (95% CI 1.0 to 1.9) times higher risk of having low testes volume (< 15 mL), in addition to 20% (95% CI - 40 to 9) lower total sperm count and a 1.6 (95% CI 0.9 to 2.9) times higher risk of having a low total sperm count (< 39 million) compared with sons of mothers with vitamin D levels > 75 nmol/L. Continuous models, spline plots and an instrumental variable analysis supported these findings. Low maternal vitamin D levels were associated with lower testes volume and lower total sperm count with indications of dose-dependency. Maternal vitamin D level above 75 nmol/L during pregnancy may be beneficial for testes function in adult sons.

Measures of fetal growth and preterm birth and risk of endometriosis and adenomyosis in adult life: a systematic review and meta-analysis.

INTRODUCTION: Exposures in utero are suggested to play a role in the etiology of endometriosis and adenomyosis, although the current evidence is inconclusive. Knowledge about potential prenatal programming and early life exposures that may affect this risk is of high importance, to focus potential preventive strategies for the diseases already during pregnancy. The aim of this study was to review systematically the literature of the association between measures of fetal growth and preterm birth and endometriosis and adenomyosis in adult life. MATERIAL AND METHODS: A systematic review according to Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines and by search on PubMed and EMBASE was carried out. We included published case-control and cohort studies. We excluded studies without a reference group, eg case series, case reports as well as commentaries, letters and editorials. The quality of the studies was assessed using the Newcastle-Ottawa Scale. Meta-analyses using a random-effect inverse variance weighted model were performed. PROSPERO registration number is CRD42021249322. RESULTS: A total of 11 studies were included. In general, the quality scores of the studies were moderate. We found that the risk of endometriosis was 26% higher in women born with a birthweight <2.5 kg (pooled odds ratio [pOR] 1.26, 95% confidence interval [CI] 1.05-1.52) and 32% higher in women born preterm (pOR 1.32, 95% CI 1.01-1.72) than in the reference groups. The studies on adenomyosis pointed towards no association, but a meta-analysis was unfeasible due to the small number of studies. CONCLUSIONS: This systematic review and meta-analysis found that low birthweight and being born preterm were associated with endometriosis in adult life, but the results must be interpreted cautiously. No solid conclusion could be made regarding adenomyosis due to a limited number of published studies, but the studies included found no association. The results support the hypothesis of a potential early programming effect of endometriosis. However, the body of evidence is sparse and this hypothesis needs to be investigated further.

Continuing bonds in parents after a loss in pregnancy, or a death at or shortly after birth: A population-based study.

In this study, we describe continuing bonds and grief reactions and assess their association in 980 parents bereaved in pregnancy, at or shortly after birth. We found that most parents experienced continuing bonds. However, they differed by type of loss. Parents losing their child due to termination of pregnancy or miscarriage experienced bonds less frequently and had the least intense grief reaction. Parents losing their child postpartum experienced bonds most frequently and had the most intense grief reaction. Continuing bonds were associated with intensified grief in parents losing their child after termination or miscarriage, while this relationship was less obvious after stillbirth or postpartum death.

In utero exposure to perfluoroalkyl and polyfluoroalkyl substances and attention and executive function in the offspring: A study in the Danish National Birth Cohort.

BACKGROUND: Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are ubiquitous in the environment and accumulate in humans. PFAS are suspected to affect the neuropsychological function of children, but only few studies have evaluated the association with childhood attention and executive function. OBJECTIVES: To investigate the association between intrauterine exposure to PFAS and offspring attention and executive function. METHODS: A total of 1593 children from the Danish National Birth Cohort, born 1996-2003, were included. The levels of 16 PFAS were measured in maternal plasma during pregnancy. At 5 years of age, the Test of Everyday Attention for Children at Five (TEACh-5) and the Behavior Rating Inventory of Executive Function (BRIEF) were performed. TEACh-5 scores were standardized to a mean of 0 and standard deviation (SD) of 1. BRIEF scores were standardized to a mean of 50 and a SD of 10. The associations between levels of seven PFAS and TEACh-5 and BRIEF were examined by multivariable linear regression adjusted for potential confounders. RESULTS: Perfluorooctane sulfonamide (PFOSA) was associated with poorer selective attention [standardized mean difference (95% confidence interval) -0.5 (-0.7, -0.3), highest versus lowest quartile]. Other PFAS were not clearly associated with selective attention, and we found no clear associations between PFAS exposure and sustained attention. For parent rated executive function, perfluorooctanoate (PFOA) was associated with poorer scores, standardized mean difference 3.8 (95% confidence interval 1.6, 6.0), highest versus lowest quartile. Regarding other PFAS, the associations were less clear. We found no clear associations between any PFAS and executive function rated by preschool teachers. CONCLUSION: Intrauterine exposure to PFOSA was associated with poorer selective attention, while PFOA was associated with poorer executive function. Given the widespread nature of PFAS exposure, these findings may have public health implications, warranting further investigation.

Endometriosis and preterm birth: A Danish cohort study.

INTRODUCTION: Emerging evidence shows that women with endometriosis face a higher risk of preterm birth. However, the pathways are unclear. The objective of this study is to further investigate at different gestational ages the association between endometriosis and different pathways of preterm birth including, medically indicated preterm birth, premature pre-labor rupture of membranes (PPROM), and spontaneous labor contractions. MATERIAL AND METHODS: In this population-based cohort study we linked singleton pregnancies from the Aarhus Birth Cohort to the Danish National Patient Registry, the Danish Medical Birth Registry, the Danish National Pathology Registry and Data Bank, and the Danish in vitro fertilization registry to gather information on endometriosis status, outcomes and maternal characteristics. We investigated preterm birth before 37 completed weeks of gestation and very preterm birth before 32 completed weeks of gestation. We explored different pathways including medically indicated preterm birth defined as induction of labor with intact membranes and no prior labor contractions, PPROM defined as rupture of membranes, and spontaneous labor contractions defined as contractions with intact membranes resulting in labor. RESULTS: We found that women with endometriosis had an increased risk of preterm birth before 37 gestational weeks overall (adjusted hazard rate [aHR] 1.6, 95% confidence interval [CI] 1.3-1.9) and very preterm birth before 32 gestational weeks (aHR 1.8, 95% CI 1.1-2.9) compared with women without endometriosis. Medically indicated preterm birth was more prominent in women with endometriosis in deliveries before 37 gestational weeks (aHR 2.4, 95% CI 1.8-3.2) whereas spontaneous labor contractions were more common before 32 gestational weeks (aHR 2.2, 95% CI 1.1-4.5) in women with endometriosis compared with women without endometriosis. Further, in the analyses restricted to women with a histologically verified diagnosis of endometriosis, the results were strengthened overall and showed that women with endometriosis had an increased risk of PPROM before 32 gestational weeks (aHR 3.49, 95% CI1.36-8.98). CONCLUSIONS: Endometriosis was associated with both preterm and very preterm birth; however, apparently through different pathways. Women with endometriosis were more prone to have medically indicated preterm births before 37 gestational weeks and spontaneous preterm births before 32 gestational weeks compared with women without endometriosis.

Early-term elective Caesarean sections did not increase the risk of behavioural problems at six to eight years of age.

AIM: Our aim was to explore the under-researched associations between an elective Caesarean section (C-section) at early-term or full-term gestation and behaviour at 6-8 years of age. METHODS: We identified 1220 eligible children born by elective C-sections at Danish hospital from 2009 to 2011. Their mothers were randomised to elective C-sections at either 38+3 (early-term) or 39+3 (full-term) weeks of gestation. From December 2017 to August 2018, the parents completed the Strengths and Difficulties Questionnaire. The results were adjusted for maternal education, parity and the child's sex. RESULTS: Of the 574 (45%) children followed up, 288 were delivered early-term and 286 were delivered full-term. The groups had similar baseline characteristics. There were no differences in the total difficulties score, subscale scores or the risk of being classified as having a possible or probable psychiatric disorder. Early-term boys had a lower risk of being classified as having a possible or probable psychiatric disorder and early-term girls had higher risk, but the results were not statistically significant. CONCLUSION: We found no difference in behaviour at 6-8 years of age between children born by elective C-section at early- versus full-term gestation.

Alcohol Intake in Early Pregnancy and Risk of Attention-Deficit/Hyperactivity Disorder in Children Up to 19 Years of Age: A Cohort Study.

BACKGROUND: Little is known about maternal alcohol intake in early pregnancy and the risk of attention-deficit/hyperactivity disorder (ADHD) in children beyond 5 years of age. We examined the association between alcohol binge drinking and weekly alcohol intake in early pregnancy and the risk of ADHD in children followed from birth to 19 years of age. METHODS: We included 48,072 children born between 1998 and 2012, whose mothers participated in the Aarhus Birth Cohort. Maternal alcohol intake was obtained from a self-administered questionnaire completed in early pregnancy. ADHD diagnoses were retrieved from the Danish Psychiatric Central Research Register and the Danish National Patient Register. Crude hazard ratio and adjusted hazard ratio (aHR) of ADHD according to alcohol binge drinking or weekly intake of alcohol were calculated using the Cox regression. RESULTS: Compared to children of women with no binge drinking episodes, we observed an aHR for ADHD of 0.91 (95% CI 0.76 to 1.08), 0.73 (95% CI 0.56 to 0.96), and 0.77 (95% CI 0.57 to 1.06) among children of women reporting 1, 2, and 3 or more binge drinking episodes, respectively. Among children of women drinking <1 drink per week, 1 drink per week, 2 drinks per week, and 3 or more drinks per week, we observed an aHR for ADHD of 0.87 (95% CI 0.74 to 1.03), 0.63 (95% CI 0.40 to 0.98), 1.30 (95% CI 0.89 to 1.92), and 0.78 (95% CI 0.38 to 1.59), respectively, when compared to children of women not drinking on a weekly basis. CONCLUSION: We found no evidence that binge drinking or low alcohol intake in early pregnancy was associated with the risk of ADHD in children.

Alcohol Intake in Early Pregnancy and Spontaneous Preterm Birth: A Cohort Study.

BACKGROUND: Limited research has addressed whether maternal alcohol intake in early pregnancy increases the risk of spontaneous preterm birth. In the current study, we examined how alcohol binge drinking and weekly alcohol intake in early pregnancy were associated with spontaneous preterm birth in a contemporary cohort of Danish women. METHODS: We included 15,776 pregnancies of 14,894 women referred to antenatal care at Copenhagen University Hospital, Denmark, between 2012 and 2016. Self-reported alcohol intake in early pregnancy was obtained from a Web-based questionnaire completed prior to the women's first visit at the department. Information on spontaneous preterm birth was extracted from the Danish Medical Birth Register. Adjusted hazard ratios (aHRs) with 95% confidence intervals (CIs) of spontaneous preterm birth according to self-reported alcohol binge drinking and weekly intake of alcohol in early pregnancy were derived from Cox regression. RESULTS: Women reporting 1, 2, and ≥ 3 binge drinking episodes had an aHR for spontaneous preterm birth of 0.88 (95% CI 0.68 to 1.14), 1.34 (95% CI 0.98 to 1.82), and 0.93 (95% CI 0.62 to 1.41), respectively, compared to women with no binge drinking episodes. Women who reported an intake of ≥ 1 drink per week on average had an aHR for spontaneous preterm birth of 1.09 (95% CI 0.63 to 1.89) compared to abstainers. When restricting to nulliparous women or cohabiting women with ≥ 3 years of higher education, this estimate was 1.28 (95% CI 0.69 to 2.40) and 1.20 (95% CI 0.67 to 2.15), respectively. CONCLUSION: We found no evidence that maternal alcohol intake in early pregnancy was associated with a higher risk of spontaneous preterm birth, neither for alcohol binge drinking nor for a low average weekly intake of alcohol.

Risk of selection bias due to non-participation in a cohort study on pubertal timing.

BACKGROUND: Non-participation in aetiologic studies of pubertal timing is frequent. However, little effort has been given to explore the risk and potential impact of selection bias in studies of pubertal timing. OBJECTIVE: We aimed to explore the risk of selection bias due to non-participation in a newly established puberty cohort. METHODS: We evaluated whether three maternal exposures chosen a priori (pre-pregnancy obesity, smoking, and alcohol drinking during pregnancy) were associated with participation, whether pubertal timing was associated with participation, and whether selection bias influenced the associations between these exposures and pubertal timing. In total, 22 439 children from the Danish National Birth Cohort born 2000-2003 were invited to the Puberty Cohort and 15 819 (70%) participated. Exposures were self-reported during pregnancy. Pubertal timing was measured using a previously validated marker, "the height difference in standard deviations" (HD:SDS), which is the difference between pubertal height and adult height, both in standard deviations. For this study, pubertal height at around 13 years in sons and around 11 years in daughters was obtained from an external database, and adult height was predicted based on parental height reported by mothers. RESULTS: Participation was associated with most exposures but not with pubertal timing, measured by HD:SDS. The associations between exposures and HD:SDS were comparable for participants only and all invited for participation. CONCLUSION: In conclusion, the risk of selection bias in aetiologic studies on pubertal timing in the Puberty Cohort appears minimal.

Identification of Alcohol Risk Drinking Behaviour in Pregnancy Using a Web-Based Questionnaire: Large-Scale Implementation in Antenatal Care.

AIMS: This study aimed to examine the feasibility of a web-based questionnaire when collecting information on alcohol consumption in pregnancy to identify women with risk drinking behaviour, and to describe factors associated with risk drinking behaviour, and the use of specialized care for prenatal risk drinking. METHODS: In 2413 women referred to antenatal care at Odense University Hospital, Denmark, April-October 2018, self-reported alcohol intake was retrieved from a web-based questionnaire. Replies were screened for risk drinking behaviour: current intake of ≥7 drinks/week, ≥3 binge drinking episodes (intake of ≥5 drinks on a single occasion) in pregnancy, binge drinking after recognition of pregnancy and/or a TWEAK-score ≥ 2 points. Women with risk drinking behaviour were called to clarify the need for specialized care. A summary of the interview was obtained from the medical records. RESULTS: Overall, 2168 (90%) completed the questionnaire. Of 2097 women providing information on alcohol intake, 77 (4%) had risk drinking behaviour. Risk drinking was associated with higher alcohol intake prior to pregnancy, spontaneous conception, younger age, nulliparity and higher level of physical activity in pregnancy. Amongst 47 women with risk drinking behaviour reached by phone, five (11%, 95% CI 4-23%) accepted examinations of the child by paediatrician and child psychologist, and <3 (not further specified due to small numbers) were referred to specialized antenatal care. CONCLUSIONS: A web-based questionnaire was feasible when collecting information on alcohol consumption in pregnancy to identify risk drinking behaviour. Women with risk drinking behaviour had a low acceptance of referral to specialized care.

Fetal Heart Defects and Measures of Cerebral Size.

OBJECTIVES: To estimate the association between fetal congenital heart defects (CHDs) and measures of brain size throughout pregnancy, from the end of the first trimester to birth. STUDY DESIGN: The cohort consisted of all fetuses scanned in Western Denmark in 2012 and 2013. Anthropometric measures in fetuses with isolated CHDs diagnosed within 12 months after birth were compared with those in the fetuses without CHDs. Z-scores standardized to gestational age were calculated for first trimester biparietal diameter, second trimester head circumference, fetal weight, birthweight, head circumference, and placental weight. RESULTS: We obtained data from 63 349 pregnancies and identified 295 fetuses with isolated CHDs (major n = 145; minor n = 150). The first trimester mean biparietal diameter Z-scores were not different between those with and those without CHDs. The head circumference mean Z-score difference was -0.13 (95% CI, -0.24 to -0.01; P = .03) in the second trimester and -0.22 (95% CI, -0.35 to -0.09; P < .001) at birth. Fetuses with univentricular physiology or tetralogy of Fallot showed the most pronounced compromise in cerebral size. CONCLUSIONS: Our results suggest that the brain alterations inducing an increased risk of impaired neurodevelopment in children with CHDs begin during pregnancy. Although fetuses with univentricular physiology or tetralogy of Fallot exhibited the most pronounced compromise in cerebral size, we recommend neurodevelopmental follow-up for all children with CHDs.

Timing of puberty in boys and girls: A population-based study.

BACKGROUND: A secular trend towards earlier puberty has been observed in girls, while a similar trend has been more uncertain in boys. We estimated current ages at pubertal development in both boys and girls. METHODS: In this population-based cohort study, 14 759 of 22 439 invited boys and girls born from 2000 to 2003 in the Danish National Birth Cohort gave half-yearly self-reported information on puberty from the age of 11.5 years and throughout puberty. This late start of follow-up limits the estimation of age at onset of puberty but not later pubertal milestones. We estimated mean age at attaining the following pubertal milestones in years with 95% confidence intervals (CI): age at menarche, voice break, first ejaculation of semen and Tanner stages for pubic hair development and breast development or genital development. Further, the difference in mean age at menarche between mothers and daughters was estimated. RESULTS: In boys, voice break occurred at 13.1 (95% CI 13.0, 13.1) years, first ejaculation of semen occurred at 13.4 (95% CI 13.3, 13.4) years, and Tanner Genital Stage 5 occurred at 15.6 (95% CI 15.5, 15.6) years. In girls, age at menarche occurred at 13.0 (95% CI 13.0, 13.1) years and Tanner Breast Stage 5 occurred at 15.8 (95% CI 15.7, 15.9) years. Daughters had menarche 3.6 (95% CI 3.1, 4.2) months earlier than their mothers had. CONCLUSION: These data indicate that age at menarche has declined and to some extent support a decline in age at attaining other markers of pubertal development among boys.

Physical activity during pregnancy and intelligence in sons; A cohort study.

The purpose was to examine the association between exercise during pregnancy and intelligence score in offspring. We analyzed data from 4008 women from the Aarhus Birth Cohort, Aarhus University Hospital, Denmark, recruited during pregnancy from July 1989 to November 1991 and their sons who were registered at conscription at 17-20 years of age. The women gave information by self-administered questionnaires during the first trimester including leisure-time physical activity and weekly hours of sport. This information was linked to the sons' measures of intelligence by Børge Priens test scores from the Danish Conscription Registry. Only sons were included since very few women register at conscription in Denmark. The main outcome measure was the Børge Priens test score as a continuous variable and with a low score defined as <10% of the population score. Analyses were adjusted for maternal body mass index, years in school, and smoking. Sons of women with light and moderate to heavy leisure-time physical activity had lower risk of having a low intelligence score compared with sons of women with sedentary activity: adjusted odds ratio (aOR) 0.66 (95% CI 0.49;0.88) and 0.46 (95% CI 0.23;0.93), respectively. Furthermore, sons of women engaged in sports had lower risk of a low intelligence score: aOR 0.50 (95% CI 0.30; 0.83) for 1-2 h/wk and 0.62 (95% CI 0.35; 1.10) for ≥3 h/wk compared with no weekly sports activity. In conclusion, a higher level of physical activity during pregnancy was associated with a lower risk of low intelligence score in early adulthood in sons.