Kristjana Einarsdóttir

The impact of maternal physical activity on infant body composition remains understudied. This study aimed to investigate the association between maternal activity levels during pregnancy and infant body fat percentage, utilising data from the Western Australian ORIGINS birth cohort. A total of 323 pregnant women and their male (148) and female (175) infants born during 2016–2024 were included in the analysis. Maternal physical activity was measured with the International Physical Activity Questionnaire (IPAQ) and the Godin Leisure-Time Exercise (Godin) questionnaire during the second trimester. Infant body composition was measured within 7 d of birth using infant air displacement plethysmography (PEA POD). Associations were calculated using linear regression models adjusted for confounders. A significant difference in neonatal body fat percentage was observed between sexes, with males averaging 11.7% and females 13.0% (p = 0.005). Analyses of maternal physical activity during the second trimester demonstrated sex-specific effects on infant body fat percentage. High maternal activity levels were associated with lower body fat percentage for female infants (IPAQ: −3.23, 95% CI: −5.22, −1.23 and Godin: −1.73, 95% CI: −3.26, −0.22), while for males, no association was observed. These results suggest that tailored prenatal care strategies that promote exercise and a healthy diet would be beneficial to pregnant women. Further research is needed to explore additional factors that could influence infant body fat percentage, which in turn could enhance prenatal care recommendations.

Objective: Cesarean section (CS) rates have increased substantially in Australia, with particularly high use observed in private maternity care and for pre‐labor CS. The aim of the present study was to describe the CS rates and the clinical indications for pre‐labor CS in the ORIGINS birth cohort. Methods: This study analyzed data from the ORIGINS birth cohort, a large birth cohort in Western Australia, including 9473 births occurring at Joondalup Health Campus between 2016 and 2024. Rates of CS and pre‐labor CS were compared across study periods (2016–2020 and 2021–2024) and by facility type (public vs. private). Indications for pre‐labor CS were described and compared across study periods and facility type. Poisson regression was used to assess the change in CS rates across study periods, adjusted for maternal demographic and pregnancy characteristics. Results: Overall CS rates were 50.4% for the study cohort. They increased from 48.2% in 2016–2020 to 52.3% in 2021–2024 (adjusted risk ratio [aRR] 1.10, 95% confidence interval [CI] 1.06–1.14) and were 46.2% in public facilities and 62.0% in private facilities. Pre‐labor CS rates increased from 31.4% to 36.2% (aRR 1.15, 95% CI 1.10–1.23) and were 28.5% in public facilities and 49.1% in private facilities. Previous cesarean section was the most common indication for pre‐labor CS and increased in prevalence across study periods (from 50% to 53.2%). Pre‐labor CS performed at maternal request also increased (from 10.8% to 15.3%) and was more common in private hospital facilities (public, 10.8%; private, 17.7%). Conclusions: CS rates in the ORIGINS birth cohort appeared to be higher than in the broader Western Australian birthing population. Pre‐labor CS contributed substantially to rising CS rates in this cohort and was particularly common in private settings. Similarly, pre‐labor CS performed at maternal request increased over time and was more common in private settings. Identifying the factors driving CS use is increasingly important.

This study investigates the association between ambient air pollutants, from traffic and geothermal sources, and asthma medication dispensation (AMD) in young children. The study participants were drawn from the Icelandic Mother-and-Child Health Study (ICE-MCH) and included 17,536 children residing in the Reykjavík Capital Area, born 2009-2014 and followed up to 2021(aged 7–12 years). Exposure was the daily averages of hourly air pollution measurements in the area collected 2009–2021 for particulate matter (PM), nitrogen dioxide (NO2), sulfur dioxide (SO2), and hydrogen sulfide (H2S). Incidence rate odds ratios (IRORs) estimated via Poisson generalized linear models and adjusted for season, sex, and birth weight, found that elevated concentrations of SO2 and H2S were associated with increased odds of both first AMD and indicative asthma after various number of days, with maximum IRORs of 2.07 (95% CI 1.87–2.30) for SO2 and 1.54 (95% CI 1.39–1.70) for H2S. NO2 and PM10 showed comparatively lower associations. For children aged 1–3 years, AMD risk was assessed using a case-crossover design. Exposure to the highest quartile of SO2 and H2S at a 7-day lag was associated with increased odds of AMD, with ORs of 1.19 (95%CI 1.03–1.37) and 1.27 (95% CI 1.12–1.43), respectively. Elevated odds were also observed with NO2 exposure. In conclusion, the findings indicate that exposure to higher levels of NO2, SO2, and H2S—originating from both traffic and geothermal sources—is associated with an increased risk of AMD in children, particularly among those aged one to three years.

Few studies have explored associations between indexes incorporating both breastfeeding and complementary feeding and future risk of overweight/obesity. The aim of this study was to explore associations between a previously developed Infant Diet Score (IDS; higher score reflecting better alignment with breastfeeding and complementary feeding guidelines in the first year of life), and the risk of overweight and/or obesity in childhood. Nutrition and anthropometric data for all children born in Iceland in January 2009 to June 2015 were gathered from national health records. Logistic regression models were used to test associations between IDS and BMI‐for‐age z ‐scores (WHO standards). Among children for which the IDS could be calculated, anthropometric data was available for 6,335 children at 2.5 years (thereof 7% with overweight/obesity), 2,486 at 4 years (4% with overweight/obesity), 8,946 at 6 years (19% with overweight and 8% obesity) and 5,626 at 9 years (23% with overweight and 15% obesity). Compared to children in the highest IDS quintile, those in quintiles 1 and 2 had higher odds of obesity at 6 years (aOR: 1.42; 95% CI: 1.05–1.93 and aOR: 1.58; 95% CI: 1.18–2.14) and 9 years (aOR: 1.37; 95% CI: 1.02–1.85 and aOR: 1.46; 95% CI: 1.10–1.94). The same applied for IDS quintile 3 in partly, but not fully adjusted models. Associations were inconsistent at 2.5 years and not observed at 4 years. In this national cohort, lower alignment with infant nutrition guidelines was associated with higher risk of obesity at school age.

Introduction: This study describes the stillbirth rate (SBR) in Iceland 1996–2021 and the causes of stillbirth according to the Stockholm classification of stillbirth, comparing time periods and gestational age (GA) groups. Material and Methods: Clinical information was obtained from medical records of mothers who had stillbirths and their infants ( n = 395). Infants were divided into groups according to GA at diagnosis of stillbirth: early preterm: ≥22 but n = 140), late preterm: ≥28 but n = 130), and term: ≥37 weeks ( n = 125). Autopsy records and gross descriptions of the placenta were reviewed, and microscopic slides were reevaluated, and findings classified according to the Amsterdam Consensus. Primary and associated causes of death were assigned according to the Stockholm classification of stillbirth. The SBR, maternal and fetoplacental characteristics, and causes of death were compared between two 13‐year periods (1996–2008 and 2009–2021) and between GA groups. Results: The SBR decreased from 4.10 to 2.88/1000 births ( p = 0.009) between the two periods, but this decrease was limited to stillbirths diagnosed before term. Fewer stillbirths in the latter period were attributed to causes such as infection and placental abruption, and unexplained stillbirths reduced (0.59 vs. 0.16/1000, p < 0.05). The most common primary causes of stillbirth were reduced circulation in the umbilical cord (25.6%) and placental insufficiency (25.2%); both increased in incidence with more advanced gestation. Despite no difference in small‐for‐gestational‐age infants, a larger percentage of stillbirths had low placental weight (21.3% vs. 30.3%, p = 0.002) and high fetoplacental ratio for GA (15.7% vs. 24.2%, p = 0.005) in the latter period, when a larger proportion of stillbirths were attributed to placental insufficiency (17.0% vs. 37.0%, p = 0.0002). Conclusions: The SBR decreased in the latter period due to a reduction in preterm stillbirth, whereas the SBR at term was unchanged. Reduced circulation of the umbilical cord and placental insufficiency were the commonest causes, and both increased with GA. Stillbirth due to infection and placental abruption, as well as unexplained stillbirths, decreased during the study period, whereas deaths attributed to placental insufficiency became more common, reflecting a lack of reduction of stillbirth at term in the latter period.

Objective: Twin pregnancies are associated with increased antepartum and intrapartum risks. Limited multiple embryo transfers are associated with decreased twin birth rates. We aimed to study the effect of 2009 Icelandic regulations on twin birth rates and examine obstetric intervention rates for twin births during the study period.Methods: The study included all births (N = 94 028) in Iceland during 1997–2018. Twin birth rates and obstetric intervention rates were compared over birth year periods using modified Poisson regression adjusted for confounders.Results: An observed decrease in the twin birth rate trend was most notable from 2006 until 2009. Twin birth decreased in 2009–2013 (prevalence ratio [PR] 0.74, 95% confidence interval [CI] 0.64–0.86) and in 2014–2018 (PR 0.74, 95% CI 0.64–0.86) compared with 1997–2002. This decrease was only evident for women aged 30+ years in stratified analysis. Induction of labor rates increased from 26% in 1997–2002 to 44% in 2014–2018 (adjusted rate ratio [ARR] 2.10, 95% CI 1.72–2.57) whereas elective cesarean section (ARR 0.80, 95% CI 0.59–1.07) and urgent cesarean section (ARR 0.79, 95% CI 0.63–1.00) rates appeared to decline.Conclusion: Twin births decreased during the study period. International guidelines published before the Icelandic regulations may have affected twin birth rates in Iceland. Induction of labor rates for twins increased while cesarean section rates decreased.

Background: Antenatal corticosteroids (ACS) are widely prescribed to improve outcomes following preterm birth. Significant knowledge gaps surround their safety, long-term effects, optimal timing and dosage. Almost half of women given ACS give birth outside the “therapeutic window” and have not delivered over 7 days later. Overtreatment with ACS is a concern, as evidence accumulates of risks of unnecessary ACS exposure. Methods: The Consortium for the Study of Pregnancy Treatments (Co-OPT) was established to address research questions surrounding safety of medications in pregnancy. We created an international birth cohort containing information on ACS exposure and pregnancy and neonatal outcomes by combining data from four national/provincial birth registers and one hospital database, and follow-up through linked population-level data from death registers and electronic health records. Results and discussion: The Co-OPT ACS cohort contains 2.28 million pregnancies and babies, born in Finland, Iceland, Israel, Canada and Scotland, between 1990 and 2019. Births from 22 to 45 weeks’ gestation were included; 92.9% were at term (≥ 37 completed weeks). 3.6% of babies were exposed to ACS (67.0% and 77.9% of singleton and multiple births before 34 weeks, respectively). Rates of ACS exposure increased across the study period. Of all ACS-exposed babies, 26.8% were born at term. Longitudinal childhood data were available for 1.64 million live births. Follow-up includes diagnoses of a range of physical and mental disorders from the Finnish Hospital Register, diagnoses of mental, behavioural, and neurodevelopmental disorders from the Icelandic Patient Registers, and preschool reviews from the Scottish Child Health Surveillance Programme. The Co-OPT ACS cohort is the largest international birth cohort to date with data on ACS exposure and maternal, perinatal and childhood outcomes. Its large scale will enable assessment of important rare outcomes such as perinatal mortality, and comprehensive evaluation of the short- and long-term safety and efficacy of ACS.

Preterm birth (PTB) is the leading cause of infant mortality worldwide. Changes in PTB rates, ranging from −90% to +30%, were reported in many countries following early COVID-19 pandemic response measures (‘lockdowns’). It is unclear whether this variation reflects real differences in lockdown impacts, or perhaps differences in stillbirth rates and/or study designs. Here we present interrupted time series and meta-analyses using harmonized data from 52 million births in 26 countries, 18 of which had representative population-based data, with overall PTB rates ranging from 6% to 12% and stillbirth ranging from 2.5 to 10.5 per 1,000 births. We show small reductions in PTB in the first (odds ratio 0.96, 95% confidence interval 0.95–0.98, P value <0.0001), second (0.96, 0.92–0.99, 0.03) and third (0.97, 0.94–1.00, 0.09) months of lockdown, but not in the fourth month of lockdown (0.99, 0.96–1.01, 0.34), although there were some between-country differences after the first month. For high-income countries in this study, we did not observe an association between lockdown and stillbirths in the second (1.00, 0.88–1.14, 0.98), third (0.99, 0.88–1.12, 0.89) and fourth (1.01, 0.87–1.18, 0.86) months of lockdown, although we have imprecise estimates due to stillbirths being a relatively rare event. We did, however, find evidence of increased risk of stillbirth in the first month of lockdown in high-income countries (1.14, 1.02–1.29, 0.02) and, in Brazil, we found evidence for an association between lockdown and stillbirth in the second (1.09, 1.03–1.15, 0.002), third (1.10, 1.03–1.17, 0.003) and fourth (1.12, 1.05–1.19, <0.001) months of lockdown. With an estimated 14.8 million PTB annually worldwide, the modest reductions observed during early pandemic lockdowns translate into large numbers of PTB averted globally and warrant further research into causal pathways.

Women who are obese before pregnancy have a higher risk of caesarean section than normal weight women. We investigated the combined effect of pre-pregnancy weight and gestational weight gain on pre-labour and intrapartum caesarean section risk. We collected data on 22,763 singleton, term, live deliveries in 2003–2014 from the Icelandic Maternal and Child Health Study (ICE-MCH), based on Icelandic registries. These were the Icelandic Medical Birth Registry and the Saga Maternal and Child Health Database. Pre-pregnancy body mass index was categorised into underweight, normal weight, overweight and obese. Gestational weight gain was classified according to the Institute of Medicine´s recommendation into below, within and above the recommended range. Logistic regression models, adjusted for maternal and gestational characteristics, were used to calculate adjusted odds ratios (AOR) and 95% confidence intervals (CI) for the risk of caesarean section. Obese women had a higher risk of pre-labour (AOR 1.56, 95% CI 1.34–1.81) and intrapartum caesarean section (AOR 1.92, 95% CI 1.70–2.17) than normal weight women in all categories of gestational weight gain. Gestational weight gain above the recommended range, compared to within the range, increased the risk of intrapartum caesarean section among normal weight (AOR 1.46, 95% CI 1.23–1.73) and overweight women (AOR 1.291, 95% CI 1.04–1.60). Gestational weight gain below the recommended range, compared to within the range, increased the risk of pre-labour caesarean section (AOR 1.64, 95% CI 1.20–2.25), but only among overweight women. Women who are obese before pregnancy have a high risk of caesarean section regardless of gestational weight gain. However, women who are normal weight or overweight before pregnancy and gain weight above the recommended range during pregnancy may also have an increased risk of caesarean section.