Validation of maternal reported pregnancy and birth characteristics against the Medical Birth Registry of Norway

Pregnancy outcomes as related to in utero exposure to air pollution and greenness: The Life-GAP Project

Background

Lower birth weight and preterm birth may increase the risk of adverse health outcomes later in life. We examined whether maternal exposure to air pollution and greenness during pregnancy is associated with offspring birth weight and preterm birth.

Methods

We analyzed data on 4286 singleton births from 2358 mothers from Respiratory Health in Northern Europe, a prospective questionnaire-based cohort study (1990-2010). Mixed-effects regression models with random intercepts for mothers and centers were used to estimate the association of exposures to particulate matter (PM2.5 and PM10), nitrogen dioxide (NO2), ozone (O3), black carbon (BC), and greenness (Normalized Difference Vegetation Index in 300m-buffers [NDVI300m]) with birth outcomes, adjusting for potential confounders.

Results

Median (interquartile range [IQR]) exposures to PM2.5, PM10, NO2, O3, BC, and NDVI300m during pregnancy were 8.4(5.0) µg/m3, 14.4(8.3) µg/m3, 14.0(11.0) µg/m3, 54.7(10.2) µg/m3, 0.47(0.41) µg/m3, and 0.31(0.20), respectively. IQR increases in air pollution exposures during pregnancy were associated with decreased birth weight and the strongest association was seen for PM2.5 (-49g; 95% confidence interval [CI] = -83, -16). However, O3 showed an opposite association. IQR increase in NDVI300m was associated with an increase in birth weight of 25 g (95% CI = 7, 44). Preterm birth was not associated with the exposures.

Conclusion

Increased greenness and decreased air pollution may contribute to healthier pregnancies and improve overall health in the next generation. This emphasizes the need to adopt policies that target the reduction of air pollution emissions and exposure of the population.

The Association between Threatened Miscarriage and Autism Spectrum Disorder and Attention-Deficit/Hyperactivity Disorder in Offspring by Age 14 Years

OBJECTIVE

To examine the association between threatened miscarriage, and neurodevelopmental disorders, including autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) in offspring by age 14 years.

METHODS

We used data from the Millennium Cohort Study, a nationally representative longitudinal study of children born in the UK. Data on threatened miscarriage and potential confounders were maternal-reported and collected at 9 months postpartum. Data on ASD and ADHD were based on maternal-reported doctor diagnoses and collected when children were aged 5, 7, 11 and 14 years. A diagnosis of ASD or ADHD was assumed if parents reported ASD or ADHD at age 5, 7, 11 or 14 years. Crude and adjusted logistic regression examined threatened miscarriage and ASD and ADHD relationship, adjusting for several sociodemographic, maternal and lifestyle factors.

RESULTS

A total of 18,294 singleton babies were included at baseline, and 1,104 (6.0%) women experienced a threatened miscarriage during their pregnancy. Adjusted results suggested an association between threatened miscarriage and ASD (OR: 1.55, 95% CI 1.15, 2.08), and ADHD (OR: 1.51, 95% CI 1.09, 2.10) by age 14 years. E-values for threatened miscarriage and ASD were 2.47, while the lower limits of the 95% CI were 1.57. E-values for threatened miscarriage and ADHD were 2.39, while the corresponding lower limits of the 95% CI were 1.40.

CONCLUSION

Threatened miscarriage was associated with an increased likelihood of ASD and ADHD by the age of 14 years, however, residual confounding cannot be ruled out. Placental pathology may be a potential mechanism for the observed associations.

Validation of Parent-reported Gestational Age Categories for Children Less Than 6 Years of Age

BACKGROUND

Preterm birth is an important outcome or exposure in epidemiologic research. When administrative data on measured gestational age is not available, parent-reported gestational age can be obtained from questionnaires, which is subject to potential bias. To our knowledge, few studies have assessed the validity of parent-reported gestational age categories, including commonly defined categories of preterm birth.

METHODS

We used linked data from primarily healthy children <6 years of age in TARGet Kids! in Toronto, Canada, and ICES administrative healthcare data from April 2011 to March 2020. We assessed the criterion validity of questionnaire-based parent-reported gestational age by calculating sensitivity and specificity for term (≥37 weeks), late preterm (34-36 weeks), and moderately preterm (32-33 weeks) gestational age categories, using administrative healthcare records of gestational age as the criterion standard. We conducted subgroup analyses for various parent and socioeconomic factors that may influence recall.

RESULTS

Of the 4684 participants, 97.3% correctly classified the gestational age category according to administrative healthcare data. Parent-reported gestational age sensitivity ranged from 83.7% to 98.5% and specificity ranged from 88.3% to 99.8%, depending on category. For each subgroup characteristic, sensitivity and specificity were all ≥70%. Lower educational attainment, lower family income, father reporting, ≥1 year since birth, ≥2 children, lower parent age, and reported gestational diabetes and/or hypertension were associated with slightly lower sensitivity and/or specificity.

CONCLUSIONS

In this linked cohort, parent-reported gestational age categories had high accuracy. Criterion validity varied minimally among some parent and socioeconomic factors. Our findings can inform future quantitative bias analyses.

Hypertensive Disorders of Pregnancy and Risk of Stroke in U.S. Black Women

BACKGROUND: Black women have a disproportionately higher burden of both preeclamptic pregnancy and stroke compared with White women, but virtually all existing evidence on this possible association has been generated from women of European ancestry. METHODS: In the Black Women’s Health Study, a prospective cohort of U.S. Black women who enrolled in 1995, 42,924 participants were parous and free of cardiovascular disease at baseline. Biennial questionnaires included questions on preeclampsia, gestational hypertension, and stroke. We sought the medical records for participants who reported a stroke, and we reviewed them blinded to reproductive history. Cox proportional-hazards models, with control for potential confounders, were used to estimate hazard ratios and 95% confidence intervals (CIs). RESULTS: Over a median of 22 years of follow-up, there were 1555 incident strokes, including 310 among 4938 women with a history of hypertensive disorders of pregnancy (HDOP). The multivariable hazard ratio for stroke for women with any HDOP compared with those who had never experienced HDOP was 1.66 (95% CI, 1.46 to 1.89). Comparable hazard ratios were 1.53 (95% CI, 1.29 to 1.82) for preeclampsia and 1.81 (95% CI, 1.53 to 2.13) for gestational hypertension only. Associations were similar among women under age 55 years and those aged 55 years and older. CONCLUSIONS: In this prospective study of Black women, a history of HDOP was associated with an estimated 66% increased long-term risk of stroke. This association may contribute to the disproportionately higher stroke incidence in Black women given the higher prevalence of HDOP in this population. (Funded by the U.S. National Institutes of Health.)

Prevalence of preterm birth in Scandinavian countries: a systematic review and meta-analysis

OBJECTIVES

As welfare societies, Scandinavian countries share characteristics of equality related to healthcare access, gender, and social services. However, cultural and lifestyle variations create country-specific health differences. This meta-analysis assessed the prevalence of preterm birth (PTB) and its categories in Scandinavian countries.

METHODS

A systematic search in key databases of literature published between 1990 and 2021 identified studies of the prevalence of PTB and its categories. Following the use of the Freeman-Tukey double arcsine transformation, a meta-analysis of weighted data was performed using the random-effects model and meta-prop method.

RESULTS

We identified 109 observational studies that involved 86,420,188 live births. The overall pooled prevalence (PP) of PTB was 5.3% (PP = 5.3%, 95% confidence interval [CI] 5.1%, 5.5%). The highest prevalence was in Norway (PP = 6.2%, 95% CI 5.3%, 7.0%), followed by Sweden (PP = 5.3%, 95% CI 5.1%, 5.4%), Denmark (PP = 5.2%, 95% CI 4.9%, 5.3%), and Iceland (PP = 5.0%, 95% CI 4.4%, 5.7%). Finland had the lowest PTB rate (PP = 4.9%, 95% CI 4.7%, 5.1%).

CONCLUSIONS

The overall PP of PTB was 5.3%, with small variations among countries (4.9%-6.2%). The highest and lowest PPs of PTB were in Norway and Finland, respectively.

Patterns of Labour Interventions and Associated Maternal Biopsychosocial Factors in Australia: a Path Analysis

In Australia, nearly half of births involve labour interventions. Prior research in this area has relied on cross-sectional and administrative health data and has not considered biopsychosocial factors. The current study examined direct and indirect associations between biopsychosocial factors and labour interventions using 19 years of population-based prospective data. The study included singleton babies among primiparous women of the 1973-1978 cohort of the Australian Longitudinal Study on Women's Health. Data from 5459 women who started labour were analysed using path analysis. 42.2% of babies were born without intervention (episiotomy, instrumental, or caesarean delivery): Thirty-seven percent reported vaginal birth with episiotomy and instrumental birth interventions, 18% reported an unplanned caesarean section without episiotomy and/or instrumental interventions, and 3% reported unplanned caesarean section after episiotomy and/or instrumental interventions. Vaginal births with episiotomy and/or instrumental interventions were more likely among women with chronic hypertension (RRR(95%-CI):1.50(1.12-2.01)), a perceived length of labour of more than 36 h (RRR(95%-CI):1.86(1.45-2.39)), private health insurance (RRR(95%-CI):1.61(1.41-1.85)) and induced labour (RRR(95%-CI):1.69(1.46-1.94)). Risk factors of unplanned caesarean section without episiotomy and/or instrumental birth intervention included being overweight (RRR(95%-CI):1.30(1.07-1.58)) or obese prepregnancy (RRR(95%-CI):1.63(1.28-2.08)), aged ≥ 35 years (RRR(95%-CI):1.87(1.46-2.41)), having short stature (< 154 cm) (RRR(95%-CI):1.68(1.16-2.42)), a perceived length of labour of more than 36 h (RRR(95%-CI):3.26(2.50-4.24)), private health insurance (RRR(95%-CI):1.38(1.17-1.64)), and induced labour (RRR(95%-CI):2.56(2.16-3.05)). Prevention and management of hypertension, diabetes, and obesity during preconception and/or antenatal care are keys for reducing labour interventions and strengthening the evidence-base around delivery of best practice obstetric care.

Women report better experiences from maternity care after postnatal consultations: A cross sectional study

OBJECTIVE

To determine if the patient reported experiences (PREMs) of women in maternity care differ by whether or not they had a postnatal consultation before leaving the birth institution.

METHODS

Secondary analysis of cross-sectional data to compare PREMs of women who had received an individual consultation (86 %), a group consultation (3 %), and women who had received no consultation (11 %). PREMs were collected using a self-administered questionnaire. Eight summated scales were constructed from 29 single items, pertaining to different parts of the received care. Scores ranged between 0 and 100, with high scores representing positive experiences.

RESULTS

Among the 8156 sampled women, 3387 (42 %) responded. There were statistically significant (p ≤ 0.002) differences (from 3.7 to 16.3 points) on all eight scales. The scores from women who had an individual postnatal consultation were consistently higher than the scores from the other groups. The largest difference was in the scale with the worst score: information about women's health during the postnatal stay.

CONCLUSION

Women who participated in individual postnatal consultations reported more positive experiences compared to those who did not.

PRACTICE IMPLICATION

The consistent differences found in this study provide support for administering individual postnatal consultations.

Preconception origins of asthma, allergies and lung function: The influence of previous generations on the respiratory health of our children

Emerging research suggests that exposures occurring years before conception are important determinants of the health of future offspring and subsequent generations. Environmental exposures of both the father and mother, or exposure to disease processes such as obesity or infections, may influence germline cells and thereby cause a cascade of health outcomes in multiple subsequent generations. There is now increasing evidence that respiratory health is influenced by parental exposures that occur long before conception. The strongest evidence relates adolescent tobacco smoking and overweight in future fathers to increased asthma and lower lung function in their offspring, supported by evidence on parental preconception occupational exposures and air pollution. Although this literature is still sparse, the epidemiological analyses reveal strong effects that are consistent across studies with different designs and methodologies. The results are strengthened by mechanistic research from animal models and (scarce) human studies that have identified molecular mechanisms that can explain the epidemiological findings, suggesting transfer of epigenetic signals through germline cells, with susceptibility windows in utero (both male and female line) and prepuberty (male line). The concept that our lifestyles and behaviours may influence the health of our future children represents a new paradigm. This raises concerns for future health in decades to come with respect to harmful exposures but may also open for radical rethinking of preventive strategies that may improve health in multiple generations, reverse the imprint of our parents and forefathers, and underpin strategies that can break the vicious circle of propagation of health inequalities across generations.

Aryl hydrocarbon receptor activity in human breast milk and cryptorchidism: A case-control study within the prospective Norwegian HUMIS cohort

BACKGROUND

The etiology of cryptorchidism remains poorly understood. Endocrine disrupting chemicals can impact estrogen signaling by interacting with aryl hydrocarbon receptor (AhR) activity.

OBJECTIVE

To evaluate whether AhR activity in breast milk samples is associated with cryptorchidism.

METHOD

We conducted a case-control study based on 199 mother-child pairs (n = 91 cases/108 controls) selected from the Norwegian Human Milk Study (2002-2009). We defined cases for cryptorchidism based on maternal reports at 1-, 6-, 12-, and 24- months after birth. Chemically- and biologically stable AhR activity (pg 2,3,7,8-TCDD equivalent (TEQ)/g lipid) was determined by DR- CALUX® assay in the mothers' milk collected at a median of 33 (10th-90th percentile: 18-57) days after delivery. We used multivariate logistic regression to compare AhR activity levels between cases and controls, and linear regression separately, to establish the relationship with the presence of 27 potential EDCs measured in breast milk and AhR activity.

RESULTS

The average estimated daily intake (EDI) of dioxin and (dioxin-like (dl)-compounds via breast milk is 33.7 ± 17.9 pg TEQ/kg bodyweight per day among Norwegian children. There were no significant differences in AhR activation in breast milk samples between cases with cryptorchidism and controls. Among the 27 chemicals measured in breast milk, AhR activity was (borderline) significantly associated with all dl-PCBs, three non-dioxin-like (ndl)-PCBs (PCB-74, PCB-180, PCB-194) and two organochlorine pesticides (OCPs; HCB, β-HCH). No associations between AhR activity and brominated flame retardants (PBDEs) or poly- and perfluoroalkyl substances (PFASs).

CONCLUSION

No association between AhR activity and cryptorchidism was found among Norwegian boys. The average EDI of dioxin and dl-compounds in exclusively breastfed Norwegian infants remains above the safety threshold and, therefore requires further reduction measures. Consistent with a possible role in the observed AhR activity, all dl-PCBs were associated with AhR activity whereas the association was null for either PBDEs or PFASs.

Family Educational Attainment and Racial Disparities in Low Birth Weight

OBJECTIVES

To evaluate the effect of grandmother and mother educational attainment on low birth weight (LBW) in children and grandchildren.

METHODS

The National Longitudinal Study of Adolescent to Adult Health is a multigenerational study that collected survey data from 1994 to 2018. Using this database, we constructed a cohort of 2867 non-Hispanic Black (NHB) and non-Hispanic White (NHW) grandmother-mother-grandchild triads to evaluate how education affects the likelihood of having LBW children and grandchildren, while adjusting for socioeconomic and maternal health factors using multivariable logistic regression.

RESULTS

Similar to previous studies, NHB women were more likely to have LBW descendants compared with NHW women in unadjusted and adjusted analyses. The prevalence of LBW descendants was lower in women with college education, regardless of race. Irrespective of race, mother and grandmother college education was associated with decreased odds of LBW children and grandchildren after adjusting for individual variables. When mother and grandmother education were examined together, and after adjusting for all individual, community, and health variables together, mother college education remained associated with lower odds of LBW (adjusted odds ratio, 0.58; 95% confidence interval, 0.44-0.77). There were no statistically significant differences in these effects between NHW and NHB populations.

CONCLUSIONS

Educational attainment in mothers is associated with decreased odds of LBW descendants after adjusting for multiple individual, community, and health covariates, regardless of race. Targeting improvements in education may ameliorate adverse pregnancy outcomes that disproportionately affect minority communities and cause significant lifelong consequences.

Cohort profile: the multigeneration Respiratory Health in Northern Europe, Spain and Australia (RHINESSA) cohort

PURPOSE

The Respiratory Health in Northern Europe, Spain and Australia (RHINESSA) cohort was established to (1) investigate how exposures before conception and in previous generations influence health and disease, particularly allergies and respiratory health, (2) identify susceptible time windows and (3) explore underlying mechanisms. The ultimate aim is to facilitate efficient intervention strategies targeting multiple generations.

PARTICIPANTS

RHINESSA includes study participants of multiple generations from ten study centres in Norway (1), Denmark (1), Sweden (3), Iceland (1), Estonia (1), Spain (2) and Australia (1). The RHINESSA core cohort, adult offspring generation 3 (G3), was first investigated in 2014-17 in a questionnaire study (N=8818, age 18-53 years) and a clinical study (subsample, n=1405). Their G2 parents participated in the population-based cohorts, European Community Respiratory Heath Survey and Respiratory Health In Northern Europe, followed since the early 1990s when they were 20-44 years old, at 8-10 years intervals. Study protocols are harmonised across generations.

FINDINGS TO DATE

Collected data include spirometry, skin prick tests, exhaled nitric oxide, anthropometrics, bioimpedance, blood pressure; questionnaire/interview data on respiratory/general/reproductive health, indoor/outdoor environment, smoking, occupation, general characteristics and lifestyle; biobanked blood, urine, gingival fluid, skin swabs; measured specific and total IgE, DNA methylation, sex hormones and oral microbiome. Research results suggest that parental environment years before conception, in particular, father's exposures such as smoking and overweight, may be of key importance for asthma and lung function, and that there is an important susceptibility window in male prepuberty. Statistical analyses developed to approach causal inference suggest that these associations may be causal. DNA methylation studies suggest a mechanism for transfer of father's exposures to offspring health and disease through impact on offspring DNA methylation.

FUTURE PLANS

Follow-up is planned at 5-8 years intervals, first in 2021-2023. Linkage with health registries contributes to follow-up of the cohort.

Validation of birth certificate and maternal recall of events in labor and delivery with medical records in the Iowa health in pregnancy study

Background

Epidemiological research of events related to labor and delivery frequently uses maternal interview or birth certificates as a primary method of data collection; however, the validity of these data are rarely confirmed. This study aimed to examine the validity of birth certificate data and maternal interview of maternal demographics and events related to labor and delivery with data abstracted from medical records in a US setting.

Methods

Birth certificate and maternal recall data from the Iowa Health in Pregnancy Study (IHIPS), a population-based case-control study of risk factors for preterm and small-for-gestational age births, were linked to medical record data to assess the validity of events that occurred during labor and delivery along with reported maternal demographics. Sensitivity, specificity, positive and negative predictive values, and kappa scores were calculated.

Results

Postpartum maternal recall and birth certificate data were excellent for infant characteristics (birth weight, gestational age, infant sex) and variables related to labor and delivery (mode of delivery) when compared with medical records. Birth certificate data for labor induction had low sensitivity (46.3%) and positive predictive value (18.3%) compared to medical records. Compared to maternal interview, birth certificate data also had poor agreement for smoking and alcohol use during pregnancy. Agreement between all three methods of data collection was very low for pregnancy weight gain (kappa = 0.07-0.08).

Conclusions

Maternal interview and birth certificate data can be a valid source for collecting data on infant characteristics and events that occurred during labor and delivery. However, caution should be used if solely using birth certificate data to gather data on maternal demographic and/or lifestyle factors.

Anti-androgenic compounds in breast milk and cryptorchidism among Norwegian boys in the HUMIS birth cohort

The prevalence of cryptorchidism has increased over the past decades, yet its origins remain poorly understood. Testis descent is dependent on androgens and likely affected by endocrine disrupting compounds (EDCs), targeting the androgen receptor (AR). We investigated the association between anti-androgenic activity, not derived from natural hormones, in maternal breast milk and impaired testis descent among boys. We performed a case-control study based on 199 breast milk samples from 94 mothers of cryptorchid boys and 105 random non-cryptorchid boys participating in the Norwegian HUMIS (Human Milk Study) cohort. For each participant, apolar, and polar fractions were extracted, and combined to reconstitute a mixture. Anti-androgenic activity was measured in all three fractions using the human cell-based in vitro anti-AR CALUX® assay and expressed in μg of flutamide equivalent, a well-known antiandrogen. Results from fraction analyses were compared among boys with cryptorchidism and controls using multiple logistic regression, controlling for appropriate confounders identified using a directed acyclic graph. Children's daily exposure to anti-androgenic EDCs through breastfeeding was estimated to 78 μg flutamide eq./kg of body weigh/day. The activity was higher in the polar fraction (1.48 ± 1.37 μg flutamide eq./g of milk) mainly representing non-persistent chemicals, in contrast to other fractions. However, the activity in the polar extracts was decreased when in mixtures with the apolar fraction, indicating synergistic interactions. No significant difference in the activity was observed according to cryptorchid status for polar, apolar or mixed breast milk fractions. The study showed anti-androgenic activity in nearly all human milk samples, and at levels higher than the advisory threshold. However, no significant association was observed between cryptorchidism and antiandrogenic activity measured in either polar, apolar, or mixture fractions derived from breast milk.

A case-cohort study of perinatal exposure to potential endocrine disrupters and the risk of cryptorchidism in the Norwegian HUMIS study

BACKGROUND

Exposure to endocrine-disrupting chemicals (EDCs) during the critical period of testicular descent may increase the risk of cryptorchidism and male fertility.

OBJECTIVE

To investigate 27 potential EDCs measured in breast milk as a proxy for perinatal exposure and the risk of cryptorchidism in a prospective cohort.

METHOD

The Norwegian Human Milk Study (2002-2009) enrolled 2606 mother-infant pairs, of which 1326 were mother-son pairs. In a case-cohort design, we studied 641 male infants who had 27 EDCs already quantified in milk samples: 5 organochlorine pesticides, 14 polychlorinated biphenyls (PCBs), 6 brominated flame retardants, and 2 poly- and perfluoroalkyl substances. We defined cases of congenital, recurrent, persistent and ever-reported cryptorchidism based on questionnaires mothers completed when children were 1, 6, 12 and 24 months old. Variable selection via elastic net logistic regression identified the best cryptorchidism predictors while multivariable logistic regression models determined their effect estimates.

RESULTS

The prevalence of reported congenital cryptorchidism was 6.1%, with half spontaneously descending within six months of birth, after which prevalence stabilized between 2.2 and 2.4%. The ever-reported prevalence of cryptorchidism at 1, 6, 12, or 24 months was 12.2%. Elastic net models identified PCB-74 (OR = 1.31, 95% CI: 1.001-1.703), PCB-114 (OR = 1.36, 95% CI: 1.05-1.77), PCB-194 (OR = 1.28, 95% CI: 1.03-1.53) and β-HCH (OR = 1.26, 95% CI: 1.03-1.53 (per interquartile range increase in concentration of EDCs) as best predictors of congenital cryptorchidism. No EDCs were selected for either recurrent or persistent cryptorchidism, and only PCB-194 was selected by elastic net for ever-reported cryptorchidism (OR = 1.23, 95% CI: 1.01-1.51), in contrast to unpenalized multivariable logistic regression, where most of the individual congeners of PCBs showed significant associations.

CONCLUSION

In the largest multi-pollutant analysis to date considering potential confounding from co-exposure to other chemicals, perinatal exposure to PCB-74, PCB-114, PCB-194 and β-HCH were associated with increased odds of congenital cryptorchidism. Many PCBs may falsely be associated with cryptorchidism when assessed individually, due to confounding by highly correlated chemicals. Experimental studies are warranted to confirm our findings.

The German Multiple Sclerosis and Pregnancy Registry: rationale, objective, design, and first results

Objectives:

Multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD) predominantly affect women of reproductive age. During the last few decades many disease-modifying therapies (DMTs) have been approved. It is therefore important to provide epidemiological structures for the collection of safety information on exposed pregnancies. Data on disease activity after withdrawal of DMTs are in high demand especially as severe relapses have been described after ceasing highly effective DMTs. Although breastfeeding is recommended, it is still unclear if the early reintroduction, especially of highly effective DMTs, has a beneficial effect on postpartum relapse risk or a combination of both, however safety data are lacking.

Methods:

The German MS and Pregnancy Registry (DMSKW) is a nationwide, observational, cohort study of pregnant women with MS or NMOSD, founded in 2006. As the study procedure has undergone important adaptation in recent years, described here is the updated methodology including data source and acquisition as well as variables collected within the DMSKW.

Results:

As of December 2020, the DMSKW database comprises 2579 pregnancies, 2568 with MS and 11 with NMOSD. Women are enrolled at a median gestational week of 11 (range: 0.02–42.1), have a median postpartum follow up of 1.2 years (range: 0–9.2) with 76% of all pregnancies being exposed to a DMT, mostly in the first trimester. Spontaneous abortion and preterm birth occurred in 7% and 10%, respectively; 19% of all women suffered from at least one relapse during pregnancy, with a minimum of 6% during the third trimester of pregnancy.

Conclusion:

The DMSKW is a valuable structure in providing safety data on drug exposure during pregnancy and lactation in combination with information on disease activity up to 6 years postpartum. This article will be the reference for describing the methods of future publications from the DMSKW.

Exposures during the prepuberty period and future offspring's health: evidence from human cohort studies†

Emerging evidence suggests that exposures in prepuberty, particularly in fathers-to-be, may impact the phenotype of future offspring. Analyses of the RHINESSA cohort find that offspring of father’s exposed to tobacco smoking or overweight that started in prepuberty demonstrate poorer respiratory health in terms of more asthma and lower lung function. A role of prepuberty onset smoking for offspring fat mass is suggested in the RHINESSA and ALSPAC cohorts, and historic studies suggest that ancestral nutrition during prepuberty plays a role for grand-offspring’s health and morbidity. Support for causal relationships between ancestral exposures and (grand-)offspring’s health in humans has been enhanced by advancements in statistical analyses that optimize the gain while accounting for the many complexities and deficiencies in human multigeneration data. The biological mechanisms underlying such observations have been explored in experimental models. A role of sperm small RNA in the transmission of paternal exposures to offspring phenotypes has been established, and chemical exposures and overweight have been shown to influence epigenetic programming in germ cells. For example, exposure of adolescent male mice to smoking led to differences in offspring weight and alterations in small RNAs in the spermatozoa of the exposed fathers. It is plausible that male prepuberty may be a time window of particular susceptibility, given the extensive epigenetic reprogramming taking place in the spermatocyte precursors at this age. In conclusion, epidemiological studies in humans, mechanistic research, and biological plausibility, all support the notion that exposures in the prepuberty of males may influence the phenotype of future offspring.

Changes in maternal risk factors and their association with changes in cesarean sections in Norway between 1999 and 2016: A descriptive population-based registry study

BACKGROUND

Increases in the proportion of the population with increased likelihood of cesarean section (CS) have been postulated as a driving force behind the rise in CS rates worldwide. The aim of the study was to assess if changes in selected maternal risk factors for CS are associated with changes in CS births from 1999 to 2016 in Norway.

METHODS AND FINDINGS

This national population-based registry study utilizes data from 1,055,006 births registered in the Norwegian Medical Birth Registry from 1999 to 2016. The following maternal risk factors for CS were included: nulliparous/≥35 years, multiparous/≥35 years, pregestational diabetes, gestational diabetes, hypertensive disorders, previous CS, assisted reproductive technology, and multiple births. The proportion of CS births in 1999 was used to predict the number of CS births in 2016. The observed and predicted numbers of CS births were compared to determine the number of excess CS births, before and after considering the selected risk factors, for all births, and for births stratified by 0, 1, or >1 of the selected risk factors. The proportion of CS births increased from 12.9% to 16.1% (+24.8%) during the study period. The proportion of births with 1 selected risk factor increased from 21.3% to 26.3% (+23.5%), while the proportion with >1 risk factor increased from 4.5% to 8.8% (+95.6%). Stratification by the presence of selected risk factors reduced the number of excess CS births observed in 2016 compared to 1999 by 67.9%. Study limitations include lack of access to other important maternal risk factors and only comparing the first and the last year of the study period.

CONCLUSIONS

In this study, we observed that after an initial increase, proportions of CS births remained stable from 2005 to 2016. Instead, both the size of the risk population and the mean number of risk factors per birth continued to increase. We observed a possible association between the increase in size of risk population and the additional CS births observed in 2016 compared to 1999. The increase in size of risk population and the stable CS rate from 2005 and onward may indicate consistent adherence to obstetric evidence-based practice in Norway.

Psychosocial and peripartum determinants of postpartum depression: Findings from a prospective population-based cohort. The ABCD study

BACKGROUND

Postpartum depression is prevalent and concerns a serious health problem for women and their families. The current large-scale birth cohort study investigated: (1) the associations of various potential determinants of postpartum depression using a multidimensional approach, and (2) the individual contribution of obstetric and perinatal determinants and pregnancy-specific anxiety to the risk of postpartum depression.

METHODS

This study was based on a large-scale birth cohort study in Amsterdam, the Netherlands (ABCD-study). In 5109 women depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale (cut-off ≥16 indicating high risk of postpartum depression). Determinants were assessed using self-report or perinatal registries.

RESULTS

In the final multivariable model, other-Western and non-Western ethnic background, increased antepartum depressive symptoms, increased antepartum anxiety, increased pregnancy-specific anxiety, being unemployed, poor sleep quality, unwanted pregnancy, abuse, multiparity, and congenital abnormality were all independently related to an increased risk of postpartum depression. The strongest risk factors for postpartum depression were antepartum depressive symptoms (adjusted odds ratio (AOR) = 3.86, 95% confidence interval (CI) 3.02-4.92), having a baby with a congenital abnormality (AOR = 2.33, 95% CI 1.46-3.73), and abuse (AOR = 1.95, 95% CI 1.02-3.73). The final model accounted for 24.5% of the variance.

LIMITATIONS

Our dataset did not provide information on social support or maternal and family history of depression. Next to these determinants, future research should include biological factors.

CONCLUSIONS

The determinants identified provide opportunities for the development of multidimensional early screening and early intervention strategies for women with an increased risk of postpartum depression.

Rates of Neuropsychiatric Disorders and Gestational Age at Birth in a Danish Population

IMPORTANCE

Nonoptimal gestational durations could be associated with neurodevelopmental disabilities, yet evidence regarding finer classification of gestational age and rates of multiple major neuropsychiatric disorders beyond childhood is limited.

OBJECTIVE

To comprehensively evaluate associations between 6 gestational age groups and rates of 9 major types and 8 subtypes of childhood and adult-onset neuropsychiatric disorders.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study evaluated data from a nationwide register of singleton births in Denmark from January 1, 1978, to December 31, 2016. Data analyses were conducted from October 1, 2019, through November 15, 2020.

EXPOSURES

Gestational age subgroups were classified according to data from the Danish Medical Birth Register: very preterm (20-31 completed weeks), moderately preterm (32-33 completed weeks), late preterm (34-36 completed weeks), early term (37-38 completed weeks), term (39-40 completed weeks, reference), and late or postterm (41-45 completed weeks).

MAIN OUTCOMES AND MEASURES

Neuropsychiatric diagnostic records (International Statistical Classification of Diseases and Related Health Problems, Tenth Revision codes F00-F99) were ascertained from the Danish Psychiatric Central Register up to August 10, 2017. Poisson regression was used to estimate the incidence rate ratio (IRR) and 95% CI for neuropsychiatric disorders, adjusting for selected sociodemographic factors.

RESULTS

Of all 2 327 639 singleton births studied (1 194 925 male newborns [51.3%]), 22 647 (1.0%) were born very preterm, 19 801 (0.9%) were born moderately preterm, 99 488 (4.3%) were born late preterm, 388 416 (16.7%) were born early term, 1 198 605 (51.5%) were born at term, and 598 682 (25.7%) were born late or postterm. A gradient of decreasing IRRs was found from very preterm to late preterm for having any or each of the 9 neuropsychiatric disorders (eg, very preterm: IRR, 1.49 [95% CI, 1.43-1.55]; moderately preterm: IRR, 1.23 [95% CI, 1.18-1.28]; late preterm: IRR, 1.17 [95% CI, 1.14-1.19] for any disorders) compared with term births. Individuals born early term had 7% higher rates (IRR, 1.07 [95% CI, 1.06-1.08]) for any neuropsychiatric diagnosis and a 31% higher rate for intellectual disability (IRR, 1.31 [95% CI, 1.25-1.37]) compared with those born at term. The late or postterm group had lower IRRs for most disorders, except pervasive developmental disorders, for which the rate was higher for postterm births compared with term births (IRR, 1.06 [95% CI, 1.03-1.09]).

CONCLUSIONS AND RELEVANCE

Higher incidences of all major neuropsychiatric disorders were observed across the spectrum of preterm births. Early term and late or postterm births might not share a homogeneous low risk with individuals born at term. These findings suggest that interventions that address perinatal factors associated with nonoptimal gestation might reduce long-term neuropsychiatric risks in the population.

Pregnancies and Time to Pregnancy in Women With and Without a Previous Chlamydia trachomatis Infection

BACKGROUND

A Chlamydia trachomatis infection (chlamydia) can result in tubal factor infertility in women. To assess if this association results in fewer pregnant women, we aimed to assess pregnancy incidences and time to pregnancy among women with a previous chlamydia infection compared with women without one and who were participating in the Netherlands Chlamydia Cohort Study (NECCST).

METHODS

The NECCST is a cohort of women of reproductive age tested for chlamydia in a chlamydia screening trial between 2008 and 2011 and reinvited for NECCST in 2015 to 2016. Chlamydia status (positive/negative) was defined using chlamydia screening trial-nucleic acid amplification test results, chlamydia immunoglobulin G presence in serum, or self-reported chlamydia infections. Data on pregnancies were collected via questionnaires in 2015-2016 and 2017-2018. Overall pregnancies (i.e., planned and unplanned) and time to pregnancy (among women with a pregnancy intention) were compared between chlamydia-positive and chlamydia-negative women using Cox regressions.

RESULTS

Of 5704 women enrolled, 1717 (30.1%; 95% confidence interval [CI], 28.9-31.3) women was chlamydia positive. Overall pregnancy proportions were similar in chlamydia-positive and chlamydia-negative women (49.0% [95% CI, 46.5-51.4] versus 50.5% [95% CI, 48.9-52.0]). Pregnancies per 1000 person-years were 53.2 (95% CI, 51.5-55.0) for chlamydia negatives and 83.0 (95% CI, 78.5-87.9) for chlamydia positives. Among women with a pregnancy intention, 12% of chlamydia-positive women had a time to pregnancy of >12 months compared with 8% of chlamydia negatives (P < 0.01).

CONCLUSIONS

Overall pregnancy rates were not lower in chlamydia-positive women compared with chlamydia-negative women, but among women with a pregnancy intention, time to pregnancy was longer and pregnancy rates were lower in chlamydia-positive women.

TRIAL REGISTRATION NUMBER

Dutch Trial Register NTR-5597.

Caesarean section and the association with migraine: a retrospective register-linked HUNT population cohort study

OBJECTIVES

To evaluate the association between caesarean section and migraine in a population-based register-linked cohort study.

SETTING

Data from the population-based Nord-Trøndelag Health Studies (HUNT2 and HUNT3) were linked to information from the Norwegian Medical Birth Registry.

PARTICIPANTS

65 343 participants responded to the headache questions in any of the two HUNT studies. Only those answering the headache questions in HUNT2 or 3 and had information about mode of delivery in the Norwegian Medical Birth Registry (born after 1967) were included. Our final sample consisted of 6592 women and 4602 men, aged 19-41 years.

OUTCOMES

ORs for migraine given caesarean section. Analyses were performed in multivariate logistic regression models.

RESULTS

After adjusting for sex, age and fetal growth restriction, delivery by caesarean section was not associated with migraine later in life (OR 0.86, 95% CI 0.64 to 1.15). Delivery by caesarean section was associated with a reduced OR of non-migrainous headache (OR 0.77, 95% CI 0.60 to 0.99).

CONCLUSION

No association was found between caesarean section and migraine in this population-based register-linked study.

High birth weight and risk of multiple sclerosis: A multicentre study in Argentina

BACKGROUND

Multiple sclerosis (MS) is now recognized as a multifactorial disease in which genetic and environmental factors intervene. Considerable efforts have been made to identify external risk factors present in childhood, adolescence and youth, though only a few perinatal risk factors have been positively associated with MS. Previously, we found an association between high birth weight and MS in male patients in a small study in Argentina. The present research was designed to further assess the association between high birth weight and MS in a larger sample of patients, using an extensive and validated general population database as control.

METHODS

We present an analytical observational, multicentre, population-based, and case-control study. A total of 637 patients (cases) with confirmed MS diagnosis attending five MS specialized centres in Argentina were included. Birth weight (BW) data was recalled by the patient's mother, which is a validated approach. A two-way comparison was performed. First, we used the standard categories of high, adequate and low BW in grams. Then, we applied the weight percentile distribution to provide reproducible results for further research. For a proper assessment and comparison of variables, we adopted the guidelines of the American Academy of Pediatrics for neonate classification according to gestational weeks and to BW in grams. The neonate's BW distribution of the general population was used as control. For the purposes of the study, we adapted Urquía's et al. curves, which are based on an extensive database of all the live births registered in the country from 2003 to 2007. To measure the magnitude of the proportional differences between low, adequate and high BW, the odds ratio (OR) and their 95% confidence interval (CI) were estimated. The mean BW and percentile values for each sex were compared using a z-Normal test. The respective MS patients and general population BW distribution curves by sex were compared between each other.

RESULTS

Cases and controls were comparable in their demographic, geographic and environmental characteristics. Males showed higher BW than females both in the MS patients and the general population groups. When we applied the sex stratified analysis separately, we found that males in the MS group showed an almost seven times higher risk of high birth weight than males from the general population (OR 6.58 [95% CI 4.81-8.99]). Female patients showed an almost five times higher risk of high BW than their respective controls (OR 4.5 [95% CI 3.06-6.58]). The comparison based on the BW percentile distribution confirmed that MS patients showed higher BW than the general population. This result reached statistical significance from the 75^th percentile onwards for both sexes.

CONCLUSION

In summary, our findings suggested that high BW could be one of the earliest risk factors for MS in life. If this results were reproduced in other centres, high birth weight would emerge as a novel and very early risk factor, potentially modifiable in utero or immediately postpartum, representing a unique opportunity to prevent the disease in future generations.

Childbirth outcomes and ethnic disparities in Suriname: a nationwide registry-based study in a middle-income country

Background

Our study aims to evaluate the current perinatal registry, analyze national childbirth outcomes and study ethnic disparities in middle-income country Suriname, South America.

Methods

A nationwide birth registry study was conducted in Suriname. Data were collected for 2016 and 2017 from the childbirth books of all five hospital maternity wards, covering 86% of all births in the country. Multinomial regression analyses were used to assess ethnic disparities in outcomes of maternal deaths, stillbirths, teenage pregnancy, cesarean delivery, low birth weight and preterm birth with Hindustani women as reference group.

Results

18.290 women gave birth to 18.118 (98%) live born children in the five hospitals. Hospital-based maternal mortality ratio was 112 per 100.000 live births. Hospital-based late stillbirth rate was 16 per 1000 births. Stillbirth rate was highest among Maroon (African-descendent) women (25 per 1000 births, aOR 2.0 (95%CI 1.3–2.8) and lowest among Javanese women (6 stillbirths per 1000 births, aOR 0.5, 95%CI 0.2–1.2). Preterm birth and low birthweight occurred in 14 and 15% of all births. Teenage pregnancy accounted for 14% of all births and was higher in Maroon women (18%) compared to Hindustani women (10%, aOR 2.1, 95%CI 1.8–2.4). The national cesarean section rate was 24% and was lower in Maroon (17%) than in Hindustani (32%) women (aOR 0.5 (95%CI 0.5–0.6)). Cesarean section rates varied between the hospitals from 17 to 36%.

Conclusion

This is the first nationwide comprehensive overview of maternal and perinatal health in a middle income country. Disaggregated perinatal health data in Suriname shows substantial inequities in outcomes by ethnicity which need to be targetted by health professionals, researchers and policy makers.

Maternal and Infant Anthropometric Characteristics and Breast Cancer Incidence in the Daughter

The intrauterine and early life environments have been linked to the etiology of breast cancer in prior studies. We prospectively examined whether maternal and newborn anthropometric factors as reported by the mother are related to an increased incidence of adult breast cancer in the daughter. We used data from 35,133 mother-daughter dyads of the Nurses’ Health Study (NHS) II and the Nurses’ Mothers’ Cohort Study. In 2001, living mothers of NHS II participants who were free of cancer completed a questionnaire on their pregnancy with the nurse and their nurse daughter’s early life experience. During 403,786 years of follow-up, 865 daughters developed incident cases of invasive breast cancer. Nurses with a birthweight of ≥4000 g had a 32% greater risk for breast cancer (multivariable-adjusted hazard ratio (HR) = 1.32, 95% confidence interval (CI) = 1.02–1.71, p-trend = 0.09) compared with those with birthweights of 3000–3499 g. Higher birth length tended to increase risk of premenopausal breast cancer (p for trend = 0.05). We further noted a modest U-shaped relation between maternal weight gain during pregnancy and premenopausal breast cancer incidence in the daughter. Fetal growth may contribute to shaping later life risk for breast cancer, especially prior to menopause.

Altered cortical structure and psychiatric symptom risk in adolescents exposed to maternal stress in utero: A retrospective investigation

Maternal exposure to stress during pregnancy is associated with increased risk for cognitive and behavioral sequelae in offspring. Animal research demonstrates exposure to stress during gestation has effects on brain structure. In humans, however, little is known about the enduring effects of in utero exposure to maternal stress on brain morphology. We examine whether maternal report of stressful events during pregnancy is associated with brain structure and behavior in adolescents. We compare gray matter morphometry of typically-developing early adolescents (11-14 years of age, mean 12.7) at a single timepoint, based on presence/absence of retrospectively-assessed maternal report of negative major life event stress (MLES) during pregnancy: prenatal stress (PS; n = 28), comparison group (CG; n = 55). The Drug Use Screening Inventory Revised (DUSI-R) assessed adolescent risk for problematic behaviors. Exclusionary criteria included pre-term birth, low birth weight, and maternal substance use during pregnancy. Groups were equivalent for demographic (age, sex, IQ, SES, race/ethnicity), and birth measures (weight, length). Compared to CG peers, adolescents in the PS group exhibited increased gray matter density in bilateral posterior parietal cortex (PPC): bilateral intraparietal sulcus, left superior parietal lobule and inferior parietal lobule. Additionally, the PS group displayed greater risk for psychiatric symptoms and family system dysfunction, as assessed via DUSI-R subscales. These preliminary findings suggest that prenatal exposure to maternal MLES may exact enduring associations on offspring brain morphology and psychiatric risk, highlighting the importance of capturing these data in prospective longitudinal research studies (beginning at birth) to elucidate these associations.

Being overweight in childhood, puberty, or early adulthood: Changing asthma risk in the next generation?

BACKGROUND

Overweight status and asthma have increased during the last decades. Being overweight is a known risk factor for asthma, but it is not known whether it might also increase asthma risk in the next generation.

OBJECTIVE

We aimed to examine whether parents being overweight in childhood, adolescence, or adulthood is associated with asthma in their offspring.

METHODS

We included 6347 adult offspring (age, 18-52 years) investigated in the Respiratory Health in Northern Europe, Spain and Australia (RHINESSA) multigeneration study of 2044 fathers and 2549 mothers (age, 37-66 years) investigated in the European Community Respiratory Health Survey (ECRHS) study. Associations of parental overweight status at age 8 years, puberty, and age 30 years with offspring's childhood overweight status (potential mediator) and offspring's asthma with or without nasal allergies (outcomes) was analyzed by using 2-level logistic regression and 2-level multinomial logistic regression, respectively. Counterfactual-based mediation analysis was performed to establish whether observed associations were direct or indirect effects mediated through the offspring's own overweight status.

RESULTS

We found statistically significant associations between both fathers' and mothers' childhood overweight status and offspring's childhood overweight status (odds ratio, 2.23 [95% CI, 1.45-3.42] and 2.45 [95% CI, 1.86-3.22], respectively). We also found a statistically significant effect of fathers' onset of being overweight in puberty on offspring's asthma without nasal allergies (relative risk ratio, 2.31 [95% CI, 1.23-4.33]). This effect was direct and not mediated through the offspring's own overweight status. No effect on offspring's asthma with nasal allergies was found.

CONCLUSION

Our findings suggest that metabolic factors long before conception can increase asthma risk and that male puberty is a time window of particular importance for offspring's health.

Prevalence of cerebral palsy, intellectual disability, hearing loss, and blindness, National Health Interview Survey, 2009-2016

BACKGROUND

Developmental disabilities are present in a significant proportion of US children. Surveillance of developmental disabilities is crucial for monitoring population trends, guiding research into risk factors, and informing resource allocation.

OBJECTIVE/HYPOTHESIS

We examined overall prevalence, prevalence by demographic characteristics, and trends over time for cerebral palsy (CP), intellectual disability (ID), moderate to severe hearing loss (MSHL), and blindness.

METHODS

Data from the 2009-2016 National Health Interview Survey (NHIS) were analyzed for children 3-17 years of age. Question wording was consistent over time except for ID, which changed in 2011 to replace the term "mental retardation." Demographic differences and linear trends (over three time periods) were assessed by Chi-square tests and Wald-F tests.

RESULTS

Prevalence estimates per 1000 children ages 3-17 years for CP, ID, MSHL, and blindness were 3.2 (95% CI: 2.7, 3.7), 11.1 (95% CI: 10.2, 12.1), 6.4 (95% CI: 5.6, 7.2), and 1.6 (95% CI: 1.3, 2.0), respectively. Disability prevalence was higher for children with low birthweight and from families of lower parental education, income ≤200% of federal poverty level, and public insurance. Older children had higher ID prevalence; boys had significantly higher CP and ID prevalences. Only ID demonstrated a significantly increased trend over time (p = 0.0002).

CONCLUSIONS

We provide nationally representative prevalence estimates for four developmental disabilities; recent estimates are comparable to those from records-based studies. Prevalences were stable except for ID, which increased after 2010, coincident with the questionnaire change. A substantial number of US children continue to have these disabilities and service needs.