Medical Birth Registry Of Norway Research Articles

Use of specialist health care among Norwegian-born children with one immigrant parent

Abstract Background An increasing number of children grow up with one immigrant and one native born parent. We know little about health in this group. Our aim was to compare the risk of receiving diagnoses of physical health conditions in specialist health care among Norwegian-born children with one immigrant parent compared to Norwegian background children. Methods Data from Medical Birth Registry of Norway were linked to data from the Norwegian Patient Registry (diagnoses in specialist health care), and Statistics Norway (parental country of origin, education, and household income). We estimated hazard ratios (HR) with Cox proportional hazard regressions, with Norwegian background children as reference category, adjusted for sex, birth year, parental education, and household income. Results Children with an immigrant parent had lower hazards than Norwegian background children of diagnoses of most types of infections, but higher hazards of some, including tuberculosis, and skin infections. They also had higher hazards than Norwegian background children of receiving diagnoses of obesity and other nutritional deficiencies, and skin diseases, but lower hazards for other conditions, including chronic lower respiratory disease, disease of the digestive system, and visual or hearing impairment. The hazards of diagnoses of any neurological condition, sleeping disorders and epilepsy were lower among children with an immigrant mother, but higher among those with an immigrant father. Differences between children with one immigrant parent and Norwegian background could not be explained by differences in parental education or household income. Conclusions Children of one immigrant parent do not overall use specialist health care for physical health issues more than other children. Key messages • Awareness of diagnoses given most frequently to children of one immigrant parent can help promote timely diagnoses and adequate use of services, which is important for prevention of later illness. • Barriers to health care use among children of immigrants should be further researched.

Diagnoses of mental health disorders among Norwegian youth and young adults with immigrant parents

Abstract Introduction Adolescence and early adulthood are associated with an increase in mental health problems. Migration is also a risk factor for mental disorders. Yet, there is a notable gap in research concerning the mental well-being of descendants of immigrants. This study investigates the risk of a diagnosis of a mental health disorder among those aged 16-30 years, born in Norway with at least one immigrant parent. Methods Data were sourced from the Medical Birth Registry of Norway, the Norwegian Patient Register, and Statistics Norway. Cox proportional hazard regressions were used to estimate hazard ratios (HR) of being diagnosed with different mental disorders, in total and by parental region of origin, compared to individuals of Norwegian background. Analyses were adjusted for sex, year of birth, and parental education. Results Individuals with two immigrant parents had a lower risk of most mental disorder diagnoses, while those of one immigrant parent had a higher risk. With the exception of schizophrenia, individuals with two immigrant parents had a lower risk of most mental disorder diagnoses compared to those with Norwegian-born parents. The HR for the risk of a diagnosis of anxiety for those with two immigrant parents was: 0.79 [95% CI 0.76 - 0.81], with immigrant mother: 1.07 [95% CI 1.04-1.10], with immigrant father: 1.28 [95% CI 1.24 -1.30]. Similarly, for depression, two immigrant parents: 0.85 [95% CI 0.82-0.88], immigrant mother: 1.13 [95% CI 1.09 - 1.17], immigrant father: 1.31 (95% CI 1.28-1.37). Bipolar disorders, two immigrant parents: 0.67 [95% CI 0.60-0.76], immigrant mother: 1.19 [95% CI 1.07 - 1.31], immigrant father: 1.47 [95% CI 1.35-1.61]. The pattern was relatively consistent across parental regions of origin. Conclusions Those with one immigrant parent are more likely to use specialist mental health services, while those with two immigrant parents are not. These need special attention in adulthood. Key messages • Differences in risk of diagnosis for mental disorders could be due to differences in the utilization of mental health services. • Early prevention of mental health issues seems to be especially important among children and youth raised in families with one immigrant parent.

Associations between term cesarean delivery in the first pregnancy and second-pregnancy preterm delivery.

Cesarean delivery has been shown to increase the risk of preterm delivery in future pregnancies. The association could be a direct result of the procedure, or because the indications that led to the cesarean delivery also increase the risk of preterm delivery in later pregnancies. 298 901 mothers with first and second singleton deliveries from 1999 to 2020 were investigated using data from the Medical Birth Registry of Norway linked with Statistics Norway. The mothers were categorized by mode of cesarean delivery (total, emergency and planned) and vaginal delivery at term in the first pregnancy. We used log-binomial regression models to estimate relative risks with 95% confidence intervals (CI) of iatrogenic and spontaneous preterm delivery <37 gestational weeks in the second pregnancy. Second, we explored the role of recurrent placental disease in preterm delivery by comparing estimates in mothers with placental disease in neither or both pregnancies. 8243 mothers (2.8%) had a preterm delivery in the second pregnancy. The adjusted relative risk (aRR) of preterm delivery was 1.24 (95% CI 1.17-1.32) after cesarean compared with vaginal delivery in the first pregnancy. The association was stronger in previous planned compared with emergency cesarean delivery (aRR 1.52, 95% CI 1.30-1.77 and aRR 1.21, 95% CI 1.14-1.29, respectively). Spontaneous preterm delivery was not associated with the previous mode of delivery; the risk was confined to iatrogenic preterm delivery after both emergency and planned cesarean delivery (aRR 1.69, 95% CI 1.52-1.87 and aRR 2.65, 95% CI 2.12-3.30, respectively). Mothers with placental disease in both pregnancies had a sixfold increased risk of preterm delivery in the second pregnancy compared with mothers with no placental disease, however, the association between mode of delivery and subsequent preterm delivery was similar in mothers with and without placental disease in the pregnancies. Compared with vaginal term delivery in the first pregnancy, cesarean delivery increases the risk of iatrogenic, but not spontaneous preterm delivery in the next pregnancy. Although strongly associated with preterm delivery, placental disease had limited influence on the estimates.

Validity of self-reported number of pregnancies and maternal age at first birth among females attending organized mammographic screening.

Reproductive history conveys information about potential health risks later in adulthood. This study aimed to examine the validity of self-reported number of pregnancies and maternal age at first birth (AFB) among females attending BreastScreen Norway. Participants were identified through the Janus Serum Bank cohort in Norway and were eligible for this cross-sectional validation study if they participated in a health survey issued by BreastScreen Norway between 2006 and 2015. Retrospective self-reported survey information on number of pregnancies and AFB in years was validated against prospectively collected information from the Medical Birth Registry of Norway (MBRN) using the Spearman rank (rs) and intraclass correlation coefficients (ICC) with 95% confidence intervals (CI). After exclusions, 51,598 subjects were included in the analysis on number of pregnancies and 46,919 in the analysis on AFB. On average, study subjects were 59-60 years old when completing the health survey and had become first-time mothers roughly 36 years earlier. Survey-based information about number of pregnancies was highly correlated and demonstrated high agreement with the registry data (rs=0.967, 95% CI 0.964-0.969; ICC=0.884, 95% CI 0.882-0.885). Survey-based information about AFB demonstrated even higher correlation and very high agreement with the registry data (rs=0.975, 95% CI 0.973-0.976; ICC=0.974, 95% CI 0.974-0.975). Retrospectively recalled survey-based information about number of pregnancies and AFB was highly accurate when validated against prospectively collected information in the MBRN. These survey-based data are valuable for future epidemiological research, and linkage to the MBRN may not be required when these data are available.

Organic food consumption during pregnancy and symptoms of neurodevelopmental disorders at 8 years of age in the offspring: the Norwegian Mother, Father and Child Cohort Study (MoBa)

BackgroundPartially driven by public concerns about modern food production practices, organic food has gained popularity among consumers. However, the impact of organic food consumption during pregnancy on offspring health is scarcely studied. We aimed to investigate the association between maternal intake of organic food during pregnancy and symptoms of attention deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) in offspring at 8 years of age.MethodsThis study was based on the Norwegian Mother, Father and Child Cohort Study (MoBa) and the Medical Birth Registry of Norway (MBRN). The total study sample included 40,707 mother–child pairs (children born 2002–2009). Organic food consumption during pregnancy was assessed by six questions from a food frequency questionnaire in mid-pregnancy (sum score 0–18). Symptoms of ADHD and ASD in the offspring aged 8 years were measured by ADHD (0–54) and ASD (0–39) symptom scores based on the Parent/Teacher Rating Scale for Disruptive Behaviour disorders and the Social Communication Questionnaire. Associations between maternal intake of organic food during pregnancy and symptoms of ADHD and ASD in the offspring were analyzed using regression models with adjustment for covariates such as maternal anxiety and depression, including sibling analysis.ResultsMean ADHD and ASD symptom scores in the offspring differed only slightly by maternal intake of organic food. The covariate-adjusted unstandardized regression coefficient (adjusted(Adj)beta) with 95% confidence interval for the ADHD symptom score with one unit increase in organic food sum score was 0.03 (0.01, 0.05). Similarly, Adjbeta for autism symptom score was 0.07 (0.04, 0.10). For ADHD, the adjusted estimates weakened when adjusting for maternal symptoms of ADHD. The sibling analyses showed no significant results with Adjbeta − 0.07 (− 0.15, 0.01) and − 0.001 (− 0.12, 0.12) for ADHD and ASD outcomes, respectively.ConclusionsWe observed weak positive associations between frequent maternal organic food consumption during pregnancy and offspring ADHD and ASD symptom levels at 8 years of age. This trend weakened or disappeared after adjusting for maternal symptoms of ADHD, and in sibling analyses, suggesting that the associations mainly reflect genetic confounding. Our study indicates that consumption of organic food during pregnancy should neither be considered a risk factor nor protective against symptoms of ADHD and ASD in offspring.

Daily snuff use during pregnancy, gestational length and birth weight; register-based study

BackgroundSnuff is a smokeless source of nicotine that is common in Scandinavia and increasingly used by women of fertile age. Persistent use of snuff during pregnancy has been associated with adverse pregnancy outcomes. Emerging data from the Medical Birth Registry of Norway distinguishes between occasional use and daily use. We provide preliminary estimates of associations between frequency of snuff and gestational length and birth weight.MethodsData on snuff use during pregnancies delivered in 2020 and 2021 were available for the west and central regions of Norway. Associations of snuff use with gestational length and birth weight at term (39–41 weeks) were estimated using quantile regression at the 25th, the 50th and the 75th percentiles, with adjustments for mother’s age, pre-pregnancy weight, and parity. We compared associations with the pregnancy outcomes according to maternal snuff and cigarette use.Results12.4% of 18 042 non-smoking women reported daily use of snuff before pregnancy, and 4.6% reported continuing use during pregnancy, with 1.2% still reporting daily use in the last trimester. Women with daily use through the last trimester delivered babies with a median gestational length reduced by 3.4 days (95% CI: -5.0 to -1.7 days) compared with women who never used snuff. The reduction was even stronger at the 25th percentile of gestational age. The median term birth weight was reduced by 44 g (95% CI: -134 to 46 g). These associations were much weaker for women who quit snuff at some point during pregnancy or used snuff only occasionally. Mothers who smoked daily through the last trimester had a median gestational length reduced by 2.1 days (95% CI: -2.7 to -1.4) and a median term birth weight reduced by 294 g (95% CI: -325 to -262) compared with never-smokers.ConclusionsDaily snuff use through the last trimester reduced the median gestational length by more than three days. Snuff reduced birth weight, but not as much as smoking, suggesting that the predominant effect of smoking on fetal growth is not through nicotine but through the additional toxic chemicals in cigarettes or by reduced oxygen supply to the fetus.

Feeding Method, Nicotine Exposure, and Growth during Infancy

ObjectiveTo answer three questions: 1) Are infants breastfed by smokers at risk of rapid weight and length gain? 2) Is rapid growth during infancy partially attributable to ingestion of smokers’ breastmilk? 3) If so, what are the implications for breastfeeding by smokers? Study DesignUsing data from the Norwegian Mother, Father and Child Cohort Study and Medical Birth Registry of Norway (N=54,522) we examined changes in weight, length, weight-for-length z-score (WFLZ) during infancy in the context of maternal smoking (0, 1-10, >10 cigarettes/day) and feeding method during the first 6 months (breastfed, formula-fed, mixed-fed). We fit generalized linear models, adding a smoking by feeding method interaction term to evaluate the effect of ingesting smokers’ breastmilk. ResultsBreastfed infants of both light and heavy smokers experienced WFLZ gains of 0.05 (95% CI: 0.01, 0.09), and 0.13(95% CI: 0.07, 0.18) respectively. Among mixed-fed infants, only heavy maternal smoking predicted WFLZ gain (0.10; 95% CI: 0.05, 0.16). Among exclusively formula-fed infants maternal smoking did not predict rapid growth. Interaction models suggest that infants ever-breastfed (i.e., breastfed and mixed-fed groups combined) by heavy smokers gained weight (100 grams; 95%CI: 30, 231) and length (2.8 mm; 95%CI:0.1, 5.6) attributable to ingesting smoker’s breastmilk. ConclusionsInfants breastfed by smokers experience rapid growth, some of these gains are attributable to ingesting smokers’ breastmilk. Among infants breasted by light smokers, these gains are within the range of normative growth patterns for healthy, breastfed infants.

Associations between non-registered ultrasound examination in pregnancy and adverse perinatal outcomes in immigrant and non-immigrant women: a Norwegian population-based study 1999-2016.

Prenatal ultrasound examinations are important to detect placental dysfunction. Several ultrasound-detected abnormalities can be managed during pregnancy or childbirth, thus improve health outcomes. Maternal birth country is known to influence the risk of placental dysfunction, but little is known about the possible mechanisms of this relation. (a) To estimate the proportion of non-registered prenatal ultrasound examinations; (b) to examine associations between non-registered ultrasound examinations and adverse perinatal outcomes, by migrant-related factors, in women giving birth in Norway. Individually linked data from the Medical Birth Registry of Norway and Statistics Norway, 1999-2016, comprising 999,760 singleton pregnancies to immigrants (n=196,220) and non-immigrants (n=803,540). Crude and adjusted odds ratios (aORs) with 95% confidence intervals (CIs) were estimated using logistic regression with robust standard error estimations, adjusted for year of childbirth, maternal age, parity, maternal smoking, educational level and Norwegian health region at birth. Compared with non-immigrants, immigrant women had a higher proportion of non-registered ultrasound examinations (2.3% vs. 4.3%; aOR 2.0 (95% CI 1.9, 2.0)). Compared with women with ultrasound examination, the aOR for perinatal mortality for women with non-registered ultrasound was 2.27 (95% CI 1.85, 2.79) for immigrants and 3.61 (3.21, 4.07) for non-immigrants. Non-registered ultrasound examination was also associated with placental abruption (aOR 1.32 (1.08, 1.63)) for non-immigrant women, but it was not associated with preeclampsia.

Growth Restriction in the Offspring of Mothers With Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a common endocrine disorder, characterized by subfertility, increased risk of metabolic diseases, and pregnancy complications. Previous studies diverge regarding the association between maternal PCOS and newborn anthropometrics. To explore the association between maternal PCOS and newborn anthropometrics and the modifying effects of maternal body mass index, PCOS phenotype, and gestational diabetes. This cohort study followed up women from the first half of pregnancy to birth and combined data from 3 clinical trials of pregnant women with PCOS and a reference population consisting of participants in the Norwegian Mother, Father, and Child Cohort (MoBa) Study, with data from the Medical Birth Registry of Norway. The recruitment period for the clinical trials was between October 1, 2000, and August 31, 2017, and for MoBa, between July 1, 1999, and December 31, 2008. Participants included women with singleton pregnancies and live-born children. Data were analyzed from January 1 to June 15, 2023. Maternal PCOS status. Newborn birth weight, birth length, and head circumference as continuous variables and z scores, and ponderal index (calculated as the birth weight in grams × 100 divided by the birth length in centimeters cubed), placenta weight, and ratio of birth weight to placenta weight (BWPW). The cohort included 390 pregnant women with PCOS (mean [SD] age, 29.6 [4.2] years) and 68 708 women in the reference group (mean [SD] age, 30.4 [4.5] years). Offspring in the PCOS group had lower birth weight, birth length, and head circumference than in the reference group offspring. The estimated mean differences in z scores were -0.26 (95% CI, -0.38 to -0.14) for birth weight, -0.19 (95% CI, -0.33 to -0.05) for birth length, and -0.13 (95% CI, -0.26 to -0.01) for head circumference. The PCOS group also had a lower ponderal index (-0.04 [95% CI, -0.07 to -0.004] g × 100/cm3) and placenta weight (-24 [95% CI, -43 to -5)] g), and higher BWPW ratio (0.4 [95% CI, 0.3 to 0.5]). The association between growth restriction and PCOS was more apparent when additionally adjusting for body mass index. Neither PCOS phenotype nor gestational diabetes diagnosis was associated with neonatal anthropometry in women with PCOS. In this cohort of mother-infant pairs, maternal PCOS status was associated with lower birth weight, shorter birth length, and smaller head circumference in the offspring. This growth restriction was more pronounced when adjusting for BMI, providing insight into the association between PCOS and body mass index. The study contributed to the understanding of how PCOS affects the offspring.

Down syndrome and associated atrioventricular septal defects in a nationwide Norwegian cohort: Prevalence, time trends, and outcomes.

The prevalence of Down syndrome (DS) is approximately 1 per 1000 births and is influenced by increasing maternal age over the last few decades. DS is strongly associated with congenital heart defects (CHDs), especially atrioventricular septal defect (AVSD). Our objectives were to investigate the prevalence of live-born infants with DS having a severe CHD in the Norwegian population over the last 20 years and compare outcomes in infants with AVSD with and without DS. Information on all births from January 1, 2000 to December 31, 2019 was obtained from the Medical Birth Registry of Norway. We also obtained data on all infants with severe CHDs in Norway registered in Oslo University Hospital's Clinical Registry for Congenital Heart Defects during 2000-2019 and accessed individual-level patient data from the electronic hospital records of selected cases. Infants with AVSD and DS were compared to infants with AVSD without chromosomal defects. Crude and adjusted odds ratios (ORs) of infant mortality and need for surgery during the first year of life, with associated 95% confidence intervals (CIs), were estimated by logistic regression. A total of 1 177 926 infants were live-born in Norway during the study period. Among these, 1456 (0.1%) had DS. The prevalence of infants with DS having a severe CHDs was relatively stable, with a mean of 17 cases per year. The most common CHD associated with DS was AVSD (44.4%). Infants with AVSD and DS were more likely to have cardiac intervention during their first year of life compared to infants with AVSD without chromosomal defects (adjusted OR [aOR]: 2.52; 95% CI 1.27, 4.98). However, we observed no difference in infant mortality during first year of life between the two groups (aOR: 1.08; 95% CI 0.43, 2.70). The prevalence of live-born infants with severe CHDs and DS has been stable in Norway across 20 years. Infants with AVSD and DS did not have higher risk of mortality during their first year of life compared to infants with AVSD without chromosomal defects, despite a higher risk of operative intervention.

Short inter-pregnancy interval and birthweight: a reappraisal based on a follow-up study of all women in Norway with two singleton deliveries during 1970–2019

We studied mean changes in birthweight from the first to the second delivery according to length of the inter-pregnancy interval. We also studied recurrence risk of low birthweight, preterm birth and perinatal death. We followed all women in Norway from their first to their second singleton delivery at gestational week 22 or beyond during the years 1970–2019, a total of 654 100 women. Data were obtained from the Medical Birth Registry of Norway. Mean birthweight increased from the first to the second delivery, and the increase was highest in pregnancies conceived < 6 months after the first delivery; adjusted mean birthweight increase 227 g (g) (95% CI; 219–236 g), 90 g higher than in pregnancies conceived 6–11 months after the first delivery (137 g (95% CI; 130–144 g)). After exclusion of women with a first stillbirth, the mean increase in birthweight at inter-pregnancy interval < 6 months was attenuated (152 g, 95% CI; 143–160 g), but remained higher than at longer inter-pregnancy intervals. This finding was particularly prominent in women > 35 years (218 g, 95% CI; 139 –298 g). In women with a first live born infant weighing < 2500 g, mean birthweight increased by around 1000 g to the second delivery, and the increase was most prominent at < 6 months inter-pregnancy interval. We found increased recurrence risk of preterm birth at inter-pregnancy interval < 6 months, but no increased recurrence risk of low birthweight, small for gestational age infant or perinatal death. In conclusion, we found the highest mean increase in birthweight when the inter-pregnancy interval was short. Our results do not generally discourage short pregnancy intervals.

Pre-pregnancy obesity among immigrant and non-immigrant women in Norway: Prevalence, trends, and subgroup variations.

This study assessed prevalence and time trends of pre-pregnancy obesity in immigrant and non-immigrant women in Norway and explored the impact of immigrants' length of residence on pre-pregnancy obesity prevalence. Observational data from the Medical Birth Registry of Norway and Statistics Norway for the years 2016-2021 were analyzed. Immigrants were categorized by their country of birth and further grouped into seven super regions defined by the Global Burden of Disease study. Pre-pregnancy obesity was defined as a body mass index ≥30.0 kg/m2, with exceptions for certain Asian subgroups (≥27.5 kg/m2). Statistical analysis involved linear regressions for trend analyses and log-binomial regressions for prevalence ratios (PRs). Among 275 609 pregnancies, 29.6% (N = 81 715) were to immigrant women. Overall, 13.6% were classified with pre-pregnancy obesity: 11.7% among immigrants and 14.4% among non-immigrants. Obesity prevalence increased in both immigrants and non-immigrants during the study period, with an average yearly increase of 0.62% (95% confidence interval [CI]: 0.55, 0.70). Obesity prevalence was especially high in women from Pakistan, Chile, Somalia, Congo, Nigeria, Ghana, Sri Lanka, and India (20.3%-26.9%). Immigrant women from "Sub-Saharan Africa" showed a strong association between longer residence length and higher obesity prevalence (≥11 years (23.1%) vs. <1 year (7.2%); adjusted PR = 2.40; 95% CI: 1.65-3.48), particularly in women from Kenya, Eritrea, and Congo. Prevalence of maternal pre-pregnancy obesity increased in both immigrant and non-immigrant women from 2016 to 2021. Several immigrant subgroups displayed a considerably elevated obesity prevalence, placing them at high risk for adverse obesity-related pregnancy outcomes. Particular attention should be directed towards women from "Sub-Saharan Africa", as their obesity prevalence more than doubled with longer residence.

Stability and change in maternal wellbeing and illbeing from pregnancy to three years postpartum

PurposeMotherhood affects women’s mental health, encompassing aspects of both wellbeing and illbeing. This study investigated stability and change in wellbeing (i.e., relationship satisfaction and positive affect) and illbeing (i.e., depressive and anxiety symptoms) from pregnancy to three years postpartum. We further investigated the mutual and dynamic relations between these constructs over time and the role of genetic propensities in their time-invariant stability.Data and methodsThis four-wave longitudinal study included 83,124 women from the Norwegian Mother, Father, and Child Cohort Study (MoBa) linked to the Medical Birth Registry of Norway. Data were collected during pregnancy (30 weeks) and at 6, 18 and 36 months postpartum. Wellbeing and illbeing were based on the Relationship Satisfaction Scale, the Differential Emotions Scale and Hopkins Symptoms Checklist-8. Genetics were measured by the wellbeing spectrum polygenic index. Analyses were based on random intercept cross-lagged panel models using R.ResultsAll four outcomes showed high stability and were mutually interconnected over time, with abundant cross-lagged predictions. The period of greatest instability was from pregnancy to 6 months postpartum, followed by increasing stability. Prenatal relationship satisfaction played a crucial role in maternal mental health postpartum. Women’s genetic propensity to wellbeing contributed to time-invariant stability of all four constructs.ConclusionUnderstanding the mutual relationship between different aspects of wellbeing and illbeing allows for identifying potential targets for health promotion interventions. Time-invariant stability was partially explained by genetics. Maternal wellbeing and illbeing develop in an interdependent way from pregnancy to 36 months postpartum.

Intrapartum fetal monitoring practices in Norway: A population-based study

ObjectiveTo describe intrapartum fetal monitoring methods used in all births in Norway in 2019–2020, assess adherence to national guidelines, investigate variation by women’s risk status, and explore associations influencing monitoring practices. MethodsA nationwide population-based study. We collected data about all pregnancies with a gestational age ≥ 22 weeks during 2019–2020 from the Medical Birth Registry of Norway. We used descriptive analyses, stratified for risk status, to examine fetal monitoring methods used in all deliveries. Univariable and multivariable logistic regression models were used to determine factors associated with monitoring with cardiotocography (CTG) in low-risk, straightforward births. ResultsIn total, 14 285 (14%) deliveries were monitored with only intermittent auscultation (IA), 46214 (46%) with only CTG, and 33417 (34%) with IA and CTG combined. Four percent (2 067/50 533) of women with risk factors were monitored with IA only. Half (10589/21 282) of the low-risk women with straightforward births were monitored with CTG. Maternal and fetal characteristics, size of the birth unit and regional practices influenced use of CTG monitoring in this group. ConclusionsMost births are monitored with CTG only, or combined with IA. Half the women with low-risk pregnancies and straightforward births were monitored with CTG although national guidelines recommending IA.

Parity, infertility, age at first birth and risk of atrial fibrillation: data from the HUNT study.

Although parity, infertility, and age at first birth are important for later development of cardiovascular disease, research on their association with atrial fibrillation (AF) is limited. We linked data from the population-based HUNT study, the Medical Birth Registry of Norway (MBRN) and validated medical records from local hospitals. A total of 24,015 women aged 45 years or older were followed for verified incident AF. Parity and age at first birth were retrieved from the MBRN or from self-reported questionnaires in the HUNT. History of infertility was self-reported on the HUNT questionnaire. Cox-proportional hazard models were used to calculate hazard ratios (HR) for the multivariable-adjusted associations of parity, infertility, and age at first birth with risk of AF. During a median follow-up of 12.8 years, 1,448 (6.0%) participants developed AF. Women with higher parity (four or more births vs. two births) were at 21% higher risk of AF (HR 1.21, 95% confidence interval (CI), 1.05-1.39). History of infertility was also associated with risk of AF (HR 1.20, 95% CI, 1.02-1.42). Among parous women, younger age at first birth (<20 years vs. 20-29 years) was associated with a 20% higher risk of AF (HR 1.20, 95% CI, 1.03-1.40). Women with four or more births, or a history of infertility, or younger age at first birth have approximately a 20% higher risk of AF among women over 45 years old.

Prenatal exposure to benzodiazepine and z-hypnotics and fifth-grade scholastic skills – emulating target trials using data from the Norwegian Mother, Father and Child Cohort Study

Abstract Evidence is limited regarding the effect of prenatal benzodiazepine and z-hypnotic exposure and long-term neurodevelopment in childhood. The objective of this study was to investigate the effects of initiating benzodiazepine or z-hypnotic treatment in early, mid and late pregnancy on fifth-grade numeracy and literacy scholastic skills in children, by emulating three target trials. The trials are identical except for the timing of enrollment and the number of eligible individuals. Eligibility to the trials required a history of anxiety and/or depression prior to pregnancy. We used data from the Norwegian Mother, Father and Child Cohort Study, linked to the Medical Birth Registry of Norway, to emulate the trials. We adjusted for baseline covariates that were available at time 0 for each trial by inverse probability of treatment weighting using the propensity score. The findings of this study did not show any effect of mothers’ initiation of treatment with benzodiazepines or z-hypnotics in early, mid or late pregnancy on the children’s 5th grade test scores in numeracy and literacy. The study results provide reassurance for patients in need of benzodiazepines and z-hypnotics during pregnancy; however, these findings need to be interpreted with caution due to low study power in some of the analyses.

Perinatal mortality among pregnant undocumented migrants in Norway 1999–2020: A register-based population study

BackgroundIrregular legal status is a recognized health risk factor in the context of migration. However, undocumented migrants are rarely included in health surveys and register studies. Adverse perinatal outcomes are especially important because they have long-term consequences and societal risk factors are modifiable. In this study, we compare perinatal outcomes in undocumented migrants to foreign-born and Norwegian-born residents, using a population-based register. MethodsWe included women 18–49 years old giving birth to singletons as registered in the Medical Birth Registry of Norway from 1999 to 2020. Women were categorized as ‘undocumented migrants’ (without an identity number), ‘documented migrants’ (with an identity number and born abroad), and ‘non-migrants’ (with an identity number and born in Norway). The main outcome was perinatal mortality, i.e., death of a foetus ≥ gestational week 22, or neonate up to seven days after birth. We used log-binominal regression to estimate the association between legal status and perinatal mortality, adjusting for several maternal pre-gestational and gestational factors. Direct standardization was used to adjust for maternal region of origin. Ethical approvalRegional Ethical Committee (REK South East, case number 68329). ResultsWe retrieved information on 5856 undocumented migrant women who gave birth during the study period representing 0.5% of the 1 247 537 births in Norway. Undocumented migrants had a relative risk of 6.17 (95% confidence interval 5.29 ̶7.20) of perinatal mortality compared to non-migrants and a relative risk of 4.17 (95% confidence interval 3.51 ̶4.93) compared to documented migrants. Adjusting for maternal region of origin attenuated the results slightly. ConclusionBeing undocumented is strongly associated with perinatal mortality in the offspring. Disparities were not explained by maternal origin or maternal health factors, indicating that social determinants of health through delays in receiving adequate care and factors negatively influencing gestational length may be of importance.

Telomere length in relation to fecundability and use of assisted reproductive technologies: the Norwegian Mother, Father, and Child Cohort Study.

In women, shorter telomeres have been reported to be associated with conditions such as endometriosis and polycystic ovary syndrome, whereas other studies have reported the opposite. In men, studies mostly report associations between shorter telomeres and sperm quality. To our knowledge, no studies have thus far investigated the associations between TL and fecundability or the use of ART. This study is based on the Norwegian Mother, Father, and Child Cohort (MoBa) Study and uses data from the Medical Birth Registry of Norway (MBRN). We included women (24,645 with genotype data and 1,054 with TL measurements) and men (18,339 with genotype data and 965 with TL measurements) participating between 1998 and 2008. We investigated the associations between leukocyte TL and fecundability, infertility, and the use of ART. We also repeated the analyses using instrumental variables for TL, including genetic risk scores for TL and genetically predicted TL. Approximately 11% of couples had experienced infertility and 4% had used ART. TL was not associated with fecundability among women (fecundability ratio [FR], 0.98; 95% confidence interval [CI], 0.92-1.04) or men (FR, 0.99; CI, 0.93-1.06), nor with infertility among women (odds ratio [OR], 1.03; CI, 0.85-1.24) or men (OR, 1.05; CI, 0.87-1.28). We observed an increased likelihood of using ART with increasing TL among men (OR, 1.22; CI, 1.03-1.46), but not among women (OR, 1.10; CI, 0.92-1.31). No significant associations were observed using the instrumental variables. Our results indicate that TL is a poor biomarker of fecundability, infertility and use of ART in MoBa. Additional studies are required to replicate the association observed between TL and ART in men.

Prevalence, infant outcomes and gestational risk factors for transverse reduction deficiencies at or above the wrist: a population-based study.

We identified individuals born in Norway between 1970 and 2019 with transverse reduction deficiency at or above the wrist (TRDAW) from the Medical Birth Registry of Norway and from the CULA (congenital upper limb anomaly) North Oslo Registry. Infant outcomes and parental factors were compared for 202 individuals with TRDAW to 2,741,013 living individuals without TRDAW born during the same period. We found an overall TRDAW prevalence of 0.74/10,000. Infants with TRDAW had a higher risk for being small for gestational age, an Apgar score <7 and transfer to neonatal intensive care units after delivery. Nine of the infants with TRDAW had associated anomalies, most commonly in the lower limb, and at a higher proportion than the reference population. Other than twin pregnancies, we are unable to identify with certainty any other risk factors for TRDAW.Level of evidence: I.

Trends in severe postpartum haemorrhage among nulliparous women with spontaneous onset of labour: A population-based cohort study.

To investigate the incidence of severe postpartum haemorrhage among nulliparous women with a spontaneous onset of labour at term from 2000 to 2020. Population-based cohort study. National, using the Medical Birth Registry of Norway. Women (n = 330 244) who gave birth to their first singleton child in a cephalic presentation after a spontaneous onset of labour at term. Cross-tabulations and regression analysis with generalised linear models were used to assess time trends and adjust for potential confounding factors. We also stratified the analyses by maternal age groups, obstetric interventions, mode of delivery and institution size. Time trends were analysed using periods of 5 or 6 years as a unit, and the period from 2000 to 2004 was used as the reference. Severe postpartum haemorrhage (PPH) was defined as blood loss of >1500 mL within 24 h and/or in combination with blood transfusion. Severe PPH occurred in 7601/330 244 (2.30%) women. The incidence increased from 1.24% in 2000-2004 to 3.83% in 2015-2020 (adjusted relative risk, aRR 2.90; 95% CI 2.70-3.12). Changes in maternal characteristics or obstetric interventions did not explain the increase, and we found similar increases across institutions of all sizes. The incidence of severe PPH among nulliparous women increased almost threefold over 21 years. The current high incidence warrants urgent efforts to assess unknown risk factors, the health care provided and health system factors that may contribute to the increase, to inform improvements in care.