Swedish Pregnancy Register Research Articles

Midwifery Continuity of Care During Pregnancy, Birth, and the Postpartum Period: A Matched Cohort Study.

To compare pregnancy outcomes in a midwifery continuity of care (MCoC) model to standard midwifery care in Sweden. Matched cohort study. Public healthcare during pregnancy and childbirth, Stockholm, Sweden. Women giving birth at Karolinska University Hospital site Huddinge in Stockholm between January 1, 2019, and August 31, 2021. Data on all births including MCoC and standard care, during the time period, were retrieved from the national Swedish Pregnancy Register. Propensity score matching was applied to obtain a matched set from the standard care group for every woman in the MCoC model. Based on the matched cohort, we estimated risk ratios (RR) for binary outcomes with 95% confidence intervals (CI). Interventions during labor, mode of birth, and preterm birth (< 37 gestational weeks). Compared with standard care, women in the MCoC model were more likely to give birth spontaneously (RR 1.06 95% CI 1.02-1.10) and less likely to have an elective cesarean on maternal request (RR 0.24 95% CI 0.11-0.51). The risk of preterm birth was also reduced in the MCoC group (RR 0.51 95% CI 0.32-0.82). The MCoC model was associated with fewer medical interventions and improved pregnancy outcomes.

Women's use of Swedish health care during the postpartum period in relation to maternal country of birth-A population-based study.

Migrant women are a heterogenous group with both higher and lower risk for pregnancy complications and adverse birth outcomes compared with women in the receiving countries. This study aimed to investigate women's use of Swedish healthcare postpartum, in terms of hospital stay >48 h, readmission to hospital, and specialized out-patient clinic visits, in relation to maternal country of birth. A population-based register study including 278 219 primiparous and 367 776 multiparous women in Sweden (2014-2019) using data from Swedish Pregnancy Register, National Patient Register and Statistics Sweden. Multivariable logistic regression analyses were used to estimate associations between maternal country of birth and outcomes, adjusting for year of birth, maternal age, education, pre-gestational hypertension and diabetes, and healthcare region, presented as crude and adjusted odds ratios (aOR) with 95% confidence interval (CI) with Swedish-born women as reference. Subgroups of migrant women had higher odds of postpartum hospital stays > 48 h, particularly women from Eritrea (primiparous aOR 2.80, CI 2.49-3.15; multiparous aOR 2.78, CI 2.59-2.98), Somalia (primiparous aOR 2.61, CI 2.34-2.92; multiparous aOR 1.87, CI 1.79-1.97), and India (primiparous aOR 2.52, CI 2.14-2.97; multiparous aOR 2.61, CI 2.33-2.93), compared to Swedish-born women. Primiparous women from Afghanistan (aOR 1.32, CI 1.08-1.6), Iraq (aOR 1.30, CI 1.16-1.46), and Iran (aOR 1.23, CI 1.04-1.45) had slightly higher odds of hospital readmission, along with multiparous women from India (aOR 1.34, CI 1.02-1.76) and Somalia (aOR 1.24, CI 1.11-1.38). Specialized out-patient clinic visits were most common in primiparous women from Somalia (aOR 1.47, CI 1.35-1.59), Iran (aOR 1.31, CI 1.22-1.42) and Afghanistan (aOR 1.31, CI 1.18-1.46), and in multiparous women from Iran (aOR 1.30, CI 1.20-1.41) and Iraq (aOR 1.15, CI 1.11-1.20), however less common in women from some other countries. The use of Swedish health care during the postpartum period varied among women, depending on their country of birth. Women from certain countries had particularly high odds of postpartum hospital stays exceeding 48 h, compared to Swedish-born women, regardless of parity and pre-gestational medical disorders. Further studies are needed to determine whether the individual needs of migrant women are being met during the postpartum period or not.

Association between ambient air pollution a week prior to delivery and preterm birth using a nationwide study in Sweden

BackgroundAir pollution exposure has been linked with increased risk of preterm birth, which is one of the leading causes of infant mortality. Limited studies have attempted to explore these associations in low-polluted areas. In this study, we aimed to assess the association between short-term exposure to ambient air pollution and preterm birth in Sweden. MethodIn this population-based study we included preterm births between 2014 and 2019 from the Swedish Pregnancy Register. We applied a spatiotemporal model to estimate daily levels of particulate matter <2.5 μm (PM2.5), PM < 10 μm (PM10), nitrogen dioxide (NO2), and ozone (O3) at the residential address of each participant. We applied a time-stratified case-crossover design with conditional logistic regression analysis to estimate odds ratios (OR) of preterm birth per 10 μg/m3 (PM10, NO2, O3) and 5 μg/m3 (PM2.5) increase in air pollution exposure at 0–6-day lag. Two-pollutant models were applied to evaluate the independent association of each exposure on preterm birth. We also stratified by maternal characteristics to identify potential effect modifiers. Results28,216 (4.5%) preterm births were included. An increase in O3 exposure was associated with increased odds of preterm birth [OR = 1.06 per 10 μg/m3 (95% CI, 1.02; 1.10]. PM2.5 and PM10 were not significantly associated with preterm birth, and NO2 displayed a negative nonlinear association with preterm birth. We did not observe any notable effect modification, but we found suggestive larger associations between O3 and preterm birth when stratifying by male sex, spontaneous delivery, and spring season. ConclusionsIncreased O3 exposure one week before delivery was associated with an increased risk of preterm birth in Sweden, a country with levels of air pollution below the current World Health Organization air quality guidelines. Increases in O3 levels with climate change make these findings especially concerning.

Midwifery continuity of care, breastfeeding and neonatal hyperbilirubinemia: A retrospective cohort study

AimTo examine the association between Midwifery Continuity of Care (MCoC) and exclusive breastfeeding at hospital discharge and neonatal hyperbilirubinemia. MethodsA matched cohort design was employed using data from the Swedish Pregnancy Register. The study included 12,096 women who gave birth at a university hospital in Stockholm, Sweden from January 2019 to August 2021. Women and newborns cared for in a MCoC model were compared with a propensity-score matched set receiving standard care. Risk ratios (RR) were determined with 95 % confidence intervals (CI) based on the matched cohort through modified Poisson regressions with robust standard error. A mediation analysis assessed the direct and indirect effects of MCoC on exclusive breastfeeding at hospital discharge and neonatal hyperbilirubinemia and to what extent the association was mediated by preterm birth. FindingFindings showed that MCoC was associated with a higher chance of exclusive breastfeeding rate (RR: 1.06, 95 % CI: 1.01–1.12) and lower risk of neonatal hyperbilirubinemia (RR: 0.51, 95 % CI: 0.32–0.82) compared with standard care. Mediation analysis demonstrated that lower preterm birth accounted for approximately 28 % of total effect on the reduced risk of neonatal hyperbilirubinemia. Discussion/ConclusionThis matched cohort study provided preliminary evidence that MCoC models could be an intervention for improving exclusive breastfeeding rates at hospital discharge and reducing the risk of neonatal hyperbilirubinemia.

Breastfeeding in primiparous women with congenital heart disease − a register study

BackgroundThe number of pregnant women with congenital heart disease (CHD) is rising, and the disease poses increased risks of cardiovascular and obstetric complications during pregnancy, potentially impacting breastfeeding success. This study aimed to investigate breastfeeding in primiparous women with CHD compared to primiparous women without CHD, and to examine potential hindering factors for breastfeeding in women with CHD.MethodsThe data were gathered between 2014 and 2019 and obtained by merging the Swedish Congenital Heart Disease Register (SWEDCON) with the Swedish Pregnancy Register. Primiparous women ≥ 18 years of age with CHD (n = 578) were matched by age and municipality to 3049 women without CHD, giving birth after 22 gestational weeks. Multivariable logistic regression analysis was used to identify factors associated with non-breastfeeding in women with CHD.ResultsFewer women with CHD breastfed than women without CHD two days (94% vs. 97%, p = 0.001) and four weeks after birth (84% vs. 89%, p = 0.006). When all women were analysed, having CHD was associated with non-breastfeeding at both two days and four weeks after birth. For women with CHD, body mass index (BMI) ≥ 30 (OR 3.1; 95% CI 1.4, 7.3), preterm birth (OR 6.4; 95% CI 2.1, 19.0), self-reported history of psychiatric illness (OR 2.4; 95% CI 1.2, 5.1), small for gestational age (OR 4.2; 95% CI 1.4, 12.2), and New York Heart Association Stages of Heart Failure class II − III (OR 6.0; 95% CI 1.4, 26.7) were associated with non-breastfeeding two days after birth. Four weeks after birth, factors associated with non-breastfeeding were BMI ≥ 30 (OR 4.3; 95% CI 2.1, 9.0), self-reported history of psychiatric illness (OR 2.2; 95% CI 1.2, 4.2), and preterm birth (OR 8.9; 95% CI 2.8, 27.9).ConclusionsThe study shows that most women with CHD breastfeed, however, at a slightly lower proportion compared to women without CHD. In addition, factors related to the heart disease were not associated with non-breastfeeding four weeks after birth. Since preterm birth, BMI ≥ 30, and psychiatric illness are associated with non-breastfeeding, healthcare professionals should provide greater support to women with CHD having these conditions.

Time to childbirth and assisted reproductive treatment in women with congenital heart disease

ObjectiveTo investigate the time to first childbirth and to compare the prevalence of assisted reproductive treatment (ART) in women with congenital heart disease (CHD) compared with women without CHD.MethodsAll women...

Fetal growth after fresh and frozen embryo transfer and natural conception: A population-based register study.

To investigate fetal growth trajectories and risks of small and large for gestational age (SGA and LGA), and macrosomia in pregnancies after fresh and frozen embryo transfer (ET), and natural conception (NC). Longitudinal population-based cohort study. Swedish national registers. A total of 196 008 singleton pregnancies between 2013 and 2017. Of all singleton pregnancies resulting in live births in the Swedish Pregnancy Register, 10 970 fresh ET, 6520 frozen ET, and 178 518 NC pregnancies with ultrasound data were included. A general least squares model was used to examine the effect of fresh or frozen ET on fetal growth while adjusting for confounders. Fetal growth velocity. SGA, LGA and macrosomia. At 120 days, fetal weights were lower in fresh ET pregnancies compared with NC pregnancies. Thereafter fresh ET as well as FET fetuses had higher fetal weights than NC fetuses, with no differences between themselves until the second trimester. From 210 days, FET fetuses were heavier than fresh ET fetuses, whereas fresh ET fetuses had lower fetal weights than NC fetuses from 245 days. After fresh ET, SGA was more frequent, whereas LGA and macrosomia were less frequent, than after FET. This study gives new insights into the differences in fetal growth dynamics between fresh and frozen ET and NC pregnancies. Clinically relevant differences in proportions of SGA, LGA and macrosomia were observed.

The impact of exclusion due to COVID-19 restrictions on partners' satisfaction with Swedish hospital postnatal ward care: A multi-methods approach.

To prevent the spread of SARS-CoV-2, hospitals around the world adopted protocols that, in varying ways, resulted in the exclusion of partners from hospital postnatal care wards. The objective of this study was to examine the effect this exclusion had on partners' satisfaction with postnatal care. An online survey (the Swedish Pregnancy Panel) including free-text comments was conducted before and during the first wave of the COVID-19 pandemic; partners of pregnant women were recruited at an early ultrasound appointment and followed until 2 months after childbirth. Data were linked to the Swedish Pregnancy Register. The survey was completed by 524 partners of women who gave birth during the pandemic and 203 partners of women who gave birth before. Partners' satisfaction with hospital postnatal care dropped 29.8 percent (-0.94 OLS, 95% CI = -1.17 to -0.72). The drop was largest for partners of first-time mothers (-1.40 OLS, 95% CI = -1.69 to -1.11), but unrelated to clinical outcomes such as mode of birth and most social backgrounds, except higher income. The qualitative analysis showed that partners (1) felt excluded as partners and parents, (2) thought the strain on staff led to deficiencies in the care provided, and (3) perceived the decision about partner restrictions as illogical. The exclusion of partners from the hospital postnatal wards clearly impaired satisfaction with care, and partners of first-time mothers were particularly affected. Planning for future restrictions on partners from hospital wards should factor in these consequences.

Incidence and risk factors for umbilical cord prolapse in labor when amniotomy is used and with spontaneous rupture of membranes: A Swedish nationwide register study.

Umbilical cord prolapse (UCP) is a rare but severe obstetric complication in the presence of a rupture of the membranes. Although it is not possible to prevent a spontaneous rupture of the membranes (SROM), it is possible to prevent an amniotomy, which is a commonly used intervention in labor. This study aimed to explore the incidence and risk factors that are associated with UCP in labor when amniotomy is used vs SROM. A retrospective nationwide register study was conducted of all births in Sweden from January 2014 to June 2020 that were included in the Swedish Pregnancy Register (n = 717 336). The main outcome, UCP, was identified in the data by the International Classification of Diseases (ICD-10) diagnosis code O69.0. Multiple binary logistic regression analysis was used to identify the risk factors. Amniotomy was performed in 230 699 (43.6%) of all pregnancies. A UCP occurred in 293 (0.13%) of these cases. SROM occurred in 298 192 (56.4%) of all cases, of which 352 (0.12%) were complicated by UCP. Risk factors that increased the odds of UCP for both amniotomy and SROM were: higher parity, non-cephalic presentation and an induction of labor. Greater gestational age reduced the odds of UCP. Risk factors associated with only amniotomy were previous cesarean section and the presence of polyhydramnios. Identified risk factors for UCP in labor with SROM were a higher maternal age and maternal origin outside of the EU. UCP is a rare complication in Sweden. Beyond confirming the previously recognized risk factors, this study found induction of labor and previous cesarean section to be risk factors in labor when amniotomy is used.

Gestational diabetes mellitus and time in active labor: A population-based cohort study.

Women with gestational diabetes mellitus (GDM) have higher rates of adverse perinatal outcomes compared with women without GDM, including an increased risk for having labor induced and for cesarean section. The findings from previous studies analyzing duration of labor in women with GDM are contradictory. The aim of the study was to evaluate the impact of GDM on time in spontaneous and induced active labor. This was a population-based cohort study including 247 524 primiparous women who gave birth to a singleton fetus with cephalic presentation, ≥34+0 (completed gestational weeks + additional days) between January 2014 and May 2020 in Sweden. Data was obtained from the Swedish Pregnancy Register. Time in active labor was compared between women with GDM and without GDM with a spontaneous labor onset or induction of labor using Kaplan Meier survival analysis and Cox regression analysis. Women with GDM had significantly longer time in active labor, both with a spontaneous onset and induction of labor compared to women without GDM. Women with GDM had a decreased chance of vaginal delivery at a certain time-point compared to women without GDM, with adjusted hazard ratio of 0.92 (0.88-0.96) and 0.83 (0.76-0.90) for those with spontaneous onset and induction of labor, respectively. Women with GDM had increased risk for time in active labor ≥12 h both in spontaneous labor onset (adjusted odds ratio 1.14 [1.04-1.25]) and in induction of labor (adjusted odds ratio 1.55 [1.28-1.87]). Women with GDM seem to spend a longer time in active labor, both in spontaneous and induced active labor compared to women without GDM. To be able to individualize care intrapartum, there is a need for more studies demonstrating the impact of hyperglycemia during pregnancy on outcomes during childbirth.

IMplementing best practice post-partum contraceptive services through a quality imPROVEment initiative for and with immigrant women in Sweden (IMPROVE it): a protocol for a cluster randomised control trial with a process evaluation

BackgroundImmigrant women’s challenges in realizing sexual and reproductive health and rights (SRHR) are exacerbated by the lack of knowledge regarding how to tailor post-partum contraceptive services to their needs. Therefore, the overall aim of the IMPROVE-it project is to promote equity in SRHR through improvement of contraceptive services with and for immigrant women, and, thus, to strengthen women’s possibility to choose and initiate effective contraceptive methods post-partum.MethodsThis Quality Improvement Collaborative (QIC) on contraceptive services and use will combine a cluster randomized controlled trial (cRCT) with a process evaluation. The cRCT will be conducted at 28 maternal health clinics (MHCs) in Sweden, that are the clusters and unit of randomization, and include women attending regular post-partum visits within 16 weeks post birth. Utilizing the Breakthrough Series Collaborative model, the study’s intervention strategies include learning sessions, action periods, and workshops informed by joint learning, co-design, and evidence-based practices. The primary outcome, women’s choice of an effective contraceptive method within 16 weeks after giving birth, will be measured using the Swedish Pregnancy Register (SPR). Secondary outcomes regarding women’s experiences of contraceptive counselling, use and satisfaction of chosen contraceptive method will be evaluated using questionnaires completed by participating women at enrolment, 6 and 12 months post enrolment. The outcomes including readiness, motivation, competence and confidence will be measured through project documentation and questionnaires. The project’s primary outcome involving women’s choice of contraceptive method will be estimated by using a logistic regression analysis. A multivariate analysis will be performed to control for age, sociodemographic characteristics, and reproductive history. The process evaluation will be conducted using recordings from learning sessions, questionnaires aimed at participating midwives, intervention checklists and project documents.DiscussionThe intervention’s co-design activities will meaningfully include immigrants in implementation research and allow midwives to have a direct, immediate impact on improving patient care. This study will also provide evidence as to what extent, how and why the QIC was effective in post-partum contraceptive services.Trial registrationNCT05521646, August 30, 2022.

Association between SARS-CoV-2 infection and newly diagnosed hypertension during pregnancy: prospective, population based cohort study

ObjectiveTo study the association between SARS-CoV-2 infection and newly diagnosed hypertension during pregnancy.DesignProspective, population based cohort study.SettingAll singleton pregnancies after 22 completed gestational weeks registered in the Swedish Pregnancy Register...

Clinical characteristics and predictors of neonatal outcomes in chorioamnionitis at term gestation: A cohort study.

To investigate the association between clinical and laboratory characteristics of chorioamnionitis in deliveries at term gestation with adverse neonatal outcomes. Retrospective cohort study. The study is based on data from the Swedish Pregnancy Register, enriched with clinical data extracted from medical charts. A cohort of 500 term singleton deliveries in Stockholm County with registered diagnosis of chorioamnionitis (based on the assessment of the responsible obstetrician) in the Swedish Pregnancy Register between 2014 and 2020. Logistic regression was used to estimate odds ratios (ORs) as a measurement of the association between clinical and laboratory characteristics and neonatal complications. Neonatal infection and asphyxia-related complications. The prevalence of neonatal infection and asphyxia-related complications was 10% and 22%, respectively. First leukocyte count in the second tertile (OR2.14, 95%CI 1.02-4.49), maximum C-reactive protein (CRP) level in the third tertile (OR4.01, 95%Cl 1.66-9.68) and positive cervical culture (OR2.22, 95%Cl 1.10-4.48) were associated with an increased risk of neonatal infection. Maximum level of CRP in the third tertile (OR1.93, 95%Cl 1.09-3.41) and fetal tachycardia (OR1.63, 95%Cl 1.01-2.65) were associated with an increased risk of asphyxia-related complications. Elevated inflammatory laboratory markers were associated with both neonatal infection and asphyxia-related complications, and fetal tachycardia was associated with asphyxia-related complications. Based on these findings, the incorporation of maternal CRP in the management of chorioamnionitis should be considered, and a continuous communication between obstetric and neonatal care extending past the delivery time point endorsed.

More than time: travel time to the delivery ward and maternal outcomes – onset of labour, postpartum haemorrhage and obstetric anal sphincter injury

BackgroundClosing delivery units increases travel time for some women. Whether increased travel time is associated with maternal outcomes is important for understanding the consequences of such closures. Previous studies are limited in measuring travel time and restricted to the outcome of caesarean section. MethodsOur population-based cohort includes data from the Swedish Pregnancy Register for women giving birth between 2014 and 2017 (N = 364,630). We estimated travel time from home to the delivery ward using coordinate pairs of actual addresses. The association between travel time and onset of labour was modelled using multinomial logistic regression, and logistic regression was used for the outcomes postpartum haemorrhage (PPH) and obstetric anal sphincter injury (OASIS). FindingsOver three-quarters of women had ≤30 min travel time (median 13.9 min). Women who travelled ≥60 min arrived to care sooner and laboured there longer. Women with further to travel had increased adjusted odds ratio (aOR) of having an elective caesarean section (31–59 min aOR 1.11; 95% confidence interval [CI] 1.07–1.16; ≥60 min aOR 1.25; 95% CI 1.16–1.36) than spontaneous onset of labour. Women (at full term with spontaneous onset) living ≥60 min away had reduced odds of having a PPH (aOR 0.84; 95% CI 0.76–0.94) or OASIS (aOR 0.79; 95% CI 0.66–0.94). InterpretationLonger travel time increased the odds of elective caesarean section. Women with furthest to travel arrived sooner and spent more time in care; although they had a lower risk of PPH or OASIS, they also tended to be younger, have a higher body mass index and were Nordic born.

Pre-pregnancy participation and performance in world's largest cross-country ski race as a proxy for physical exercise and fitness, and perinatal outcomes: Prospective registry-based cohort study.

Investigate associations between pre-pregnancy participation and performance in a demanding cross-country ski race (proxy for exercise volume and fitness) and perinatal outcomes. Pre-registered protocol: osf.io/aywg2. Prospective cohort study. Based on entire overlap between the Vasaloppet registry and the population-based Swedish Pregnancy Register. All female Vasaloppet participants 1991-2017 with subsequent singleton delivery (skiers), and age- and county-matched non-skiers. We calculated odds ratios (ORs) for non-skiers versus skiers (model 1) and, among skiers, by performance (model 2), in Bayesian logistic regressions adjusted for socio-demographics, lifestyle factors, and comorbidities. We repeated calculations adjusting for early pregnancy body mass index (potential mediator) and explored robustness (selection/exposure settings; multiple comparisons correction). Twenty-nine important perinatal outcomes, predefined based on existing expert consensus. Non-skiers (n=194 384) versus skiers (n=15 377) (and slower versus faster performance, not shown) consistently had higher odds of gestational diabetes mellitus (GDM) (OR 1.70, 95% highest density interval: 1.40-2.09), excessive gestational weight gain (GWG) (1.28, 1.22-1.38), psychiatric morbidity (1.60, 1.49-1.72), any caesarean section (CS) (1.34, 1.28-1.40), elective CS (1.39, 1.29-1.49), and large-for-gestational-age babies (>90th percentile, 1.11, 1.04-1.18); lower odds of inadequate GWG (0.83, 0.79-0.88); and no associations with fetal/neonatal complications (e.g. preterm birth [1.09, 0.98-1.20], small for gestational age [SGA] [1.23, 1.05-1.45]). Adjustment for body mass index attenuated associations with excessive (1.20, 1.14-1.30) and inadequate GWG (0.87, 0.83-0.92) and large for gestational age (1.07, 1.00-1.13). Non-skiers compared with skiers, and slower versus faster performance, consistently displayed higher odds of GDM, excessive GWG, psychiatric morbidity, CS and large-for-gestational-age babies; and lower odds of inadequate GWG, after adjustment for socio-demographic and lifestyle factors and comorbidities. There were no associations with fetal/neonatal complications.

The association of smoking, use of snuff, and preconception alcohol consumption with spontaneous abortion: A population-based cohort study.

It is unclear whether tobacco in early pregnancy and alcohol use preceding pregnancy are associated with spontaneous abortion. The purpose was to investigate if use of tobacco and/or alcohol is associated with spontaneous abortion among women attending antenatal care, and if age and body mass index (BMI) attenuate the risk. A population-based cohort study based on data from the Swedish Pregnancy Register. All pregnant women having had the first antenatal visit from January 2014 to July 2018 were included (n=525 604). The register had information about smoking and use of snuff before and in early pregnancy, as well as data on alcohol habits before pregnancy, measured by the Alcohol Use Disorders Identification Test (AUDIT), a validated questionnaire. Logistic regression analysis was used to estimate the association between lifestyle factors and spontaneous abortion, and multiple imputation was used to impute missing data. In total, 34 867 (6.6%) pregnancies ended in a spontaneous abortion after the first visit to maternal health care. At the first maternal healthcare visit, daily smoking was reported by 24 214 (5.1%), and 6403 (1.2%) used snuff. For 19 837 (4.2%) women, a high alcohol score was reported for the year preceding pregnancy. After adjusting for potential confounders and multiple imputation, use of tobacco was associated with spontaneous abortion; smoking 1-9 cigarettes/day (adjusted odds ratio [aOR] 1.11, 95% confidence interval [CI] 1.04-1.18), smoking 10 or more cigarettes/day (aOR 1.12, 95% CI 1.-1.26), and use of snuff (aOR 1.20, 95% CI 1.06-1.37). Higher AUDIT scores were not significantly associated with spontaneous abortion (AUDIT 6-9: aOR 1.03, 95% CI 0.97-1.10 and AUDIT 10 or more: aOR 1.07, 95% CI 0.94-1.22). Increasing maternal age showed the highest risk of spontaneous abortion from the age of 35, and BMI of 30 kg/m2 or more increased the risk. There were interactions between different lifestyle factors associated with spontaneous abortion that could either increase or decrease the risk of spontaneous abortion. Smoking and use of snuff were associated with an increased risk of spontaneous abortion. The AUDIT scores preceding pregnancy were not associated with an increased risk of spontaneous abortion, which contradicts the results from previous studies.

Alcohol exposure prior to pregnancy-does hazardous consumption affect placenta- and inflammatory-mediated pregnancy outcomes? A Swedish population-based cohort study.

Alcohol consumption during pregnancy is related to severe birth complications such as low birthweight, preterm birth and birth defects. During the last decade, the Alcohol Use Disorders Identification Test (AUDIT) has been used as a screening tool in Swedish maternal healthcare units to identify hazardous, pre-pregnancy alcohol use. However, evaluation of the screening with AUDIT, as well as adverse maternal or neonatal outcomes, has not been assessed at a national level. This was a population-based cohort study of 530 458 births from 2013 to 2018 using demographic, reproductive and maternal health data from the Swedish Pregnancy Register. Self-reported alcohol consumption in the year before pregnancy, measured as AUDIT scores, was categorized into moderate (6-13 points) and high-risk (14-40 points) consumption, with low-risk (0-5 points) consumption as the reference group. Associations with pregnancy- and birth outcomes were explored with logistic regressions using generalized estimating equation models, adjusting for maternal and socioeconomic characteristics. Estimates are presented as adjusted odds ratios (aORs) with 95% confidence intervals (CIs). High-risk and moderate pre-pregnancy alcohol consumption was associated with preeclampsia, preterm birth and birth of an infant small for gestational age (SGA), but these associations were nonsignificant after adjustments. Prior moderate-risk (aOR 1.29, 95% CI 1.17-1.42) and high-risk consumption (aOR 1.62, 95% CI 1.17-2.25) increased the likelihood of intrapartum and neonatal infections. Apart from identifying hazardous alcohol consumption prior to pregnancy and the offer of counseling, screening with the AUDIT in early pregnancy indicates a high risk of inflammatory-/placenta-mediated pregnancy and birth outcomes. For most outcomes, AUDIT was not an independent contributor when adjusting for confounding factors. Hazardous alcohol use prior to pregnancy was independently linked to intrapartum and neonatal infections; conditions associated with morbidity and long-term sequalae. These associations may be explained by alcohol-induced changes in the maternal or fetal immune system in early pregnancy or persistent alcohol intake during pregnancy, or may depend on unidentified confounding factors.

Prevalence of amniotomy in Sweden: a nationwide register study

BackgroundAmniotomy is a commonly used labor intervention with uncertain evidence, and there are complications connected to the intervention. Yet, the Swedish prevalence of amniotomy is unknown. The aim of the study was therefore to describe the prevalence of amniotomy in Sweden.MethodsThis nationwide register-based study included 330,913 women giving birth in 2017–2020. Data were collected from the Swedish Pregnancy Register in which the majority of data is collected via direct transfer from medical records. Prevalence of amniotomy was described for all births, for nulliparous and multiparous women with spontaneous onset of labour, and at the hospital level. Descriptive statistics and chi-square test were used to analyse the data.ResultsFor all births, the prevalence of amniotomy was 40.6%. More amniotomies were performed in Robson group 1 compared to Robson group 3; 41.1% vs 32.3% (p < 0.001). The prevalence for all births remained the same during the study period; however, a decrease from 37.5 to 34.1%, was seen in Robson group 1 and Robson group 3 (p < 0.001). Variations in the prevalence between hospitals were reported. The hospitals with the fewest number of births annually had the highest prevalence of amniotomy (45.0%), and the lowest prevalence was reported at the University hospitals (40.4%) (p < 0.001).ConclusionsAmniotomy is a common labor intervention in Sweden, given that almost half of the laboring women underwent the intervention. Our results, regarding variations in the prevalence between hospitals, could imply a potential for fewer amniotomies in Swedish childbirth care.

Associations between ambient temperature and risk of preterm birth in Sweden: A comparison of analytical approaches

BackgroundEvidence indicates that high temperatures are a risk factor for preterm birth. Increasing heat exposures due to climate change are therefore a concern for pregnant women. However, the large heterogeneity of study designs and statistical methods across previous studies complicate interpretation and comparisons. We investigated associations of short-term exposure to high ambient temperature with preterm birth in Sweden, applying three complementary analytical approaches. MethodsWe included 560,615 singleton live births between 2014 and 2019, identified in the Swedish Pregnancy Register. We estimated weekly mean temperatures at 1-km2 spatial resolution using a spatiotemporal machine learning methodology, and assigned them at the residential addresses of the study participants. The main outcomes of the study were gestational age in weeks and subcategories of preterm birth (<37 weeks): extremely preterm birth (<28 weeks), very preterm birth (from week 28 to <32), and moderately preterm birth (from week 32 to<37). Case-crossover, quantile regression and time-to-event analyses were applied to estimate the effects of short-term exposure to increased ambient temperature during the week before birth on preterm births. Furthermore, distributed lag nonlinear models (DLNM) were applied to identify susceptibility windows of exposures throughout pregnancy in relation to preterm birth. ResultsA total of 1924 births were extremely preterm (0.4%), 2636 very preterm (0.5%), and 23,664 moderately preterm (4.2%). Consistent across all three analytical approaches (case-crossover, quantile regression and time-to-event analyses), higher ambient temperature (95th vs 50th percentile) demonstrated increased risk of extremely preterm birth, but associations did not reach statistical significance. In DLNM models, we observed no evidence to suggest an increased effect of high temperature on preterm birth risk. Even so, a suggested trend was observed in both the quantile regression and time-to-event analyses of a higher risk of extremely preterm birth with higher temperature during the last week before birth. ConclusionsIn Sweden, with high quality data on exposure and outcome, a temperate climate and good quality ante-natal health care, we did not find an association between high ambient temperatures and preterm births. Results were consistent across three complementary analytical approaches.

Self-rated health in Swedish pregnant women: a comprehensive population register study

Background/Aims Sociodemographic factors are associated with perceived overall health status or ‘self-rated health’. However, research using data from the comprehensive population register in Sweden to examine self-rated health in pregnant women is limited. This study aimed to examine sociodemographic factors associated with self-rated health before, during and after pregnancy in low-risk pregnant women, based on comprehensive population register data in Sweden. Methods This was a retrospective analysis of the Swedish pregnancy register (Graviditets registret). Data from 167 523 women were tested with group comparisons and ordinal regression analyses. Results Women between the ages of 25 and 29 years and primiparas were less likely to self-rate their health lower. Women born outside Scandinavia, those whose education did not reach university level, jobseekers, those on parental leave and students were more likely to report lower self-rated health. Women with risky behaviours, such as alcohol consumption and those who smoked and/or snuffed were more likely to report lower self-rated health. Conclusions The findings indicate that preventive and health promoting actions in the midwifery profession should build on awareness of possible associated sociodemographic factors.