Socioeconomic status, maternal risk factors, and gestational diabetes mellitus across reproductive years: a Finnish register-based study.

INTRODUCTION: To evaluate the degree to which socioeconomic differences in gestational diabetes mellitus (GDM) are accounted for by differences in maternal risk factors, to assess whether age-related risks of GDM differ across socioeconomic groups, and to identify priority populations for future interventions. RESEARCH DESIGN AND METHODS: We performed a register-based study using data from the Finnish Medical Birth Register and Statistics Finland on the 474 166 women who gave birth in Finland from 2008 to 2015. We collected information on GDM based on the International Classification of Diseases 10th Revision codes O24.4 and O24.9. We used multivariable models to examine the association between socioeconomic status, maternal risk factors, and GDM. We further tested interaction on multiplicative and additive scales. RESULTS: The incidence of GDM was 8.7% in 2008-2011 and 12.5% in 2012-2015. Lower socioeconomic levels than upper level employees were associated with an increased risk of GDM. Up to 64.0% of socioeconomic differences in GDM were attributed to body mass index and 5.5% to smoking. There was evidence for effect modification. Relative to women in the upper level category who were aged less than 19 years, GDM adjusted ORs (95% CIs) for women 35 years or older in upper level versus long-term unemployed groups were 3.28 (2.08-5.18) and 5.29 (3.35-8.35), respectively. CONCLUSIONS: There is a paradox that socioeconomic advantage increases the incidence of GDM at the population level while reducing the incidence of GDM within the population. Nevertheless, socioeconomic differences in GDM persist and widen with increasing maternal age, even after accounting for maternal risk factors.

Use of antihypertensive medication and formation of de novo intracranial aneurysms.

BACKGROUND AND PURPOSE: Hypertension is a risk factor for subarachnoid hemorrhage and is also considered a risk factor for saccular intracranial aneurysm (sIA) formation. However, there is little direct evidence that antihypertensive medication will reduce sIA formation. METHODS: The impact of antihypertensive medication on de novo sIA formation was studied in an angiographically followed cohort of 1419 patients. Patients were identified from our population-based Kuopio Intracranial Aneurysm Database, and data on the purchases of antihypertensive medication were obtained from a national registry. Univariate and multivariate analyses were used to investigate the risk factors. RESULTS: Of the 966 sIA patients who were prescribed with antihypertensive medication, 841 patients used the medication regularly; 20 of them had de novo sIA. One hundred and twenty-five patients used the medication irregularly and 12 of them developed de novo sIAs. Four hundred and fifty-three patients did not use antihypertensive medication even though 27 of them had a diagnosis of hypertension, and 10 of them developed de novo sIAs. In the multivariate analysis antihypertensive medication did not significantly reduce de novo sIA formation (hazard ratio [HR] 1.60, 95% confidence interval [CI] 0.84-3.06). Age at primary diagnosis (HR: 0.95, 95%: CI 0.93-0.98) and smoking history (HR: 5.53, 95% CI: 2.77-11.05) were significant risk factors for de novo sIA formation. Also, irregular usage of antihypertensive medication was a significant risk factor (HR: 3.84, 95% CI: 1.59-9.29) for de novo sIA formation. CONCLUSIONS: Antihypertensive agents were not associated with a reduction of de novo sIA formation, but irregular use of antihypertensive agents was associated with an increased risk of de novo sIA formation.

Risk factor management matters more than pharmaceutical cyclooxygenase-2 inhibition in the prevention of de novo intracranial aneurysms.

BACKGROUND AND PURPOSE: Pathophysiological studies of saccular intracranial aneurysm (sIA) disease have shown that inflammation plays a crucial role in sIA development. Pharmaceutical inhibition of COX-2-PGE2-NF-κB signaling (COX-2, cyclooxygenase-2; PGE2, prostaglandin E2; NF-κB, nuclear factor κB) has been shown in animal models to inhibit sIA formation and progression suggesting that use of medication inhibiting COX-2 could reduce intracranial aneurysm formation also in patients. METHODS: The impact of COX-2 inhibition on de novo sIA formation was studied in two cohorts: in a previously described angiographically followed cohort of 1419 sIA patients and in a cohort of 117 sIA patients treated with stenting or stent-assisted embolization. Patients were identified from our population-based Kuopio Intracranial Aneurysm Database. Data on the use of anti-inflammatory medications and hospital diagnoses were obtained from national registries. Risk factors were identified by univariate and multivariate analyses. RESULTS: De novo sIA patients were younger and more often smokers. Use of COX-2 selective inhibitors or nonsteroidal anti-inflammatory drugs did not significantly reduce de novo sIA formation, but the percentage of patients with de novo sIA formation was smaller in patients with prescribed regular acetylsalicylic acid medication (1.1% vs. 3.6%). In the multivariate analysis, however, neither acetylsalicylic acid use nor other type of pharmaceutical inhibition of COX-2 reduced the formation of de novo sIAs. The risk was mostly affected by age, smoking history and irregular usage of antihypertensive medication regardless of used COX-2 inhibition level. CONCLUSION: For the prevention of de novo sIA formation, risk factor management with focus on cessation of smoking and treating hypertension adequately seems more important than pharmaceutical COX-2 inhibition.

Associations between maternal age and socioeconomic status with smoking during the second and third trimesters of pregnancy: a register-based study of 932 671 women in Finland from 2000 to 2015.

OBJECTIVES: This study aimed to explore the association between maternal age and smoking during the second and third trimesters of pregnancy across socioeconomic groups and to evaluate the interacting effect of maternal age and socioeconomic status on smoking with a view to informing public health interventions. DESIGN: This is a register-based study. SETTINGS: Data from the Finnish Medical Birth Register were cross-linked with background data from Statistics Finland. PARTICIPANTS: The information of 932 671 pregnant women who gave birth in Finland from 2000 to 2015. MAIN OUTCOME MEASURES: Maternal smoking during the second and third trimesters of pregnancy by occupation and maternal age. RESULTS: The proportion of women who smoked during the second and third trimesters of pregnancy was 10.5%. Using women 30-34 years as the reference group, adjusted ORs (aOR) and 95% CIs for smoking were 6.02 (5.81 to 6.24) in women below 20 years and 2.77 (2.71 to 2.84) in women 20 to 24 years. The prevalence of smoking across socioeconomic groups compared with upper-level employees increased, peaking for women in manual occupations (aOR 3.39, 95% CI 3.25 to 3.52) and unemployed women (aOR 4.49, 95% CI 4.30 to 4.68). Significant interactions on the additive scale with the relative excess risk due to interaction >2 were found for unemployed women aged 25-29 years and for teenage mothers and mothers aged 20-24 years across all socioeconomic groups, but not for self-employed women. CONCLUSIONS: Smoking during the second and third trimesters of pregnancy was most common among teenage mothers across all socioeconomic groups. The association between maternal age and smoking differed by socioeconomic status for young mothers. Interventions should address a wider range of maternal risk factors among young mothers with low socioeconomic status and simultaneously target a broader number of women who smoke during the pregnancy.

Adverse perinatal outcomes in 665,244 term and post-term deliveries-a Norwegian population-based study.

OBJECTIVE: To assess the prevalence and risk of adverse perinatal outcomes in early-term (37+0-38+6 weeks), full-term (39+0-40+6 weeks), late-term (41+0-41+6 weeks), and post-term (>42+0 weeks) deliveries with spontaneous labor onset. STUDY DESIGN: A population-based cohort with data from the Medical Birth Registry Norway (MBRN) and Statistics Norway (SSB) was conducted. The study population consisted of 665,244 women with cephalic singleton live births at term or post-term with spontaneous labor onset during the period of 1999-2014 in Norway. Maternal, obstetric, and fetal characteristics were obtained from the MBRN. Maternal education data were obtained from the SSB. The prevalence rates of adverse perinatal outcomes for each gestational age (GA) group were estimated. Inter-group differences were detected with Chi square tests. Multivariable regression analysis adjusted for maternal age, educational level, smoking, parity, maternal diabetes, and preeclampsia was used to assess adverse outcome prevalence for early- late-, and post-term births compared to full-term births. RESULTS: Deliveries at early-term were associated with an increased prevalence of neonatal jaundice, polyhydramnios, small for gestational age (SGA) status, respiratory support, and neonatal intensive care unit (NICU) admission compared with deliveries at GAs of 39-43 weeks (p < 0.001). Low 5-min Apgar scores and newborn antibiotic treatment occurred at an increased prevalence in both early-term and post-term infants, relative to the full-term group (p < 0.001). The prevalence of oligohydramnios, meconium-stained amniotic fluid, and newborn birth injuries increased with increasing GA. CONCLUSIONS: More perinatal morbidity was observed among early-term infants compared to infants with later term deliveries, underscoring the need for cautious management of low-risk early-term deliveries.

Association between maternal pregestational diabetes mellitus and spina bifida: A population-based case-control study, Finland, 2000-2014.

BACKGROUND: Maternal pregestational diabetes mellitus (PGDM) is a known risk factor for neural tube defects. We examined the association between maternal PGDM and spina bifida in the offspring using PGDM status from medical records in Finland. METHODS: We conducted a nationally representative, multiregistry, population-based case-control study in Finland. Cases were included if they were live or stillborn infants and diagnosed with spina bifida and delivered between years 2000 and 2014 in Finland. Controls were Finnish infants without spina bifida or other major structural birth defects and delivered during the same time period as cases. Clinical and demographic data were obtained by linking multiple national health registers and census. Crude and adjusted odds ratios (ORs) and 95% confidence intervals (CI) for PGDM were estimated using logistic regression analysis. Interaction by maternal obesity was examined. RESULTS: Our study included 181 spina bifida cases (61% isolated) and 876,672 controls. Overall, 2.2% percent of all case, and 0.5% of control mothers, had PGDM during pregnancy. Maternal PGDM was significantly associated with an increased odds of spina bifida (adjusted OR 4.35; 95% CI 1.37, 13.82). A similar association was found in our subanalysis on isolated spina bifida cases (adjusted OR 4.41; 95% CI 1.07, 18.24). There was no significant interaction by maternal obesity. CONCLUSIONS: Maternal PGDM was positively associated with spina bifida in Finland, and maternal obesity did not modify this effect. We lacked information on maternal PGDM for electively terminated and spontaneously aborted cases; results should be interpreted with caution.

Prevalence and risk of pre-eclampsia and gestational hypertension in twin pregnancies: a population-based register study.

OBJECTIVES: The aim of this study was to assess the prevalence and risk of pre-eclampsia and gestational hypertension in twin pregnancies compared with singleton pregnancies. DESIGN: Population-based cohort study. SETTING: Medical Birth Registry of Norway and Statistics Norway. PARTICIPANTS: 929 963 deliveries with 16 174 twin pregnancies in 1999-2014. METHODS: Pre-eclampsia prevalences in twin and singleton pregnancies were described in percentages. Multivariable regression analyses were performed to assess the risks of pre-eclampsia and gestational hypertension in twin pregnancies compared with those in singleton pregnancies, adjusted for previously known risk factors. PRIMARY AND SECONDARY OUTCOME MEASURES: Prevalence and risk of pre-eclampsia and gestational hypertension. RESULTS: The prevalence of pre-eclampsia in the study population was 3.7% (3.4% in singleton pregnancies, 11.8% in twin pregnancies (p=0.001)). The OR for pre-eclampsia in twin pregnancies was three to fourfold compared with singleton pregnancies (OR 3.78; 95% CI 3.59 to 3.96). After adjustment for known risk factors, twin pregnancy remained an independent risk factor for pre-eclampsia (adjusted OR 4.07; 95% CI 3.65 to 4.54). The prevalence of gestational hypertension was 1.7% in women with singleton pregnancies and 2.2% in those with twin pregnancies (OR 1.27; 95% CI 1.14 to 1.41). After adjustment for known risk factors, gestational hypertension was not significantly associated with twin pregnancy. CONCLUSIONS: The risk of pre-eclampsia in twin pregnancies was three to fourfold compared with singleton pregnancies, regardless of maternal age, parity, educational level, smoking, maternal comorbidity or in vitro fertilisation. The risk of gestational hypertension was not increased in women with twin pregnancies after adjustment for the main risk factors.

Impact of Young Age on the Presentation of Saccular Intracranial Aneurysms: Population-Based Analysis of 4082 Patients.

BACKGROUND: Formation and rupture of saccular intracranial aneurysms (sIAs) may have different pathobiologies in patients with younger age at first diagnosis of sIA disease. OBJECTIVE: To study the phenotype of sIA disease and formation of new (de novo) sIAs in patients below 40 yr. METHODS: A population-based cohort study was conducted in 613 young (<40 yr) sIA patients with first diagnosis between 1980 and 2014 and total angiographic follow-up of 3768 yr. RESULTS: Of the 613 sIA patients <40 yr, 508 had aneurysmal subarachnoid hemorrhage (sIA-SAH) and 105 unruptured sIA(s) at first sIA diagnosis. Hypertension was 2 times less common among <40 than >40-yr-old patients (unruptured and ruptured). Smoking was very prevalent in <40-yr-old patients (33% in SAH, 68% unruptured). SAH patients <40 yr more often had family history of sIA, and lower PHASES scores (age omitted, P < .001). Ruptured sIAs were small (<7 mm) in 33% of 39 to 30 yr patients, in 44% of 29 to 20 yr patients, and 57% of <19 yr patients. Their shape was irregular in 90%, 94%, and 95%, respectively. Smoking history (hazard ratio [HR] 2.8, 95% confidence interval [CI] 1.2-7.0), family history for sIAs (HR 3.1, 95% CI 1.3-7.7), and age at presentation (HR .91 per year, 95% CI .85-.98) were risk factors for de novo sIA formation, diagnosed in 4% even after 20 yr (median 11.8 yr). CONCLUSION: Smoking and family history are risk factors for sIA formation and aneurysmal SAH at young age. Young aneurysmal SAH patients had lower PHASES scores and often rupture from a small sIA, suggesting need for more aggressive management.

De Novo Aneurysm Formation in Carriers of Saccular Intracranial Aneurysm Disease in Eastern Finland.

BACKGROUND AND PURPOSE: Formation of new (de novo) aneurysms in patients carrying saccular intracranial aneurysm (sIA) disease has been published, but data from population-based cohorts are scarce. METHODS: Kuopio sIA database (http://www.uef.fi/ns) contains all unruptured and ruptured sIA patients admitted to Kuopio University Hospital from its Eastern Finnish catchment population. We studied the incidence and risk factors for de novo sIA formation in 1419 sIA patients with ≥5 years of angiographic follow-up, a total follow-up of 18 526 patient-years. RESULTS: There were 42 patients with a total of 56 de novo sIAs, diagnosed in a median of 11.7 years after the first sIA diagnosis. The cumulative incidence of de novo sIAs was 0.23% per patient-year and that of subarachnoid hemorrhage from a ruptured de novo sIA 0.05% per patient-year. The risk of de novo sIA discovery per patient-year increased with younger age at the first sIA diagnosis: 2.2% in the patients aged <20 years and 0.46% in the patients aged between 20 and 39 years. In Cox regression analysis, smoking history and younger age at the first sIA diagnosis significantly associated with de novo sIA formation, but female sex, multiple sIAs, and sIA family did not. CONCLUSIONS: Patients aged < 40 years at the first sIA diagnosis are in a significant risk of developing de novo sIAs, and they should be scheduled for long-term angiographic follow-up. Smoking increases the risk of de novo sIA formation, suggesting long-term follow-up for smokers. Antismoking efforts are highly recommended for sIA patients.

Placenta previa and risk of major congenital malformations among singleton births in Finland.

BACKGROUND: Placenta previa has been associated with adverse birth outcomes, but its association with congenital malformations is inconclusive. We examined the association between placenta previa and major congenital malformations among singleton births in Finland. METHODS: We performed a retrospective population register-based study on all singletons born at or after 22+0 weeks of gestation in Finland during 2000 to 2010. We linked three national health registers: the Finnish Medical Birth Register, the Hospital Discharge Register, and the Register of Congenital Malformations, and examined several demographic and clinical characteristics among women with and without placenta previa, in association with major congenital malformations. We estimated adjusted odds ratios and 95% confidence intervals using multivariable logistic regression models. RESULTS: The prevalence of placenta previa was estimated as 2.65 per 1000 singleton births in Finland (95% confidence interval, 2.53-2.79). Overall, 6.2% of women with placenta previa delivered a singleton infant with a major congenital malformation, compared with 3.8% of unaffected women (p ≤ 0.001). Placenta previa was positively associated with almost 1.6-fold increased risk of major congenital malformations in the offspring, after controlling for maternal age, parity, fetal sex, smoking, socio-economic status, chorionic villus biopsy, In vitro fertilization, pre-existing diabetes, depression, preeclampsia, and prior caesarean section (adjusted odds ratio = 1.55; 95% confidence interval, 1.27-1.90). CONCLUSION: Using a large population-based study, we found that placenta previa was weakly, but significantly associated with an increased risk of major congenital malformations in singleton births. Future studies should examine the association between placenta previa and individual types of congenital malformations, specifically in high-risk pregnancies.

Maternal socioeconomic status and the risk of asthma among offspring.

BACKGROUND: To evaluate the association between maternal socioeconomic status (SES) during pregnancy and asthma among offspring. METHODS: A retrospective observational hospital-based birth cohort study in a university-based Obstetrics and Gynecology department in Finland. A total of 40 118 women with singleton live births between 1989 and 2007 were linked with data from the register for asthma medication for their offspring (n = 2518). Pregnancy and maternal SES factors were recorded during pregnancy and labor. SES was categorized thus: upper white-collar workers (highest SES), lower white-collar workers, blue-collar workers, others (lowest SES) and cases with missing information. Logistic regression analysis was used to determine the association between maternal SES and childhood asthma. RESULTS: We found no convincing evidence of a direct association between maternal SES and childhood asthma. Parental smoking was the clearest factor affecting asthma among children of lower white-collar workers. Differences in pregnancy and delivery characteristics were observed between the SES groups. CONCLUSIONS: Maternal socioeconomic status had no significant direct impact on the prevalence of asthma in this Finnish birth cohort. Finnish public health services appeared to offer equal quality services independently of SES. TRIAL REGISTRATION: The study is registered in Kuopio University Hospital register (TUTKI): ID 5302448 .

Risk factors for and perinatal outcomes of major depression during pregnancy: a population-based analysis during 2002-2010 in Finland.

OBJECTIVES: To identify risk factors for and the consequences (several adverse perinatal outcomes) of physician-diagnosed major depression during pregnancy treated in specialised healthcare. DESIGN: A population-based cross-sectional study. SETTING: Data were gathered from Finnish health registers for 1996-2010. PARTICIPANTS: All singleton births (n=511,938) for 2002-2010 in Finland. PRIMARY OUTCOME MEASURES: Prevalence, risk factors and consequences of major depression during pregnancy. RESULTS: Among 511,938 women, 0.8% experienced major depression during pregnancy, of which 46.9% had a history of depression prior to pregnancy. After history of depression, the second strongest associated factor for major depression was fear of childbirth, with a 2.6-fold (adjusted OR (aOR=2.63, 95% CI 2.39 to 2.89) increased prevalence. The risk profile of major depression also included adolescent or advanced maternal age, low or unspecified socioeconomic status (SES), single marital status, smoking, prior pregnancy terminations, anaemia and gestational diabetes regardless of a history of depression. Outcomes of pregnancies were worse among women with major depression than without. The contribution of smoking was substantial to modest for small-for-gestational age newborn (<-2 SD below mean birth), low birth weight (<2500 g), preterm birth (<37 weeks) and admission to neonatal intensive care associated with major depression, whereas SES made only a minor contribution. CONCLUSIONS: Physician-diagnosed major depression during pregnancy was found to be rare. The strongest risk factor was history of depression prior to pregnancy. Other associated factors were fear of childbirth, low SES, lack of social support and unhealthy reproductive behaviour such as smoking. Outcomes of pregnancies were worse among women with major depression than without. Smoking during pregnancy made a substantial to modest contribution to adverse outcomes associated with depression during pregnancy.

Unemployment at municipality level is associated with an increased risk of small for gestational age births--a multilevel analysis of all singleton births during 2005-2010 in Finland.

INTRODUCTION: Neighbourhood level deprivation has been shown to influence adverse perinatal outcomes independent of individual level socioeconomic status (SES) in countries with high income inequality, such as the United States. The present study evaluates whether municipality level deprivation defined based on education (proportion of inhabitants with university level education), income (mean income per capita) and unemployment were associated with the prevalence of preterm birth (<37 weeks) and small for gestational age (SGA, birth weight <2 standard deviations) after adjustment for individual level socio-demographics (age, parity, prior preterm births, smoking during pregnancy and SES defined based on maternal occupation at birth) in Finland. METHODS: The study design was cross-sectional. The data gathered from the Medical Birth Register included all singleton births (n = 345,952) in 2005-2010. We fitted Generalized Estimating Equations (GEE) models to account for correlation of preterm birth and SGA clustering within municipality. RESULTS: Of all the women with singleton pregnancies, 4.5% (n = 15,615) gave birth preterm and 3.8% (n = 13,111) of their newborns were classified as SGA. Individual level SES and smoking were important risk factors for each outcome in adjusted models. Controlling for individual level factors, women living in intermediate and high unemployment class municipalities were 6.0% (adjusted odds ratio (aOR) = 1.06; 95% confidence interval (CI) 1.01-1.12) and 13.0% (aOR = 1.13; 95% CI 1.06-1.20), respectively, more likely to give birth to an SGA newborn than women living in low unemployment class municipalities. CONCLUSIONS: After adjustment for individual level socio-demographics, the prevalence of SGA was around 6-13% higher in municipalities with an intermediate or high unemployment rate than municipalities with the lowest unemployment rate. The results suggested that the unemployment rate has an important public health effect with clinical implications since SGA is associated with a higher risk of adverse long-term health outcomes.

Smoking during pregnancy was up to 70% more common in the most deprived municipalities - a multilevel analysis of all singleton births during 2005-2010 in Finland.

OBJECTIVE: We investigated whether there was an association between maternal smoking habits during pregnancy and municipality level deprivation defined based on education, income and unemployment after adjustment for individual level covariates, including socioeconomic status (SES), in Finland, a Nordic welfare state. METHODS: Data were gathered from the Medical Birth Register and comprised all singleton births (n=337,876) during 2005-2010. To account for any correlation of women clustered within a municipality, we fitted generalized estimating equation (GEE) models. RESULTS: In total, 15.3% of the women with singleton pregnancies smoked during pregnancy. After adjustment for individual level confounders, smoking during pregnancy was 5.4-fold higher among women with the lowest as compared with highest individual SES. Controlling for individual SES, age and year of birth, women living in municipalities defined as intermediately and highly deprived based on education were 53.7% (adjusted odds ratio [aOR] 1.537, 95% confidence interval [CI] 1.493-1.583) and 71.5% (aOR 1.715, 95% CI 1.647-1.785), respectively, more likely to smoke during pregnancy than women in the least deprived municipalities. CONCLUSIONS: Individual SES is the strongest correlate of smoking during pregnancy but conditional on individual variables; lower municipality aggregate education is associated with up to 70% higher smoking prevalence.

Placenta previa and the risk of delivering a small-for-gestational-age newborn.

OBJECTIVE: To evaluate whether there is an association between placenta previa and delivery of a small-for-gestational-age (SGA) newborn and to quantify the contribution of individual risk factors for SGA that are associated with placenta previa stratified by maternal parity. METHODS: A cross-sectional study using the Finnish Medical Birth Register during 2000-2010. All singleton births (N=596,562) were included; major congenital anomalies were excluded. An association between SGA (less than 2 standard deviations below the mean) and placenta previa was modeled by parity-specific unadjusted and adjusted statistical models. RESULTS: Placenta previa complicated 625 of 249,476 singleton births among nulliparous women (2.50/1,000) and 915 of 347,086 singleton births among multiparous women (2.64/1,000). Among nulliparous women, the most common risk factor for placenta previa was in vitro fertilization; placenta previa was not associated with an increased prevalence of SGA controlling for maternal age, smoking, in vitro fertilization, socioeconomic status, and preeclampsia (adjusted odds ratio [OR] 0.81, 95% confidence interval [CI] 0.57-1.17). Among multiparous women, placenta previa was associated with a twofold increased risk of SGA controlling for maternal age, parity, prior preterm birth, prior caesarean delivery, prior SGA newborn, prior preeclampsia, smoking, in vitro fertilization, socioeconomic status, and preeclampsia (adjusted OR 2.08, 95% CI 1.50-2.89). Furthermore, only one-fourth of the association between SGA and placenta previa could be explained by controlling for risk factors clustering with placenta previa among multiparous women. CONCLUSION: Placenta previa is associated with impaired fetal growth in multiparous but not nulliparous women. LEVEL OF EVIDENCE: II.

The use of epidural analgesia for intrapartum pain relief in publicly funded healthcare.

BACKGROUND: Epidural analgesia is the most effective way to relieve pain during birth. In a population-based case-control study, we evaluated whether socioeconomic status (SES) affects the use of epidural analgesia for intrapartum pain relief in publicly funded health care. METHODS: Data gathered from the Finnish Medical Birth Register included all singleton births (n = 521,179) in 2000-2010. The likelihood of receiving epidural analgesia according to vaginal birth order, socio-demographic factors and delivery characteristics was determined by using logistic regression analysis. RESULTS: Overall, 66.6% of women with first vaginal births and 22.4% of women with second or subsequent vaginal births had epidural analgesia. The use of epidural analgesia was associated with several factors, such as post-term pregnancy, gestational diabetes, maternal diabetes mellitus, single marital status, smoking, depression and fear of childbirth, induction, high birth weight and giving birth by vacuum extraction regardless of vaginal birth order. Epidural use did not vary substantially by SES in first vaginal births, but a minor difference was found in second or subsequent vaginal births. The prevalence of epidural analgesia was 3% [adjusted odds ratio (aOR) 0.97, 95% confidence interval (CI) 0.93-1.00] and 13% (aOR 0.87, 95% CI 0.83-0.90) lower among lower white-collar workers and blue-collar workers, respectively, compared with upper white-collar workers. CONCLUSIONS: In Finland, the use of epidural analgesia for intrapartum pain relief reflected clinical indications and did not substantially vary by SES regardless of vaginal birth order. This could be considered as an important indicator measuring health equality.

Smoking cessation in the first trimester reduces most obstetric risks, but not the risks of major congenital anomalies and admission to neonatal care: a population-based cohort study of 1,164,953 singleton pregnancies in Finland.

BACKGROUND: In industrialised countries, approximately 5-20% of women smoke during pregnancy. We aim to study the association between smoking during pregnancy and adverse perinatal outcomes. METHODS: A retrospective population-based cohort study using data on all singleton births between 1991 and 2010 (n=1,164,953) derived from the Finnish Medical Birth Register. RESULTS: Of all the mothers included, 82.3% were non-smokers, 2.6% quit smoking during the first trimester of pregnancy, 12.5% smoked throughout pregnancy and 2.7% had no information on smoking. Continuing smoking after the first trimester of the pregnancy was associated with an increased prevalence of admission to a neonatal intensive care unit, stillbirth, preterm birth (<37 gestational weeks), low birth weight (LBW, <2500 g), small for gestational age (SGA, < -2 SDs) and major congenital anomaly compared with non-smokers. Smoking cessation reduced the risk of prematurity, stillbirth, LBW and SGA close to or at similar levels as those of non-smokers. Tobacco exposure in early pregnancy resulted in a 19% increased prevalence of admission to neonatal intensive care unit and a 22% increased prevalence of major congenital anomaly compared with non-smokers. CONCLUSIONS: Smoking cessation appeared to reduce pregnancy risks close to those of non-smoking peers. Exposure to early pregnancy smoking was, however, associated with an increased admission to neonatal intensive care and an increased prevalence of major congenital anomalies.

Social disparity affects the incidence of placental abruption among multiparous but not nulliparous women: a register-based analysis of 1,162,126 singleton births.

OBJECTIVES: To identify risk factors for placental abruption and to evaluate associations between adverse perinatal outcomes and placental abruption stratified by parity among women with singleton births from 1991 to 2010 in Finland. STUDY DESIGN: A retrospective population-based case-control study of singleton births in Finland from 1991 to 2010 (n=1,162,126 from the Finnish Medical Birth Register). We modelled the group-specific risk factors for placental abruption in unadjusted and adjusted models. RESULTS: In total 3.5 and 3.7 per 1000 nulliparous and multiparous women, respectively, were affected by placental abruption. The recurrence rate was 8.6 per 1000 births. The adjusted risk for placental abruption increased in pregnancies characterised by advanced maternal age, low birth weight, smoking, major congenital anomaly, preeclampsia and male foetal sex in both parity groups. In vitro fertilisation increased the risk only in nulliparae whereas anaemia, a prior caesarean section and the lowest socioeconomic status increased the risk in multiparae. Births affected by placental abruption were associated with an increased admission for neonatal intensive care, preterm birth, low birth weight (<2500 g), small for gestational age infants, low Apgar scores, and low newborn umbilical vein pH (<7.15). Placental abruption resulted in increased risks of stillbirth and early neonatal death in both parity groups. CONCLUSIONS: The burden of placental abruption is equal in nulliparae and multiparae, but risk factors vary substantially. Social disparity only affects the incidence of placental abruption among multiparous women, indicating that factors related to lifestyle and health behaviour have different effects on the parity groups.

The burden of OASIS increases along with socioeconomic position--register-based analysis of 980,733 births in Finland.

BACKGROUND: Obstetric anal sphincter injury (OASIS) has been identified as a major preventable risk factor for anal incontinence. OBJECTIVE: Aim was to measure national variation in incidence of OASIS by socioeconomic status (SES). METHODS: A retrospective population based case-control study using the data derived from the Finnish Medical Birth Register for the years 1991-2010. A total population of singleton vaginal births was reviewed. We calculated unadjusted incidences of OASIS stratified by SES and vaginal parity, and adjusted risks for OASIS in each social class, after controlling for parity, birthweight, mode of delivery, maternal age and maternal smoking. SES was recorded into five categories based on mother's occupation at time of birth; upper white-collar workers such as physicians, lower white-collar workers such as nurses, blue-collar workers such as cleaners, others such as students, and cases with missing information. RESULTS: Seven per thousand (6,404 of 980,733) singleton births were affected by OASIS. In nulliparae the incidence of OASIS was 18% higher (adjusted OR 1.18 95% CI 1.04-1.34) for upper white-collar workers and 12% higher (adjusted OR 1.12 95% CI 1.02-1.24) for lower white-collar workers compared with blue-collar workers. Among women in these higher SES groups, 40% of the excess OASIS risk was explained by age, non-smoking, birthweight and mode of delivery. Despite the large effect of SES on OASIS, inclusion of SES in multivariable models caused only small changes in estimated adjusted effects for other established risk factors. CONCLUSIONS: OASIS at the first vaginal delivery demonstrates a strong positive social gradient. Higher SES is associated with a number of risk factors for OASIS, including higher birthweight and non-smoking, but only 40% of the excess incidence is explained by these known risk factors. Further research should address other underlying causes including differences in lifestyle or environmental factors, and inequalities in healthcare provision.

Socioeconomic status affects the prevalence, but not the perinatal outcomes, of in vitro fertilization pregnancies.

STUDY QUESTION: Does maternal socioeconomic status (SES) confound or modify the association between IVF and perinatal outcome among singleton births? SUMMARY ANSWER: There were substantial socioeconomic differences in the frequency of IVF pregnancies, but maternal SES was not associated with the outcome of IVF pregnancies. WHAT IS KNOWN ALREADY: The use of IVF is associated with SES. Additionally, women with lower SES tend to have an increased risk of adverse perinatal outcomes such as preterm birth and small for gestational age birth. STUDY DESIGN, SIZE, DURATION: We conducted a population-based cohort study using the Finnish Medical Birth Register (2006-2010). PARTICIPANTS/MATERIALS, SETTING, METHODS: We analyzed the total population of singleton births in Finland (n = 291 004) and then compared the unadjusted and adjusted incidences of adverse perinatal outcomes for singleton births after IVF (n = 5647) and non-IVF pregnancies (n = 285 357) in relation to SES. MAIN RESULTS AND THE ROLE OF CHANCE: SES did not confound or modify the association between IVF and perinatal outcomes after adjustments for age, parity, smoking, gestational diabetes, maternal diabetes and pre-eclampsia. However, the prevalence of IVF pregnancies increased with SES; on average 1.9% of singleton infants were born after IVF pregnancies, while the corresponding percentages were 3.2 and 1.2% for the highest and lowest SES strata, respectively. IVF was statistically significantly associated with 1.27-, 1.49-, 1.63-, 1.47-, 1.35-, 1.40-, 4.97- and 1.14-fold higher incidences of admission to a neonatal unit, stillbirth, preterm birth, low birthweight, low Apgar scores (<7 at 5 min), Cesarean section, placenta previa and major congenital anomaly, respectively. Irrespective of the SES group, women who became pregnant through IVF were older and more often nulliparous and non-smokers compared with women with non-IVF pregnancies. LIMITATIONS, REASONS FOR CAUTION: The occupation of 22% of the women was unknown and that of a further 25% did not match any of the criteria for our SES strata. Additionally, infertility is a problem for couples but the definition of SES in this study was based only on the mother's occupation at the time of birth. WIDER IMPLICATIONS OF THE FINDINGS: The prevalence of IVF-conceived pregnancies was highest among the highest SES group, but SES did not confound the perinatal outcomes of IVF pregnancies after adjusting for background factors. However, the magnitude of risks associated with the IVF technique itself may be more significant than previously thought. STUDY FUNDING/COMPETING INTEREST(S): None of the authors received any funding specifically for this study, and we have no competing interests.