Social inequalities in the provision of obstetric services in Norway 1967-2009: a population-based cohort study.

BACKGROUND: Socioeconomic (SE) inequalities have been observed in a number of adverse outcomes of pregnancy and many of the risk factors for such outcomes are associated with a low SE level. However, SE inequalities persist even after adjustment for these risk factors. Less well-off women are more vulnerable, but may also get less adequate health services. The objective of the present study was to assess possible associations between SE conditions in terms of maternal education as well as ethnic background and obstetric care. METHODS: A population-based national cohort study from the Medical Birth Registry of Norway. The study population comprised 2 305 780 births from the observation period 1967-2009. Multilevel analysis was used because of the hierarchical structure of the data. Outcome variables included induction of labour, epidural analgesia, caesarean section, neonatal intensive care and perinatal death. RESULTS: While medical interventions in the 1970s were employed less frequently in women of short education and non-western immigrants, this difference was eliminated or even reversed towards the end of the observation period. However, an excess perinatal mortality in both the short-educated [adjusted relative risk (aRR) = 2.49] and the non-western immigrant groups (aRR = 1.75) remained and may indicate increasing health problems in these groups. CONCLUSION: Even though our study suggests a fair and favourable development during the last decades in the distribution across SE groups of obstetric health services, the results suggest that the needs for obstetric care have increased in vulnerable groups, requiring a closer follow-up.

Perinatal outcome in births after a previous cesarean section at high trial of labor rates.

INTRODUCTION: Trial of labor (TOLAC) is an option in most preganancies after a cesarean section The objective of the study was to compare perinatal outcome in TOLAC and non-TOLAC deliveries in a population with high TOLAC rates. MATERIAL AND METHODS: This was a cohort study based on population data from the Medical Birth Registry of Norway. We included term, cephalic, single, second deliveries, 1989-2009, after a first cesarean section (n = 43 422). TOLAC, TOLAC failure, non-TOLAC deliveries, and after high-risk and low-risk pregnancies (no risk/any risk), were compared with respect to offspring mortality, 5-minute Apgar score Apgar < 7 and < 4, transfer to a neonatal intensive care unit, and neonatal respiratory distress syndrome. RESULTS: Statistically significant differences were observed (P <0.05). In the low-risk group the offspring mortality was 2.3/1000 in TOLAC compared with 0.9/1000 in non-TOLAC. In the high-risk group, the offspring mortality was 3.7/1000 in TOLAC compared with 0.9/1000 in non-TOLAC, and the 5-minute Apgar score < 4 was 3.1/1000 in TOLAC compared with 0.9/1000 in non-TOLAC. In both risk groups, TOLAC delivery had a higher rate of 5-minute Apgar score < 7. In the low-risk group, non-TOLAC deliveries had a higher rate of neonatal respiratory distress syndrome than TOLAC deliveries. CONCLUSIONS: We observed higher risk of offspring mortality and lower 5-minute Apgar score in TOLAC than in non-TOLAC. Possible causes and preventive measures should be explored.

Risk factors for recurrence of hypertensive disorders of pregnancy, a population-based cohort study.

INTRODUCTION: Hypertensive disorders of pregnancy (HDP) tend to recur from one pregnancy to the next. The aims of the study were to assess the recurrence risk according to type of HDP defined by gestational age at birth and to examine whether recurrence is associated with the following additional risk factors for HDP: maternal age, smoking, inter-delivery interval, diabetes, body mass index, and fetal growth restriction, and to assess temporal trends in these associations. MATERIAL AND METHODS: All women with two singleton births in the Medical Birth Registry of Norway 1967-2012 (n = 742 980) were included in this population-based cohort study. Logistic regression was used to calculate odds ratios for the risk of recurrent HDP according to type of HDP. RESULTS: The highest odds ratio of recurrence was observed for the same type of HDP based on gestational age at delivery. After gestational hypertension and term preeclampsia, the risk for the same type to recur increased 10-fold, whereas after late and early preterm preeclampsia, the risk increased 27- and 97-fold, respectively. The recurrence of early preterm preeclampsia was less influenced by additional risk factors compared with term HDP. Recurrence of early preterm HDP was significantly lower from 1993 onwards. CONCLUSIONS: Recurrent HDP tended to be of the same type as the previous HDP. Risk of recurrence associated with additional risk factors was observed particularly after term. The odds ratio of recurrence of early preterm HDP was significantly lower from 1993 onwards.

Socio-economic risk factors for preterm birth in Norway 1999-2009.

AIMS: Preterm birth is a major cause of perinatal mortality and morbidity and is strongly associated with socio-economic factors. The objective of this study was to examine the associations of maternal education, marital status and ethnicity with preterm birth and to determine the extent to which such associations can be explained by the established risk factors of maternal age, parity and smoking. METHODS: This was a register-based cohort study with data from the Medical Birth Registry of Norway 1999-2009 and Statistics Norway. The sample included all singleton spontaneous births in Norway from 1999 to 2009 (n=494,073). The main outcome measure was preterm birth (gestational age <37 weeks). RESULTS: Low maternal education and single motherhood were associated with preterm birth. After adjustment for the established risk factors, the excess risks were reduced, but remained statistically significant. The relative risk for low education was reduced from 1.50 to 1.36 and for single motherhood from 1.50 to 1.28. Women from Asia had a higher risk of preterm birth than Norwegian-born women (relative risk 1.29) with minor effects of adjustment. CONCLUSIONS SEVERAL SOCIO-ECONOMIC RISK FACTORS ARE ASSOCIATED WITH PRETERM BIRTH IN NORWAY IN ADDITION TO THE ESTABLISHED RISK FACTORS, PRENATAL HEALTH CARE SHOULD FOCUS ON HIGH-RISK GROUPS DEFINED BY MATERNAL EDUCATION, MARITAL STATUS AND ETHNICITY.

Maternal Sick Leave Due to Psychiatric Disorders Following the Birth of a Child With Special Health Care Needs.

OBJECTIVE: Child-related stress following the birth of a child with special health care needs (SHCN) can take a toll on parental health. This study examined how the risk of sick leave due to psychiatric disorders (PD) among mothers of children with SHCN compares with that of mothers of children without SHCN during early motherhood. METHODS: Responses from 58,532 mothers participating in the Norwegian Mother and Child Cohort Study were linked to national registries and monitored for physician-certified sick leave from the month of their child's first birthday until the month of their child's fourth birthday. RESULTS: As compared with mothers of children without SHCN, mothers of children with mild and moderate/severe care needs were at substantial risk of a long-term sick leave due to PD in general and due to depression more specifically. CONCLUSIONS: Extensive childhood care needs are strongly associated with impaired mental health in maternal caregivers during early motherhood.

Breastfeeding surveyed using routine data.

BACKGROUND: The purpose of this study was to investigate breastfeeding as a health indicator through routine data registered at public child health centres. The prevalence and course of breastfeeding were surveyed, as well as factors that affect breastfeeding. MATERIAL AND METHOD: Breastfeeding status at six weeks and six months of age and other routine data were systematically recorded in a newly developed electronic medical records system (Health Profile 0-20 years) for infants attending public child health centres in Bergen in the period 2010-11. This information was linked to data from the Medical Birth Registry. RESULTS: Of 6,093 infants, 73.6% were exclusively breastfed at six weeks of age and 18.9% at six months. In adjusted analyses, there was an association between breastfeeding cessation before six months and the factors smoking, low maternal age, marital status as single, unsatisfactory family situation and social network, and birth weight under 2,500 g. Attendance at a specialist breastfeeding centre and uncertain/abnormal sleep patterns in infants were associated with continued breastfeeding after six months. INTERPRETATION: The medical records system «Health Profile 0-20 years¼, linked to the Medical Birth Registry, was well suited to studying factors that can affect breastfeeding. Mothers and infants with increased need for follow-up were identified.

The association of high birth weight with intelligence in young adulthood: a cohort study of male siblings.

We aimed to explore why, in population studies, the positive association between normal-range birth weight and intelligence becomes negative at the highest birth weights. The study population comprised 217,746 Norwegian male singletons born at term between 1967 and 1976. All had data on birth weight and intelligence quotient (IQ) score at the time of military conscription; 137,574 had data on sibling birth weights; and 62,906 had data on male sibling birth weights. We estimated associations between birth weight and IQ score by ordinary least squares regression for the total study population and by fixed-effects regression for comparisons of brothers. The crude mean IQ score was 1.2 points (95% confidence interval (CI): 0.3, 2.2) lower for those with birth weights of 5,000 g or more compared with the reference group (with birth weights of 4,000-4,499 g). This difference leveled off to 0.0 (95% CI: -0.8, 0.9) in multivariable ordinary least squares regression and reversed to 2.2 points (95% CI: 0.3, 4.2) higher in fixed-effects regression. Results differed mainly because, at a given birth weight, participants who had a sibling with macrosomia had a lower mean IQ score. Nevertheless, within families with 1 or more macrosomic siblings, as in other families, men with higher birth weights tended to have higher IQ scores. Thus, a family-level confounder introduces a cross-level bias that cannot be detected in individual-level studies. We suggest ways in which future studies might elucidate the nature of this confounder.

Risk of cerebral palsy in term-born singletons according to growth status at birth.

AIMS: An excess risk of cerebral palsy (CP) has been reported in children of both low and high birthweight. However, the risk associated with deviations from the mean of other anthropometric measurements has been less well studied. The aim of our study therefore was to determine the association between size measurements at birth and incidence of CP in singletons born at term. METHOD: Standard deviation z-scores for weight, length, head circumference, and ponderal index at birth of term-born singletons born between 1996 and 2006 were calculated using data from the Medical Birth Registry of Norway. The measurements of 398 children with CP recorded in the Cerebral Palsy Registry of Norway were compared with those of 490,022 typically developing infants. RESULTS: Children with low birthweight (p<0.001; <10th centile) as well as low and high z-scores for length (p<0.001 and p<0.001) and head circumference (p<0.001 and p<0.003; <90th centile) had an excess risk of CP, in particular of spastic bilateral CP. Spastic unilateral CP was associated only with low z-scores, whereas children with the greatest body length and largest head circumference, but with low ponderal index, had an excess risk of spastic quadriplegic and dyskinetic CP. INTERPRETATION: Our results are consistent with the notion that most subtypes of CP are due to antenatal factors leading to poor intrauterine growth, whereas CP in children who were large at birth is more likely to be due to intrapartum factors.

Employment trends during preschool years among mothers of term singletons born with low birth weight.

Children born at term with low birth weight (LBW) are regarded growth restricted and are at particular risk of adverse health outcomes requiring a high degree of parental participation in the day-to-day care. This study examined whether their increased risk of special health care needs compared to other children may influence mothers' opportunities for participation in the labor market at different times after delivery. Data from 32,938 participants in the population-based Norwegian Mother and Child Cohort Study with singleton children born at term in 2004-2006 were linked to national registers in order to investigate the mothers' employment status when their children were 1-3 years in 2007 and 4-6 years in 2010. Children weighing less than two standard deviations below the gender-specific mean were defined as LBW children. Although not significantly different from mothers of children in the normal weight range, mothers of LBW children had the overall highest level of non-employment when the children were 1-3 years. At child age 4-6 years on the other hand, LBW was associated with an increased risk of non-employment (RR 1.39: 95 % CI 1.11-1.75) also after adjustment for factors associated with employment in general. In accordance with employment trends in the general population, our findings show that while mothers of normal birth weight children re-enter the labor market as their children grow older, mothers of LBW children born at term participate to a lesser extent in paid employment and remain at levels similar to those of mothers with younger children.

The impact of a child's special health care needs on maternal work participation during early motherhood.

BACKGROUND: Many women temporarily reduce work hours or stop working when caring for small children. However, mothers of children with special health care needs may face particular challenges balancing childrearing responsibilities and employment demands. This study examines how the work participation among mothers of children with special health care needs compares with that of mothers in general during early motherhood, focusing in particular on the extent of the child's additional health care needs. METHODS: By linkage of the population-based Norwegian Mother and Child Cohort Study with national registers on employment, child health care needs, and social background factors, 41,255 mothers employed prior to childbirth were followed until child age 3 years to investigate associations between the child's care needs and mother's dropping out of employment. RESULTS: In total, 16.3% of the formerly employed mothers were no longer employed at child age 3 years. Mothers of children with mild care needs did not differ from mothers in general, whereas mothers of children with moderate [Risk Ratio (RR) 1.45; 95% confidence interval (CI) 1.17, 1.80] and severe care needs [RR 2.19; 95% CI 1.67, 2.87] were at substantial risk of not being employed at follow-up. The impact of the child's health care needs remained strong also after adjusting for several factors associated with employment in general. CONCLUSIONS: Extensive childhood health care needs are associated with reduced short-term employment prospects and remain a substantial influence on mothers' work participation during early motherhood, irrespective of other important characteristics associated with maternal employment.

Pregnancy and delivery in women with chronic inflammatory arthritides with a specific focus on first birth.

OBJECTIVE: To examine possible associations between chronic inflammatory arthritides and pregnancy outcomes with separate analyses of first and subsequent births before and after diagnosis. METHODS: Linkage of data from a registry of patients with chronic inflammatory arthritides and the Medical Birth Registry of Norway enabled a comparison of pregnancy outcomes in women with chronic inflammatory arthritides and pregnancy outcomes in reference subjects. Outcomes of first birth and subsequent births before and after diagnosis were analyzed separately. Associations between chronic inflammatory arthritides and the women's health during pregnancy and delivery as well as perinatal outcomes were assessed in logistic regression analyses with adjustments for maternal age at delivery and gestational age. RESULTS: We analyzed 128 first births and 151 subsequent births after diagnosis and 286 first births and 262 subsequent births before diagnosis in patients and compared them with first and subsequent births in reference subjects. Firstborn children of women diagnosed as having chronic inflammatory arthritides were more often preterm (odds ratio [OR] 1.85 [95% confidence interval (95% CI) 1.09-3.13]) and small for gestational age (OR 1.60 [95% CI 1.00-2.56]). They also had lower mean birth weight (P=0.01) and higher perinatal mortality (OR 3.26 [95% CI 1.04-10.24]). Birth by caesarean section (all classifications) was more frequent in patients than in reference subjects, and elective caesarean section was 2-fold more frequent in patients, both in first birth (OR 2.60 [95% CI 1.43-4.75]) and in subsequent births (OR 2.18 [95% CI 1.33-3.58]). No excess risks of clinical importance were observed prior to diagnosis of chronic inflammatory arthritides. CONCLUSION: Excess risks were related to first birth in women diagnosed as having chronic inflammatory arthritides, including a higher rate of perinatal mortality. A higher caesarean section rate was related to all patient deliveries. Mainly, pregnancy outcomes before diagnosis did not differ from those in reference subjects.

Prediction of outcome at 5 years from assessments at 2 years among extremely preterm children: a Norwegian national cohort study.

AIM: To examine the predictive value of early assessments on developmental outcome at 5 years in children born extremely preterm. METHODS: This is a prospective observational study of all infants born in Norway in 1999-2000 with gestational age (GA) <28 weeks or birth weight (BW) <1000 g. At 2 years of age, paediatricians assessed mental and motor development from milestones. At 5 years, parents completed questionnaires on development and professional support before cognitive function was assessed with Wechsler Preschool and Primary Scale of Intelligence-Revised (WPPSI-R) and motor function with the Movement Assessment Battery for children (ABC test). RESULTS: Twenty-six of 373 (7%) children had cerebral palsy at 2 and 29 of 306 (9%) children at 5 years. Of children without major impairments, 51% (95% CI 35-67) of those with and 22% (95% CI 16-28) without mental delay at 2 years had IQ <85 at 5 years, and 36% (95% CI 20-53 with and 16% (95% CI 11-21) without motor delay at 2 years had an ABC score >95th percentile (poor function). Approximately half of those without major impairments but IQ <85 or ABC score >95th percentile had received support or follow-up beyond routine primary care. CONCLUSION: Previous assessments had limited value in predicting cognitive and motor function at 5 years in these extremely preterm children without major impairments.

Preeclampsia and the risk of end-stage renal disease.

BACKGROUND: It is unknown whether preeclampsia is a risk marker for subsequent end-stage renal disease (ESRD). METHODS: We linked data from the Medical Birth Registry of Norway, which contains data on all births in Norway since 1967, with data from the Norwegian Renal Registry, which contains data on all patients receiving a diagnosis of end-stage renal disease (ESRD) since 1980, to assess the association between preeclampsia in one or more pregnancies and the subsequent development of ESRD. The study population consisted of women who had had a first singleton birth between 1967 and 1991; we included data from up to three pregnancies. RESULTS: ESRD developed in 477 of 570,433 women a mean (+/-SD) of 17+/-9 years after the first pregnancy (overall rate, 3.7 per 100,000 women per year). Among women who had been pregnant one or more times, preeclampsia during the first pregnancy was associated with a relative risk of ESRD of 4.7 (95% confidence interval [CI], 3.6 to 6.1). Among women who had been pregnant two or more times, preeclampsia during the first pregnancy was associated with a relative risk of ESRD of 3.2 (95% CI, 2.2 to 4.9), preeclampsia during the second pregnancy with a relative risk of 6.7 (95% CI, 4.3 to 10.6), and preeclampsia during both pregnancies with a relative risk of 6.4 (95% CI, 3.0 to 13.5). Among women who had been pregnant three or more times, preeclampsia during one pregnancy was associated with a relative risk of ESRD of 6.3 (95% CI, 4.1 to 9.9), and preeclampsia during two or three pregnancies was associated with a relative risk of 15.5 (95% CI, 7.8 to 30.8). Having a low-birth-weight or preterm infant increased the relative risk of ESRD. The results were similar after adjustment for possible confounders and after exclusion of women who had kidney disease, rheumatic disease, essential hypertension, or diabetes mellitus before pregnancy. CONCLUSIONS: Although the absolute risk of ESRD in women who have had preeclampsia is low, preeclampsia is a marker for an increased risk of subsequent ESRD.

Fertility in women with chronic inflammatory arthritides.

OBJECTIVE: To compare fertility rates in women with RA, other chronic arthritides (OCAs) and JIA with reference women from the general population. METHODS: Each woman from a Norwegian patient registry was matched by year of birth with 100 reference women randomly selected from the National Population Registry. Data linkage of patients and references with the Medical Birth Registry of Norway (MBRN) identified all offspring in patients and references until October 2007, and indirectly also nulliparous (childless) women. Groups were compared with Mann-Whitney U-test for continuous variables and chi-squared tests for categorical variables. Poisson regression analysis was applied to calculate relative fertility rates in the diagnostic groups vs references. RESULTS: Among 631 patients 849 children were registered in MBRN. Of these, 289 children (34.0%) were born after time of diagnosis vs 44.3% in references. Altogether, 206 of 631 patients (32.6%) were nulliparous vs 26.4% in references (P < 0.001). Among RA patients, 28.4% (96 of 338) were nulliparous vs 24.5% in references (P = 0.09), 30.7% (67 of 218) in OCA patients vs 24.5% in references (P = 0.03) and 57.3% (43 of 75) in JIA patients vs 40.9% in references (P = 0.004). Adjusted relative fertility rates in RA, OCA and JIA after diagnosis were 0.88, 0.84 and 0.84, respectively, compared with references. CONCLUSION: A higher proportion of women with chronic inflammatory arthritides were nulliparous compared with references, and relative fertility rates were reduced in all patient groups.

Placental abruption and premature rupture of membranes.

OBJECTIVE: To assess whether premature rupture of membranes (PROM) is associated with placental abruption. DESIGN: Population-based study. SETTING: Data were extracted from the Medical Birth Registry of Norway. POPULATION: All women with PROM (18,889 cases), including 3,077 cases of preterm premature rupture of membranes (p-PROM), among a total of 355 416 singleton births in Norway during 1999-2005 with gestational age 17-44 weeks. METHODS: Logistic regression was used to assess whether placental abruption was associated with PROM in preterm and term births. MAIN OUTCOME MEASURES: Placental abruption. RESULTS: The occurrence of placental abruption in p-PROM was higher than in the total study population, 11.0 per 1,000 (34 of 3 077) vs. 4.2 per 1 000 (1 495 of 355 416; adjusted odds ratio 2.6, 95% confidence interval 1.8-3.7). Restricting the analyses to preterm births, the occurrence of placental abruption was less in p-PROM (11.0 per 1,000) than in births without p-PROM (36.1 per 1 000; adjusted odds ratio 0.3, 95% confidence interval 0.2-0.4). In term births, no statistically significant association was observed. CONCLUSIONS: The findings suggest that in p-PROM the risk of placental abruption is not higher than in other preterm births; rather the opposite. However, comparing the risks in p-PROM and the total gestational age range, the present study confirmed results reported in previous studies of a higher risk of placental abruption in p-PROM than in the total birth population.

Induction of labor and cerebral palsy: a population-based study in Norway.

OBJECTIVE: To investigate the association between labor induction and later development of cerebral palsy (CP). DESIGN: Registry-based cohort study. SETTING: Perinatal data on all children born in Norway 1996-1998 were obtained from the Medical Birth Registry of Norway (MBRN). Neurodevelopmental data were collected from the Norwegian Cerebral Palsy Registry (CPRN). POPULATION: A total of 176,591 children surviving the neonatal period. Of 373 children with CP, detailed data were available on 241. METHODS: Unadjusted and adjusted odds ratios (OR) with 95% confidence intervals (CI) were calculated as estimates of the relative risk that a child with CP was born after labor induction. MAIN OUTCOME MEASURES: Total CP and spastic CP subtypes. RESULTS: Bilateral cerebral palsy was more frequently observed after induced labor (OR: 3.1; 95% CI 2.1-4.5). For children born at term the association between bilateral CP and labor induction was stronger (OR: 4.4; 95% CI 2.3-8.6). The association persisted after adjustment for maternal disease, gestational age, standard deviation score for birthweight (z-score) and prelabor rupture of membranes (PROM) (adjusted OR: 3.7; 95%CI 1.8-7.5). Among children with CP born at term, four-limb involvement (quadriplegia) was significantly more frequent after induced (45.5%) compared with non-induced labor (8.0%). There was no significant association between labor induction and unilateral CP subtype or CP in preterm born children. CONCLUSIONS: In this study population, we found that labor induction at term was associated with excess risk of bilateral spastic CP and in particular CP with four-limb involvement.

Recurrence of stillbirth in sibships: Population-based cohort study.

Knowledge of stillbirth recurrence risk is of clinical interest and may give etiological insight. The authors studied "gestational age-" and "weight-by-gestation-specific" stillbirth recurrence, and evaluated time trends in a population-based cohort study from the Medical Birth Registry of Norway, from 1967 to 2004. Singleton births, including stillbirths from 20 weeks' gestation, were linked to their mothers by national identification numbers. Stillbirth rates in second pregnancies among mothers with (N = 5,091) and without (N = 562,057; the reference group) a stillbirth in first pregnancies were compared across 4 gestational age and 3 weight-by-gestation groups. A remarkable symmetric pattern of gestational age-specific recurrence of stillbirth was found, with highest odds of stillbirth in the same age group. The adjusted odds ratio values associated with preterm stillbirth recurrence were high, for example, 25.7 (95% confidence interval: 19.8, 33.3) for stillbirth at 20-27 weeks' gestation (73/1,511 vs. 1,021/562,057), while lower for term stillbirth: adjusted odds ratio = 2.3 (95% confidence interval: 1.2, 4.7) (9/1,844 vs. 1,021/538,499). The proportion of second early stillbirths in the population attributable to previous early stillbirth was 6.4%, compared with 0.5% for second term stillbirth. Over time, recurrence of early stillbirth decreased, whereas that of mid/late stillbirth did not change significantly. A symmetric pattern of recurring stillbirth in similar weight-by-gestation groups was not found.

Are adverse pregnancy outcomes risk factors for development of end-stage renal disease in women with diabetes?

BACKGROUND: It is unknown whether adverse pregnancy-related outcomes in women with pregestational diabetes are associated with later development of end-stage renal disease (ESRD) or death. METHODS: We linked data from the Medical Birth Registry of Norway with data from the Norwegian Renal Registry and the Norwegian Cause of Death Registry. Data from up to three pregnancies for women with a first singleton delivery from 1967 to 1994 were included and analysed in a cohort design using Cox regression. RESULTS: Altogether, 639,018 women were included in the analyses, among whom 2204 women had diabetes mellitus before pregnancy. Their first pregnancy was complicated by pre-eclampsia in 13.2%, low birth weight offspring (<2.5 kg) in 11.0% and preterm birth in 25.1%, and their risk of ESRD and death in the follow-up period of up to 37 years was markedly higher. In women with pregestational diabetes, pre-eclampsia and preterm birth were associated with significantly increased risks of ESRD and death in women with only one pregnancy, but not in women with two or more pregnancies. CONCLUSIONS: In women with pregestational diabetes, pre-eclampsia and preterm birth were associated with long-term increased risk of ESRD and death, but only in women who had only one pregnancy.

Macrosomia: mode of delivery and pregnancy outcome.

OBJECTIVE: To assess associations between birthweight and selected adverse outcomes in vaginal and cesarean deliveries and to clarify to which extent macrosomic births are delivered by cesarean section or are centralized to larger maternity units. DESIGN: Cohort study. SETTING: National study based on the Medical Birth Registry of Norway. POPULATION: All births in Norway for the duration 1999-2005 comprising 304,968 vaginal and 47,702 cesarean deliveries. METHODS: Rates of adverse pregnancy outcomes by birthweight in vaginal and cesarean deliveries were compared by odds ratios (ORs) obtained in logistic regression analysis with birthweight 2,500-3,999 g as the reference and adjusted for maternal age, birth order and size of maternity unit. MAIN OUTCOME MEASURES: Analgesia, interventions, complications and neonatal outcomes. RESULTS: For all the adverse outcomes, the ORs increased continuously from the reference group up to > or =5,000 g in which the highest adjusted ORs were observed for shoulder dystocia [64.2 (confidence interval 55.7-74.0)] and plexus injuries [47.7 (confidence interval 35.7-62.4)]. The proportion of adverse outcomes attributable to macrosomia (birthweight > or =4,500 g) ranged from 56.8% of all shoulder dystocia cases to 0.5% of all stillbirths. Macrosomic births were not centralized to larger maternity units and planned cesarean delivery was not more frequent in macrosomic births. CONCLUSIONS: Macrosomic births involved excess risks of a series of adverse pregnancy outcomes, the births were not centralized to larger maternity units and planned cesarean section was not more frequent in macrosomic births.

Low risk pregnancies after a cesarean section: Determinants of trial of labor and its failure.

INTRODUCTION: In pregnancies after a previous cesarean section (CS), a planned repeat CS delivery has been associated with excess risk of adverse outcome. However, also the alternative, a trial of labor after CS (TOLAC), has been associated with excess risks. A TOLAC failure, involving a non-planned CS, carries the highest risk of adverse outcome and a vaginal delivery the lowest. Thus, the decision regarding delivery mode is pivotal in clinical handling of these pregnancies. However, even with a high TOLAC rate, as seen in Norway, repeat CSs are regularly performed for no apparent medical reason. The objective of the present study was to assess to which extent demographic, socioeconomic, and health system factors are determinants of TOLAC and TOLAC failure in low risk pregnancies, and whether any effects observed changed with time. MATERIALS AND METHODS: The study group comprised 24 645 second deliveries (1989-2014) after a first delivery CS. Thus, none of the women had prior vaginal deliveries or more than one CS. Included pregnancies were low risk, cephalic, single, and had gestational age ≥ 37 weeks. Data were obtained from the Medical Birth Registry of Norway (MBRN). The exposure variables were (second delivery) maternal age, length of maternal education, maternal country of origin, size of the delivery unit, health region (South-East, West, Mid, North), and maternal county of residence. The outcomes were TOLAC and TOLAC failure, as rates (%), relative risk (RR) and relative risk adjusted (ARR). Changes in determinant effects over time were assessed by comparing rates in two periods, 1989-2002 vs 2003-2014, and including these periods in an interaction model. RESULTS: The TOLAC rate was 74.9%, with a TOLAC failure rate of 16.2%, resulting in a vaginal birth rate of 62.8%. Low TOLAC rates were observed at high maternal age and in women from East Asia or Latin America. High TOLAC failure rates were observed at high maternal age, in women with less than 11 years of education, and in women of non-western origin. The effects of health system factors, i.e. delivery unit size and administrative region were considerable, on both TOLAC and TOLAC failure. The effects of several determinants changed significantly (P < 0.05) from 1989-2002 to 2003-2014: The association between non-TOLAC and maternal age > 39 years became weaker, the association between short education and TOLAC failure became stronger, and the association between TOLAC failure and small size of delivery unit became stronger. CONCLUSION: Low maternal age, high education, and western country of origin were associated with high TOLAC rates, and low TOLAC failure rates. Maternity unit characteristics (size and region) contributed with effects on the same level as individual determinants studied. Temporal changes were observed in determinant effects.