Obstetric anal sphincter injury by maternal origin and length of residence: a nationwide cohort study.

OBJECTIVE: To estimate the association between maternal origin and obstetric anal sphincter injury (OASI), and assess if associations differed by length of residence. DESIGN: Population-based cohort study. SETTING: The Medical Birth Registry of Norway. POPULATION: Primiparous women with vaginal livebirth of a singleton cephalic fetus between 2008 and 2017 (n = 188 658). METHODS: Multivariable logistic regression models estimated adjusted odds ratios (aORs) for OASI with 95% CI by maternal region of origin and birthplace. We stratified models on length of residence and paternal birthplace. MAIN OUTCOME MEASURES: OASI. RESULTS: Overall, 6373 cases of OASI were identified (3.4% of total cohort). Women from South Asia were most likely to experience OASI (6.2%; aOR 2.24, 95% CI 1.87-2.69), followed by those from Southeast Asia, East Asia & the Pacific (5.7%; 1.59, 1.37-1.83) and Sub-Saharan Africa (5.2%; 1.85, 1.55-2.20), compared with women originating from Norway. Among women born in the same region, those with short length of residence in Norway (0-4 years), showed the highest odds of OASI. Migrant women across most regions of origin had the lowest risk of OASI if they had a Norwegian partner. CONCLUSIONS: Primiparous women from Asian regions and Sub-Saharan Africa had up to two-fold risk of OASI, compared with women originating from Norway. Migrants with short residence and those with a foreign-born partner had higher risk of OASI, implying that some of the risk differential is due to sociocultural factors. Some migrants, especially new arrivals, may benefit from special attention during labour to reduce morbidity and achieve equitable outcomes. TWEETABLE ABSTRACT: Anal sphincter injury during birth is more common among Asian and Sub-Saharan migrants and particularly among recent arrivals.

Prelabour uterine rupture: characteristics and outcomes.

OBJECTIVE: To describe the characteristics and outcomes of prelabour uterine ruptures. DESIGN: Descriptive study based on population data from the Medical Birth Registry of Norway, the Patient Administration System and medical records. SAMPLE: Maternities with uterine rupture before start of labour in Norway during the period 1967-2008 (8 complete ruptures among 2 334 712 women with unscarred uteri, and 22 complete and 45 partial ruptures among 121 085 women with scarred uteri). METHOD: We measured the rate of perinatal deaths and peripartum hysterectomy following ruptures. In addition, we studied the characteristics of ruptures. RESULTS: The eight complete ruptures in women with unscarred uteri were associated with trauma from traffic accidents (n = 3; 37.5%), previous curettage (n = 3; 37.5%) and congenital uterine malformations (n = 2; 25%), resulting in seven perinatal deaths and two hysterectomies. The 22 complete ruptures in scarred uteri were mostly outside the lower uterine segment (n = 17; 72.7%). Abnormally invasive placenta (AIP) and previous rupture were present in four (18.2%) and three women (13.6%), respectively. They resulted in nine perinatal deaths (39.1%) and two hysterectomies (9.1%). The 45 partial ruptures involved mostly scars in the lower uterine segment (n = 39; 86.7%). None of them resulted in perinatal death or hysterectomy. Perinatal deaths have decreased dramatically in recent years, despite increasing prelabour rupture rates. CONCLUSION: Although complete uterine ruptures before labour start were rare, they often resulted in catastrophic outcomes, such as perinatal death. Scars outside the lower segment were associated with a higher percentage of catastrophic prelabour ruptures compared with scars in the lower segment (Video S1). TWEETABLE ABSTRACT: Complete prelabour uterine ruptures were rare, but resulted in high perinatal deaths, especially if they were in scars outside the lower segment.

Reproductive factors and risk of melanoma: a population-based cohort study.

BACKGROUND: The association between reproductive factors and risk of cutaneous melanoma (CM) is unclear. We investigated this issue in the Norwegian Women and Cancer cohort study. OBJECTIVES: To examine the association between the reproductive factors age at menarche, menstrual cycle length, parity, age at first and last birth, menopausal status, breastfeeding duration and length of ovulatory life, and CM risk, overall and by histological subtypes and anatomical site. METHODS: We followed 165 712 women aged 30-75 years at inclusion from 1991-2007 to the end of 2015. Multivariable Cox regression was used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs). RESULTS: The mean age at cohort enrolment was 49 years. During a median follow-up of 18 years, 1347 cases of CM were identified. No reproductive factors were clearly associated with CM risk. When stratifying by histological subtype we observed significant heterogeneity (P = 0·01) in the effect of length of ovulatory life on the risk of superficial spreading melanoma (HR 1·02, 95% CI 1·01-1·04 per year increase) and nodular melanoma (HR 0·97, 95% CI 0·94-1·01 per year increase). When stratifying by anatomical site, menopausal status (HR 0·54, 95% CI 0·31-0·92, postmenopausal vs. premenopausal) and menstrual cycle length (HR 1·07, 95% CI 1·01-1·13, per day increase) were associated with CM of the trunk, and significant heterogeneity between anatomical sites was observed for menopausal status (P = 0·04). CONCLUSIONS: In this large population-based Norwegian cohort study, we did not find convincing evidence of an association between reproductive factors and risk of CM.

The effectiveness of surgical interventions for women with FGM/C: a systematic review.

BACKGROUND: Female genital mutilation/cutting (FGM/C) changes normal genital functionality and can cause complications. There is an increasing demand for treatment of FGM/C-related complications. OBJECTIVES: We conducted a systematic review of empirical quantitative research on the outcomes of interventions for women with FGM/C-related complications. SEARCH STRATEGY: A search specialist searched 16 electronic databases. SELECTION CRITERIA: Selection was performed independently by two researchers. We accepted quantitative studies that examined the outcome of an intervention for an FGM/C-related concern. DATA COLLECTION AND ANALYSIS: We extracted data into a pre-designed form, calculated effect estimates, and performed meta-analyses. MAIN RESULTS: We included 62 studies (5829 women), which investigated the effect of defibulation, excision of cysts, and clitoral reconstruction. Meta-analyses of defibulation versus no defibulation showed a significantly lower risk of caesarean section (relative risk, RR: 0.33; 95% confidence interval, 95% CI: 0.25-0.45) and perineal tears with defibulation: second-degree tear (RR: 0.44, 95% CI: 0.24-0.79), third-degree tear (RR: 0.21, 95% CI: 0.05-0.94), fourth-degree tear (RR: 0.06, 95% CI: 0.01-0.41). The meta-analyses detected no significant differences in obstetric outcomes of antenatal versus intrapartum defibulation. Except for one study, none of the studies on the excision of cysts indicated any complications, and the results were deemed favourable. Reconstructive surgery resulted in a visible clitoris in about 77% of women. Most women self-reported improvements in their sexual life, but up to 22% experienced a worsening in sexuality-related outcomes after reconstruction. CONCLUSIONS: Women with FGM/C who seek therapeutic surgery should be informed about the scarcity of evidence for benefits and the potential harms of the available procedures. TWEETABLE ABSTRACT: Systematic review shows defibulation after FGM/C has obstetric benefits; effect of reconstruction is uncertain.

Assisted reproductive technology and severe postpartum haemorrhage: a case-control study.

OBJECTIVE: To investigate the association between assisted reproductive technology and severe postpartum haemorrhage. DESIGN: Case-control study. SETTING: The study was conducted in Norway; Division of Gynaecology and Obstetrics at Oslo University Hospital and Department of Obstetrics and Gynaecology at Drammen Hospital. POPULATION: A source population including all women admitted for delivery at Oslo University Hospital and Drammen Hospital during the time period 1 January 2008 to 31 December 2011. The study population consisted of all cases of severe postpartum haemorrhage (n = 1064) and a random sample of controls (n = 2059). METHODS: We used an explanatory strategy in the analysis, with multivariable logistic regression. MAIN OUTCOME MEASURES: Severe postpartum haemorrhage; defined as blood loss ≥1500 ml or need for blood transfusion. RESULTS: Assisted reproductive technology was associated with an increased risk of severe postpartum haemorrhage (crude OR = 2.92; 95% CI 2.18-3.92, P < 0.001). Mode of delivery and anticoagulant medication had significant confounding effects. Strong interaction was found for multiple pregnancies. After adjusting for confounding and interaction, an increased risk was observed both in the strata of multiple pregnancies (adjusted OR = 7.00, 95% CI 2.70-18.12, P < 0.001), and in the strata of single gestation (adjusted OR = 1.58, 95% CI 1.12-2.24, P = 0.010). CONCLUSIONS: Our findings warrant an increased awareness of the risk of severe postpartum haemorrhage in women conceiving with assisted reproductive technology. Furthermore, the high risk of severe postpartum haemorrhage in the presence of a twin or triplet pregnancy is an additional argument for single embryo transfer. TWEETABLE ABSTRACT: Assisted reproductive technology is associated with an increased risk of severe postpartum haemorrhage.

Uterine rupture: trends over 40 years.

OBJECTIVE: To follow trends of uterine rupture over a period of 40 years in Norway. DESIGN: Population-based study using data from the Medical Birth Registry, the Patient Administration System, and medical records. SETTING: Norway. SAMPLE: Women giving birth in 21 maternity units in Norway during the period 1967-2008 (n = 1 441 712 maternities). METHODS: The incidence and outcomes of uterine rupture were compared across four decades: 1967-1977; 1978-1988; 1989-1999; and 2000-2008. Multivariable logistic regression was used to determine the odds ratio (OR) for uterine rupture in each decade compared with the second decade. MAIN OUTCOME MEASURE: Trends in uterine rupture. RESULTS: We identified 359 uterine ruptures. The incidence rates per 10 000 maternities in the first, second, third, and fourth decade were 1.2, 0.9, 1.7, and 6.1, respectively. The ORs for complete and partial ruptures in the fourth versus the second decade were 6.4 (95% confidence interval, 95% CI 3.8-10.8) and 7.2 (95% CI 4.2-12.3), respectively. Significant contributing factors to this increase were the higher rates of labour augmentation with oxytocin, scarred uteri from a previous caesarean section, and labour induction with prostaglandins or prostaglandins combined with oxytocin. After adjusting for risk factors, the ORs for complete and partial ruptures were 2.2 (95% CI 1.3-3.8) and 2.8 (95% CI 1.6-4.8), respectively. Severe postpartum haemorrhage, hysterectomy, intrapartum death and infant death after complete uterine ruptures decreased significantly over time. CONCLUSIONS: A sharply increasing trend of uterine rupture was found. Obstetric interventions contributed to this increase, but could not explain it entirely. TWEETABLE ABSTRACT: A sharply increasing trend of uterine ruptures has been found in Norway in recent years.

Cancer risk among parous women following assisted reproductive technology.

STUDY QUESTION: Do women who give birth after assisted reproductive technology (ART) have an increased risk of cancer compared with women who give birth without ART? SUMMARY ANSWER: Without correction, the results indicate an increase in overall cancer risk, as well as a 50% increase in risk of CNS cancer for women giving birth after ART, however the results were not significant after correcting for multiple analyses. WHAT IS KNOWN ALREADY: Studies regarding the effects of hormonal treatments involved with ART on subsequent cancer risk have provided inconsistent results, and it has also been suggested that infertility itself could be a contributory factor. STUDY DESIGN, SIZE, DURATION: A population-based cohort consisting of all women registered in the Medical Birth Registry of Norway as having given birth between 1 January 1984 and 31 December 2010 was assembled (n = 812 986). Cancers were identified by linkage to the Cancer Registry of Norway. Study subjects were followed from start of first pregnancy during the observational period until the first cancer, death, emigration, or 31 December 2010. PARTICIPANTS/MATERIALS, SETTING, METHODS: Of the total study population (n = 806 248), 16 525 gave birth to a child following ART. Cox regression analysis computed hazard ratios (HR) and 95% confidence intervals (CI) comparing cancer risk between ART women and non-ART women; for overall cancer, and for cervical, ovarian, uterine, central nervous system (CNS), colorectal and thyroid cancers, and for malignant melanoma. MAIN RESULTS AND THE ROLE OF CHANCE: A total of 22 282 cohort members were diagnosed with cancer, of which 338 were ART women and 21 944 non-ART women. The results showed an elevated risk in one out of seven sites for ART women. The HR for cancer of the CNS was 1.50 (95% CI 1.03- 2.18), and among those specifically subjected to IVF (without ICSI) the HR was 1.83 (95% CI 1.22-2.73). Analysis of risk of overall cancer gave an HR of 1.16 (95% CI 1.04-1.29). Among those who had delivered only one child by the end of follow-up, the HR for ovarian cancer was 2.00 (95% CI 1.08-3.65), and for those nulliparous at entry the HR was 1.80 (95% CI 1.04-3.11). However, all findings became non-significant after correcting for multiple analyses. LIMITATIONS, REASONS FOR CAUTION: The results of elevated risk of overall cancer and CNS cancer lost significance when adjusting for multiple analyses, implying an important limitation of the study. The follow-up time was relatively short, especially for ART women. In addition, as the cohort was relatively young, there were few incident cancers, especially for some rarer cancer forms, such as uterine cancer. Risk assessments according to different causes of infertility could not be done. WIDER IMPLICATIONS OF THE FINDINGS: In light of the findings in the present study, further studies should be made on risk of CNS and ovarian cancer, and continued monitoring of all those treated with ART is encouraged. Our findings may only be generalizable to women who give birth after ART, and the risk for women who remain nulliparous after ART remains to be assessed. STUDY FUNDING/COMPETING INTEREST: The study was funded by the Norwegian National Advisory Unit on Women's Health. All authors claim no competing interests.

Maternal age and emergency operative deliveries at term: a population-based registry study among low-risk primiparous women.

OBJECTIVE: To study the association between maternal age and emergency operative delivery. The roles of in-labour indications, and birthweight ≥ 4000 g, gestational age ≥ 42 weeks, induction of labour, and epidural use, according to maternal age were explored. DESIGN: Population-based study. SETTING: Medical Birth Registry of Norway and Statistics Norway. POPULATION: We studied 169 583 low-risk primiparous mothers with singleton, cephalic labours, at ≥37 weeks of gestation, from 1999 to 2009. METHODS: The associations between maternal age and mode of delivery were analysed using multinomial regression analyses, adjusting for sociodemographic factors. MAIN OUTCOME MEASURES: Emergency caesarean section and operative vaginal delivery. RESULTS: Of women aged ≥40 years, 22% had emergency caesarean sections and 24% had operative vaginal deliveries, giving adjusted relative risk ratios (RRRs) of 6.60 (95% confidence interval, 95% CI 5.53-7.87) and 3.30 (95% CI 2.79-3.90), respectively, when compared with women aged 20-24 years. Adjustments for sociodemographic factors only slightly changed the estimates. Dystocia was the main indication, followed by fetal distress. All of the listed factors increased the level of emergency operative deliveries, mainly because of an increase in dystocia. The increase in risk for emergency caesarean section by all factors, and for operative vaginal deliveries by epidural, were greater in older than in younger women, but were significant for epidural only. CONCLUSIONS: We found a close association between maternal age and emergency operative delivery in low-risk primiparas. Contributory factors increased the risk for both emergency operative delivery and epidural more in older than in younger women.

Breastfeeding and pelvic girdle pain: a follow-up study of 10,603 women 18 months after delivery.

OBJECTIVE: To study the associations of patterns and duration of breastfeeding with the persistence of pelvic girdle pain 18 months after delivery. DESIGN: Longitudinal population study. SETTING: Norway, for the period 1999-2011. POPULATION: A follow-up of 10 603 women with singleton deliveries in the Norwegian Mother and Child Cohort Study who reported pelvic girdle pain at 0-3 months postpartum. METHODS: Data were obtained by four self-administered questionnaires and linked to the Medical Birth Registry of Norway. MAIN OUTCOME MEASURE: Pelvic girdle pain, defined as combined anterior and bilateral posterior pelvic pain, 18 months after delivery. RESULTS: Eighteen months after delivery, 7.8% of respondents (829/10,603) reported pelvic girdle pain. Breastfeeding patterns at 5 months after delivery were not associated with persistence of pelvic girdle pain. The proportion of women with pelvic girdle pain 18 months after delivery increased as the duration of breastfeeding decreased (test for trend, P < 0.001). The estimated associations attenuated after adjustment for educational level, smoking status, and body mass index, but remained statistically significant for the association between 0 and 2 months of breastfeeding and persistent pelvic girdle pain (adjusted odds ratio 1.34; 95% confidence interval 1.03-1.75). The association of short breastfeeding duration with persistent pelvic girdle pain was only present in women with body mass index ≥25 kg/m(2) . CONCLUSIONS: Breastfeeding was associated with a small beneficial effect on the recovery process of pelvic girdle pain in women with a body mass index ≥25 kg/m(2) . Among women with pelvic girdle pain, breastfeeding should be encouraged in accordance with the existing child-feeding recommendations.

Sexual violence and mode of delivery: a population-based cohort study.

OBJECTIVE: This study aimed to explore the association between sexual violence and mode of delivery. DESIGN: National cohort study. SETTING: Women presenting for routine ultrasound examinations were recruited to the Norwegian Mother and Child Cohort Study between 1999 and 2008. POPULATION: A total of 74,059 pregnant women. METHODS: Sexual violence was self-reported during pregnancy using postal questionnaires. Mode of delivery, other maternal birth outcomes and covariates were retrieved from the Medical Birth Registry of Norway. Risk estimations were performed using multivariable logistic regression analysis. MAIN OUTCOME MEASURES: Mode of delivery and selected maternal birth outcomes. RESULTS: Of 74,059 women, 18.4% reported a history of sexual violence. A total of 10% had an operative vaginal birth, 4.9% had elective caesarean section and 8.6% had an emergency caesarean section. Severe sexual violence (rape) was associated with elective caesarean section, adjusted odds ratio (AOR) 1.56 (95% CI 1.18-2.05) for nulliparous women and 1.37 (1.06-1.76) for multiparous women. Those exposed to moderate sexual violence had a higher risk of emergency caesarean section, AOR 1.31 (1.07-1.60) and 1.41 (1.08-1.84) for nulliparous and multiparous women, respectively. No association was found between sexual violence and operative vaginal birth, except for a lower risk among multiparous women reporting mild sexual violence, AOR 0.73 (0.60-0.89). Analysis of other maternal outcomes showed a reduced risk of episiotomy for women reporting rape and a higher frequency of induced labour. CONCLUSIONS: Women with a history of rape had higher odds of elective caesarean section and induction and significantly fewer episiotomies.

Objectively recorded physical activity and the association with gestational diabetes.

The aim of this population-based study was to assess the association between objectively recorded physical activity (PA) in early gestation and gestational diabetes mellitus (GDM) identified at 28 weeks of gestation in a multi-ethnic cohort of healthy pregnant women in Oslo, Norway. In total, 759 women were included. In early gestation (<20 weeks), light-, moderate-, and vigorous-intensity PA and number of steps were objectively recorded (SenseWear™ Armband Pro3), and self-reported PA, demographics, and anthropometrics were collected. The 75-g oral glucose tolerance test was performed at 28 weeks of gestation. Women with GDM had fewer objectively recorded steps (mean 7964 steps/day vs 8879 steps/day, P < 0.001) and minutes of moderate-to-vigorous-intensity PA (median 62 min/day vs 75 min/day, P = 0.004) in early gestation than women without GDM. Additionally, 30% of women with GDM compared with 44% (P < 0.001) of women without GDM self-reported regular PA before pregnancy. The significant inverse association between objectively recorded steps per day in early gestation and GDM persisted after adjustment for ethnic origin, weeks of gestation, age, parity, pre-pregnancy BMI, early life socioeconomic position, and self-reported regular PA before pregnancy. The adjusted odds ratio for GDM decreased 19% per standard deviation (3159 steps) increase in objectively recorded steps per day (P = 0.039). Daily life PA in early gestation measured as steps/day was associated with lower risk of GDM.

Hyperemesis gravidarum and birth outcomes-a population-based cohort study of 2.2 million births in the Norwegian Birth Registry.

OBJECTIVE: To study associations between hyperemesis gravidarum (HG) and birth outcomes. DESIGN: Population-based cohort study. SETTING: Norway. SAMPLE: Singleton births in the Norwegian Birth Registry, 1967-2009 (n = 2 270 363). METHODS: Multiple logistic regression was applied to study associations between HG and dichotomous outcomes; multiple linear regression to study associations between HG, birthweight and gestational length. Generalised estimating equations were applied to obtain valid standard errors. Sub-analysis on data with available information on smoking was conducted (1999-2009). MAIN OUTCOME MEASURES: Small and large for gestational age (SGA/LGA), Apgar score after 5 minutes, very preterm and preterm birth (VPTB/PTB), perinatal death, stillbirth, neonatal death, birthweight and gestational length. RESULTS: No associations between HG and adverse pregnancy outcomes were observed in crude analyses, except for VPTB (odds ratio [OR] 0.79, 95% CI 0.67-0.93). In adjusted analysis, HG was associated with perinatal death (OR 1.27, 95% CI 1.08-1.48). Inverse associations were observed between HG and VPTB (OR 0.80, 95% CI 0.68-0.94) and LGA (OR 0.95, 95% CI 0.90-0.99). Sub-analyses showed no associations between HG and perinatal death (OR 1.29, 95% CI 0.91-1.83). The inverse associations between HG, VPTB and LGA were strengthened (OR 0.66, 95% CI, 0.48-0.91 and OR 0.86, 95% CI 0.79-0.93, respectively). Exposed babies had reduced birthweight and gestational length compared with unexposed, adjusted difference - 21.4 g and - 0.5 days, respectively. Adjustment for smoking slightly strengthened the impact of HG on birthweight. CONCLUSIONS: Inverse associations for HG and VPTB and LGA were observed. HG was associated with slight reductions in birthweight and gestational age.

Is hyperemesis gravidarum associated with placental weight and the placental weight-to-birth weight ratio? A population-based Norwegian cohort study.

INTRODUCTION: Studies have suggested a link between placental weight, placental weight-to-birth weight ratio (PW/BW) and adult health. Hyperemesis gravidarum (HG) may also have implications for adult health. No studies on HG and placental characteristics have been identified. We therefore explored the relationship between HG, placental weight and the PW/BW-ratio in a population-based cohort. METHODS: Singleton births to primiparous women between 1999 and 2009 with data on HG, placental weight and birth weight in the Medical Birth Registry of Norway (MBRN) comprised the study base (n = 200,390). HG was defined through ICD-10 code 021.0, 021.1 and 021.9. Gender and gestational age specific percentile curves for placenta weight and PW/BW ratio were used to define those below the 10th and above the 90th percentile of both outcomes. Associations between HG and dichotomous outcomes were studied by multiple logistic regression. Multiple linear regression was applied to study placental weight as a continuous variable. Male and female offspring were analyzed separately. RESULTS: The prevalence of HG was 1.2%. Women with HG and female offspring had significantly higher risk of a PW/BW-ratio above the 90th percentile (OR = 1.17, 95% CI: 1.03-1.34). HG and PW/BW-ratio below the 10th percentile were inversely associated (OR = 0.70, 95% CI: 0.56-0.89). For male offspring no association was observed for HG and PW/BW-ratio below the 10th or above the 90th percentile. DISCUSSION/CONCLUSIONS: We observed positive associations between HG and high PW/BW ratio limited to female offspring only. The high PW/BW-ratio suggests that there may be a possible link between HG and adult health.

Hormonal contraception and pelvic girdle pain during pregnancy: a population study of 91,721 pregnancies in the Norwegian Mother and Child Cohort.

STUDY QUESTION: Is pre-pregnancy hormonal contraception use associated with the development of pelvic girdle pain during pregnancy? SUMMARY ANSWER: In contrast to combined oral contraceptive pills, long lifetime exposure to progestin-only contraceptive pills or the use of a progestin intrauterine device during the final year before pregnancy were associated with pelvic girdle pain. WHAT IS ALREADY KNOWN: Pelvic girdle pain severely affects many women during pregnancy. Smaller studies have suggested that hormonal contraceptive use is involved in the underlying mechanisms, but evidence is inconclusive. STUDY DESIGN, SIZE, DURATION: A population study during the years 1999-2008. PARTICIPANTS/MATERIALS, SETTING, METHODS: A total of 91,721 pregnancies included in the Norwegian Mother and Child Cohort Study. Data were obtained by two self-administered questionnaires during pregnancy weeks 17 and 30. MAIN RESULTS AND THE ROLE OF CHANCE: Pelvic girdle pain was present in 12.9% of women who had used combined oral contraceptive pills during the last pre-pregnancy year, 16.4% of women who had used progestin-only contraceptive pills, 16.7% of women who had progestin injections and 20.7% of women who had used progestin intrauterine devices, compared with 15.3% of women who did not report use of hormonal contraceptives. After adjustment for other study factors, the use of a progestin intrauterine device was the only factor based on the preceding year associated with pelvic girdle pain [adjusted odds ratios (OR) 1.20; 95% confidence interval (CI): 1.11-1.31]. Long lifetime exposure to progestin-only contraceptive pills was also associated with pelvic girdle pain (adjusted OR 1.49; 95% CI: 1.01-2.20). LIMITATIONS, REASONS FOR CAUTION: The participation rate was 38.5%. However, a recent study on the potential biases of skewed selection in the Norwegian Mother and Child Cohort Study found the prevalence estimates but not the exposure-outcome associations to be influenced by the selection. WIDER IMPLICATIONS OF THE FINDINGS: The results suggest that combined oral contraceptives can be used without fear of developing pelvic girdle pain during pregnancy. However, the influence of progestin intrauterine devices and long-term exposure to progestin-only contraceptive pills requires further study. STUDY FUNDING/COMPETING INTEREST(S): The present study was supported by the Norwegian Research Council. None of the authors has a conflict of interest.

Perinatal and infant mortality in term and preterm births among women with type 1 diabetes.

AIMS/HYPOTHESIS: The aim of this study was to estimate the risks of adverse birth outcomes such as stillbirth, infant death, preterm birth and pre-eclampsia in women with type 1 diabetes, compared with the background population. We further aimed to explore the risks of adverse birth outcomes in preterm and term deliveries separately. METHODS: By linkage of two nationwide registries, the Medical Birth Registry of Norway and the Norwegian Childhood Diabetes Registry, we identified 1,307 births among women with pregestational type 1 diabetes registered in the Diabetes Registry, and 1,161,092 births in the background population during the period 1985-2004. The ORs with 95% CIs for adverse outcome among women with type 1 diabetes vs the background population were estimated using logistic regression. RESULTS: The OR for stillbirth (≥22 weeks of gestation) was 3.6 (95% CI 2.5, 5.3), and for perinatal death (stillbirth or death in the first week of life) it was 2.9 (95% CI 2.0, 4.1). The OR for infant death (first year of life) was 1.9 (95% CI 1.1, 3.2). For preterm birth (< 37 weeks of gestation) and pre-eclampsia the ORs were 4.9 (95% CI 4.3, 5.5) and 6.3 (95% CI 5.5, 7.2), respectively. When preterm and term deliveries were analysed separately, the excess risk of stillbirth and infant death in women with diabetes was confined to term deliveries. CONCLUSIONS/INTERPRETATION: Pregestational type 1 diabetes was associated with a considerably higher risk of adverse pregnancy outcomes, including infant death, compared with the background population. A novel finding of the study was that the increased risk was confined to term births.

Childhood abuse and caesarean section among primiparous women in the Norwegian Mother and Child Cohort Study.

We examined the association between a history of childhood abuse and caesarean section in the population-based Norwegian Mother and Child Cohort Study (MoBa). Our sample consisted of 26 923 primiparous women with singleton pregnancies at term. Of all women, 18.8% (5060) had experienced any childhood abuse, 14.3% (3856) reported emotional abuse, 5.2% (1413) reported physical abuse and 6.4% (1730) reported sexual abuse. The proportion of caesarean sections before labour was not affected by any childhood abuse. Any childhood abuse was associated with a slightly increased risk of caesarean sections during labour (adjusted odds ratio 1.16; 95% CI 1.03-1.30).

Uterine rupture after previous caesarean section.

OBJECTIVE: To determine the risk factors, percentage and maternal and perinatal complications of uterine rupture after previous caesarean section. DESIGN: Population-based registry study. POPULATION: Mothers with births > or =28 weeks of gestation after previous caesarean section (n = 18 794), registered in the Medical Birth Registry of Norway, from 1 January 1999 to 30 June 2005. METHODS: Associations of uterine rupture with risk factors, maternal and perinatal outcome were estimated using cross-tabulations and logistic regression. MAIN OUTCOME MEASURE: Odds of uterine rupture. RESULTS: A total of 94 uterine ruptures were identified (5.0/1000 mothers). Compared with elective prelabour caesarean section, odds of rupture increased for emergency prelabour caesarean section (OR: 8.63; 95% CI: 2.6-28.0), spontaneous labour (OR: 6.65; 95% CI: 2.4-18.6) and induced labour (OR: 12.60; 95% CI: 4.4-36.4). The odds were increased for maternal age > or =40 years versus <30 years (OR: 2.48; 95% CI: 1.1-5.5), non-Western (mothers born outside Europe, North America or Australia) origin (OR: 2.87; 95% CI: 1.8-4.7) and gestational age > or =41 weeks versus 37-40 weeks (OR: 1.73; 95% CI: 1.1-2.7). Uterine rupture after trial of labour significantly increased severe postpartum haemorrhage (OR: 8.51; 95% CI: 4.6-15.1), general anaesthesia exposure (OR: 14.20; 95% CI: 9.1-22.2), hysterectomy (OR: 51.36; 95% CI: 13.6-193.4) and serious perinatal outcome (OR: 24.51 (95% CI: 11.9-51.9). Induction by prostaglandins significantly increased the odds for uterine rupture compared with spontaneous labour (OR: 2.72; 95% CI: 1.6-4.7). Prelabour ruptures occurred after latent uterine activity or abdominal pain in mothers with multiple or uncommon uterine scars. CONCLUSION: Trial of labour carried greater risk and graver outcome of uterine rupture than elective repeated caesarean section, although absolute risks were low. A review of labour management and induction protocol is needed.

Somali women and their pregnancy outcomes postmigration: data from six receiving countries.

OBJECTIVE: This study aimed to investigate pregnancy outcomes in Somali-born women compared with those women born in each of the six receiving countries: Australia, Belgium, Canada, Finland, Norway and Sweden. DESIGN: Meta-analyses of routinely collected data on confinements and births. SETTING: National or regional perinatal datasets spanning 3-6 years between 1997 and 2004 from six countries. SAMPLE: A total of 10 431 Somali-born women and 2 168 891 receiving country-born women. METHODS: Meta-analyses to compare outcomes for Somali-born and receiving country-born women across the six countries. MAIN OUTCOME MEASURES: Events of labour (induction, epidural use and proportion of women using no analgesia), mode of birth (spontaneous vaginal birth, operative vaginal birth and caesarean section) and infant outcomes (preterm birth, birthweight, Apgar at 5 minutes, stillbirths and neonatal deaths). RESULTS: Compared with receiving country-born women, Somali-born women were less likely to give birth preterm (pooled OR 0.72, 95% CI 0.64-0.81) or to have infants of low birthweight (pooled OR 0.89, 95% CI 0.82-0.98), but there was an excess of caesarean sections, particularly in first births (pooled OR 1.41, 95% CI 1.25-1.59) and an excess of stillbirths (pooled OR 1.86, 95% CI 1.38-2.51). CONCLUSIONS: This analysis has identified a number of disparities in outcomes between Somali-born women and their receiving country counterparts. The disparities are not readily explained and they raise concerns about the provision of maternity care for Somali women postmigration. Review of maternity care practices followed by implementation and careful evaluation of strategies to improve both care and outcomes for Somali women is needed.