Lifetime induced abortions and live births. A 40-year historical cohort study.

OBJECTIVE: Little is known about whether induced abortions are associated with the final lifetime number of live births (life births). The objective of this study was to examine the association of number of life births with number of abortions a female has had in her lifetime. METHODS: In a national cohort design, we followed all Danish females from ages 15 to 44 years through the period 1977-2017 for induced abortions and live births. For each lifetime number of induced abortions, the average number of life births were assessed, and rates with 95% confidence limits calculated. RESULTS: The study included 409 497 females who completed 222 482 induced abortions and 831 742 live births. In 265 573 (64.9%) females who did not have any induced abortion, the average number of life births was 2.09 (95% CI 2.08-2.10). For females with 1 (23.4%), 2 (7.4%), 3 (2.6%), 4 (1.0%), and ≥5 (0.7%) induced abortions during their reproductive lifespan, the average number of life births was 1.88 (1.87-1.89), 1.99 (1.98-2.00), 2.09 (2.06-2.11), 2.13 (2.09-2.15), and 2.25 (2.21-2.29), respectively. The increase in number of life births in females with 1 to females with 5+ induced abortions was 4.7% for each additional induced abortion. CONCLUSION: We found number of induced abortions during a woman's reproductive lifespan to be positively correlated to the number of live births. This association is likely explained by a high fecundity in females with multiple pregnancies including induced abortions, and suggests that even several induced abortions do not compromise a woman's general reproductive end points.

Risk of Bowel Obstruction after Hysterectomy for Benign Indication According to Surgical Method in Denmark, 1984-2013.

STUDY OBJECTIVE: To estimate the risk of bowel obstruction (BO) after hysterectomy for benign indications depending on the surgical method (abdominal, vaginal, or laparoscopic) and identify risk factors for adhesive BO. DESIGN: A national registry-based cohort. SETTING: Danish hospitals during the period 1984-2013. PATIENTS: Danish women who underwent hysterectomy for benign indications (N = 125 568). INTERVENTIONS: Abdominal hysterectomies were compared with vaginal hysterectomies, laparoscopic hysterectomies, and minimally invasive (vaginal and laparoscopic) hysterectomies. MEASUREMENTS AND MAIN RESULTS: The incidence of BO according to the surgical method was compared using Cox proportional hazard regression. The covariates included were the time period, age, concomitant operations, previous abdominal surgery or disease, and socioeconomic factors. In a subanalysis (n = 35 712 women) of the period 2004-2013, detailed information from the Danish Hysterectomy Database enabled the inclusion of patient-, surgery-, and complication-related covariates. The overall crude incidence of BO was 17.4 of 1000 hysterectomies (2196 incident cases). The 10-year cumulative incidence of BO differed among the surgical routes (abdominal, 1.7%; laparoscopic, 1.4%; and vaginal, 0.9%). In multiple-adjusted analyses, the risk of BO was higher after abdominal hysterectomy than after vaginal (hazard ratio 1.64 [95% confidence interval, 1.39-1.93]) and minimally invasive (vaginal or laparoscopic) hysterectomy (hazard ratio 1.54 [1.33-1.79]). Additional pre-existing risk factors for BO at the time of hysterectomy were increased age, low education, low income, smoking, high American Society of Anesthesiologists comorbidity score, history of infertility, abdominal infection, and previous abdominal surgery (apart from cesarean section), penetrating lesions in abdominal organs, or operative adhesiolysis. Perioperative risk factors at the time of hysterectomy included concomitant removal of the ovaries, adhesiolysis, blood transfusion, readmission, and overall presence of perioperative complications. CONCLUSION: Abdominal hysterectomy is associated with a 54% higher risk of BO than minimally invasive (laparoscopic or vaginal) hysterectomy.

Incidence of shoulder dystocia and risk factors for recurrence in the subsequent pregnancy-A historical register-based cohort study.

INTRODUCTION: Shoulder dystocia is a rare obstetric complication, and the risk of recurrence is important for planning future deliveries. MATERIAL AND METHODS: The objectives of our study were to estimate the incidence and risk factors for recurrence of shoulder dystocia and to identify women at high risk of recurrence in a subsequent vaginal delivery. The study design was a nationwide register-based study including data from the Danish Medical Birth Registry and National Patient Register in the period 2007-2017. Nulliparous women with a singleton fetus in cephalic presentation were included for analysis of risk factors in index and subsequent delivery. RESULTS: During the study period, 6002 cases of shoulder dystocia were reported with an overall incidence among women with vaginal delivery of 1.2%. Among 222 225 nulliparous women with vaginal births, shoulder dystocia complicated 2209 (1.0%) deliveries. A subsequent birth was registered in 1106 (50.1%) of the women with shoulder dystocia in index delivery of which 837 (77.8%) delivered vaginally. Recurrence of shoulder dystocia was reported in 60 (7.2%) with a six-fold increased risk compared with women without a prior history of shoulder dystocia (risk ratio [RR] 5.70, 95% confidence interval [CI]: 4.41 to 7.38; adjusted RR 3.06, 95% CI: 2.03 to 4.68). Low maternal height was a significant risk factor for recurrence of shoulder dystocia. In the subsequent delivery, significant risk factors for recurrence were birthweight >4000 g, positive fetal weight difference exceeding 250 g from index to subsequent delivery, stimulation with oxytocin and operative vaginal delivery. In the subsequent pregnancy following shoulder dystocia, women who underwent a planned cesarean (n = 176) were characterized by more advanced age and a higher prevalence of diabetes in the subsequent pregnancy. Furthermore, they had more often experienced operative vaginal delivery, severe perineal lacerations, and severe neonatal complications at the index delivery. CONCLUSIONS: The incidence of shoulder dystocia among nulliparous women with vaginal delivery was 1.0% with a 7.2% risk of recurrence in a population where about 50% had a subsequent birth and of these 78% had subsequent vaginal delivery. Important risk factors for recurrence were low maternal height, increase of birthweight ≥250 g from index to subsequent delivery and operative vaginal delivery.

Winter, spring, summer or fall: temporal patterns in placenta-mediated pregnancy complications-an exploratory analysis.

PURPOSE: Placenta-mediated pregnancy complications, like growth restriction and hypertensive disorders, are leading causes of maternal, fetal and neonatal morbidity and mortality in high-income countries. The purpose was to investigate if there is a seasonal variation in placenta-mediated pregnancy complications (small for gestational age, intrauterine growth restriction, preeclampsia, preterm birth and intrauterine fetal death). METHODS: This is a Danish cohort study including all singleton deliveries at gestational week 22 up to and including week 41 conceived from December 2006 to November 2016 (N = 555,459). We used statistical process control charts to visualize data and to test for patterns of non-random variation in data over time for pregnancies with risk factors (BMI, diabetes, in vitro fertilization, maternal age > 40 years, primipara, previous caesarean and smoking) and each of the following outcome: fetal growth restriction, hypertensive disorders, preterm birth and intrauterine fetal death. The study was approved by the Danish Data Protection agency; REG-039-2019. RESULTS: We found a seasonal pattern in hypertensive disorders during pregnancy with dips in pregnancies conceived in the fall season and highest risk by conception in the spring and summer season. We found no apparent seasonality in cases of preterm delivery, small for gestational age and intrauterine mortality. Individual risk factors (e.g. smoking and obesity) for placenta-mediated complicated over time were in consistency with the general trends. CONCLUSIONS: We found a significant seasonal variation in the risk of hypertensive disorders of pregnancy with highest risk by conception in the spring and summer season. This study found no seasonal variation in other placenta-mediated complications.

Maternal age and risk of cesarean section in women with induced labor at term-A Nordic register-based study.

INTRODUCTION: Over the last decades, induction of labor has increased in many countries along with increasing maternal age. We assessed the effects of maternal age and labor induction on cesarean section at term among nulliparous and multiparous women without previous cesarean section. MATERIAL AND METHODS: We performed a retrospective national registry-based study from Denmark, Finland, Iceland, Norway, and Sweden including 3 398 586 deliveries between 2000 and 2011. We investigated the impact of age on cesarean section among 196 220 nulliparous and 188 158 multiparous women whose labor was induced, had single cephalic presentation at term, and no previous cesarean section. Confounders comprised country, time-period, and gestational age. RESULTS: In nulliparous women with induced labor the rate of cesarean section increased from 14.0% in women less than 20 years of age to 39.9% in women 40 years and older. Compared with women aged 25-29 years, the corresponding relative risks were 0.60 (95% confidence interval [95% CI] 0.57 to 0.64) and 1.72 (95% CI 1.66 to 1.79). In multiparous induced women the risk of cesarean section was 3.9% in women less than 20 years rising to 9.1% in women 40 years and older. Compared with women aged 25-29 years, the relative risks were 0.86 (95% CI 0.54 to 1.37) and 1.98 (95% CI 1.84 to 2.12), respectively. There were minimal confounding effects of country, time-period, and gestational age on risk for cesarean section. CONCLUSIONS: Advanced maternal age is associated with increased risk of cesarean section in women undergoing labor induction with a single cephalic presentation at term without a previous cesarean section. The absolute risk of cesarean section is 3-5 times higher across 5-year age groups in nulliparous relative to multiparous women having induced labor.

Cesarean section trends in the Nordic Countries - a comparative analysis with the Robson classification.

INTRODUCTION: The cesarean rates are low but increasing in most Nordic countries. Using the Robson classification, we analyzed which obstetric groups have contributed to the changes in the cesarean rates. MATERIAL AND METHODS: Retrospective population-based registry study including all deliveries (3 398 586) between 2000 and 2011 in Denmark, Finland, Iceland, Norway and Sweden. The Robson group distribution, cesarean rate and contribution of each Robson group were analyzed nationally for four 3-year time periods. For each country, we analyzed which groups contributed to the change in the total cesarean rate. RESULTS: Between the first and the last time period studied, the total cesarean rates increased in Denmark (16.4 to 20.7%), Norway (14.4 to 16.5%) and Sweden (15.5 to 17.1%), but towards the end of our study, the cesarean rates stabilized or even decreased. The increase was explained mainly by increases in the absolute contribution from R5 (women with previous cesarean) and R2a (induced labor on nulliparous). In Finland, the cesarean rate decreased slightly (16.5 to 16.2%) mainly due to decrease among R5 and R6-R7 (breech presentation, nulliparous/multiparous). In Iceland, the cesarean rate decreased in all parturient groups (17.6 to 15.3%), most essentially among nulliparous women despite the increased induction rates. CONCLUSIONS: The increased total cesarean rates in the Nordic countries are explained by increased cesarean rates among nulliparous women, and by an increased percentage of women with previous cesarean. Meanwhile, induction rates on nulliparous increased significantly, but the impact on the total cesarean rate was unclear. The Robson classification facilitates benchmarking and targeting efforts for lowering the cesarean rates.

Use of ICD-10 codes to monitor uterine rupture: validation of a national birth registry.

OBJECTIVES: Uterine rupture is a rare but severe complication in pregnancies after a previous cesarean section. In Denmark, the monitoring of uterine rupture is based on reporting of relevant diagnostic codes to the Danish Medical Birth Registry (MBR). The aim of our study was to examine the validity of registration of uterine rupture in the MBR within the population of pregnant women with prior cesarean section by conducting a review of the medical records. STUDY DESIGN: We reviewed 1709 medical records within the population of singleton pregnant woman delivering at term between 1997 and 2007. We retrieved the medical records of all women in the MBR with a code for uterine rupture during labor regardless of whether or not a prior cesarean section had been reported to the registry. In addition medical records of all women with a code for previous cesarean section and delivery of a child with adverse perinatal outcome were retrieved. RESULTS: Among women recorded in the MBR with a previous cesarean section and uterine rupture, only 60.4% actually had a uterine rupture (partial or complete). At least 16.2% of complete uterine ruptures were not reported to the registry. Considering only complete uterine ruptures, the sensitivity and specificity of the codes for uterine rupture were 83.8% and 99.1%, respectively. CONCLUSION: During the study period the monitoring of uterine rupture in the MBR was inadequate.