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.

The fetal circadian rhythm in pregnancies complicated by pregestational diabetes is altered by maternal glycemic control and the morning cortisol concentration.

Circadian rhythmicity is fundamental to human physiology, and is present even during fetal life in normal pregnancies. The impact of maternal endocrine disease on the fetal circadian rhythm is not well understood. The present study aimed to determine the fetal circadian rhythm in pregnancies complicated by pregestational diabetes mellitus (PGDM), compare it with a low-risk reference population, and identify the effects of maternal glycemic control and morning cortisol concentrations. Long-term fetal electrocardiogram recordings were made in 40 women with PGDM at 28 and 36 weeks of gestation. Two recordings were made in 18 of the women (45.0%) and one recording was made in 22 (55.0%). The mean fetal heart rate (fHR) and the fHR variation (root mean square of squared differences) were extracted in 1-min epochs, and circadian rhythmicity was detected by cosinor analysis. The study cohort was divided based on HbA1c levels and morning cortisol concentrations. Statistically, significant circadian rhythms in the fHR and the fHR variation were found in 45 (100%) and 44 (95.7%) of the 45 acceptable PGDM recordings, respectively. The rhythms were similar to those of the reference population. However, there was no statistically significant population-mean rhythm in the fHR among PGDM pregnancies at 36 weeks, indicating an increased interindividual variation. The group with higher HbA1c levels (>6.0%) had no significant population-mean fHR rhythm at 28 or 36 weeks, and no significant fHR-variation rhythm at 36 weeks. Similarly, the group with a lower morning cortisol concentration (≤8.8 µg/dl) had no significant population-mean fHR-variation rhythm at 28 and 36 weeks. These findings indicate that individual fetal rhythmicity is present in pregnancies complicated by PGDM. However, suboptimal maternal glycemic control and a lower maternal morning cortisol concentration are associated with a less-well-synchronized circadian system of the fetus.

Can oxytocin augmentation modify the risk of epidural analgesia by maternal age in cesarean sections?

INTRODUCTION: Maternal age is an established risk factor for cesarean section; epidural analgesia and oxytocin augmentation may modify this association. We investigated the effects and interactions of oxytocin augmentation, epidural analgesia and maternal age on the risk of cesarean section. MATERIAL AND METHODS: In all, 416 386 nulliparous women with spontaneous onset of labor, ≥37 weeks of gestation and singleton infants with a cephalic presentation during 2000-2011 from Norway and Denmark were included [Ten-group classification system (Robson) group 1]. In this case-control study the main exposure was maternal age; epidural analgesia, oxytocin augmentation, birthweight and time period were explanatory variables. Chi-square test and logistic regression were used to estimate associations and interactions. RESULTS: The cesarean section rate increased consistently with advancing maternal age, both overall and in strata of epidural analgesia and oxytocin augmentation. We observed strong interactions between maternal age, oxytocin augmentation and epidural analgesia for the risk of cesarean section. Women with epidural analgesia generally had a reduced adjusted odds ratio when oxytocin was used compared with when it was not used. In Norway, this applied to all maternal age groups but in Denmark only for women ≥30 years. Among women without epidural, oxytocin augmentation was associated with an increased odds ratio for cesarean section in Denmark, whereas no difference was observed in Norway. CONCLUSIONS: Oxytocin augmentation in nulliparous women with epidural analgesia is associated with a reduced risk of cesarean section in labor with spontaneous onset.

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.

Velamentous or marginal cord insertion and the risk of spontaneous preterm birth, prelabor rupture of the membranes, and anomalous cord length, a population-based study.

INTRODUCTION: Anomalous cord insertion is associated with increased risk of adverse maternal and perinatal outcome. Our aim was to study whether anomalous cord insertion is associated with prelabor rupture of membranes (PROM), preterm PROM (pPROM), long or short umbilical cord, and time trend of spontaneous preterm birth (SPTB) and anomalous cord insertion. MATERIAL AND METHODS: A population-based register study using data from the Medical Birth Register of Norway including all singleton births (gestational age >16 weeks and <45 weeks) during 1999-2013 (n = 860 465) to calculate odds ratios (ORs) for PROM, pPROM, SPTB, and cord length (>95th or <5th centile) according to the cord insertion site by logistic regression with adjustment for possible confounders. We also assessed time trends of SPTB and anomalous cord insertion. RESULTS: Velamentous insertion of the cord was associated with an increased risk of PROM (OR 1.6, 95% CI 1.5-1.7), pPROM (OR 2.7, 95% CI 2.4-3.0), SPTB (OR 2.0, 95% CI 1.9-2.2), and a short cord (OR 1.7, 95% CI 1.5-1.8). Marginal insertion was to a lesser extent associated with these complications. Occurrences of SPTB and anomalous insertion declined. The decline in SPTB persisted after including an interaction term between anomalous insertion and time. CONCLUSIONS: Velamentous and, to a lesser extent, marginal cord insertions were associated with increased risk of PROM, pPROM, SPTB, and short cord. This suggests a common pathogenesis behind altered function of the membranes, cord, and placenta. The decline in SPTB could not be explained by the reduction in the occurrence of anomalous cord insertion.

Neonatal outcome of singleton term breech deliveries in Norway from 1991 to 2011.

INTRODUCTION: The objective of this study was to examine the association between planned mode of delivery and neonatal outcomes in breech deliveries. MATERIAL AND METHODS: In this retrospective cohort study we studied singleton term breech deliveries in Norway from 1991 to 2011 (n = 30 861) using the Medical Birth Registry of Norway. We compared planned vaginal delivery with planned cesarean delivery across two time periods: from 1 January 1991 to 31 October 2000 (first period) and from 1 November 2000 to 31 December 2011 (second period). Intrapartum and neonatal deaths were validated against source data in medical records, autopsy reports, and other relevant documents. The main outcome measures were intrapartum and neonatal mortality within the first 28 days of life, 5-min Apgar-scores <7 and <4, neonatal intensive care unit stays ≥4 days, respiratory morbidity, and intracranial bleeding disorders. RESULTS: Rate of planned cesarean delivery increased from 34.4 to 51.3% over the period. Simultaneously, early neonatal mortality rate (0-6 days) declined (from 0.10% to 0.04%, p = 0.04). During the second period, 30.7% of term breech presentations were delivered vaginally. Eight deaths in the planned vaginal vs. four in the planned cesarean groups were observed (OR 2.11 95% CI 0.64-7.01). Neonatal morbidity outcomes were significantly worse in planned vaginal deliveries compared with planned cesarean deliveries in both periods. CONCLUSION: Overall intrapartum and neonatal mortality decreased during the entire period. Higher mortality in planned vaginal delivery relative to planned cesarean delivery in the second period was not statistically significant. However, neonatal morbidity was significantly higher in planned vaginal than planned cesarean deliveries in both periods. This warrants continuous surveillance of breech deliveries.

Third stage of labor risks in velamentous and marginal cord insertion: a population-based study.

OBJECTIVE: To assess whether anomalous cord insertion is associated with risk of complications in the third stage of labor. DESIGN: A population-based study. SETTING: Norwegian Medical Birth Register. POPULATION: All singleton births (gestational age >16 weeks and <45 weeks) during the period 1999-2011 (n = 738,443 singletons). Deliveries by cesarean were excluded, leaving 628,680 vaginal singleton deliveries for the analyses. METHODS: Calculation of odds ratios for complications in the third stage of labor (postpartum hemorrhage, manual delivery of the placenta, curettage) in velamentous and marginal cord insertion by logistic regression with adjustment for confounders. MAIN OUTCOME MEASURES: Complications in the third stage of labor, postpartum hemorrhage, manual placental removal and curettage. RESULTS: Anomalous cord insertion was associated with an increased risk of complications in the third stage of labor, the risk being higher for velamentous than for marginal insertion. The risks persisted after adjusting for possible confounding factors. Velamentous cord insertion carried a 5.6% risk of a need for manual removal of the placenta, compared with the risk of 1.1% for nonvelamentous insertion (odds ratio = 5.21, 95% confidence interval 4.71-5.76) in vaginal delivery, and we found increased risks of curettage (odds ratio = 3.29, 95% confidence interval 2.87-3.77) and postpartum hemorrhage (odds ratio = 2.06, 95% confidence interval 1.77-2.39). CONCLUSIONS: Marginal and especially velamentous cord insertion is associated with an increased risk of hemorrhage in the third stage of labor, need for manual removal of the placenta and curettage. Anomalous cord insertion can be identified prenatally and so possibly influence obstetric management.

Norwegian PUQE (Pregnancy-Unique Quantification of Emesis and nausea) identifies patients with hyperemesis gravidarum and poor nutritional intake: a prospective cohort validation study.

OBJECTIVE: The English questionnaire Pregnancy-Unique Quantification of Emesis and nausea (PUQE) identifies women with severe Hyperemesis Gravidarum. Our aim was to investigate whether scores from the translated Norwegian version; SUKK (SvangerskapsUtløst Kvalme Kvantifisering) was associated with severity of hyperemesis and nutritional intake. DESIGN: A prospective cohort validation study. SETTING: Hospital cohort of Hyperemesis Gravidarum (HG) patients from western Norway and healthy pregnant women from Bergen, Norway. SAMPLE: 38 women hospitalized due to HG and 31 healthy pregnant controls attending routine antenatal check-up at health centers. METHODS: Data were collected May 2013-January 2014. The study participants answered the Norwegian PUQE-questionnaire (scores ranging from 3 to 15) and registered prospectively 24-hours nutritional intake by a food list form. MAIN OUTCOME MEASURES: Differences of PUQE-scores, QOL-score and nutritional intake between hyperemesis patients and controls. RESULTS: Hyperemesis patients had shorter gestational age compared to controls (median 9.7 weeks; 95% CI 8.6-10.6 versus 11.9; 95% CI 10.1-12.9, p=0.004), and larger weight-change from pre-pregnant weight (loss of median 3 kg; 95% CI 3-4 versus gain of 2 kg; 95% CI 0.5-2, p<0.001) otherwise groups were similar regarding pre-pregnant BMI, age, gravidity, and inclusion weight. Compared to controls, hyperemesis patients had significant higher PUQE-score (median 13; 95% CI 11-14 vs. 7; 95% CI 4-8), lower QOL (median score 3; 95% CI 2-4 vs. 6; 95% CI 4.5-8) and lower nutritional intake (energy intake median 990 kcal/24 hours; 95% CI 709-1233 vs. 1652; 95% CI 1558-1880 all p<0.001). PUQE-score was inversely correlated to nutritional intake (-0.5, p<0.001). At discharge PUQE-score had fallen to median 6 (95% CI 5-8) and QOL score risen to 7 (95% CI 6-8) in the HG group, (both p<0.001 compared to admission values). CONCLUSION: PUQE-scoring has been validated as a robust indicator of severe hyperemesis gravidarum and insufficient nutritional intake in a Norwegian setting.

Delay in intervention increases neonatal morbidity in births monitored with cardiotocography and ST-waveform analysis.

OBJECTIVE: To assess the effect of the time interval from indication of hypoxia to delivery on neonatal outcome in high-risk pregnancies monitored with cardiotocography (CTG) and ST-waveform analysis. DESIGN: Prospective observational study. SETTING: University hospital, Norway, 2004-08. POPULATION: Singleton high-risk births with a gestational age above 35(+6) weeks, monitored with CTG and ST-waveform analysis. METHODS: Logistic regression analysis and Kaplan-Meier survival plots. MAIN OUTCOME MEASURE: Neonatal morbidity in relation to the rapidity of intervention. RESULTS: Of 6010 deliveries monitored with ST-waveform analysis, 1131 (19%) had an indication to intervene for fetal distress according to clinical guidelines. Those fetuses were at increased risk of an adverse neonatal outcome, and if delivered later than 20 min after the indication of hypoxia their risk increased further; i.e. transfer to the neonatal intensive care unit (NICU) from an odds ratio of 1.6 (95% confidence interval 1.2-2.2) to an odds ratio of 3.3 (95% confidence interval 2.5-4.3). The indication-to-delivery interval was longer for neonates with a 5-min Apgar score of <7, transfer to NICU and neonatal encephalopathy than for those without adverse outcome. CONCLUSION: In deliveries monitored with CTG and ST-waveform analysis, the risk of an adverse neonatal outcome was dependent on the time between indication of hypoxia and delivery. Nonadherence to the specific clinical guidelines increased the risk of neonatal morbidity.

Prevalence, risk factors and outcomes of velamentous and marginal cord insertions: a population-based study of 634,741 pregnancies.

OBJECTIVES: To determine the prevalence of, and risk factors for anomalous insertions of the umbilical cord, and the risk for adverse outcomes of these pregnancies. DESIGN: Population-based registry study. SETTING: Medical Birth Registry of Norway 1999-2009. POPULATION: All births (gestational age >16 weeks to <45 weeks) in Norway (623,478 singletons and 11,263 pairs of twins). METHODS: Descriptive statistics and odds ratios (ORs) for risk factors and adverse outcomes based on logistic regressions adjusted for confounders. MAIN OUTCOME MEASURES: Velamentous or marginal cord insertion. Abruption of the placenta, placenta praevia, pre-eclampsia, preterm birth, operative delivery, low Apgar score, transferral to neonatal intensive care unit (NICU), malformations, birthweight, and perinatal death. RESULTS: The prevalence of abnormal cord insertion was 7.8% (1.5% velamentous, 6.3% marginal) in singleton pregnancies and 16.9% (6% velamentous, 10.9% marginal) in twins. The two conditions shared risk factors; twin gestation and pregnancies conceived with the aid of assisted reproductive technology were the most important, while bleeding in pregnancy, advanced maternal age, maternal chronic disease, female foetus and previous pregnancy with anomalous cord insertion were other risk factors. Velamentous and marginal insertion was associated with an increased risk of adverse outcomes such as placenta praevia (OR = 3.7, (95% CI = 3.1-4.6)), and placental abruption (OR = 2.6, (95% CI = 2.1-3.2)). The risk of pre-eclampsia, preterm birth and delivery by acute caesarean was doubled, as was the risk of low Apgar score, transferral to NICU, low birthweight and malformations. For velamentous insertion the risk of perinatal death at term was tripled, OR = 3.3 (95% CI = 2.5-4.3). CONCLUSION: The prevalence of velamentous and marginal insertions of the umbilical cord was 7.8% in singletons and 16.9% in twin gestations, with marginal insertion being more common than velamentous. The conditions were associated with common risk factors and an increased risk of adverse perinatal outcomes; these risks were greater for velamentous than for marginal insertion.

Intrapartum monitoring of high-risk deliveries with ST analysis of the fetal electrocardiogram: an observational study of 6010 deliveries.

OBJECTIVE: To evaluate the clinical use of ST analysis (STAN) for intrapartum monitoring of high-risk pregnancies. DESIGN: Prospective observational study. SETTING: University hospital, Norway, 2004-2008. POPULATION: Singleton pregnancies with a gestational age above 35(+6) weeks. METHODS: Analysis of maternal and neonatal outcomes for all deliveries according to the method of intrapartum monitoring. MAIN OUTCOME MEASURES: Prevalence of cord metabolic acidosis (pH < 7.05, extracellular fluid base deficit (extracellular fluid) >12 mmol/L). RESULTS: Of 23 203 deliveries, 6010 (25.9%) were monitored with STAN. Fetal blood sampling was performed in 146 (2.4%) of the 6010 cases. During the study period, the prevalence of cord metabolic acidosis and moderate cord acidosis (pH < 7.15) decreased in STAN-monitored deliveries from 1.4 to 0.3% (p = 0.01) and from 16.4 to 11.7% (p = 0.001), respectively. The prevalence of moderate and severe neonatal encephalopathy was 0.38%. In the birth population, the proportion of cesarean deliveries decreased from 10.1 to 8.8%. The risk of emergency cesarean section after STAN monitoring compared with those monitored with auscultation/cardiotocography was high (odds ratio 5.4, 95% confidence interval = 4.9-6.1) but remained stable during the study period. CONCLUSIONS: ST analysis is a useful tool for identification of fetuses at risk of intrapartum hypoxia. Despite the restricted use of fetal blood sampling, we found a low proportion of cord metabolic acidosis and newborn morbidity.

Pregnancy outcome in women before and after cervical conisation: population based cohort study.

OBJECTIVES: To examine the consequences of cervical conisation in terms of adverse outcome in subsequent pregnancies. DESIGN: Population based cohort study. DATA SOURCES: Data on cervical conisation derived from the Cancer Registry of Norway and on pregnancy outcome from the Medical Birth Registry of Norway, 1967-2003. 15 108 births occurred in women who had previously undergone cervical conisation and 57 136 who subsequently underwent cervical conisation. In the same period there were 2 164 006 births to women who had not undergone relevant treatment (control). RESULTS: The proportion of preterm delivery was 17.2% in women who gave birth after cervical conisation versus 6.7% in women who gave birth before cervical conisation and 6.2% in women who had not undergone cervical conisation. The relative risk of a late abortion (<24 weeks' gestation) was 4.0 (95% confidence interval 3.3 to 4.8) in women who gave birth after cervical conisation compared with no cervical conisation. The relative risk of delivery was 4.4 (3.8 to 5.0) at 24-27 weeks, 3.4 (3.1 to 3.7) at 28-32 weeks, and 2.5 (2.4 to 2.6) at 33-36 weeks. The relative risk of preterm delivery declined during the study period and especially of delivery before 28 weeks' gestation. CONCLUSION: Cervical conisation influences outcome in subsequent pregnancies in terms of an increased risk of preterm delivery, especially in the early gestational age groups in which the clinical significance is highest. A careful clinical approach should be taken in the selection of women for cervical conisation and in the clinical care of pregnancies after a cervical conisation.

Maternal and paternal contribution to intergenerational recurrence of breech delivery: population based cohort study.

OBJECTIVE: To investigate intergenerational recurrence of breech delivery, with a hypothesis that both women and men delivered in breech presentation contribute to increased risk of breech delivery in their offspring. DESIGN: Population based cohort study for two generations. SETTING: Data from the medical birth registry of Norway, based on all births in Norway 1967-2004 (2.2 million births). PARTICIPANTS: Generational data were provided through linkage by national identification numbers, forming 451,393 mother-offspring units and 295,253 father-offspring units. We included units where both parents and offspring were singletons and offspring were first born, forming 232,704 mother-offspring units and 154,851 father-offspring units for our analyses. MAIN OUTCOME MEASURE: Breech delivery in the second generation. RESULTS: Men and women who themselves were delivered in breech presentation had more than twice the risk of breech delivery in their own first pregnancies compared with men and women who had been cephalic presentations (odds ratios 2.2, 95% confidence interval 1.8 to 2.7, and 2.2, 1.9 to 2.5, for men and women, respectively). The strongest risks of recurrence were found for vaginally delivered offspring and were equally strong for men and women. Increased risk of recurrence of breech delivery in offspring was present only for parents delivered at term. CONCLUSION: Intergenerational recurrence risk of breech delivery in offspring was equally high when transmitted through fathers and mothers. It seems reasonable to attribute the observed pattern of familial predisposition to term breech delivery to genetic inheritance, predominantly through the fetus.

Foetal size and body proportion at 17-19 weeks of gestation and neonatal size, proportion, and outcome.

OBJECTIVE: To determine whether proportionate or disproportionate foetal smallness at 17 to 19 weeks of gestation in low-risk pregnancies was associated with size, body constitution, and adverse outcome at birth. METHODS: We included ultrasound measurements at 17-19 weeks of gestation in 7285 uncomplicated pregnancies with reliable information on last menstrual period. We considered a foetus with both mean abdominal diameter (MAD) and biparietal diameter (BPD) below the 10th percentile for gestational age, gender, and parity as symmetrically small. Those who had MAD below the 10th percentile and BPD at or above the 10th percentile were asymmetrically small (thin and small). RESULTS: The occurrence of small for gestational age (SGA) (birth weight below the 10th percentile) decreased with increasing second trimester MAD percentile (P<0.0001). The risk in foetuses which were both thin and extremely small (MAD below the 2.5th percentile) of having weight, ponderal index, crown-heel length, or head circumference below the 10th percentile at birth was 19-28%. The risk of perinatal composite outcome (prenatal death, Apgar score after 5 min < or =7, birth weight below the 10th percentile, or <1500 g, or preterm birth) was 37%. Apgar score of < or =7 at 5 min and explained foetal death both occurred in 7%, which was significantly higher than those with larger MAD. CONCLUSION: Asymmetric as well as symmetric foetal smallness may start early in pregnancy. Symmetric and particularly asymmetric small foetuses at 17-19 weeks of gestation were generally lighter, shorter, and thinner at birth and had more often adverse perinatal outcome.

[External cephalic version of breech presentation at term]. / Ytre vending av foster i seteleie til termin.

BACKGROUND: External cephalic version could be an alternative to either vaginal delivery or caesarean section in breech presentation at term. MATERIAL AND METHODS: A systematic literature review about external cephalic version in breech presentation. RESULTS: The numbers of breech presentation delivered by caesarean section could probably be reduced in Norway by offering version, but this would not affect perinatal mortality.