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Concept: Pre-eclampsia

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To determine if “early rupture of membranes” (early ROM) during induction of labor is associated with an increased risk of cesarean section in term nulliparas.

Concepts: Childbirth, Obstetrics, Epidural, Caesarean section, Breech birth, Labor induction, Ventouse, Pre-eclampsia

170

Pre-eclampsia (PE), a severe pregnancy-specific disease characterized by the new onset of hypertension, proteinuria, edema, and a series of other systematic disorders, is a state of widespread mitochondrial dysfunction of the placenta.

Concepts: Mitochondrion, Proteomics, Placenta, Pre-eclampsia

170

Caesarean section incidence is steadily rising worldwide; the major contributor to this rise is pregnancies with previous caesarean section. Hence, it is important to scrutinise carefully the indication of primary caesarean sections. Preterm births, breech presentation and twin pregnancies together complicate 12-18% of all births. The role of caesarean section in these pregnancies is controversial and lacks good evidence-based guidelines. Policy on mode of delivery in these three important obstetric groups is bound to influence overall primary caesarean section rates. In this chapter, we review the evidence on the place of caesarean delivery in these three important groups.

Concepts: Childbirth, Obstetrics, Caesarean section, Breech birth, Ventouse, Pre-eclampsia

169

BACKGROUND: British women are increasingly delaying childbirth. The proportion giving birth over the age of 35 rose from 12% in 1996 to 20% in 2006. Women over this age are at a higher risk of perinatal death, and antepartum stillbirth accounts for 61% of all such deaths. Women over 40 years old have a similar stillbirth risk at 39 weeks as women who are between 25 and 29 years old have at 41 weeks.Many obstetricians respond to this by suggesting labour induction at term to forestall some of the risk. In a national survey of obstetricians 37% already induce women aged 40–44 years. A substantial minority of parents support such a policy, but others do not on the grounds that it might increase the risk of Caesarean section. However trials of induction in other high-risk scenarios have not shown any increase in Caesarean sections, rather the reverse. If induction for women over 35 did not increase Caesareans, or even reduced them, it would plausibly improve perinatal outcome and be an acceptable intervention. We therefore plan to perform a trial to test the effect of such an induction policy on Caesarean section rates.This trial is funded by the NHS Research for Patient Benefit (RfPB) Programme. DESIGN: The 35/39 trial is a multi-centre, prospective, randomised controlled trial. It is being run in twenty UK centres and we aim to recruit 630 nulliparous women (315 per group) aged over 35 years of age, over two years. Women will be randomly allocated to one of two groups:Induction of labour between 390/7 and 396/7 weeks gestation.Expectant management i.e. awaiting spontaneous onset of labour unless a situation develops necessitating either induction of labour or Caesarean Section.The primary purpose of this trial is to establish what effect a policy of induction of labour at 39 weeks for nulliparous women of advanced maternal age has on the rate of Caesarean section deliveries. The secondary aim is to act as a pilot study for a trial to answer the question, does induction of labour in this group of women improve perinatal outcomes? Randomisation will occur at 360/7 – 396/7 weeks gestation via a computerised randomisation programme at the Clinical Trials Unit, Nottingham University Hospitals NHS Trust. There will be no blinding to treatment allocation. DISCUSSION: The 35/39 trial is powered to detect an effect of induction of labour on the risk of caesarean section, it is underpowered to determine whether it improves perinatal outcome. The current study will also act as a pilot for a larger study to address this question.Trial registration: ISRCTN11517275.

Concepts: Childbirth, Randomized controlled trial, Obstetrics, Oxytocin, Caesarean section, Breech birth, Labor induction, Pre-eclampsia

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BACKGROUND: Two years after implementing the free-CS policy, we assessed the non-financial factors associated with caesarean section (CS) in women managed by referral hospitals in Senegal and Mali METHODS: We conducted a cross-sectional survey nested in a cluster trial (QUARITE trial) in 41 referral hospitals in Senegal and Mali (10/01/2007–10/01/2008). Data were collected regarding women’s characteristics and on available institutional resources. Individual and institutional factors independently associated with emergency (before labour), intrapartum and elective CS were determined using a hierarchical logistic mixed model. RESULTS: Among 86 505 women, 14% delivered by intrapartum CS, 3% by emergency CS and 2% by elective CS. For intrapartum, emergency and elective CS, the main maternal risk factors were, respectively: previous CS, referral from another facility and suspected cephalopelvic-disproportion (adjusted Odds Ratios from 2.8 to 8.9); vaginal bleeding near full term, hypertensive disorders, previous CS and premature rupture of membranes (adjusted ORs from 3.9 to 10.2); previous CS (adjusted OR=19.2 [17.2-21.6]). Access to adult and neonatal intensive care, a 24-h/day anaesthetist and number of annual deliveries per hospital were independent factors that affected CS rates according to degree of urgency. The presence of obstetricians and/or medical-anaesthetists was associated with an increased risk of elective CS (adjusted ORs [95%CI] = 4.8 [2.6-8.8] to 9.4 [5.1-17.1]). CONCLUSIONS: We confirm the significant effect of well-known maternal risk factors affecting the mode of delivery. Available resources at the institutional level and the degree of urgency of CS should be taken into account in analysing CS rates in this context.

Concepts: Childbirth, Epidemiology, Risk, Obstetrics, Anesthesia, Caesarean section, Pre-eclampsia, Premature rupture of membranes

154

Objective To study the strength and validity of associations between adiposity and risk of any type of obstetric or gynaecological conditions.Design An umbrella review of meta-analyses.Data sources PubMed, Cochrane database of systematic reviews, manual screening of references for systematic reviews or meta-analyses of observational and interventional studies evaluating the association between adiposity and risk of any obstetrical or gynaecological outcome.Main outcomes Meta-analyses of cohort studies on associations between indices of adiposity and obstetric and gynaecological outcomes.Data synthesis Evidence from observational studies was graded into strong, highly suggestive, suggestive, or weak based on the significance of the random effects summary estimate and the largest study in the included meta-analysis, the number of cases, heterogeneity between studies, 95% prediction intervals, small study effects, excess significance bias, and sensitivity analysis with credibility ceilings. Interventional meta-analyses were assessed separately.Results 156 meta-analyses of observational studies were included, investigating associations between adiposity and risk of 84 obstetric or gynaecological outcomes. Of the 144 meta-analyses that included cohort studies, only 11 (8%) had strong evidence for eight outcomes: adiposity was associated with a higher risk of endometrial cancer, ovarian cancer, antenatal depression, total and emergency caesarean section, pre-eclampsia, fetal macrosomia, and low Apgar score. The summary effect estimates ranged from 1.21 (95% confidence interval 1.13 to 1.29) for an association between a 0.1 unit increase in waist to hip ratio and risk endometrial cancer up to 4.14 (3.61 to 4.75) for risk of pre-eclampsia for BMI >35 compared with <25. Only three out of these eight outcomes were also assessed in meta-analyses of trials evaluating weight loss interventions. These interventions significantly reduced the risk of caesarean section and pre-eclampsia, whereas there was no evidence of association with fetal macrosomia.Conclusions Although the associations between adiposity and obstetric and gynaecological outcomes have been extensively studied, only a minority were considered strong and without hints of bias.

Concepts: Pregnancy, Childbirth, Systematic review, Obstetrics, Hysterectomy, Caesarean section, Pre-eclampsia

28

The aim of this study was to describe the distribution of indications for vacuum extraction (VE) and emergency cesarean section (EMCS) from 1999 to 2010. Furthermore, we investigated the association of induction of labor and epidural analgesia (EA) on the risk of operative delivery.

Concepts: Childbirth, Obstetrics, Epidural, Caesarean section, Breech birth, Labor induction, Ventouse, Pre-eclampsia

28

The purpose of this study was to determine whether there is an increase in the cesarean delivery rate in women who undergo induction when oxytocin is discontinued in the active phase of labor.

Concepts: Childbirth, Obstetrics, Oxytocin, Epidural, Caesarean section, Breech birth, Labor induction, Pre-eclampsia

28

Haplotypes formed by polymorphisms (T-786C, rs2070744; a variable number of tandem repeats in intron 4, and Glu298Asp, rs1799983) of the eNOS gene were associated previously with gestational hypertension (GH) and preeclampsia (PE). However, no study has explored the Tag SNPs rs743506 and rs7830 in these disorders. The aim of the current study was to compare the distribution of the genotypes and haplotypes formed by the five eNOS polymorphisms mentioned among healthy pregnant (HP, n=122), GH (n=138), and PE (n=157). The haplotype formed by “C b G G C” was more frequent in HP compared to GH and PE (p=0.0071), which is supported by previous findings that demonstrated the association of the combination “C b G” with a higher level of nitrite (NO marker). Our results suggest a protective effect of the haplotype “C b G G C” against the development of hypertensive disorders of pregnancy.

Concepts: DNA, Gene, Pregnancy, Hypertension, Obstetrics, Population genetics, Pre-eclampsia, International HapMap Project

28

OBJECTIVE: To estimate the association between elective induction of labor and cesarean section in low-risk parous women, and to assess if the association is influenced by induction method. DESIGN: Cohort study. SETTING: University hospital in Sweden. Population Parous women without pregnancy complications or previous cesarean section, and with a planned vaginal term (37-41 weeks), singleton birth, in vertex position were included. METHODS: Information was collected from a local database containing prospectively entered antenatal and delivery data. Odds ratios for cesarean section were calculated using generalized estimating equations logistic regression and adjusted for parity, maternal age, gestational length, birthweight, use of epidural anesthesia and year of birth. MAIN OUTCOME MEASURE: Emergency cesarean section. RESULTS: Among 7973 pregnancies that fulfilled the inclusion criteria, 343 (4%) had an elective induction of labor. Intravenous oxytocin was administered in 5% of these inductions, amniotomy was performed in 62%, and a cervical ripening agent was used in 33%. Electively induced labor more than doubled the risk of cesarean section compared with spontaneous labor onset (OR 2.5, 95% 1.4-4.2) and this risk was more than tripled when cervical ripening was used (OR 3.6, 95% confidence interval 1.7-7.6). CONCLUSIONS: In low-risk parous women, electively induced labor has an increased risk of emergency cesarean section compared with spontaneous onset labor. This risk increase is more pronounced if cervical ripening agents are required. Women need to be counseled about these risks before elective induction of delivery is decided. © 2012 The Authors Acta Obstetricia et Gynecologica Scandinavica © 2012 Nordic Federation of Societies of Obstetrics and Gynecology.

Concepts: Pregnancy, Childbirth, Obstetrics, Oxytocin, Epidural, Caesarean section, Labor induction, Pre-eclampsia