Maternal sepsis: a Scottish population-based case-control study

OBJECTIVE

To describe the risk of maternal sepsis associated with obesity and other understudied risk factors such as operative vaginal delivery.

DESIGN

Population-based, case-control study.

SETTING

North NHS region of Scotland.

POPULATION

All cases of pregnant, intrapartum and postpartum women with International Classification of Disease-9 codes for sepsis or severe sepsis recorded in the Aberdeen Maternal and Neonatal Databank (AMND) from 1986 to 2009. Four controls per case selected from the AMND were frequency matched on year-of-delivery.

METHODS

Cases and controls were compared; significant variables from univariable regression were adjusted in a multivariable logistic regression model.

MAIN OUTCOME MEASURES

Dependent variables were uncomplicated sepsis or severe ('near-miss') sepsis. Independent variables were demographic, medical and clinical delivery characteristics. Unadjusted and adjusted odds ratios (OR) with 95% confidence intervals (95% CI) are reported.

RESULTS

Controlling for mode of delivery and demographic and clinical factors, obese women had twice the odds of uncomplicated sepsis (OR 2.12; 95% CI 1.14-3.89) compared with women of normal weight. Age <25 years (OR 5.15; 95% CI 2.43-10.90) and operative vaginal delivery (OR 2.20; 95% CI 1.02-4.87) were also significant predictors of sepsis. Known risk factors for maternal sepsis were also significant in this study (OR for uncomplicated and severe sepsis respectively): multiparity (OR 6.29, 12.04), anaemia (OR 3.43, 18.49), labour induction (OR 3.92 severe only), caesarean section (OR 3.23, 13.35), and preterm birth (OR 2.46 uncomplicated only).

CONCLUSIONS

Obesity, operative vaginal delivery and age <25 years are significant risk factors for sepsis and should be considered in clinical obstetric care.

Myocardial infarction in pregnancy and postpartum in the UK

AIM

Cardiac disease is a leading cause of maternal death in the developed world, responsible for one-fifth of all maternal deaths in the UK. The aim of this study was to estimate the incidence of myocardial infarction (MI) in pregnancy and up to one week postpartum in the UK and describe risk factors, management and outcomes.

METHODS

A prospective population-based study with nested case control analysis used the UK Obstetric Surveillance System to identify all women in the UK with MI in pregnancy (in the years 2005-2010). A control group of 1360 women was used for comparison. Multivariable unconditional logistic regression was conducted to identify potential risk factors for MI in pregnancy and calculate adjusted odds ratios with 95% confidence intervals.

RESULTS

Twenty-five cases of MI in pregnancy were reported, giving an estimated incidence of 0.7 per 100,000 maternities (95%CI 0.5-1.1). Maternal age, smoking, hypertension, twin pregnancy and pre-eclampsia were independently associated with MI in pregnancy. Fifteen (60%) women underwent coronary angiography; nine (60%) had coronary atherosclerosis, three (21%) had coronary artery dissection, one (7%) had a coronary thrombus and two (13%) had normal coronary arteries. Nine women had angioplasty +/- stenting and two were thrombolysed. No women died.

CONCLUSIONS

Many risk factors are both recognisable and modifiable. Management of MI in pregnancy was highly variable indicating a clear need for further information regarding the safety and outcomes of different interventions. The addition of pregnancy status as a compulsory field in cardiac audit databases would enable routine collection of this information.

Influenza A/H1N1v in pregnancy: an investigation of the characteristics and management of affected women and the relationship to pregnancy outcomes for mother and infant

BACKGROUND

In April 2009 a novel influenza A virus (AH1N1v) of swine origin (swine flu) emerged, spreading rapidly and achieving pandemic status in June 2009. Pregnant women were identified as being at high risk of severe influenza-related complications and as a priority group for vaccination against AH1N1v. Limited information was available about the maternal and fetal risks of AH1N1v infection or of antiviral drug or AH1N1v vaccine use in pregnancy.

OBJECTIVES

To assess rates of and risk factors for adverse outcomes following AH1N1v infection in pregnancy and to assess the adverse effects of the antiviral drugs and vaccines used in prevention and management.

METHODS

Prospective national cohort studies were conducted to identify pregnant women who were (1) suspected to be infected with AH1N1v or being treated with antiviral medication in primary care; (2) vaccinated against AH1N1v; and (3) admitted to hospital with confirmed AH1N1v. Characteristics of women with influenza-like illness (ILI) in primary care were compared with those of women without symptoms accepting or declining immunisation. Characteristics of women admitted to hospital with confirmed AH1N1v infection in pregnancy were compared with a historical cohort of over 1200 women giving birth in the UK who were uninfected with AH1N1v. Outcomes examined in hospitalised women included maternal death, admission to an intensive care unit, perinatal mortality and preterm birth. Risk factors for hospital and intensive care unit admission were examined in a full regression model.

RESULTS

The weekly incidence of ILI among pregnant women averaged 51/100,000 over the study period. Antiviral drugs were offered to 4.8% [95% confidence interval (CI) 4.0% to 5.9%] and vaccination to 64.8% (95% CI 64.7% to 68.9%) of registered pregnant women. Ninety pregnant women with ILI presenting in primary care were reported to the research team, 55 of whom were prescribed antiviral drugs and in 42 (76%) cases this was within 2 days of symptom onset. After comparison with 1329 uninfected pregnant women offered vaccination, pre-existing asthma was the only maternal factor identified as increasing risk of ILI presentation [adjusted odds ratio (OR) 2.0, 95% CI 1.0 to 3.9]. Maternal obesity and smoking during pregnancy were also associated with hospital admission with AH1N1v infection. Overall, 241 pregnant women were admitted to hospital with laboratory-confirmed AH1N1v infection. Eighty-three per cent of these women were treated with antiviral agents, but only 6% received antiviral treatment before hospital admission. Treatment within 2 days of symptom onset was associated with an 84% reduction in the odds of admission to an intensive therapy unit (OR 0.16, 95% CI 0.08 to 0.34). Women admitted to hospital with AH1N1v infection were more likely to deliver preterm; a three times increased risk was suggested compared with an uninfected population cohort (OR 3.1, 95% CI 2.1 to 4.5).

CONCLUSIONS

Earlier treatment with antiviral agents is associated with improved outcomes for pregnant women and further actions are needed in future pandemics to ensure that antiviral agents and vaccines are provided promptly to pregnant women, particularly in the primary care setting. Further research is needed on longer-term outcomes for infants exposed to AH1N1v influenza, antiviral drugs or vaccines during pregnancy.

Critical illness with AH1N1v influenza in pregnancy: a comparison of two population-based cohorts

OBJECTIVE

To compare admissions to intensive care units (ICUs) with confirmed AH1N1v influenza in pregnancy in Australia, New Zealand and the UK.

DESIGN

National cohort studies.

SETTING

ICUs in Australia, New Zealand and the UK.

POPULATION

Fifty-nine women admitted to ICUs in Australia and New Zealand in June-August 2009, and 57 women admitted to ICUs in the UK in September 2009-January 2010.

METHODS

Comparison of cohort data.

MAIN OUTCOME MEASURES

Incidence of ICU admission, comparison of characteristics and outcomes.

RESULTS

There was a significantly higher ICU admission risk in Australia and New Zealand than in the UK (risk ratio 2.59, 95% CI 1.75-3.85). Indigenous women from Australia and women with Maori/Pacific Island backgrounds from New Zealand had the highest admission risk (29.7 admissions per 10 000 maternities, 95% CI 17.9-46.3). Women admitted in Australia and New Zealand were significantly more likely to have a pre-existing medical condition (51% versus 21%, P = 0.001), but were less likely to receive antiviral treatment (80% versus 93%, P = 0.038) than women admitted in the UK. Women admitted in the UK had a longer length of hospital stay (median 21 days, range 3-128 days) than women admitted in Australia and New Zealand (median 12 days, range 3-66 days), but there were no other differences in maternal or pregnancy outcomes.

CONCLUSIONS

The difference in admission risk may reflect a second phase effect from successful clinical and public health interventions, as well as differences in population characteristics between the countries. The overall severity of the AH1N1v influenza infection in pregnancy is evident, and emphasises the importance of an ongoing immunisation programme in pregnant women in both northern and southern hemispheres.

Tuberculosis in pregnancy in the UK

Tuberculosis (TB) is a globally important cause of morbidity and mortality with an increasing incidence in women of reproductive ages. This descriptive study using the UK Obstetric Surveillance System demonstrates key differences in the presentation of TB during pregnancy compared with the nonpregnant population. The disease is limited to ethnic minority women, most commonly recent immigrants. Presentation may be atypical, with extrapulmonary disease as common as pulmonary. Clinicians should be aware of the potential for nonspecific presentation of the disease in pregnancy and consider the diagnosis in women, especially recently arrived immigrants, presenting with nonspecific symptoms.

Improved spiral tube assembly for high-speed counter-current chromatography

The original spiral tube support (STS) assembly is improved by changing the shape of the tubing, with 1-cm presses perpendicularly along the length. This modification interrupts the laminar flow of the mobile phase. The tubing in the four return grooves to the center of the rotor is flattened by a specially made pressing tool to increase the number of spiral layers and decrease the dead space volume, thus increasing the column efficiency. The performance of this spiral tube assembly was tested in separations of dipeptides and proteins with suitable polar two-phase solvent systems. The results revealed that the present system yields high partition efficiency with a satisfactory level of stationary phase retention in a short elution time. The present high-speed counter-current chromatographic (HSCCC) system will be efficiently applied to a broad spectrum of two-phase solvent systems including aqueous-aqueous polymer phase systems (TPAS) which are used for separation of biopolymers such as proteins and nucleic acids.

A prospective national study of acute fatty liver of pregnancy in the UK

OBJECTIVES

To identify a national, population-based cohort of women with acute fatty liver of pregnancy (AFLP), to evaluate proposed diagnostic criteria and to document accurately the incidence, management and outcomes of the condition.

SUBJECTS AND METHODS

This was a population-based descriptive study using the UK Obstetric Surveillance System, carried out in all 229 hospitals with consultant-led maternity units in the UK. The participants comprised 57 women in the UK diagnosed with AFLP between February 2005 and August 2006 in an estimated cohort of 1 132 964 maternities (women delivering).

RESULTS

The estimated incidence of AFLP was 5.0 cases per 100 000 maternities (95% CI 3.8 to 6.5 per 100,000). Fifty-five cases (90%) were confirmed by diagnostic criteria and clinical assessment, two (3%) by clinical assessment alone, representing 97% agreement (kappa statistic = 0.78). 18% of women had twin pregnancies and 20% were underweight (body mass index (BMI) <20). 60% of women were admitted to intensive care and 15% to a specialist liver unit. One woman received a liver transplant. One woman died (case fatality rate 1.8%, 95% CI 0% to 9.4%). There were seven deaths among 67 infants (perinatal mortality rate 104 per 1000 births, 95% CI 43 to 203).

CONCLUSIONS

The largest population-based cohort of women with AFLP to date has been identified. Diagnostic criteria previously proposed agree substantially with clinical diagnosis. The incidence estimate from this study is lower than documented by earlier hospital-based studies, but maternal and neonatal outcomes are better than previously reported, possibly related to improved ascertainment. Women with twin pregnancies appear to be at higher risk, but further studies are needed to investigate the risk associated with low BMI.

Antenatal pulmonary embolism: risk factors, management and outcomes

OBJECTIVES

To estimate the incidence of antenatal pulmonary embolism and describe the risk factors, management and outcomes.

DESIGN

A national matched case-control study using the UK Obstetric Surveillance System (UKOSS).

SETTING

All hospitals with consultant-led maternity units in the UK.

PARTICIPANTS

A total of 143 women who had an antenatal pulmonary embolism between February 2005 and August 2006. Two hundred and fifty nine matched control women.

METHODS

Prospective case and control identification through the UKOSS monthly mailing.

MAIN OUTCOME MEASURES

Incidence and case fatality rates with 95% CIs. Adjusted odds ratio estimates.

RESULTS

One hundred per cent of UK consultant-led obstetric units contributed data to UKOSS. A total of 143 antenatal pulmonary embolisms were reported, representing an estimated incidence of 1.3 per 10,000 maternities (95% CI 1.1-1.5). Seventy per cent of women had identifiable classical risk factors for thromboembolic disease. The main risk factors for pulmonary embolism were multiparity (adjusted odds ratio [aOR] 4.03, 95% CI 1.60-9.84) and body mass index > or = 30 kg/m2 (aOR 2.65, 95% CI 1.09-6.45). Nine women who had a pulmonary embolism should have received antenatal thromboprophylaxis with low-molecular-weight heparin (LMWH) according to national guidelines; only three (33%) of them did. Six women (4%) had a pulmonary embolism following antenatal prophylaxis with LMWH; three of these women (50%) were receiving lower than recommended doses. Two women had recurrent pulmonary emboli (1.4%, 95% CI 0.2-5.1%). Five women died (case fatality 3.5%, 95% CI 1.1-8.0%).

CONCLUSIONS

Significant severe morbidity from thromboembolic disease underlies the maternal deaths from pulmonary embolism in the UK. This study has shown some cases where thromboprophylaxis was not provided according to national guidelines, and there may be scope for further work on guideline implementation.

434. Identification of differentially expressed proteins in ovine chorion rupture sites at preterm and term using proteomics

Introduction: A significant number of babies are delivered preterm and many of these deliveries are due to spontaneous rupture of fetal membranes. However, the mechanisms underlying fetal membrane rupture are not well defined. The sheep has proved to be a valuable model for elucidating the physiology of birth, with many of the findings clearly relevant to human parturition. In the current study we have used the sheep model to investigate changes in protein expression in the chorion in relation to the onset of spontaneous full term labour. Methods: Proteomic analysis was used to compare the protein profiles at the chorion rupture site between mid/late gestation (136 days, n = 6) and term delivery (145days, n = 6). Proteins were solubilised and separated into soluble and insoluble fractions which were separated by 2D-electrophoresis. Relative protein expression was quantified using the PROGENESIS software and protein spots were picked and identified using Matrix Assisted Laser Desorption Ionisation-Time of Flight (MALDI-TOF) mass spectrometry. Data-mining used gene ontology (GO terms) for each protein and these were clustered into networks using DAVID bioinformatics resource (http://david.abcc.ncifcrf.gov/home.jsp). Results: A total of 150 protein spots were identified of which 60 proteins were found to differ by more than 2-fold between preterm and term samples. This group was significantly enriched for proteins from the several functional GO categories including; Oxidoreductase activity (7 proteins); negative regulation of apoptosis (4); structural molecule activity (7); protease inhibitor activity (7); Carbohydrate metabolism (10); Glucose metabolism (5); Glycolysis (5); response to stress (8) and heat shock (3). Of the differentially regulated proteins, 10 were found to be significantly upregulated at term (ANOVA P < 0.05) including isocitrate dehydrogenase, glutamate dehydrogenase 1, malate dehydrogenase 2. A further 10 proteins, including serpin peptidase inhibitor SERPINA12, serpin peptidase inhibitor SERPINH1 precursor and heat shock protein 90 kDa β were found to be downregulated.

Spiral Tube Assembly for High-Speed Countercurrent Chromatography: Choice of Elution Modes for Four Typical Two-Phase Solvent Systems

Optimal elution modes were determined for four typical two-phase solvent systems each with different physical parameters to achieve the best peak resolution and retention of the stationary phase by spiral tube high-speed countercurrent chromatography using a suitable set of test samples. Both retention of the stationary phase and partition efficiency are governed by an interplay between two forces, i.e., Archimedean Screw force and radial centrifugal force gradient of the spiral channel. In the polar solvent system represented by 1-butanol./acetic acid/water (4:1:5, v/v/v) with settling time of over 30 s, the effect by the radial centrifugal gradient force dominates giving the best separation of dipeptides either by pumping the lower phase from the inner terminal or the upper phase from the outer terminal of the spiral channel. In the moderately hydrophobic two-phase solvent system represented by hexane/ethyl acetate/methanol/0.1 M HCl (1:1:1:1) with settling time of 19 s, and two hydrophobic solvent systems of hexane/ethanol/water (5:4:1, v/v/v) and non-aqueous binary system of hexane/acetonitrile both having settling time of 9, the effect of the Archimedean screw force play a major role in hydrodynamic equilibrium, giving the best separations by pumping the lower phase from the head or the upper phase from the tail of the spiral channel.

Peripartum hysterectomy in the UK: management and outcomes of the associated haemorrhage

OBJECTIVES

To identify women undergoing peripartum hysterectomy in the UK and to describe the causes, management and outcome of the associated haemorrhage.

DESIGN

A population-based descriptive study using the UK Obstetric Surveillance System (UKOSS).

SETTING

All 229 hospitals with consultant-led maternity units in the UK.

POPULATION

All women in the UK delivering between February 2005 and February 2006.

METHODS

Prospective case identification through the UKOSS monthly mailing.

MAIN OUTCOME MEASURES

Rates with 95% CIs. Odds ratio estimates.

RESULTS

Three hundred and eighteen women underwent peripartum hysterectomy. The most commonly reported causes of haemorrhage were uterine atony (53%) and morbidly adherent placenta (39%). Women were not universally managed with uterotonic therapies. Fifty women were unsuccessfully managed with B-Lynch or other brace suture prior to hysterectomy, 28 with activated factor VII and 9 with arterial embolisation. Twenty-one percent of women suffered damage to other structures, 20% required a further operation and 19% were reported to have additional severe morbidity. Bladder damage was more likely in women with placenta accreta (OR 3.41, 95% CI 1.55-7.48) than in women with uterine atony. There were no significant differences in outcomes between women undergoing total or subtotal hysterectomy. Two women died; case fatality 0.6% (95% CI 0-1.5%).

CONCLUSIONS

For each woman who dies in the UK following peripartum hysterectomy, more than 150 survive. The associated haemorrhage is managed in a variety of ways and not universally according to existing guidelines. Further investigation of the outcomes following some of the more innovative therapies for control of haemorrhage is needed.

Eclampsia in the United Kingdom 2005

OBJECTIVES

To estimate the national incidence of eclampsia in the UK and to describe the management and associated outcomes since the introduction of magnesium sulphate.

DESIGN

A population-based descriptive study using the newly established UK Obstetric Surveillance System (UKOSS).

SETTING

All 229 hospitals with consultant-led maternity units in the UK.

POPULATION

All women in the UK delivering between February 2005 and February 2006.

METHODS

Prospective case identification through the monthly mailing of UKOSS.

MAIN OUTCOME MEASURES

Incidence and mortality rates with 95% confidence intervals.

RESULTS

Data collection was complete for 94% of women. The incidence of eclampsia was 2.7 cases per 10,000 births (95% CI 2.4-3.1). Thirty-eight percent of women had established hypertension and proteinuria in the week before their first fit. Ninety-nine percent of women were treated with magnesium sulphate. No women in the study died. Fifty-four women (26%) had recurrent fits. One hundred and nineteen women (56%) were admitted to intensive care or obstetric high dependency units for a median of 2 days (range 1-9). Twenty-two women (10%) were reported to have other severe morbidity after the eclamptic episode. Outcomes were known for 222 infants (204 singletons and 18 twins). Eight infants were stillborn and five died in the neonatal period (perinatal mortality 59/1000 births [95% CI 32-98]).

CONCLUSIONS

The incidence of eclampsia and its complications have decreased significantly in the UK since 1992, following the introduction of management guidelines for eclampsia and pre-eclampsia. These results are consistent with the findings of the randomised controlled trials of magnesium sulphate. This study has shown the practical benefits of the incorporation of research evidence into practice.