The UK Obstetric Surveillance System is a national system that allows for the collection of information on a range of rare disorders of pregnancy, enabling national descriptive, case-control and cohort studies. The population-based nature of the studies conducted renders them less susceptible to the biases typically associated with observational studies. Data collected using The UK Obstetric Surveillance System and similar systems can be used to address a range of patient safety issues. These include assessing the safety of different treatment options, using the data as an aid to service planning, as part of ongoing quality-improvement initiatives, as a benchmark against which to compare hospital-level disease incidence and outcomes, to inform and audit national guidelines, and to monitor the effect of changes in practice or policy. Studies can be introduced rapidly in response to newly arising safety concerns. International comparisons can further enhance the utility of these data for improving patient safety.
What is the UK Obstetric Surveillance System?
The UK Obstetric Surveillance System (UKOSS) is a national system that allows for the collection of information on a range of rare disorders of pregnancy, enabling national descriptive, case-control and cohort studies. The system was specifically established to study rare disorders, as such studies require multi-centre collaborations to enable sufficient information to be collected to conduct robust research, and hence to guide practice and improve patient safety. Without such collaborations, research is difficult, hence high-quality studies are rarely undertaken and management is rarely evidence-based. Importantly, in relation to patient safety, the system allows for the collection of detailed information about ‘near-miss’ severe maternal morbidities. In countries where maternal death is rare, it is increasingly recognised that the study of ‘near-miss’ events can provide important information to address the patient safety agenda, which complements detailed enquiries into maternal deaths.
In addition, the population-based nature of the studies conducted renders them less susceptible to the biases typically associated with observational studies. For example, by collecting information about all cases occurring within a population, such studies are effectively free from selection bias, a common problem with hospital-based cohorts or case-series. Cases can be defined prospectively using robust criteria, and thus the potential for inclusion of false positive cases, a frequent criticism of studies using routine data, is minimised. Furthermore, as data are specifically collected for each study, this allows for detailed and nuanced clinical information to be gathered to address specific clinical questions, compared with studies using routinely collected data, in which the clinical questions addressed are limited by the data that are routinely collected, as the items collected cannot be changed. Cases are sought actively, which also helps to maximise case ascertainment and thus minimise the possibility of missed cases, or false negatives. Studies conducted using UKOSS and similar systems can thus provide the highest quality of observational evidence available.
How does the UK Obstetric Surveillance System work?
Every month a card is mailed to nominated reporting clinical staff within all consultant-led maternity units in the UK. UKOSS reporters include obstetricians, midwives, anaesthetists and risk-management midwives. The card contains a list of the conditions currently under study, and the reporters are asked to return the card, noting the number of cases of each condition there has been in their unit over the last month. Importantly, they are also asked to return the card even if there have been no cases, as this confirms ongoing unit participation and allows for the estimation of denominator numbers of births. If a reporter returns a card indicating that there has been a case, they are then asked to complete a data collection form with further details of the characteristics of the woman, her management and outcomes. Each data-collection form is specific to each individual condition, thus allowing a wide range of questions relevant to patient safety to be addressed; all data collected are anonymous. The data are entered into a customised database, cleaned and validated before detailed analysis.
How does the UK Obstetric Surveillance System work?
Every month a card is mailed to nominated reporting clinical staff within all consultant-led maternity units in the UK. UKOSS reporters include obstetricians, midwives, anaesthetists and risk-management midwives. The card contains a list of the conditions currently under study, and the reporters are asked to return the card, noting the number of cases of each condition there has been in their unit over the last month. Importantly, they are also asked to return the card even if there have been no cases, as this confirms ongoing unit participation and allows for the estimation of denominator numbers of births. If a reporter returns a card indicating that there has been a case, they are then asked to complete a data collection form with further details of the characteristics of the woman, her management and outcomes. Each data-collection form is specific to each individual condition, thus allowing a wide range of questions relevant to patient safety to be addressed; all data collected are anonymous. The data are entered into a customised database, cleaned and validated before detailed analysis.
How can this information be used to improve patient safety?
Clinical management
Randomised-controlled trials can be challenging, and this is particularly the case when considering the management of rare conditions or those occurring in emergency situations. In the emergency situation, recruitment to trials can be difficult because of issues relating to consent, as women and their partners may not have the capacity to make an informed choice to participate in a randomised-controlled trial in such a situation. In addition, the demands of emergency management may simply not allow adequate time for clinical staff to seek consent to participate in a trial. In situations where the disorder is uncommon, such as when a hysterectomy is required to manage postpartum haemorrhage, recruitment of sufficient participants to undertake a randomised trial with adequate study power may require such a large collaboration of centres as to render it extremely difficult if not impossible.
A further area of difficulty in undertaking randomised trials arises in situations where either clinicians or participants are unwilling to randomise or be randomised. In situations where there is a lack of clinical equipoise (i.e. when the treating clinicians have clear beliefs about which management option is the safest), it may be challenging to find centres willing to recruit participants to a trial. Similarly, where women have clear opinions about which is the better management option for them (for example when thinking about choice of mode of delivery, even if clinical staff are willing to recruit), women may decline to participate in a trial. A further scenario in which a randomised-controlled trial may be difficult relates to situations in which it may be considered unethical to randomise women (for example when the outcome of the condition with no treatment is so poor that any treatment is likely to have benefit).
UKOSS national observational studies can contribute by providing important information to aid patient safety and clinical decision-making in many of these situations where a randomised-controlled trial is unable to.
In the emergency situation
Severe postpartum haemorrhage, which is resistant to first-line medical treatments and simple interventions such as intra-uterine tamponade, is clearly a life-threatening emergency. A number of further options for management exist that can be undertaken in an attempt to stop the haemorrhage and preserve the uterus. A randomised-controlled trial to compare the safety and efficacy of these approaches is difficult because of the challenges of the emergency situation, clinician preference, and availability of facilities to undertake various interventional radiological approaches.
A UKOSS study was therefore undertaken to compare the outcomes of management of postpartum haemorrhage with uterine compression sutures, interventional radiological techniques (e.g. arterial embolisation or intra-arterial balloon tamponade), pelvic vessel surgical ligation and factor VIIa, in cases where first-line medical management, intrauterine balloon tamponade, or both, had failed. The success rates of each of these treatments is shown in Fig. 1 . The study showed that both uterine compression sutures and interventional radiological techniques were equally likely to control the haemorrhage; success rates were much lower for surgical vessel ligation and factor VIIa administration. Importantly, for patient safety, almost one-quarter of cases proceeded to hysterectomy, irrespective of the intervention used, highlighting the need for the availability of a surgical team with the skills and facilities to undertake a hysterectomy whenever any of these treatments are required.
Where capacity to consent is an issue
If efforts to treat postpartum haemorrhage while preserving the uterus fail, a hysterectomy will be undertaken as a life-saving procedure. At this stage of management, it is likely that a woman will have undergone other surgical procedures in an attempt to treat the haemorrhage, and she may well be under general anaesthesia. She would not thus have the capacity to consent to participate in a trial of type of hysterectomy. A UKOSS study collecting information on all women undergoing a peripartum hysterectomy in the UK during a 13-month period examined the complications of subtotal versus total hysterectomy. No differences were observed in the rates of damage to surrounding structures, need for further surgery or transfusion requirements between women undergoing a total hysterectomy and those having a subtotal procedure. This suggests that, in these circumstances, the procedures are equally safe.
Patient and clinician preference
The choice of mode of delivery after previous delivery by caesarean section can be difficult. In these circumstances, women may have clear views as to their preferred mode of delivery and it may thus be difficult to recruit to a randomised-controlled trial. A recent study reported only 22 women recruited to such a trial, alongside a cohort of 2323 women who reported a clear preference. It may therefore by challenging to obtain information about the safety of different planned modes of delivery in these circumstances. One of the main concerns in relation to patient safety in women who have previously delivered by caesarean section is the risk of uterine rupture in the context of planned subsequent vaginal delivery. A UKOSS study of uterine rupture reported an association between uterine rupture and planned vaginal delivery in women who had undergone a prior caesarean delivery (aOR 19.4, 95% CI 8.5 to 44.0), although the absolute risk of rupture in this group was still low at about one in 500 deliveries. Importantly, the risks varied according to the management of women during labour (e.g. uterine rupture was associated with induction with prostaglandin or treatment with oxytocin during labour) ( Table 1 ). This clearly suggests that, to improve patient safety, both prostaglandin and oxytocin should be used with caution in these circumstances.
| Risk factor | Women with a uterine rupture ( n = 139) | Control women ( n = 448) | Unadjusted odds ratio (95% CI) | P value | Adjusted b odds ratio (95% confidence interval) | P value | ||
|---|---|---|---|---|---|---|---|---|
| N | % a | N | % a | |||||
| Planned elective caesarean section delivery | 20 | 17 | 250 | 58 | 1 | 1 | ||
| Planned vaginal delivery and: | ||||||||
| Laboured without prostaglandin induction c or oxytocin in labour. | 52 | 45 | 132 | 31 | 4.92 (2.82 to 8.60) | <0.0001 | 12.74 (5.44 to 29.87) | <0.0001 |
| Labour induced with prostaglandin and oxytocin not used in labour. | 10 | 9 | 9 | 2 | 13.89 (5.06 to 38.10) | <0.0001 | 35.91 (10.38 to 124.28) | <0.0001 |
| Laboured without prostaglandin induction c but oxytocin in labour. | 28 | 24 | 33 | 8 | 10.61 (5.38 to 20.91) | <0.0001 | 35.36 (13.38 to 93.41) | <0.0001 |
| Labour induced with prostaglandin and oxytocin used in labour. | 6 | 5 | 5 | 1 | 15 (4.21to 53.48) | <0.0001 | 52.05 (11.30 to 239.84) | <0.0001 |
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
