Developing a serocorrelate of protection against invasive group B streptococcus disease in pregnant women: a feasibility study

BACKGROUND

Group B streptococcus is the leading cause of infection in infants. Currently, intrapartum antibiotic prophylaxis is the major strategy to prevent invasive group B streptococcus disease. However, intrapartum antibiotic prophylaxis does not prevent maternal sepsis, premature births, stillbirths or late-onset disease. Maternal vaccination may offer an alternative strategy. Multivalent polysaccharide protein conjugate vaccine development is under way and a serocorrelate of protection is needed to expedite vaccine licensure.

OBJECTIVES

The ultimate aim of this work is to determine the correlate of protection against the major group B streptococcus disease-causing serotypes in infants in the UK. The aim of this feasibility study is to test key operational aspects of the study design.

DESIGN

Prospective cohort study of pregnant women and their infants in a 6-month period (1 July to 31 December 2018).

SETTING

Five secondary and tertiary hospitals from London and South England. National iGBS disease surveillance was conducted in all trusts in England and Wales.

PARTICIPANTS

Pregnant women aged ≥ 18 years who were delivering at one of the selected hospitals and who provided consent during the study period. There were no exclusion criteria.

INTERVENTIONS

No interventions were performed.

MAIN OUTCOME MEASURES

(1) To test the feasibility of collecting serum at delivery from a large cohort of pregnant women. (2) To test the key operational aspects for a proposed large serocorrelates study. (3) To test the feasibility of collecting samples from those with invasive group B streptococcus.

RESULTS

A total of 1823 women were recruited during the study period. Overall, 85% of serum samples were collected at three sites collecting only cord blood. At the two sites collecting maternal, cord and infant blood samples, the collection rate was 60%. A total of 614 women were screened for group B streptococcus with a colonisation rate of 22% (serotype distribution: 30% III, 25% Ia, 16% II, 14% Ib, 14% V and 1% IV). A blood sample was collected from 34 infants who were born to colonised women. Maternal and infant blood and the bacterial isolates for 15 newborns who developed invasive group B streptococcal disease during the study period were collected (serotype distribution: 29% III, 29% II, 21% Ia, 7% Ib, 7% IV and 7% V).

LIMITATIONS

Recruitment and sample collection were dependent on the presence of research midwives rather than the whole clinical team. In addition, individualised consent limited the number of women who could be approached each day, and site set-up for the national surveillance study and the limited time period of this feasibility study limited recruitment of all eligible participants.

CONCLUSIONS

We have verified the feasibility of collecting and processing rectovaginal swabs and blood samples in pregnant women, as well as samples from those with invasive group B streptococcal disease. We have made recommendations for the recruitment of cases within the proposed GBS3 study and for controls both within GBS3 and as an extension of this feasibility study.

FUTURE WORK

A large case-control study comparing specific immunoglobulin G levels in mothers whose infants develop invasive group B streptococcal disease with those in colonised mothers whose infants do not develop invasive group B streptococcal disease is recommended.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN49326091; IRAS project identification number 246149/REC reference number 18/WM/0147.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 67. See the NIHR Journals Library website for further project information.

Evaluation of training programme uptake in an attempt to reduce obstetric anal sphincter injuries: the SUPPORT programme

INTRODUCTION AND HYPOTHESIS

The objective was to assess the feedback from a quality improvement training programme to reduce obstetric anal sphincter injuries (OASIS).

METHODS

Training sessions were organised that included evidence-based information on OASIS risk factors and training on models to measure perineal body length (PBL), perform episiotomies with standard and 60° fixed angle scissors (EPISCISSORS-60®), and measure post-delivery episiotomy suture angles with protractor transparencies. Feedback forms using a Likert scale (1-4) were completed and analysed. The setting was an evidence-based quality improvement programme (Strategy for Using Practical aids for Prevention of OASIS, Recording episiotomies and clinician Training [SUPPORT]) at two National Health Service (NHS) Hospitals in the UK. The participants were midwives and doctors attending the SUPPORT training programme RESULTS: All of the participants (100 %) would recommend the training programme to a friend or colleague. 92 % felt that the training session improved their knowledge of the impact of PBL and perineal distension and their knowledge of the relationship between episiotomy angle and OASIS "a lot" or "somewhat".

CONCLUSION

Based on this feedback, we recommend the addition of the knowledge content of the SUPPORT programme to other centres providing perineal assessment and repair courses.

Comparison of obstetric anal sphincter injuries in nulliparous women before and after introduction of the EPISCISSORS-60(®) at two hospitals in the United Kingdom

AIM

To assess whether the introduction of episiotomy scissors specially designed to achieve a cutting angle of 60°, EPISCISSORS-60(®), in two hospitals in the UK would result in a reduction in obstetric anal sphincter injuries (OASIS) in nulliparous women.

METHODS

A structured training program for all doctors and midwives provided a theoretical framework around OASIS including risk factors and the role of episiotomies and a practical hands-on training element to use EPISCISSORS-60(®) correctly and to measure perineal body length and post-suturing angles. Data for perineal body length, post-suturing angles, user feedback, episiotomy use, and incidence of OASIS were collected through specifically designed forms and the general hospital data collection system.

RESULTS

Data were available for 838 nulliparous vaginal deliveries. Mean perineal body length was 37 mm in spontaneous vaginal delivery group (standard deviation [SD] =8.3, 95% confidence interval [CI] =34-39) and 38 mm in the operative vaginal delivery group (SD=8, 95% CI=35-40). Post-suturing episiotomy angles were 53° (SD=6.5, 95% CI=50.7-55.8) in spontaneous vaginal deliveries and 52° (SD=9.6, 95% CI=49-54) in operative vaginal deliveries. EPISCISSORS-60(®) were rated as "good" to "very good" by 84% of users. There was a 47% increase in the number of episiotomies in nulliparous spontaneous vaginal deliveries at Poole (P=0.007) and a 16.5% increase in the number of episiotomies in nulliparous operative vaginal deliveries in Hinchingbrooke (P=0.003). There was an overall 11% increase in episiotomy numbers in nulliparous vaginal deliveries (P=0.08). There was a statistically significant OASIS reduction of 84% in nulliparous spontaneous vaginal deliveries in women who received an episiotomy (P=0.003).

CONCLUSION

Initial results after introduction of EPISCISSORS-60(®) show that the majority of health care professionals achieve post-suturing episiotomy angles between 40° and 60°. The results also show a significant increase in the use of episiotomies in the delivery of nulliparous women. There has been a statistically significant reduction in OASIS in nulliparous spontaneous vaginal deliveries.

Cutting an episiotomy at 60 degrees: how good are we?

INTRODUCTION AND HYPOTHESIS

Episiotomy is regarded as the most common maternal obstetric surgical procedure. It is associated with a significant increase in blood loss, lower pelvic floor muscle strength, dyspareunia, and perineal pain compared with a perineal tear. We tested the hypothesis that all doctors and midwives can perform an episiotomy when prompted to, specifically cut at 60° from the midline (in a simulation model).

METHODS

Doctors and midwives attending the BMFMS Annual Meeting (2014), Croydon Perineal Trauma Course and staff at Poole General Hospital were invited to cut a paper replica of the perineum with a commonly used episiotomy incision pad. Participants were prompted to cut an episiotomy at 60° to the perineal midline with the anus as a reference point. The angles and distances were measured using protractors and rulers. A 58-62° band was deemed acceptable to account for measurement errors.

RESULTS

A total of 106 delegates participated. Only 15 % of doctors and midwives cut an episiotomy between 58 and 62°. Over one third (36 %) cut the episiotomy between 55 and 65° (inclusive). Nearly two thirds either underestimated the angle (<55°; 44 %), or overestimated the angle (>66°; 18 %). Thirty-six and 7.5 % of episiotomies were cut at <50 and >70° respectively. The origination point of the episiotomy was 5 mm away from the midline (IQR 1-8 mm).

CONCLUSIONS

This original observational study shows that doctors and midwives were poor at cutting at the prompted episiotomy angle of 60°. This highlights the need to develop structured training programmes to improve the visual accuracy of estimating angles or the use of fixed angle devices to help improve the ability to estimate the desired angle.