Screening for Group B streptococcus should be routine in pregnancy: AGAINST: Current evidence does not support the introduction of microbiological screening for identifying carriers of Group B streptococcus

For this argument, I am referring to microbiological screening, with swabs taken from the vagina and/or rectum in late pregnancy, with the intention of identifying carriers of Group B streptococcus (GBS), so that intrapartum antibiotic prophylaxis (IAP) can be offered, with the aim of preventing early-onset GBS sepsis in newborns in the UK. Given this, the question of whether screening should be routine has already been answered. The evidence has been reviewed by the National Institute for Health and Care Excellence (NICE), the Royal College of Obstetricians and Gynaecologists (RCOG), and most comprehensively by the National Screening Committee (NSC; www.screening.nhs.uk/groupbstreptococcus), and there is agreement that the current evidence does not support the introduction of microbiological screening. These bodies have acknowledged that not all countries, when reviewing this evidence, have reached the same conclusion (Verani et al. Revised guidelines from CDC MMWR 2010;59(RR10);1–36); however, given the situation in the UK, a clear policy decision has been reached. So what do we do with this policy? Well, the first question to ask is ‘how do we enact and monitor a policy of NOT initiating a screening programme?’ Most of our efforts are directed at auditing and monitoring the offer and uptake of programmes, using clinical governance processes to ensure adherence to the programme, with rigorous quality control. Should we not do the same when we have a policy of not offering screening? Should trusts audit their own practice to ensure adherence to national policy? And what role does the Care Quality Commission have in ensuring that trusts do this? Adherence to national policy, whether that is to screen or not to screen, is important when making sure that scarce resources are used most effectively. What new evidence could change this policy? Before initiating a new programme, the NSC want to see a randomised controlled trial comparing the new programme with existing care. This has infrequently happened with many existing screening programmes (e.g. cervical cancer) and, with the promise of a GBS vaccine constantly ‘round the corner’, the time and expense of running a trial of antenatal GBS screening seems unlikely to happen. In my view there are two main issues that hamper the assessment of harms and benefits of antenatal GBS screening. The first is the artefact introduced by using GBS culture-positivity when assessing the outcome of the use of IAP. The presence of antibiotic in the baby's circulation will inhibit the growth of the organism, despite the clinical picture of sepsis. This artefact means we remain uncertain how effective IAP really is. The second is the huge number of women who require IAP for the small number of symptomatic neonatal infections that are likely to be prevented, with the resulting concerns about the impact that antibiotics given at the time of labour may have on the longer-term outcomes for a large number of babies. This uncertainly about impact was highlighted by the follow-up of the ORACLE trial (Kenyon et al. Lancet 2008;376:1319–27), but extends well beyond that, with concerns that selection pressure applied to the developing microbiota may have profound long-term health consequences (Bedford Russell & Murch BJOG 2006;113:758–65; Quigley Gastroenterol Hepatol 2013;9:560–69). Added to which, there is growing international pressure to limit the use of antibiotics in the face of increasing resistance and a lack of new antibiotic development (www.gov.uk/government/uploads/system/uploads/attachment_data/file/138331/CMO_Annual_Report_Volume_2_2011.pdf). Being able to identify women and babies who would most benefit from antibiotics would be an important step in balancing the benefits versus harms of such a programme. Member of RCOG Greentop Guideline development group and advisor to the National Screening Committees review of Screening for Group B streptococcal infection in pregnancy 2012. ■