Universal antenatal screening for group B streptococcus may cause more harm than goodBMJ 2019; 364 doi: https://doi.org/10.1136/bmj.l463 (Published 20 February 2019) Cite this as: BMJ 2019;364:l463
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Re: response to Universal antenatal screening for group B streptococcus may cause more harm than good by Braillon and Bewley
Braillon and Bewley state that “since 1996, the US Centers for Disease Control and Prevention, the American College of Obstetricians and Gynecologists, and American Academy of Pediatrics have recommended that hospitals adopt formal GBS prevention policies but have failed to provide clear guidance, allowing either a mass-screening approach with late prenatal period, or a risk-based approach during labor”. They quote a reference from 1999, which is outdated. The US Centers for Disease Control and Prevention revised their recommendations in 2002 and recommended “universal prenatal screening for vaginal and rectal GBS colonization of all pregnant women at 35--37 weeks' gestation, based on recent documentation in a large retrospective cohort study of a strong protective effect of this culture-based screening strategy relative to the risk-based strategy” (1). The recommendation for screening was further reinforced in 2010 when the CDC said “Implementation of the 2002 guidelines has been quite good. One study found that 85% of pregnant women were screened for GBS colonization. Among those screened, 98% had results available at time of delivery. Eighty-five percent of women with an indication for IAP were administered treatment.” (2) They continued “Nonetheless, there is room for improvement…. even more cases of early-onset GBS disease can be prevented”. The improvements included administering intrapartum antibiotic prophylaxis (IAP) in all preterm labours, a recommendation endorsed in 2017 by the Royal College of Obstetricians and Gynaecologists in the UK (3). The 2010 CDC guidelines for enhanced screening were endorsed by the American Academy of Family Physicians, the American Academy of Pediatrics, the American College of Nurse-Midwives, the American College of Obstetricians and Gynecologists and the American Society for Microbiology.
We agree with Braillon and Bewley that ‘first do no harm’ is an important dictum. They don’t address the known harm caused to hundreds of babies each year damaged or killed by early onset GBS disease whose mothers were not given the choice of antenatal testing and intrapartum antibiotic prophylaxis (IAP) which could have prevented this disease, and mentions harms which are exceptionally rare. The paper they quote regarding maternal death from anaphylaxis (4) reported ten cases in the UK which occurred related to the intrapartum period, only one of which involved IAP for GBS, with seven related to antibiotics given prior to caesarean delivery and two to anaesthesia. Of the two women who died from 1 October 2012 to 30 September 2015 (out of an estimated 2,324,552 maternities, giving a fatality rate of one per 1,162,276 pregnancies), both had a reaction after delivery and were not therefore related to IAP (the deaths were attributed to reactions to suxamethonium and co-amoxiclav, neither of which are given for IAP).
We entirely agree that “mothers and babies need better quality research” but they should not be denied interventions which could save their babies’ lives based on incorrect quotation of the research that already exists.
(1) Schrag S, Gorwitz R, Fultz-Butts K, Schuchat A. Prevention of perinatal group B streptococcal disease. Revised guidelines from CDC. MMWR Recomm Rep 2002; 51(RR-11):1-22.
(2) MMWR. Centers for Disease Control and Prevention, Prevention of Perinatal Group B Streptococcal Disease: Revised Guidelines from CDC. 59, No. RR-10, 1-36. 2010.
(3) RCOG. Group B Streptococcal Disease, Early-onset (Green-top Guideline No. 36) 2017. https://www.rcog.org.uk/en/guidelines-research-services/guidelines/gtg36/
(4) McCall SJ, Bunch KJ, Brocklehurst P, D'Arcy R, Hinshaw K, Kurinczuk JJ et al. The incidence, characteristics, management and outcomes of anaphylaxis in pregnancy: a population-based descriptive study. BJOG 2018; 125(8):965-971.
Competing interests: We are members of the Medical Advisory Panel of GBS Support, a UK charity that campaigns for women to be offered antenatal testing for GBS.
Seedat and colleagues analysed why the UK National Screening Committee (NSC) yet again decided not to introduce routine universal antenatal screening for group B Streptococcus according to proper process and principles.(1)
The UK retains the risk-based approach in which women are evaluated during labor for obstetric risk factors and the NSC must be commended for its continued expert discernment in the face of powerful single-issue patient pressure. By contrast, since 1996, the US Centers for Disease Control and Prevention, the American College of Obstetricians and Gynecologists, and American Academy of Pediatrics have recommended that hospitals adopt formal GBS prevention policies but have failed to provide clear guidance, allowing either a mass-screening approach with late prenatal period, or a risk-based approach during labor .(2)
Screening too often relies on hope and hype from biased advocates who are unable to judge flaws or dispassionately weigh trade-offs, thus fuelling the uncontrolled medical epidemics of overdiagnosis and harm. Evidence for benefit relies at best on surrogate measures not on relevant clinical outcomes (mortality and quality of life). Harms, including maternal death from anaphylaxis,(3) are almost always overlooked despite deserving close scrutiny because: a) investigating harms is more complex than for benefits; b) screening targets the healthy - so benefit will always be modest or for very few. To balance harms and benefits, we should be guided by evidence-based principles yet in real life many “do [a test/ intervention] because I can”.
Why is “First, do no harm” forgotten? Over-optimism or under-humility? Although over 550 articles have been published in the last decade (according to PubMed "group B streptococcus" AND "newborn"), mothers and babies need better quality research not more quantity.
The UK NSC is right to stand firm on the present evidence, but the process is incomplete. Regarding pregnancy, a next courageous step would be for the NSC to formally review the screening properties of electronic fetal heart rate monitoring - one amongst many other obstetric ‘routines’ that were never shown to ‘work’.(4-6) However, resistance might be encountered from obstetricians with rigid mindsets, the vested interests of equipment manufacturers and medicolegal experts and lawyers as well as women who have not been properly informed.(7)
1 Seedat F, Geppert J, Stinton C et al. Universal antenatal screening for group B streptococcus may cause more harm than good. BMJ 2019;364:l463.
2 Centers for Disease Control and Prevention. Hospital-based policies for prevention perinatal Group B streptococcal disease--United States, 1999. MMWR Morb Mortal Wkly Rep 2000;49:936-40.
3 McCall SJ, Bunch KJ, Brocklehurst P et al. The incidence, characteristics, management and outcomes of anaphylaxis in pregnancy: a population-based descriptive study. BJOG 2018;125:965-971.
4 Mullins E, Lees C, Brocklehurst P. Is continuous electronic fetal monitoring useful for all women in labour? BMJ 2017;359:j5423.
5 British Broadcasting Corporation. Horizon A time to be born. Documentary first shown in 1974-1975. Available at https://www.bbc.co.uk/iplayer/episode/p01z4pcy/horizon-19741975-a-time-t... Accessed 27 March 2019.
6 National Institute for Health and Care Excellence. Intrapartum care for healthy women and babies. Clinical guideline [CG190]. Published date: December 2014. Last updated: February 2017 Available at https://www.nice.org.uk/guidance/cg190 Accessed 27 March 2019.
7 Bewley S, Braillon A. Electronic fetal heart rate monitoring: new research approaches are needed. BMJ 2018;360:k658
Competing interests: No competing interests
Seedat et al in their paper “Universal antenatal screening for group B streptococcus may cause more harm than good”(1) rehearse the reasons given by the UK National Screening Committee (NSC) for not recommending universal antenatal testing for group B Streptococcus, based on a NSC-commissioned review. Although they acknowledge that in the USA, authorities such as the Centre for Disease Control and Prevention (https://www.cdc.gov/groupbstrep/about/), the American College of Obstetricians and Gynecologists, and the American Academy of Pediatrics have concluded after rigorous review that testing and intrapartum antibiotic prophylaxis (IAP) should be recommended because it cause more good than harm (a conclusion echoed by the European Consensus Conference in 2014 (2) and the World Health Organisation in 2015 (3)), the title of Seedat et al’s paper (missing a question mark to indicate uncertainty) is unfortunately being interpreted by some as indicating that there is clear evidence that it causes more harm than good.
The UK’s risk-based prevention strategy has been in place since 2003. Unlike countries that have implemented GBS testing strategies, the UK rate of early-onset group B Strep infection has not fallen but increased and is now almost 20% higher than before the risk-based strategy was introduced - and more than two and a half times the rate in the USA where testing and IAP are universally recommended. Seedat et al fail to highlight not only the failure of the UK risk based approach to reduce early onset GBS infection rates, but that fact that it results in many women receiving IAP when they are not even GBS carriers. Daniels et al (4) reported that in the UK 21% of women carried group B Strep and 22% of women had risk factors for early onset neonatal GBS disease. However, the women are not in the same groups: of the women with risk factors and thus eligible for intrapartum antibiotic prophylaxis (IAP), 71% did not carry group B Strep, and of the women who carried group B Strep, 70% had no risk factors.
Group B Strep Support acknowledge that it would be ideal to avoid giving IAP to women whose babies will not develop early onset GBS disease and we would welcome research to establish which strains of GBS are pathogenic and which babies are susceptible, so that the use of IAP could be restricted to those at highest risk. We would also welcome a safe, effective and affordable group B Strep vaccine. Neither approach is currently available. Until it is, testing will prevent more group B Strep infections, disabilities and deaths than the current risk-based approach.
Seedat et al raise the concern that IAP will cause alterations to the microbiome but fail to highlight that most studies showing persistent alterations in the microbiome relate to caesarean section, and the use of broad-spectrum antibiotics prior to this procedure. GBS IAP should be predominantly with narrow spectrum penicillin, and the effects are accordingly less marked and have not been shown to persist after the first three months of life (5). Nor have long term effects been noted; for example Metz et al6 comment “We did not find a significant association between intrapartum GBS antibiotic prophylaxis and early childhood BMI Z-scores when compared to healthy controls (GBS negative with no antibiotic exposure). These findings may provide reassurance to clinicians who are concerned about the effect of fetal exposure to antibiotics for GBS prophylaxis”. Seedat et al suggest that “Maternal anaphylaxis is another important harm to consider, as it has potentially fatal consequences” but report one case of anaphylaxis resulting from GBS prophylaxis in the UK over three years – approximately one case per two million births.
We need more knowledge and better tools to combat early onset GBS disease. Until we have them, testing is the best cost-effective solution available, and we consider that the choice of whether to have testing for GBS is most appropriately made by women and their families rather than by the National Screening Committee.
(1) Seedat F, Geppert J, Stinton C, Patterson J, Freeman K, Johnson SA et al. Universal antenatal screening for group B streptococcus may cause more harm than good. BMJ 2019; 364:l463.
(2) Di Renzo GC, Melin P, Berardi A, Blennow M, Carbonell-Estrany X, Donzelli GP et al. Intrapartum GBS screening and antibiotic prophylaxis: a European consensus conference. J Matern Fetal Neonatal Med 2015; 28(7):766-782.
(3) World Health Organisation. WHO recommendation on intrapartum antibiotic administration to women with group B Streptococcus (GBS) colonization for prevention of early neonatal GBS infection. https://extranet.who.int/rhl/topics/preconception-pregnancy-childbirth-a... . accessed 22-3-2019.
(4) Daniels JP, Gray J, Pattison HM, Gray R, Hills RK, Khan KS. Intrapartum tests for group B streptococcus: accuracy and acceptability of screening. BJOG 2011; 118(2):257-265.
(5) Stearns JC, Simioni J, Gunn E, McDonald H, Holloway AC, Thabane L et al. Intrapartum antibiotics for GBS prophylaxis alter colonization patterns in the early infant gut microbiome of low risk infants. Sci Rep 2017; 7(1):16527.
(6) Metz TD, McKinney J, Allshouse AA, Knierim SD, Carey JC, Heyborne KD. Exposure to group B Streptococcal antibiotic prophylaxis and early childhood body mass index in a vaginal birth cohort. J Matern Fetal Neonatal Med 2019;1-6.
Competing interests: JP is the Chief executive of the charity GBS Support, PJS, AB-R, SK and GR are members of GBS Support's advisory panel.