Re: Streptococcus B in pregnancy: to screen or not to screen?
We were disappointed that a number of myths about Group B Strep screening were reiterated in the article “Streptococcus B in pregnancy: to screen or not to screen?”1
Dr McCartney is concerned that alongside the very apparent potential benefits of screening, the potential limitations and harms are also raised. Clearly any decision about screening should consider both. However, there are some statements in the article with which we take issue:
1. Risk of fatal anaphylaxis “The risks of antibiotic use include anaphylaxis, which is thought to be fatal in one in 10,000 women treated” is an unreferenced statement taken from the UK National Screening Committee’s 2008 review of antenatal screening for group B Streptococcus2. Potentially fatal anaphylaxis is clearly a risk but extremely rare. Law et al3 reported that 1.8 million women in the US will have been given benzylpenicillin (or ampicillin) between 1997 and 2001 and no deaths from anaphylaxis were reported. Furthermore, a review of UK data by the same authors showed no adverse drug reactions in a population of 630,000 over 6 months that were attributable to benzylpenicillin and they stated that "It can be concluded that the risk of death is negligible." Fatal anaphylaxis, although of concern, is a tiny risk.
2. Concerns about the use of broad spectrum antibiotics “Broad spectrum antibiotics lead to resistant organisms” and “The potential for long-term persistence of early-colonising bacteria suggests that much more thought should be given to the late consequences of perinatal broad-spectrum antibiotics.” This issue is of huge concern to many, including the charity’s medical advisory panel, one of whom co-authored one of the articles you quote4. The authors have written to the BMJ separately to provide the appropriate context for that statement.
3. Antibiotic resistance Studies in the USA5;6 have not shown an increase in antibiotic resistance in response to using antibiotics for early onset GBS prophylaxis except in very low birth weight babies7;8. In the latter, increased incidence of resistant E.coli infection was identified in babies whose mothers were given amoxicillin as intrapartum antibiotic prophylaxis. Anxieties raised by the ORACLE II study follow-up findings of an impaired outcome at the age of seven9 (an increase in cerebral palsy) applied only to the babies of women in threatened preterm labour given broad spectrum antibiotics (erythromycin 250mg qds orally) for up to 10 days, not high dose intravenous benzylpenicillin for 4-12 hours to women in established labour (The ORACLE I study of antibiotics given to women with ruptured membranes did not demonstrate any functional impairment at the age of 710).
4. Preterm labour Although it is true that “in several of the case studies in the media stories, the screening test for streptococcus B would not have helped,” the policy recommended by cost benefit analyses is not just to screen at 35-37 weeks, but to give benzylpenicillin to all women in preterm labour as well11-13. This is also the policy in countries which do screen, including the US14, Australia15, France16 and Spain17 which on average have seen a reduction in their incidence of early onset GBS infection of over 80%18.
5. Universal screening vs risk management “it may be that risk management rather than universal screening is more beneficial but will require nuanced discussion.” Perhaps, although research looking at just this issue repeatedly finds universal screening would be more cost effective and more clinically effective in the UK than the risk based strategy11-13;19 and these papers do not include in their analysis the fact that the Royal College of Obstetricians & Gynaecologists’s 2003 guideline20 is inconsistently applied21. A recently published UK study has shown that 81% of mothers who should have been offered intrapartum antibiotic prophylaxis because of risk factors did not receive it, and the authors estimated that 48% of babies who suffered EOGBS infection could have had their disease prevented22. Perhaps part of the problem with the risk-based strategy is that it is too complex – to be effective any strategy needs to be both easy to understand and easy to implement.
Despite pointing out that the media often don’t mention the potential harms of screening, Dr McCartney omitted to mention one of its key benefits - the major falls seen in the incidence of early onset GBS disease in all western countries which have introduced screening14-17. We know of no country presenting before and after data that has not shown a substantial reduction in the incidence after screening was introduced. In contrast, in the UK the incidence of EOGBS infection has risen since the risk-based prevention guidelines were introduced by the Royal College of Obstetricians & Gynaecologists in 200320 and is continuing to do so. The Health Protection Agency has found that voluntarily reported cases in England, Wales and Northern Ireland have risen from 229 in 200323 to 302 in 201024. The incidence of EOGBS disease in England, Wales & Northern Ireland is now 0.41 per 1,000 live births, which is higher than the USA post-universal screening (0.34 per 1,000 live births in 200814).
It is in no-one’s interest to present a one-sided argument. It is vital that the issues surrounding screening are fully explored, although perhaps we can’t expect newspapers to cover all the arguments in detail. However, when the pros and cons are explored, it is imperative that the information about potential harms and potential benefits is equally accurate. The UK National Screening Committee will be issuing their review of GBS screening for public consultation in June 2012. All of us should ensure that the relevant issues – for and against – are considered appropriately, backed up by research. The UK National Screening Committee has recently deemed it appropriate to pilot screening for Maple Syrup urine disease which may save 7 lives a year (http://www.bbc.co.uk/news/health-17628169), which makes it even more illogical not to screen for GBS which has a higher incidence and mortality.
At GBSS, we want women to be given accurate and timely information about group B Strep and offered the opportunity to have a sensitive test for GBS carriage late in pregnancy. Women should not be forced to have GBS screening, but all should be entitled to accurate and balanced information, the offer of a sensitive test, and the option to say yes or no. Wouldn't it be great if we could agree evidence-based information and then give women a proper choice? Revolutionary, even.
(1) McCartney M. Streptococcus B in pregnancy: to screen or not to screen? BMJ 2012; 344:e2803.
(2) Brocklehurst P, Kenyon SL, for UK National Screening Committee. Evaluation of antenatal screening for Group B Streptococcal (GBS) carriage against NSC Handbook Criteria . 8-10-2008.
(3) Law MR, Palomaki G, Alfirevic Z, Gilbert R, Heath P, McCartney C et al. The prevention of neonatal group B streptococcal disease: a report by a working group of the Medical Screening Society. J Med Screen 2005; 12(2):60-68.
(4) Bedford Russell AR, Murch SH. Could peripartum antibiotics have delayed health consequences for the infant? BJOG 2006; 113(7):758-765.
(5) Prevention of Perinatal Group B Streptococcal Disease, Revised Guidelines from CDC, 2010. Recommendations and Reports. November 19, 2010 / 59(RR10);1-32. 30-12-2010.
(6) Stoll BJ, Hansen NI, Sanchez PJ, Faix RG, Poindexter BB, Van Meurs KP et al. Early onset neonatal sepsis: the burden of group B Streptococcal and E. coli disease continues. Ped 2011; 127(5):817-826.
(7) Stoll BJ, Hansen NI, Higgins RD, Fanaroff AA, Duara S, Goldberg R et al. Very low birth weight preterm infants with early onset neonatal sepsis: the predominance of gram-negative infections continues in the National Institute of Child Health and Human Development Neonatal Research Network, 2002-2003. Pediatr Infect Dis J 2005; 24(7):635-639.
(8) Stoll BJ, Hansen N, Fanaroff AA, Wright LL, Carlo WA, Ehrenkranz RA et al. Changes in pathogens causing early-onset sepsis in very-low-birth-weight infants. N Engl J Med 2002; 347(4):240-247.
(9) Kenyon S, Pike K, Jones DR, Brocklehurst P, Marlow N, Salt A et al. Childhood outcomes after prescription of antibiotics to pregnant women with spontaneous preterm labour: 7-year follow-up of the ORACLE II trial. Lancet 2008; 372(9646):1319-1327.
(10) Kenyon S, Pike K, Jones DR, Brocklehurst P, Marlow N, Salt A et al. Childhood outcomes after prescription of antibiotics to pregnant women with preterm rupture of the membranes: 7-year follow-up of the ORACLE I trial. Lancet 2008; 372(9646):1310-1318.
(11) Colbourn TE, Asseburg C, Bojke L, Philips Z, Welton NJ, Claxton K et al. Preventive strategies for group B streptococcal and other bacterial infections in early infancy: cost effectiveness and value of information analyses. BMJ 2007; 335(7621):655.
(12) Colbourn T, Asseburg C, Bojke L, Philips Z, Claxton K, Ades AE et al. Prenatal screening and treatment strategies to prevent group B streptococcal and other bacterial infections in early infancy: cost-effectiveness and expected value of information analyses. Health Technol Assess 2007; 11(29):1-226, iii.
(13) Kaambwa B, Bryan S, Gray J, Milner P, Daniels J, Khan KS et al. Cost-effectiveness of rapid tests and other existing strategies for screening and management of early-onset group B streptococcus during labour. BJOG 2010; 117(13):1616-1627.
(14) Jordan HT, Farley MM, Craig A, Mohle-Boetani J, Harrison LH, Petit S et al. Revisiting the need for vaccine prevention of late-onset neonatal group B streptococcal disease: a multistate, population-based analysis. Pediatr Infect Dis J 2008; 27(12):1057-1064.
(15) Daley AJ, Isaacs D. Ten-year study on the effect of intrapartum antibiotic prophylaxis on early onset group B streptococcal and Escherichia coli neonatal sepsis in Australasia. Pediatr Infect Dis J 2004; 23(7):630-634.
(16) Albouy-Llaty M, Nadeau C, Descombes E, Pierre F, Migeot V. Improving perinatal Group B streptococcus screening with process indicators. J Eval Clin Pract 2011.
(17) Andreu A, Sanfeliu I, Vinas L, Barranco M, Bosch J, Dopico E et al. [Decreasing incidence of perinatal group B streptococcal disease (Barcelona 1994-2002). Relation with hospital prevention policies]. Enferm Infecc Microbiol Clin 2003; 21(4):174-179.
(18) Rodriguez-Granger J, Alvargonzalez JC, Berardi A, Berner R, Kunze M, Hufnagel M et al. Prevention of group B streptococcal neonatal disease revisited. The DEVANI European project. Eur J Clin Microbiol Infect Dis 2012.
(19) 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.
(20) RCOG. Royal College of Obstetricians and Gynaecologists (2003) RCOG Guideline No. 36. Prevention of early onset neonatal group B streptococcal disease. http://www rcog org uk/files/rcog-corp/uploaded-files/GT36GroupBStrep2003 pdf [ 2003 Available from: URL:http://www.rcog.org.uk/files/rcog-corp/uploaded-files/GT36GroupBStrep200...
(21) Royal College of Obstetricians and Gynaecologists andLondon School of Hygiene and Tropical Medicine. The prevention of early-onset neonatal group B streptococcus disease in UK obstetric units. www rcog org uk/files/rcog-corp/uploaded-files/neonatal_audit_full_250507 pdf [ 2007 Available from: URL:www.rcog.org.uk/files/rcog-corp/uploaded-files/neonatal_audit_full_25050...
(22) Vergnano S, Embleton N, Collinson A, Menson E, Russell AB, Heath P. Missed opportunities for preventing group B streptococcus infection. Arch Dis Child Fetal Neonatal Ed 2010; 95(1):F72-F73.
(23) CDR Weekly. Pyogenic and non-pyogenic streptococcal bacteraemia England Wales and Northern Ireland. 2003. CDR Weekly 14 No 16. 2004.
(24) Health Protection Agency. Pyogenic and non-pyogenic streptococcal bacteraemia, England, Wales and Northern Ireland: 2010. Health Protection Agency Report 2011; 5(46).
Competing interests: Professor Philip Steer, Dr Alison Bedford Russell, Dr A Christine McCartney OBE, and Ms Philippa Cox form the medical advisory panel of the charity Group B Strep Support