I think this question is ideal for shared decision making. We generally do not recommend testing or challenging pregnant women unless the need outweighs any risk of reaction, including anaphylaxis. In this case, one would need to balance the risk of a reaction to penicillin testing and challenge against the risk of alternative treatment of Group B Streptococcal infection. The risk of testing and challenge would be based upon the type of allergy reported by the patient, the time since the last reaction to penicillin or other beta lactam antibiotic and the history of co-morbidities such as asthma or anaphylaxis to other agents. If the pregnant patient has bacteruria >10 4 CFU/ml, antibiotic therapy is recommended during the pregnancy and additional treatment immediately prior to delivery. The treatment during pregnancy is ideally a beta lactam (amoxicillin, penicillin or cephalosporin) with clindamycin as an alternative if the strain is susceptible (1). The CDC guidelines (2) are to use cefazolin during labor unless history is convincing for likely IgE mediated reaction and then alternatives would be clindamycin or vancomycin. The effectiveness of the alternative therapies is less and the risk is greater.
Since greater than 90% of subjects reporting penicillin allergy are not significantly allergic, I would discuss these issues. I would document the discussion but ideally treat her as I would my pregnant family members, i.e. I would test and challenge unless the history was positive for life threatening, likely IgE mediated beta lactam allergy. If the patient agrees with me, I would skin test with penicillin, amoxicillin and major determinant and if negative challenge the patient with oral amoxicillin. If the challenge is negative, I would utilize beta lactam antibiotics for necessary treatment of infection during pregnancy and for peripartum treatment without repeat testing.
Medicine is ultimately an art of balancing risk and shared decision making and absolute risk is seldom known. I think some would chose an alternative course of action as the balance must be individualized.
I hope this information is of help to you and your patient.
All my best.
Dennis K. Ledford, MD, FAAAI
1. ACOG Committee Opinion No. 485: Prevention of early-onset group B streptococcal disease in newborns.
American College of Obstetricians and Gynecologists Committee on Obstetric Practice
Obstet Gynecol. 2011;117(4):1019.
In 2010, the Centers for Disease Control and Prevention revised its guidelines for the prevention of perinatal group B streptococcal disease. Although universal screening at 35-37 weeks of gestation and intrapartum antibiotic prophylaxis continue to be the basis of the prevention strategy, these new guidelines contain important changes for clinical practice. The Committee on Obstetric Practice endorses the new Centers for Disease Control and Prevention recommendations, and recognizes that even complete implementation of this complex strategy will not eliminate all cases of early-onset group B streptococcal disease.
2. Prevention of perinatal group B streptococcal disease--revised guidelines from CDC, 2010.
Verani JR, McGee L, Schrag SJ, Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention (CDC)
MMWR Recomm Rep. 2010;59(RR-10):1.
Despite substantial progress in prevention of perinatal group B streptococcal (GBS) disease since the 1990s, GBS remains the leading cause of early-onset neonatal sepsis in the United States. In 1996, CDC, in collaboration with relevant professional societies, published guidelines for the prevention of perinatal group B streptococcal disease (CDC. Prevention of perinatal group B streptococcal disease: a public health perspective. MMWR 1996;45[No. RR-7]); those guidelines were updated and republished in 2002 (CDC. Prevention of perinatal group B streptococcal disease: revised guidelines from CDC. MMWR 2002;51[No. RR-11]). In June 2009, a meeting of clinical and public health representatives was held to reevaluate prevention strategies on the basis of data collected after the issuance of the 2002 guidelines. This report presents CDC's updated guidelines, which have been endorsed by the American College of Obstetricians and Gynecologists, the American Academy of Pediatrics, the American College of Nurse-Midwives, the American Academy of Family Physicians, and the American Society for Microbiology. The recommendations were made on the basis of available evidence when such evidence was sufficient and on expert opinion when available evidence was insufficient. The key changes in the 2010 guidelines include the following:•expanded recommendations on laboratory methods for the identification of GBS,•clarification of the colony-count threshold required for reporting GBS detected in the urine of pregnant women,•updated algorithms for GBS screening and intrapartum chemoprophylaxis for women with preterm labor or preterm premature rupture of membranes,•a change in the recommended dose of penicillin-G for chemoprophylaxis,•updated prophylaxis regimens for women with penicillin allergy, and•a revised algorithm for management of newborns with respect to risk for early-onset GBS disease. Universal screening at 35-37 weeks' gestation for maternal GBS colonization and use of intrapartum antibiotic prophylaxis has resulted in substantial reductions in the burden of early-onset GBS disease among newborns. Although early-onset GBS disease has become relatively uncommon in recent years, the rates of maternal GBS colonization (and therefore the risk for early-onset GBS disease in the absence of intrapartum antibiotic prophylaxis) remain unchanged since the 1970s. Continued efforts are needed to sustain and improve on the progress achieved in the prevention of GBS disease. There also is a need to monitor for potential adverse consequences of intrapartum antibiotic prophylaxis (e.g., emergence of bacterial antimicrobial resistance or increased incidence or severity of non-GBS neonatal pathogens). In the absence of a licensed GBS vaccine, universal screening and intrapartum antibiotic prophylaxis continue to be the cornerstones of early-onset GBS disease prevention.