From the Guidelines
Group B streptococcus (GBS) during pregnancy is typically treated with intravenous antibiotics during labor to prevent transmission to the newborn, with the standard treatment being penicillin G, administered as a 5 million unit initial dose, followed by 2.5-3 million units every 4 hours until delivery, as recommended by the CDC guidelines 1. The indications for intrapartum antibiotic prophylaxis include previous infant with invasive GBS disease, GBS bacteriuria during any trimester of the current pregnancy, positive GBS vaginal-rectal screening culture in late gestation during current pregnancy, and unknown GBS status at the onset of labor with risk factors such as delivery at <37 weeks’ gestation, amniotic membrane rupture ≥18 hours, intrapartum temperature ≥100.4°F (≥38.0°C), or intrapartum NAAT positive for GBS 1. Some key points to consider in the management of GBS during pregnancy include:
- Women who test positive for GBS at 36-37 weeks, have previously delivered a baby with GBS disease, have GBS bacteriuria during the current pregnancy, or have unknown GBS status with risk factors should receive prophylactic antibiotics 1.
- The use of intrapartum antibiotic prophylaxis has resulted in substantial reductions in the burden of early-onset GBS disease among newborns 1.
- Penicillin remains the first-line agent for intrapartum antibiotic prophylaxis, with ampicillin an acceptable alternative, and alternatives for women with penicillin allergy include cefazolin, clindamycin, or vancomycin 1.
- Treatment is only given during labor, not earlier in pregnancy, because GBS can recolonize the vagina if treated before delivery 1.
- The CDC guidelines recommend that all pregnant women be screened at 35--37 weeks' gestation for vaginal and rectal GBS colonization, and that intrapartum chemoprophylaxis be given to all pregnant women identified as GBS carriers 1.
From the Research
Group B Strep Pregnancy Treatment
- The Centers for Disease Control and Prevention (CDC) recommends universal vaginal-rectal screening for Group B Streptococcus (GBS) colonization in pregnant women between 35 and 37 weeks of gestation, aimed at intrapartum antibiotic prophylaxis (IAP) 2.
- IAP is the only currently available and highly effective method against early onset GBS neonatal infections 2.
- The American Academy of Pediatrics and the American College of Obstetricians and Gynecologists recommend maternal intrapartum antibiotic prophylaxis based on antenatal screening for GBS colonization to prevent perinatal GBS disease 3.
- Penicillin, ampicillin, or cefazolin are recommended for prophylaxis, with clindamycin and vancomycin reserved for cases of significant maternal penicillin allergy 3.
Intrapartum Antibiotic Prophylaxis
- Beta-lactam prophylaxis given 4 or more hours before delivery is highly effective for prevention of early-onset GBS disease 4.
- Prophylaxis of shorter durations or with clindamycin is less effective, reinforcing the need for health care providers to adhere to prevention recommendations, particularly for preterm deliveries, penicillin-allergic women, and neonates exposed to fewer than 4 hours of prophylaxis 4.
- Intrapartum antibiotic prophylaxis reduces the risk of early-onset neonatal GBS infection from 4.7% to 0.4% (p = 0.02) 5.
Management of Penicillin-Allergic Pregnant Women
- For women with an allergy to penicillin, recommended agents for prophylaxis have been well-outlined, but compliance with guideline recommendations is poor 6.
- Pregnant women with a history of penicillin allergy are now recommended to undergo skin testing, because confirmation of or delabeling from a penicillin allergy can provide both short- and long-term health benefits 3.
- Clindamycin or vancomycin are generally active against Group B streptococci and carry no particular risks for the infant in case of penicillin allergy 5.