Hi-lights from the 2010 Revised CDC Guidelines on the Prevention of Perinatal GBS Disease
By Catriona Munro, LM, CPM

Read below for some hi-lights from the 2010 Revised CDC Guidelines on the Prevention of Perinatal Group B Streptococcal Disease compiled by Licensed Midwife and MAWS member, Catriona Munro, who lives and works in Bellingham, WA. A link to the complete guideline can also be found in the future by visiting the Practice Updates for Midwives section of the MAWS website under the section designed For Midwives.

Regarding collection:

  • Swab the lower vagina (vaginal introitus), followed by the rectum (i.e., insert swab through the anal sphincter) using the same swab or two different swabs. Cultures should be collected in the outpatient setting by the health-care provider or, with appropriate instruction, by the patient herself. Cervical, perianal, perirectal or perineal specimens are not acceptable, and a speculum should not be used for culture collection.

Regarding the use of Penicillin vs Ampicillin:

"... And "Penicillin remains the agent of choice for intrapartum antibiotic prophylaxis, with ampicillin as an acceptable alternative (AI).
... And "Erythromycin is no longer an acceptable alternative for intrapartum GBS prophylaxis for penicillin-allergic women at high risk for anaphylaxis."

Regarding "adequate prophylaxis":

  • "The definition of adequate intrapartum antibiotic prophylaxis is clarified as ≥4 hours of IV penicillin, ampicillin, or cefazolin before delivery (AII). All other agents or durations are considered inadequate for purposes of neonatal management."
  • So I read that NOT as "2 doses" but as "at least 4 hours of treatment." So in a perfect world the client delivers 4 hrs after the first dose of whatever antibiotic is used, even if it is a q 8hr such as cephazolin.

And there's also some suggestion about observing babies who had inadequate prophylaxis for 2 days. "Observed" is not clearly defined.

"For well-appearing infants born to mothers who had an indication for GBS prophylaxis but received no or inadequate prophylaxis, if the infant is well-appearing and ≥37 weeks and 0 days' gestational age and the duration of membrane rupture before delivery was <18 hours, then the infant should be observed for ≥48 hours, and no routine diagnostic testing is recommended (BIII). If the infant is well-appearing and either <37 weeks and 0 days' gestational age or the duration of membrane rupture before delivery was ≥18 hours, then the infant should undergo a limited evaluation and observation for ≥48 hours (BIII)."

And even if adequate prophylaxis is achieved, babies should be observed for 2 days ...

  • "Well-appearing infants of any gestational age whose mother received adequate intrapartum GBS prophylaxis (≥4 hours of penicillin, ampicillin, or cefazolin before delivery) should be observed for ≥48 hours, and no routine diagnostic testing is recommended (BIII). Such infants can be discharged home as early as 24 hours after delivery, assuming that other discharge criteria have been met, ready access to medical care exists, and that a person able to comply fully with instructions for home observation will be present (CIII)"

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