Antibiotics in obstetrics

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INDICATIONS OF INTRAPARTUM ANTIBIOTIC PROPHYLAXIS

GBS identified by screening cultures in late

gestation during the current pregnancy

Invasive GBS disease in a neonate from a

previous pregnancy

GBS bacteriuria detected during any trimester of

the current pregnancy

Intrapartum nucleic acid amplification test

(NAAT) positive for GBS

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ANTIBIOTIC PROPHYLAXIS IN OBSTETRICS

WHEN DO WE START ANTIBIOTIC PROPHYLAXIS?

Unknown GBS status AND any of the following:

SPONTANEOUS preterm onset of labour <= 37 weeks

Prolonged ROM > 18 hours

Intrapartum fever >= 38 C

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What antibiotics to give?

In these situations,

antibiotic therapy should be started on admission to hospital for labour or

rupture of membranes, ideally at least 4 hours before delivery, and continued

until the neonate is delivered.

Recommended

intra-partum antibiotic therapy:

benzylpenicillin 3 g dose followed by 1.8g 4 hourly until delivery

OR If penicillin

hypersensitivity (excluding immediate hypersensitivity), IV cephazolin 2 g dose 8 hourly until

delivery

OR If immediate penicillin hypersensitivity

and GBS isolate known to be susceptible to clindamycin, IV clindamycin 600

mg 8-hourly until delivery

OR If immediate penicillin hypersensitivity and GBS

isolate resistant to clindamycin or results of susceptibility testing are not

available, IV vancomycin

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pPROM antibiotic prophylaxis

Associated with prolonged pregnancy and a reduction in maternal and neonatal infection. Antibiotic DOES NOT alter perinatal mortality or longer term outsomes

PROPHYLAXIS DEPENDS ON PRESENCE OR ABSENCE OF INFECTION

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PRESENCE OF INFECTION

IV amoxicillin 2 g 6-hourly, IV gentamicin (as per RHH Adult Gentamicin

Guideline) and IV metronidazole 500 mg 12 hourly

If penicillin hypersensitivity (excluding immediate hypersensitivity), IV

ceftriaxone 1 g IV every 24 hours and IV metronidazole 500 mg 12 hourly

If penicillin hypersensitivity (excluding immediate hypersensitivity), IV

ceftriaxone 1 g IV every 24 hours and IV metronidazole 500 mg 12 hourly

AUGMENTIN IN CONTRAINDICATED DUE TO ITS ASSOCIATION WITH NECROTISING ENTEROCOLITIS

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ABSENCE OF INFECTION

IV amoxicillin 2g IV 6-hourly for 48 hours, followed by amoxicillin 250

mg orally 8-hourly for a total of 7 days (IV and oral)

AND

Oral erythromycin 250 mg 6 hourly for 7 days (or erythromycin (ethyl

succinate formulation) 400 mg 6-hourly for 7 days

patients with penicillin hypersensitivity, give erythromycin as a single drug.

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POST DELIVERY

the presence of chorioamnionitis, continue antibiotics to complete at least 5

days of therapy (de-escalating from IV therapy to oral therapy), otherwise

antibiotics can cease post delivery. Oral options include:

Amoxycillin-clavulanate 875/125 once every 12 hours

Cephalexin 500 mg 6 hourly and metronidazole 400 mg 8 hourly

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ANTIBIOTIC IN 3rd or 4th DEGREE TEAR

Single

pre-operative doses of Cephazolin 2g IV and

metronidazole 500 mg IV, as early as possible before repair (ideally 15 to

30 minutes) before skin incision before the

repair of a third- or fourth-degree perineal tear.

The

role of post-operative antibiotic therapy is unclear but therapy is recommended

following anal sphincter repair because infection in this setting carries a

high risk of anal incontinence and fistula formation. Use:

Oral amoxycillin+clavulanate

875+125 mg 12-hourly for 7 days

OR If penicillin

hypersensitivity (excluding immediate hypersensitivity), oral cephalexin

500 mg 6-hourly and oral metronidazole 400 mg 12-hourly for 7 days

OR If immediate penicillin

hypersensitivity, oral trimethoprim+sulfamethoxazole 160+800 mg 12-hourly

and oral metronidazole 400 mg 12-hourly for 7 days