Antimicrobials in Maternity Care – Comprehensive Study Notes

Focus: Impact of antimicrobials on maternity care and the midwife-prescriber’s responsibilities.
Core aims:
- Foster shared decision-making (“partnership”) with pregnant people who may be reluctant to medicate.
- Practise judicious, guideline-based antibiotic use to curb antimicrobial resistance (AMR).
- Shorten courses where evidence shows equal efficacy.
- Always consider: allergy history, likely organisms, scope of midwifery practice.

Revisit medication attitudes repeatedly during pregnancy; opinions often change as circumstances evolve.
Discuss home-preparedness issues (antibacterial soaps, cord-care, dummy hygiene) → educate on AMR consequences.
Explain that most cord stumps do NOT need treatment; mild ooze/colour change is normal separation.

Prescribe only when clearly indicated.
Identify causative organism whenever possible; start empiric therapy only when delay is unsafe (e.g., symptomatic UTI in pregnancy).
Prefer narrow-spectrum, single-agent therapy → avoids drug-interactions & resistance.
Use sufficiently high doses and the SHORTEST effective duration (now usually 5 days; very few agents >5 days).
Stress strict dose-timing: fixed intervals (e.g., exactly 8 h); encourage dose-schedule “planning” at start.
Complete full course even if symptoms resolve early; stopping at 3/5 days increases AMR risk.

True allergy = immunological (IgE-mediated) reaction; obtain detailed description of previous events.
Typical early signs (within 1–2 h):
- Urticaria, pruritus
- Angio-oedema (periorbital, lip swelling)
- Bronchospasm → potential progression to anaphylaxis.
Statistics: Penicillin hypersensitivity 4\text{–}8\%; anaphylaxis 1–4/10\,000, of which \approx 10\% fatal.
Rule: If convincing history, AVOID the culprit drug; cross-reactivity penicillin↔cephalosporin 3\text{–}8\%.

Mechanism: Inhibit bacterial cell-wall synthesis ⇒ bactericidal.
Two main families used in maternity:
- Penicillins (incl. amoxicillin, flucloxacillin, Augmentin)
- Cephalosporins

Indications: Mastitis, uncomplicated superficial wound infections (C-section, perineal).
Dose: 500\,\text{mg} PO q6h (4\times/\text{day}) for 5 days.
Must be taken on EMPTY stomach → \ge1 h before or \ge2 h after food (pharmacy labels this).
Rare adverse event: Cholestatic hepatitis (itch, mild jaundice) — more common with age or pre-existing LFT issues.

Rising \approx48\% E.coli resistance → NOT suitable for empiric symptomatic UTI in pregnancy.
Appropriate only when culture shows susceptibility (e.g., asymptomatic bacteriuria).
Dose: 500\,\text{mg} PO q8h for 5 days (may escalate if ineffective).
Ineffective vs. Staph. aureus.

Formulation: 500\,\text{mg} amox +125\,\text{mg} clavulanate per tab.
Use: Cystitis when β-lactamase-producing strains suspected and no allergy/liver disease.
Contraindicated in pre-term labour owing to neonatal necrotising enterocolitis risk.
Dose: 1 tab PO q8h for 5 days.

Last-line oral option for UTI because of resistance concerns; liaise with obstetric team first.
Example dose (Cefaclor): 250\,\text{mg} PO q8h; severe infections 500\,\text{mg} PO q8h, 5 days.

Erythromycin / Azithromycin → alternatives when penicillin allergy.
Must involve obstetric/ID team before prescribing.
Erythromycin for mastitis: 400\,\text{mg} PO q6h for 7 days; high GI side-effects ↓ adherence.
Azithromycin for Chlamydia: single 1\,\text{g} PO dose; partner Tx not within midwife scope (grey area). Test-of-cure required.

Indications: Pyelonephritis, septicaemia (IV in hospital).
Potent, broad-spectrum; risk of oto- & nephro-toxicity, especially if >72 h. Trough levels monitored when prolonged.

Metronidazole (Flagyl):
- Used by obstetricians for Trichomonas, Bacterial Vaginosis (BV).
- Interacts with alcohol → severe nausea/headache (disulfiram-like).
- Higher dose near term requires specialist input.
Nitrofurantoin:
- Broad activity vs. E.coli; avoid in G6PD deficiency; enhanced absorption with food.
- Standard UTI regimen: 50\,\text{mg} PO qid for 5 days.
- Avoid urine alkalinisers.
Trimethoprim:
- Contra-indicated 1st trimester (folate antagonist).
- Acute UTI (2nd–3rd trimester): 300\,\text{mg} PO nocte x 3 days (ONLY 3-day course in list).

Vaginal Candidiasis very common in pregnancy.
First-line topical imidazoles (both subsidised):
- Clotrimazole 1\% cream (6-day intravaginal course using applicators; tube contains 35\,g → 30\,g intravaginal + \approx5\,g external itching areas).
- Miconazole 2\% cream if prior success/failure of clotrimazole.
Oral Fluconazole NOT recommended in pregnancy (safe postpartum).
Oral thrush in mother/baby: Nystatin suspension.

Always consult GP/obstetrician in allergy, complex infection, renal/hepatic disease or remote settings.
Establish strong pharmacist relationships; rely on them for patient counselling (e.g., food timing labels).
Keep meticulous documentation of discussions, restrictions, allergy checks.

Memorise: drug, dose, frequency, duration.
Trimethoprim = ONLY 3-day course; all others start at 5 days; 7 days reserved for treatment failure.
Know empty-stomach rule for flucloxacillin.
Recognise AMR statistics (e.g., 48\% E.coli resistant to amoxicillin).
Remember cross-reactivity 3\text{–}8\% penicillin → cephalosporin.

Overprescribing fuels AMR, jeopardising future mothers/infants.
Balancing maternal autonomy with fetal safety requires transparent risk–benefit dialogue.
Ensuring equitable care in rural/remote areas may need tele-consultations.

Flucloxacillin mastitis \rightarrow 500\,\text{mg} PO qid x 5 d (empty stomach)
Amoxicillin asympt. bacteriuria \rightarrow 500\,\text{mg} PO tid x 5 d
Augmentin cystitis \rightarrow 1 tab (500/125\,\text{mg}) PO tid x 5 d (avoid pre-term)
Cefaclor last-line \rightarrow 250–500\,\text{mg} PO tid x 5 d (consult team)
Erythromycin (pen-allergy mastitis) \rightarrow 400\,\text{mg} PO qid x 7 d
Azithromycin chlamydia \rightarrow 1\,\text{g} PO once (test-of-cure)
Nitrofurantoin UTI \rightarrow 50\,\text{mg} PO qid x 5 d
Trimethoprim UTI (>1st T) \rightarrow 300\,\text{mg} PO nocte x 3 d
Clotrimazole vag. thrush \rightarrow 1 applicator nightly x 6 d (+ external cream)

“Aim for excellence”: consult, document, review, and reinforce patient education to safeguard both mother and baby while combating the global threat of antimicrobial resistance.