{ "$schema": "https://json-schema.org/draft/2020-12/schema", "document": { "title": "Anaemia in Pregnancy — UK Clinical Guideline: clinical logic", "version": "v1.0 DRAFT", "date": "2026-04-19", "jurisdiction": "United Kingdom", "lead_author": "Dr Muhammad Mohsin, Consultant Haematologist", "status": "DRAFT — not for clinical use until sign-off", "source": "anaemia-pregnancy-guideline-STAGE2-REVISED.html" }, "evidence_tiers": { "established_uk_standard": "Written into a current UK national guideline (BSH, NICE, RCOG) or statutory (MHRA, SPC, NHS SCT).", "specialist_consensus": "Opinion or pragmatic practice in a UK guideline without an RCT.", "emerging_optimisation": "New evidence that may revise practice; not yet UK standard.", "good_practice_statement": "Consensus-based; no direct trial evidence." }, "hb_thresholds_g_per_L": { "first_trimester": {"anaemia_if_less_than": 110, "source": "BSH 2020"}, "second_or_third_trimester": {"anaemia_if_less_than": 105, "source": "BSH 2020"}, "postpartum_first_48h": {"anaemia_if_less_than": 100, "source": "BSH 2020"} }, "iron_status_rules": { "ferritin_threshold_ug_per_L": 30, "ferritin_interpretation": "Serum ferritin <30 µg/L confirms iron deficiency in pregnancy.", "ferritin_masked_by_inflammation": { "trigger": "Normal/raised ferritin with microcytic indices, TSAT <20%, or raised CRP", "action": "Do not use ferritin alone to rule out iron deficiency; review in context.", "second_line_tests": ["transferrin saturation", "CRP"] }, "not_recommended_for_routine_use": ["hepcidin", "soluble transferrin receptor"] }, "screening": { "routine_fbc": { "timing": ["booking", "28 weeks"], "tier": "established_uk_standard", "source": ["NICE NG201", "BSH 2020"] }, "ferritin_routine_unselected": { "recommended": false, "tier": "established_uk_standard", "source": "BSH 2020" }, "ferritin_indicated_if": [ "Anaemia (Hb below trimester threshold)", "Prior iron deficiency", "Heavy menstrual bleeding before pregnancy", "Known malabsorption", "Vegan or strict vegetarian diet", "Short inter-pregnancy interval", "Multiple pregnancy", "Bariatric surgery" ], "emerging_practice": { "label": "HOW Collaborative 2025 consensus", "proposal": "Routine ferritin at booking and 24–28 weeks.", "tier": "emerging_optimisation", "uk_baseline": "Not current BSH or NICE policy." } }, "diagnostic_pathway": [ {"step": 1, "action": "Offer FBC at booking and 28 weeks."}, {"step": 2, "decision": "Hb below trimester threshold?", "branches": { "yes": {"next_step": 3}, "no": {"action": "Routine care; ferritin only if risk factors."} }}, {"step": 3, "action": "Send serum ferritin ± transferrin saturation, CRP."}, {"step": 4, "decision": "Ferritin <30 µg/L?", "branches": { "yes": {"action": "Diagnose iron deficiency anaemia; enter treatment pathway."}, "no": {"action": "Ferritin equivocal — check TSAT and CRP.", "interpretation": { "tsat_less_than_20": "Supports iron deficiency", "raised_crp": "May be masking deficiency" } } }}, {"step": 5, "action": "If iron deficiency excluded, consider B12/folate deficiency, haemoglobinopathy (do not start empirical iron), AIHA, microangiopathy, anaemia of chronic disease."}, {"step": 6, "action": "Trial of oral iron as a diagnostic test acceptable when anaemia mild and indices suggestive; Hb rise ~10 g/L in 2 weeks supports iron deficiency."} ], "pre_pregnancy_optimisation": { "iron_deficiency_correction": { "target_population": ["Heavy menstrual bleeding", "Prior iron deficiency", "Vegetarian or vegan diet", "Prior bariatric surgery", "Malabsorption"], "action": "FBC + ferritin; correct deficiency before conception where feasible", "tier": "specialist_consensus", "strength": "Conditional", "certainty": "Low" }, "folic_acid": { "standard_dose_ug_daily": 400, "high_risk_dose_mg_daily": 5, "high_risk_groups": ["Sickle cell disease", "Thalassaemia", "Diabetes mellitus", "Prior NTD pregnancy", "BMI >=30 kg/m2", "Anti-epileptic medication"], "tier": "established_uk_standard", "strength": "Strong", "certainty": "High for NTD prevention" }, "haemoglobinopathy_screening": { "action": "Offer per NHS Sickle Cell and Thalassaemia Screening Programme where status unknown", "tier": "established_uk_standard" } }, "oral_iron_first_line": { "elemental_iron_mg_daily_range": [100, 200], "regimens": [ {"product": "Ferrous sulfate 200 mg 2–3× daily", "approx_elemental_mg_daily_range": [130, 195]}, {"product": "Ferrous fumarate 210 mg 2–3× daily", "approx_elemental_mg_daily_range": [138, 207]}, {"product": "Ferrous gluconate 300 mg 2–3× daily", "approx_elemental_mg_daily_range": [105, 140]} ], "review_interval_weeks": 2, "expected_hb_rise_at_2_weeks_g_per_L": 10, "continue_after_normalisation_months": 3, "counselling": [ "Take on an empty stomach 30–60 minutes before a meal", "Avoid simultaneous tea, coffee, calcium, antacids", "Vitamin C (orange juice or 250 mg ascorbic acid) improves absorption", "Warn about nausea, constipation, black stools", "Offer stool softener or laxative if constipated" ], "intolerance_strategy": { "options": ["Dose reduction", "Change formulation (fumarate or gluconate)", "Alternate-day dosing"], "continue_review_vs_2_week_target": true }, "emerging_optimisation": { "label": "Low-dose / alternate-day oral iron", "basis": "Moretti physiological studies; Churchill 2025 UK cohort reports 36.5% achieved 10 g/L rise on ferrous sulfate 200 mg TDS", "status": "Not the UK baseline for established IDA until national guidance changes" }, "tier": "established_uk_standard", "strength": "Strong", "certainty": "Moderate", "source": "BSH 2020 (Pavord et al.)" }, "iv_iron": { "products": ["Ferric carboxymaltose", "Ferric derisomaltose"], "trimester_window": "Generally confine to 2nd and 3rd trimesters unless clearly necessary", "indications": [ {"criterion": "Oral iron intolerance despite different formulation and dose", "strength": "Conditional", "certainty": "Moderate", "tier": "established_uk_standard"}, {"criterion": "Malabsorption (coeliac, post-bariatric, IBD)", "strength": "Conditional", "certainty": "Low", "tier": "specialist_consensus"}, {"criterion": "True non-response to adequate oral iron after 2 weeks with confirmed adherence", "strength": "Conditional", "certainty": "Moderate", "tier": "established_uk_standard"}, {"criterion": "Severe anaemia (Hb <90 g/L) from second trimester", "strength": "Conditional", "certainty": "Low to Moderate", "tier": "specialist_consensus"}, {"criterion": "Late presentation >=34 weeks with iron deficiency anaemia and insufficient time for oral response", "strength": "Conditional", "certainty": "Low", "tier": "specialist_consensus"}, {"criterion": "Preference for fewer doses in selected women", "strength": "Conditional", "certainty": "Very Low", "tier": "consensus_based"} ], "dose_calculation": "Body-weight and Hb-based method per current SPC; observe per-session and per-week maxima; check medicines.org.uk before prescribing.", "administration": { "setting": "Resuscitation facilities, trained staff", "observation_minutes_after_every_dose": 30, "observation_source": "MHRA Drug Safety Update", "test_dose_routine_required": false, "contraindications": ["Known iron hypersensitivity"], "cautions": ["Active infection (delay where feasible)"], "consent_requirements": [ "Hypersensitivity risk at any exposure", "Ferric carboxymaltose: risk of symptomatic hypophosphataemia" ] }, "followup": { "hb_reassessment_not_before_weeks": 4, "align_wording_with": "current SPC", "phosphate_monitoring_after_fcm_if_any": [ "Repeated dosing or high cumulative dose", "Prior bariatric surgery", "Vitamin D deficiency", "Symptomatic phosphate-wasting disorder" ] }, "third_trimester_timing": { "label": "Pragmatic expert practice", "tier": "specialist_consensus", "note": "Not a sourced national recommendation; attending teams decide based on gestation, severity, and logistics." }, "evidence": { "cochrane_2024_nicholson": { "n_rcts": 13, "n_participants": 3939, "antenatal_hb_mean_difference_g_per_dL": 0.49, "anaemia_at_delivery_rr": 0.81, "pph_or_transfusion_difference": "Likely no meaningful difference", "certainty": "Moderate" }, "rapidiron_2025_derman": { "n": 4368, "country": "India", "baseline_hb_g_per_dL": [7.0, 9.9], "low_birth_weight_rr": 0.87, "applicability": "Baseline Hb more severe than typical UK IDA; supportive not decisive." } } }, "b12_and_folate": { "when_to_test": [ "Macrocytic anaemia (MCV above pregnancy reference)", "Unresponsive anaemia despite adequate iron", "Vegan/strict vegetarian diet", "Prior bariatric surgery", "Inflammatory bowel disease", "Pernicious anaemia", "Chronic metformin or PPI use", "Clinical features of B12 deficiency (neurological, glossitis)" ], "b12_no_neurology": { "options": [ "Oral cyanocobalamin at least 1 mg daily (if dietary cause likely and absorption intact)", "IM hydroxocobalamin 1 mg three times weekly for 2 weeks, then 1 mg every 2–3 months" ], "tier": "established_uk_standard", "source": "SPS / NICE-linked" }, "b12_with_neurology": { "action": "Seek urgent specialist advice", "if_advice_unavailable": "IM hydroxocobalamin 1 mg alternate days until no further improvement, then 1 mg every 2 months", "tier": "established_uk_standard" }, "folate_replacement": { "dose": "Folic acid 5 mg orally once daily until deficiency resolves", "then_continue": "400 µg daily (or 5 mg daily in higher-risk groups) for remainder of pregnancy", "tier": "established_uk_standard" }, "do_not_give_folate_alone": { "reason": "Risk of subacute combined degeneration of the spinal cord if B12 also deficient", "tier": "established_uk_standard" } }, "haemoglobinopathy_cross_reference": { "sickle_cell_disease": "BSH 2021 (Oteng-Ntim et al.); supersedes RCOG GTG 61", "thalassaemia": "BSH 2024 (Shah et al.); supersedes RCOG GTG 66", "screening_lab_diagnosis": "BSH 2023 (Bain et al.); NHS SCT Programme", "iron_rules": { "no_iron_without_confirmed_deficiency": true, "transfusion_dependent_thalassaemia_preconception": "Switch deferasirox/deferiprone to desferrioxamine 6–12 weeks before planned conception", "sickle_cell_folic_acid_mg_daily": 5 } }, "acute_haemolytic_and_microangiopathy": { "differential": ["HELLP", "TTP", "aHUS", "DIC", "AIHA", "Acute fatty liver of pregnancy"], "escalation_triggers": [ "Platelet count <50 ×10^9/L with haemolytic indices", "Hb fall >20 g/L in 24 h without overt bleeding", "Suspected TTP (send ADAMTS13, prepare plasma exchange)", "Deranged DIC screen" ], "tier": "good_practice_statement" }, "postpartum": { "check_hb_within_48h_if": [ "Estimated blood loss >500 mL", "Uncorrected antenatal anaemia", "Symptoms: tachycardia, breathlessness, dizziness, severe fatigue" ], "caesarean_section_alone": { "automatic_trigger": false, "note": "Record as local policy if Trust routinely checks Hb after caesarean section" }, "stratified_treatment": [ {"hb_g_per_L_at_least": 100, "action": "Oral iron; reassurance; review at 6-week postnatal check"}, {"hb_g_per_L_range": [70, 99], "stable_minimal_symptoms": true, "first_line": "Oral iron", "consider_iv_iron_if_any": ["Severe fatigue", "Established breastfeeding difficulty", "Marked morbidity", "Poor anticipated oral adherence"] }, {"hb_g_per_L_less_than": 70, "or_symptomatic_with_bleeding_or_instability": true, "action": "Red cell transfusion (typically single unit with reassessment) + IV iron to replete stores"} ], "replete_stores_months": 3, "iv_iron_does_not_prevent_ppd": true, "sources": ["BSH 2020", "Bombač Tavčar 2023 RCT", "Bombač Tavčar 2024 fatigue", "Bombač Tavčar 2025 hypophosphataemia"] }, "transfusion": { "restrictive_threshold_g_per_L": 70, "single_unit_reassess": true, "do_not_transfuse_to_target_if_alternatives": true, "product_selection": { "compatibility": "ABO and RhD compatible", "K_negative_for_women_of_childbearing_age": true, "cmv_seronegative": { "elective_pregnancy_transfusion": "Where indicated and feasible without delay", "urgent_delivery_or_postpartum": "Do NOT delay for CMV-negative", "intrauterine_transfusion": "Required", "neonatal_transfusion": "Required" }, "emergency_group": "Group O RhD-negative, K-negative (only if emergency release required)", "irradiation_indications": [ "Congenital immunodeficiency", "Recent intrauterine-transfusion recipient", "HLA-matched products", "Post purine-analogue therapy" ] }, "consent_documented": true, "sources": ["NICE NG24", "RCOG GTG47"] }, "audit_indicators": [ {"indicator": "Women with FBC at booking and 28 weeks", "numerator": "Women with both checks recorded", "denominator": "All pregnancies reaching 28 weeks", "target": ">=99%"}, {"indicator": "Ferritin sent where indicated", "denominator": "Anaemic women + higher-risk women", "target": ">=95%"}, {"indicator": "Hb >=100 g/L at delivery", "target": "Benchmark locally; improve year on year"}, {"indicator": "Postpartum red cell transfusion rate", "unit": "per 1000 deliveries"}, {"indicator": "IV iron rate", "unit": "per 1000 deliveries", "role": "Balancing measure"}, {"indicator": "Serious adverse events following IV iron", "reporting": "MHRA Yellow Card"} ], "references": [ "Pavord S et al. 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