Medical illness in pregnancy

Management— do this, in order

• Ask what you would do if she were not pregnant, then decide what genuinely needs to change — usually very little; withholding effective treatment causes more foetal harm through maternal deterioration than most drugs do directly.
• Position her left lateral or with manual uterine displacement from mid-pregnancy, because the gravid uterus compresses the inferior vena cava when supine and reduces venous return.
• Severe hypertension (160/110 mmHg or more) requires prompt reduction because timely control reduces the risk of stroke: intravenous labetalol and intravenous hydralazine are first-line, with oral nifedipine effective where intravenous access is not established, transitioning to oral agents once control is achieved.Doctor / Nurse
• Oral antihypertensives, treating to a target below 140/90 mmHg: labetalol 100 mg orally twice daily up to 600 mg four times daily; nifedipine modified-release 10 mg orally twice daily up to 40 mg twice daily; amlodipine 5–10 mg orally once daily; methyldopa 250 mg orally twice daily up to 1 g three times daily; doxazosin 0.5 mg orally twice daily up to 8 mg three times daily.
• Magnesium sulphate for eclamptic seizures and for seizure prophylaxis once severe pre-eclampsia is diagnosed and delivery planned: loading 4 g intravenously over 5–20 minutes (some regimens use 4–6 g), then maintenance 1 g/hour for 24 hours (alternative regimens use 2–3 g/hour), titrated against serum magnesium and clinical status.Doctor / NurseNot available at your setup — Infusion pump.
• A recurrent seizure despite magnesium warrants a further 2 g intravenous bolus and reconsideration of an alternative diagnosis — cerebral venous thrombosis, intracranial haemorrhage or thrombotic thrombocytopenic purpura.Doctor / Nurse
• Monitor tendon reflexes, respiratory rate and urine output during magnesium — loss of reflexes precedes respiratory depression — and keep calcium gluconate 1 g intravenously to hand as the antidote for magnesium toxicity.Doctor / Nurse
• Restrict fluid in pre-eclampsia even in the face of oliguria: low colloid osmotic pressure and capillary leak make pulmonary oedema the danger, and the resulting acute kidney injury is usually rapidly reversible after delivery.
• Give corticosteroids for foetal lung maturity where preterm birth between 24 and 34 weeks is anticipated: betamethasone 12 mg intramuscularly every 24 hours for two doses, or dexamethasone 6 mg intramuscularly every 12 hours for four doses — but do not delay delivery for steroids in unstable severe pre-eclampsia.
• Delivery is the definitive treatment for the pregnancy-specific syndromes: without severe features at or beyond 37 weeks, deliver; before 37 weeks manage expectantly with close surveillance; with severe features, deliver unless before 34 weeks with a stable mother in a setting able to offer expectant management.
• Start low-dose aspirin from 12 weeks until delivery in women at high risk or with more than one moderate risk factor — 75 mg, 81 mg or 150 mg orally once daily are all in current use, with the higher end favoured by more recent evidence — usually stopping it 10 days to 4 weeks before planned delivery; add calcium supplementation where dietary calcium intake is low.
• Treat suspected sepsis and infection with safe agents: penicillins, cephalosporins and macrolides are safe; treat asymptomatic bacteriuria (screened by urine culture, not dipstick) for 5–7 days, and suppress after recurrent bacteriuria or one episode of pyelonephritis with nitrofurantoin 50–100 mg orally at night (avoid at term) or cefalexin 250–500 mg orally at night; pyelonephritis warrants intravenous antibiotics.Doctor / Nurse
• Treat suspected influenza with oseltamivir 75 mg orally twice daily for 5 days without waiting for confirmatory testing; treat established chickenpox with aciclovir 800 mg orally four times daily for 5–7 days started within 24 hours of rash onset, and varicella pneumonia with intravenous aciclovir 10 mg/kg every 8 hours for 7–10 days.Doctor / Nurse
• Anticoagulate established venous thromboembolism with low-molecular-weight heparin (or unfractionated heparin) at therapeutic weight-based doses, avoiding direct oral anticoagulants and warfarin, and stopping prophylactic LMWH 12 hours and therapeutic LMWH 24 hours before neuraxial catheter placement.
• Do not reduce doses out of caution: increased renal and hepatic clearance and an expanded volume of distribution mean pregnant women usually require the same or higher doses, and antiepileptic drug levels in particular fall and should be monitored monthly.
• Insulin requirements rise 50–100% in the second half of pregnancy (approximately 0.7–0.8 units/kg/day in the first trimester, 0.8–1.0 in the second and 0.9–1.2 in the third); glycaemic targets are fasting below 5.3 mmol/L (95 mg/dL), 1 hour post-prandial below 7.8 mmol/L (140 mg/dL) and 2 hours post-prandial below 6.4 mmol/L (115 mg/dL).
• Levothyroxine requirements rise from as early as the fifth week: anticipate a 25–30% increase at the moment pregnancy is confirmed (two extra tablets per week), rising to 30–50% by mid-pregnancy; newly diagnosed overt hypothyroidism is treated at full replacement, levothyroxine 1.6 micrograms/kg/day orally (approximately 100–150 micrograms daily).
• Give folic acid 5 mg orally daily (rather than the standard 400 micrograms) from before conception in diabetes and in epilepsy.