Pregnancy Safety

Drug safety reference by trimester

Safety Classification

Safe — Generally safe to use

Caution — Use only if benefit outweighs risk

Contraindicated — Avoid in pregnancy

Drug	Category	Overall	T1	T2	T3	Notes
Paracetamol	Analgesic	Safe	✓	✓	!	Preferred analgesic in pregnancy. Avoid prolonged high-dose use in T3.
Ibuprofen	NSAID	Contraindicated	!	!	✕	Avoid in T3 — premature closure of ductus arteriosus. Avoid in T1 if possible.
Diclofenac	NSAID	Contraindicated	!	!	✕	Contraindicated in T3. Risk of fetal renal impairment and premature ductus closure.
Codeine	Analgesic	Caution	!	!	✕	Avoid in T3 — neonatal withdrawal syndrome and respiratory depression. Short-term use only in T1/T2 when essential.
Tramadol	Analgesic	Caution	!	!	✕	Avoid in T3 — neonatal abstinence syndrome risk. Use only short-term in T1/T2 when no alternative.
Morphine / Strong Opioids	Analgesic	Caution	!	!	✕	Used for severe pain (labour, cancer pain) under specialist supervision. T3: neonatal respiratory depression and withdrawal. Neonatal monitoring essential if used near term.
Metformin	Antidiabetic	Safe	✓	✓	✓	Safe throughout pregnancy. Used in gestational diabetes. Monitor blood glucose.
Insulin (all types)	Antidiabetic	Safe	✓	✓	✓	Drug of choice for diabetes in pregnancy. Does not cross placenta.
Glibenclamide (Glyburide)	Antidiabetic	Caution	✕	!	!	Used in some countries for GDM when insulin not accepted. Crosses placenta minimally. Not first choice — insulin preferred. Risk of neonatal hypoglycaemia.
Enalapril / ACE Inhibitors	Antihypertensive	Contraindicated	✕	✕	✕	Absolutely contraindicated. Causes fetal renal agenesis, oligohydramnios, skull defects.
Losartan / ARBs	Antihypertensive	Contraindicated	✕	✕	✕	Absolutely contraindicated. Same mechanism as ACE inhibitors — fetal toxicity.
Methyldopa	Antihypertensive	Safe	✓	✓	✓	Drug of choice for hypertension in pregnancy. Long safety record.
Labetalol	Antihypertensive	Safe	✓	✓	✓	Safe and effective. Used for severe hypertension in pregnancy.
Nifedipine	Antihypertensive	Safe	!	✓	✓	Commonly used for hypertension and preterm labour tocolysis.
Hydralazine	Antihypertensive	Safe	!	✓	✓	Used IV for hypertensive emergencies in pregnancy. Oral use in T2/T3. Avoid early T1 — limited data.
Magnesium Sulfate	Antihypertensive	Safe	✓	✓	✓	Drug of choice for eclampsia seizure prophylaxis and treatment. IV/IM. Monitor reflexes, urine output, and respiratory rate. Antidote: Calcium gluconate.
Amlodipine	Antihypertensive	Caution	!	!	!	Limited data in pregnancy. Some observational studies suggest safety. Used when Nifedipine not tolerated. Avoid if possible — prefer agents with better evidence.
Spironolactone	Antihypertensive	Contraindicated	✕	✕	✕	Contraindicated — anti-androgenic effects. Risk of feminisation of male fetus.
Atorvastatin / Statins	Lipid-lowering	Contraindicated	✕	✕	✕	Contraindicated. Teratogenic — inhibits cholesterol synthesis needed for fetal development.
Amoxicillin	Antibiotic	Safe	✓	✓	✓	Safe throughout pregnancy. Preferred antibiotic for many infections.
Cefalexin	Antibiotic	Safe	✓	✓	✓	First-generation cephalosporin. Safe throughout pregnancy. Good choice for UTI and skin infections.
Erythromycin	Antibiotic	Safe	✓	✓	✓	Safe throughout pregnancy. Used for Chlamydia, respiratory infections. Avoid Erythromycin estolate — hepatotoxicity in pregnancy.
Azithromycin	Antibiotic	Caution	!	✓	✓	Generally considered safe. Use when benefit outweighs risk in T1.
Clarithromycin	Antibiotic	Contraindicated	✕	!	!	Avoid in T1 — animal studies show teratogenicity. Limited human data. Use erythromycin or azithromycin instead.
Clindamycin	Antibiotic	Safe	✓	✓	✓	Safe throughout pregnancy. Used for BV in T1 (when Metronidazole avoided), dental infections, MRSA-sensitive strains.
Trimethoprim	Antibiotic	Caution	✕	✓	✓	Avoid in T1 — folate antagonist, risk of neural tube defects. Safe in T2/T3 for UTI. If used in T1: ensure adequate folic acid supplementation.
Co-trimoxazole (Septrin)	Antibiotic	Contraindicated	✕	!	✕	Avoid in T1 (folate antagonist) and T3 (neonatal jaundice/methaemoglobinaemia). T2 use only if no alternative — ensure high-dose folic acid.
Ciprofloxacin / Fluoroquinolones	Antibiotic	Contraindicated	✕	✕	✕	Avoid — risk of cartilage damage in fetus. Use only if no alternative.
Doxycycline / Tetracyclines	Antibiotic	Contraindicated	✕	✕	✕	Absolutely contraindicated — dental staining and bone growth inhibition in fetus. Affects fetal teeth and long bones.
Nitrofurantoin	Antibiotic	Caution	✓	✓	✕	Avoid at term (T3) — risk of neonatal hemolytic anemia.
Metronidazole	Antibiotic	Caution	!	✓	✓	Avoid in T1 if possible. Safe in T2 and T3 for bacterial vaginosis, trichomoniasis.
Aciclovir	Antibiotic	Safe	!	✓	✓	Aciclovir registry shows no increase in birth defects. Used for genital herpes, varicella in pregnancy. Caution in T1 due to limited early data — benefit outweighs risk in severe infection.
Oseltamivir (Tamiflu)	Antibiotic	Safe	✓	✓	✓	Recommended in pregnancy — influenza poses significant risk to pregnant women (ICU admission, preterm birth, stillbirth). Start within 48h of symptoms. NICE recommends treating all pregnant women with suspected influenza.
Warfarin	Anticoagulant	Contraindicated	✕	!	✕	Teratogenic in T1 (warfarin embryopathy). Risk of fetal hemorrhage in T3.
Enoxaparin (LMWH)	Anticoagulant	Safe	✓	✓	✓	Does not cross placenta. Drug of choice for anticoagulation in pregnancy.
Rivaroxaban / DOACs	Anticoagulant	Contraindicated	✕	✕	✕	All DOACs (rivaroxaban, apixaban, dabigatran, edoxaban) are contraindicated — cross placenta, teratogenic, risk of fetal bleeding. Stop before conception.
Levothyroxine	Thyroid	Safe	✓	✓	✓	Essential in pregnancy. Dose often needs to increase by 25–30%. Monitor TSH every trimester.
Carbimazole	Thyroid	Caution	✕	!	!	Avoid in T1 — risk of aplasia cutis and choanal/oesophageal atresia. Use PTU in T1, switch to Carbimazole in T2.
Propylthiouracil (PTU)	Thyroid	Caution	✓	!	!	Preferred antithyroid drug in T1 — lower teratogenicity vs carbimazole. Switch to carbimazole after T1 due to PTU hepatotoxicity risk. Monitor LFTs.
Aspirin (low dose 75 mg)	Antiplatelet	Safe	✓	✓	!	Low-dose aspirin used for pre-eclampsia prevention. Avoid high doses.
Omeprazole / PPIs	GI	Caution	!	✓	✓	Generally safe. Use when benefit outweighs risk. Antacids preferred in T1.
Antacids (Gaviscon, Rennies)	GI	Safe	✓	✓	✓	Alginate-based antacids (Gaviscon) are safe and preferred first-line for heartburn/reflux in pregnancy throughout all trimesters.
Metoclopramide	GI	Safe	✓	✓	✓	Safe antiemetic and prokinetic throughout pregnancy. Short-term use (up to 5 days per episode). Risk of tardive dyskinesia with prolonged use.
Ondansetron	GI	Caution	!	✓	✓	Used for hyperemesis gravidarum. T1 caution — older data suggested cardiac defects (cleft palate), newer large studies reassuring but avoid if possible. Safe in T2/T3.
Domperidone	GI	Caution	!	!	!	Limited data in pregnancy. Generally avoided — cardiac QT prolongation risk. Use Metoclopramide or Cyclizine as preferred alternative.
Lactulose	GI	Safe	✓	✓	✓	Safe for constipation in all trimesters. Not systemically absorbed. First-line laxative in pregnancy.
Senna	GI	Caution	!	✓	!	Stimulant laxative. Occasionally used in T2. Avoid in T1 (uterine stimulation theoretical) and near term. Use lactulose preferentially.
Cyclizine	Antiemetic	Safe	✓	✓	✓	Antihistamine antiemetic. Safe throughout pregnancy. Widely used for morning sickness and hyperemesis. First-line choice.
Promethazine	Antiemetic	Safe	✓	✓	!	Safe in T1/T2. Avoid near term — neonatal CNS depression and extrapyramidal effects possible. Sedating.
Prochlorperazine (Stemetil)	Antiemetic	Caution	!	✓	!	Phenothiazine antiemetic. Used for severe nausea/vomiting. Avoid in T1 and near term. Extrapyramidal effects in neonate if used close to delivery.
Salbutamol Inhaler	Respiratory	Safe	✓	✓	✓	Safe throughout pregnancy. Asthma control essential in pregnancy — poorly controlled asthma causes more harm than medication. Use as normal.
Budesonide / ICS Inhalers	Respiratory	Safe	✓	✓	✓	Inhaled corticosteroids are safe throughout pregnancy. Do not stop. Poorly controlled asthma has higher risk than inhaled steroid exposure.
Prednisolone (oral)	Respiratory	Caution	!	✓	✓	T1: small increased risk of oral cleft palate at high doses (>10 mg/day). Short courses for asthma exacerbations safe. Risk of uncontrolled disease far exceeds steroid risk. Neonatal adrenal suppression if prolonged high dose in T3.
Montelukast	Respiratory	Caution	!	!	!	Limited human data. Animal studies reassuring. Generally continue if asthma well-controlled and discontinuation would compromise control. Discuss with specialist.
Theophylline	Respiratory	Caution	!	!	!	Can be used if other treatments insufficient. Monitor serum levels closely — therapeutic window narrow. Levels may change in pregnancy. Risk of neonatal theophylline toxicity if used near term.
Clotrimazole (topical)	Antifungal	Safe	✓	✓	✓	Topical clotrimazole is safe for vaginal candidiasis throughout pregnancy. Preferred antifungal. Use cream/pessary — apply manually, avoid applicator in T3.
Fluconazole (oral)	Antifungal	Contraindicated	✕	!	!	Single high-dose (150 mg) associated with cardiac defects (QSUR cardiac malformation) in T1. Avoid in T1. Single dose in T2/T3 may be used for persistent/severe infection when topical fails. Avoid prolonged courses.
Nystatin (oral/topical)	Antifungal	Safe	✓	✓	✓	Nystatin is not absorbed systemically — safe throughout pregnancy. Used for oral candidiasis and topical fungal infections.
Sertraline	Mental Health	Caution	!	✓	!	Safest SSRI in pregnancy — largest evidence base. T1: small absolute risk of cardiac defects (1/100). T3: neonatal adaptation syndrome (jitteriness, poor feeding — self-limiting). Untreated depression poses greater risk. Discuss with psychiatrist.
Fluoxetine	Mental Health	Caution	!	!	!	Acceptable option. Longer half-life than sertraline. T3: neonatal adaptation syndrome. Possible link to PPHN (persistent pulmonary hypertension of newborn) with T3 use — small absolute risk.
Paroxetine	Mental Health	Caution	✕	!	!	Avoid in T1 — risk of congenital cardiac defects (ventricular septal defect), especially at doses >25 mg/day. Highest discontinuation syndrome risk among SSRIs. Switch to sertraline if possible before conception.
Venlafaxine / SNRIs	Mental Health	Caution	!	!	!	Limited data vs SSRIs. Severe neonatal discontinuation syndrome — more so than SSRIs. Continue if depression not controlled with SSRIs. T3: neonatal adaptation syndrome. Risk of miscarriage reported (association, not causation confirmed).
Amitriptyline (TCAs)	Mental Health	Caution	!	!	!	Tricyclic antidepressants have been used in pregnancy for decades. Low-dose (10–25 mg) for pain/sleep relatively safe. Neonatal withdrawal syndrome in T3 at higher doses. Limb defects historically reported — not confirmed in large studies.
Lithium	Mental Health	Contraindicated	✕	!	!	T1: Ebstein's anomaly (cardiac) risk — small but real. T2/T3 under specialist supervision for bipolar disorder when benefit outweighs risk. Requires close serum level monitoring — levels fluctuate dramatically in pregnancy and around delivery. Neonatal toxicity (hypotonia, cyanosis).
Quetiapine	Mental Health	Caution	!	!	!	Used under specialist supervision for bipolar disorder, schizophrenia, and as augmentation in depression. Limited data but widely used. Risk of neonatal extrapyramidal effects and withdrawal. Monitor neonatal blood glucose (maternal hyperglycaemia risk).
Haloperidol	Mental Health	Caution	!	!	!	Used for acute psychosis and severe hyperemesis. Relatively more data than newer antipsychotics. Neonatal extrapyramidal effects and withdrawal symptoms in T3. Use lowest effective dose for shortest duration.
Diazepam / Benzodiazepines	Mental Health	Caution	✕	!	✕	T1: oral cleft risk (small, historically debated). T3: "floppy infant" syndrome, neonatal withdrawal. Short-term use only for severe anxiety/acute agitation. Not for routine anxiety management in pregnancy.
Sodium Valproate	Antiepileptic	Contraindicated	✕	✕	✕	ABSOLUTELY CONTRAINDICATED. Highest teratogenicity risk among antiepileptics. Neural tube defects (2–3%), cardiac defects, cognitive impairment, autism, ADHD. MHRA: do not use in women of childbearing potential without Pregnancy Prevention Programme (PPP).
Carbamazepine	Antiepileptic	Caution	!	!	!	Teratogenic — spina bifida, hypospadias, cardiac defects (~2–3% risk). Enzyme inducer — reduces folate levels (high-dose folic acid 5 mg/day essential from before conception). Lower risk than valproate but not ideal.
Phenytoin	Antiepileptic	Contraindicated	✕	✕	✕	Fetal hydantoin syndrome (IUGR, dysmorphic features, digit hypoplasia, cognitive impairment). Vitamin K deficiency in neonate — give Vitamin K to mother before delivery. Avoid — switch to safer AED before conception.
Lamotrigine	Antiepileptic	Caution	!	✓	✓	Preferred AED in pregnancy for many epilepsy syndromes. Lower teratogenicity than valproate/carbamazepine. Lamotrigine clearance increases significantly in pregnancy — dose often needs major increase. Monitor levels monthly.
Levetiracetam	Antiepileptic	Caution	!	✓	✓	Increasingly favoured in pregnancy — growing safety data. Pharmacokinetics change significantly — levels may fall, monitor carefully. Less teratogenicity than valproate. Used alone or with lamotrigine.
Folic Acid 400 mcg/day	Supplements	Safe	✓	✓	✓	Essential — start 3 months before conception and continue through T1 minimum. Reduces neural tube defect risk by 70%.
Folic Acid 5 mg/day (high dose)	Supplements	Safe	✓	✓	✓	High-dose indicated: diabetes, BMI >30, enzyme-inducing AEDs, sickle cell, thalassaemia, previous NTD-affected pregnancy. Prescribe from before conception.
Vitamin D (400–1000 IU/day)	Supplements	Safe	✓	✓	✓	Recommended for all pregnant women. Higher doses (1500–2000 IU) for deficiency, dark skin, limited sun exposure, BMI >30. Essential for fetal bone development and immune function.
Iron Supplements	Supplements	Safe	✓	✓	✓	Safe throughout pregnancy. Treat iron deficiency anaemia (Hb <110 g/L in T1/T3, <105 g/L in T2). Ferrous sulfate 200 mg TDS preferred. GI side effects common — switch to ferrous fumarate or ferrous gluconate if poorly tolerated.
Vitamin C (supplement)	Supplements	Safe	✓	✓	✓	Safe at recommended doses. High-dose vitamin C (>2000 mg/day) theoretical risk of preterm labour — avoid megadoses. Normal supplementation safe and beneficial.
Calcium Supplements	Supplements	Safe	✓	✓	✓	WHO recommends calcium supplementation (1.5–2g/day elemental calcium) in populations with low dietary intake to reduce pre-eclampsia risk. Safe and beneficial throughout.
Iodine / Kelp supplements	Supplements	Caution	!	!	!	Iodine is essential for fetal brain development. Mild supplementation (150 mcg/day from prenatal vitamins) is safe. High-dose iodine supplements (kelp) — avoid, risk of neonatal hypothyroidism.
Hydroxychloroquine	Immunosuppressive	Safe	✓	✓	✓	Safe throughout pregnancy. Continue for lupus (SLE), antiphospholipid syndrome, rheumatoid arthritis. Reduces SLE flares in pregnancy, decreases risk of congenital heart block in anti-Ro positive mothers. Do not stop.
Prednisolone (systemic)	Immunosuppressive	Caution	!	✓	✓	Used for SLE, IBD, asthma, autoimmune conditions. T1: small risk of oral cleft at >10 mg/day (1/500 above background). Generally safe for disease control. Neonatal adrenal suppression if high dose in T3. Maternal GDM, hypertension, IUGR risk.
Azathioprine	Immunosuppressive	Caution	!	✓	✓	Used in IBD (Crohn's, UC), SLE, transplant recipients, autoimmune hepatitis. Generally safe — active disease poses greater risk than medication. Neonatal immunosuppression and IUGR possible. Monitor FBC.
Methotrexate	Immunosuppressive	Contraindicated	✕	✕	✕	ABSOLUTELY CONTRAINDICATED. Folate antagonist — severe teratogen (fetal death, NTD, multiple malformations). Stop at least 3 months before conception. Emergency contraception and 2 forms of contraception mandatory during use.
Certolizumab (Cimzia)	Immunosuppressive	Safe	✓	✓	✓	PEGylated anti-TNF biologic with negligible placental transfer. Safest biologic in pregnancy — no Fc region for active placental transport. Used for Crohn's, RA, psoriatic arthritis. No live vaccines in infant for 6 months if other anti-TNFs used in T3.
Adalimumab / Infliximab (anti-TNF)	Immunosuppressive	Caution	✓	✓	!	Generally safe in T1/T2. T3: high placental transfer via Fc receptor — neonatal immunosuppression for up to 6 months. Withhold live vaccines (BCG, rotavirus) in infant for 6 months. Consider stopping at 22–26 weeks gestation (if disease permits).
Chloroquine / Hydroxychloroquine	Antiparasitic	Safe	✓	✓	✓	Chloroquine-based malaria prophylaxis is safe in pregnancy. WHO recommends in endemic areas. Treat malaria aggressively in pregnancy — mortality is high. Hydroxychloroquine: also safe (see immunosuppressive section for lupus use).
Artemether-Lumefantrine	Antiparasitic	Caution	!	✓	✓	WHO-recommended ACT for uncomplicated malaria treatment in T2/T3. T1 caution — limited data, but WHO considers benefits outweigh risks even in T1 if quinine not available. Treat malaria — untreated is dangerous.
Ivermectin	Antiparasitic	Caution	✕	!	!	Avoid in T1 — animal studies show embryotoxicity. T2/T3: limited human data, used for strongyloidiasis and onchocerciasis when benefit outweighs risk. Use with specialist advice.
Mebendazole	Antiparasitic	Caution	✕	✓	✓	Avoid in T1 — antimitotic mechanism, embryotoxic in animals. WHO recommends for mass drug administration in T2/T3 for hookworm, roundworm, whipworm. Safe after T1.
Digoxin	Cardiovascular	Caution	!	!	!	Used for rate control in AF and fetal SVT. Crosses placenta — used therapeutically for fetal arrhythmias. Monitor levels closely — altered pharmacokinetics in pregnancy. Narrow therapeutic window.
Bisoprolol / Beta-blockers	Cardiovascular	Caution	!	!	!	Beta-blockers are used for hypertension, arrhythmias, thyrotoxicosis in pregnancy. T3: IUGR, neonatal bradycardia, hypoglycaemia, respiratory depression — monitor neonate. Labetalol (alpha+beta) preferred in pregnancy.
Atenolol	Cardiovascular	Contraindicated	!	✕	✕	Avoid — most evidence for IUGR and reduced birth weight among beta-blockers. If beta-blocker needed, use Labetalol or Propranolol instead.
Amiodarone	Cardiovascular	Contraindicated	✕	✕	✕	Avoid if possible — neonatal thyroid dysfunction (hypo- or hyperthyroidism), IUGR, bradycardia. Use only for life-threatening arrhythmia when no other option. High iodine content.
Heparin (unfractionated)	Anticoagulant	Safe	✓	✓	✓	Does not cross placenta — safe throughout pregnancy. Used perioperatively and when LMWH monitoring needed (e.g., mechanical heart valves). Monitor anti-Xa levels.
Influenza vaccine	Vaccines	Safe	✓	✓	✓	Strongly recommended in ALL trimesters. Inactivated influenza vaccine is safe. Protects mother and neonate (passive immunity). Reduces risk of ICU admission, preterm birth, and stillbirth from influenza.
Pertussis (Tdap) vaccine	Vaccines	Safe	✓	✓	✓	Recommended at 16–32 weeks (ideally 20 weeks). Protects neonate against whooping cough via passive antibody transfer — essential before infant can be vaccinated at 8 weeks.
COVID-19 mRNA Vaccine	Vaccines	Safe	✓	✓	✓	JCVI, WHO, RCOG: recommended in pregnancy — COVID-19 increases risk of ICU admission, preterm birth, stillbirth. mRNA vaccines do not contain live virus. No evidence of increased miscarriage or congenital malformation risk.
MMR vaccine	Vaccines	Contraindicated	✕	✕	✕	Live attenuated vaccine — contraindicated in pregnancy. Avoid conception for 1 month after vaccination. Check rubella immunity pre-conception — vaccinate if non-immune before pregnancy.
Misoprostol	Obstetric	Safe	!	✓	✓	Prostaglandin E1 analogue. Used for cervical ripening and labour induction, management of PPH, treatment of incomplete miscarriage, and medical abortion. Doses and route vary by indication. High doses can cause uterine hyperstimulation.
Oxytocin	Obstetric	Safe	✓	✓	✓	Used for labour induction, augmentation, and prevention/treatment of PPH. IV infusion monitored carefully — uterine hyperstimulation risk. Antidiuretic effect at high doses (hyponatraemia risk).
Carboprost (Haemabate)	Obstetric	Safe	✓	✓	✓	Prostaglandin F2α — used for refractory PPH unresponsive to oxytocin. IM injection. Contraindicated in asthma. Bronchospasm risk.
Tranexamic Acid	Obstetric	Safe	✓	✓	✓	Antifibrinolytic — used in PPH management (WOMAN trial: reduces PPH deaths by 30% if given within 3h). Also used for antepartum haemorrhage. Safe in all trimesters.

Important Disclaimer

This reference is for general guidance only. Always consult current national guidelines and a specialist for individual patient management. Drug safety classifications may vary by source and clinical context.