Section 1: Introduction — The Prescription That Crosses the Placenta

Every drug prescribed to a pregnant woman is prescribed to two patients.

A 28-year-old woman in her first trimester attends a health centre in Castries. She has epilepsy managed with sodium valproate 500 mg twice daily. She also takes ibuprofen occasionally for headaches and was recently started on lisinopril 10 mg daily for newly diagnosed hypertension.

All three medications carry significant risks in pregnancy. The sodium valproate is the most dangerous — it is the single most teratogenic commonly prescribed drug in clinical use, associated with neural tube defects, craniofacial abnormalities, and neurodevelopmental disorders in up to 10% of exposed pregnancies. The lisinopril is contraindicated in the second and third trimesters — ACE inhibitors cause renal agenesis, oligohydramnios, and neonatal renal failure. The ibuprofen, taken in the third trimester, can cause premature closure of the ductus arteriosus and oligohydramnios.

This is not a rare scenario. These are common drugs for common conditions in women of childbearing age. The question is not whether Caribbean clinicians will encounter this situation — it is whether they will recognise it before the prescription is written.

1.1 Why the Caribbean context matters

Three features of Caribbean clinical practice amplify the risks of prescribing in pregnancy and lactation:

High unplanned pregnancy rates. Across the Caribbean, a significant proportion of pregnancies are unplanned. This means that women may be taking teratogenic medications at the point of conception and during the critical first trimester — before they know they are pregnant and before any clinician has the opportunity to review their medications.

Limited access to specialist prescribing advice. In many Caribbean territories, particularly the OECS states, access to maternal-fetal medicine specialists, clinical pharmacologists, or even obstetricians with prescribing expertise is limited. Primary care clinicians and midwives make prescribing decisions for pregnant women without specialist backup.

Formulary constraints. The safer alternative may not be available. If the formulary drug is the teratogenic one — and in some Caribbean territories it is — the clinician faces a choice between a known risk and no treatment at all.

1.2 What this report covers

This report profiles twenty drugs commonly prescribed in the Caribbean that carry significant pregnancy or lactation risks. It is organised into three sections: drugs to stop before conception (the pre-pregnancy review), drugs to avoid or adjust during pregnancy, and drugs to watch during breastfeeding.

Each drug profile includes the FDA pregnancy category (where available), the specific risk, the trimester of greatest concern, the safer alternative, and a Caribbean Practice Note.

The report also provides a pre-pregnancy medication review checklist — a practical tool for clinicians seeing women of childbearing age on long-term medications.

Section 2: The Pre-Pregnancy Review — Drugs to Stop Before Conception

These drugs should be reviewed and, where possible, switched to safer alternatives in any woman of childbearing age — not just women who are planning pregnancy. Because unplanned pregnancies are common, waiting until a woman announces she is pregnant is too late for drugs with first-trimester teratogenic risk.

2.1 Sodium Valproate

Prescribed for: Epilepsy, bipolar disorder, migraine prophylaxis.

Pregnancy risk: The most teratogenic commonly prescribed drug. Neural tube defects (spina bifida) in 1–2% of exposed pregnancies. Major congenital malformations in 10%. Neurodevelopmental disorders (reduced IQ, autism spectrum disorder) in 30–40% of children exposed in utero. Risk is dose-dependent but present at all doses.

Trimester of concern: All — but neural tube defects occur in the first trimester (weeks 3–4), often before the woman knows she is pregnant.

Safer alternative: For epilepsy: lamotrigine or levetiracetam (both have substantially lower teratogenic risk). For bipolar disorder: quetiapine or lamotrigine. For migraine prophylaxis: propranolol. The switch should be made before conception, not during pregnancy — switching antiepileptics during pregnancy carries seizure risk.

Caribbean Practice Note: Sodium valproate remains on Caribbean essential medicines lists and is widely prescribed for epilepsy and bipolar disorder. The EMA and MHRA have issued strong warnings restricting its use in women of childbearing potential unless no alternative exists and a pregnancy prevention programme is in place. These regulatory restrictions may not be consistently applied in Caribbean practice. Any woman of childbearing age on valproate should be on effective contraception and should have a documented plan for switching before a planned pregnancy.

2.2 Methotrexate

Prescribed for: Rheumatoid arthritis, psoriasis, ectopic pregnancy (single dose).

Pregnancy risk: Category X — absolutely contraindicated. Methotrexate is an abortifacient and teratogen. It causes spontaneous abortion, and in surviving pregnancies, craniofacial, limb, and CNS malformations.

Trimester of concern: All. Must be stopped at least 3 months before conception (some guidelines recommend 6 months) to allow folate stores to recover.

Safer alternative: For rheumatoid arthritis in pregnancy: hydroxychloroquine, sulfasalazine, or low-dose prednisolone. For psoriasis: topical treatments, phototherapy, or — in severe cases — ciclosporin (with specialist supervision).

Caribbean Practice Note: Women on methotrexate for rheumatoid arthritis or psoriasis must be on effective contraception throughout treatment. The 3-month washout before conception is non-negotiable. Folic acid supplementation (5 mg daily) should begin during the washout period and continue through the first trimester.

2.3 ACE Inhibitors (Lisinopril, Enalapril, Ramipril)

Prescribed for: Hypertension, heart failure, diabetic nephropathy.

Pregnancy risk: Fetotoxic in second and third trimesters — renal tubular dysplasia, oligohydramnios, pulmonary hypoplasia, neonatal renal failure, and death. First-trimester exposure may also carry risk (cardiovascular malformations reported in some studies, though data is less consistent).

Trimester of concern: Second and third trimesters (established risk). First trimester (possible risk).

Safer alternative: Methyldopa (first-line in pregnancy for hypertension), labetalol, or nifedipine modified-release. The switch should occur as soon as pregnancy is confirmed — ideally before conception in women planning pregnancy.

Caribbean Practice Note: ACE inhibitors are the most commonly prescribed antihypertensives in the Caribbean. Many women of childbearing age with hypertension or diabetic nephropathy are on lisinopril or enalapril. The switch to methyldopa at confirmation of pregnancy is standard practice, but the reverse — switching back from methyldopa post-partum — is covered in Report 4 (Deprescribing, Drug 9).

2.4 ARBs (Losartan, Valsartan, Telmisartan)

Pregnancy risk: Same as ACE inhibitors — fetotoxic in second and third trimesters. Contraindicated throughout pregnancy.

Safer alternative: Same as ACE inhibitors — methyldopa, labetalol, or nifedipine MR.

2.5 Warfarin

Prescribed for: Atrial fibrillation, mechanical heart valves, VTE treatment and prevention.

Pregnancy risk: Warfarin embryopathy — nasal hypoplasia, stippled epiphyses, limb abnormalities — with first-trimester exposure (weeks 6–12). CNS abnormalities with exposure at any stage. Fetal and maternal haemorrhage risk throughout pregnancy.

Trimester of concern: First trimester (embryopathy). All trimesters (haemorrhage).

Safer alternative: Low-molecular-weight heparin (enoxaparin) — does not cross the placenta. For mechanical heart valves, management is complex and requires specialist anticoagulation oversight.

Caribbean Practice Note: Women with mechanical heart valves on warfarin present one of the most challenging prescribing decisions in pregnancy. Warfarin is more effective than LMWH at preventing valve thrombosis, but LMWH is safer for the fetus. This decision must involve a cardiologist and obstetrician — it should not be made in primary care alone.

2.6 Statins (Atorvastatin, Rosuvastatin, Simvastatin)

Prescribed for: Hypercholesterolaemia, cardiovascular risk reduction.

Pregnancy risk: Category X. Animal studies show skeletal malformations. Cholesterol is essential for fetal development — inhibiting its synthesis during organogenesis is theoretically harmful. Clinical data is limited because statins are routinely stopped in pregnancy, but the precautionary principle applies.

Trimester of concern: First trimester (organogenesis).

Safer alternative: Stop. Hypercholesterolaemia does not require treatment during pregnancy — the 9-month interruption carries negligible cardiovascular risk for the mother.

2.7 Isotretinoin

Prescribed for: Severe acne.

Pregnancy risk: Category X. One of the most potent human teratogens — craniofacial, cardiac, and CNS malformations in up to 35% of exposed pregnancies. Spontaneous abortion in up to 40%.

Trimester of concern: All — but first trimester is highest risk.

Safer alternative: Stop at least one month before conception (some guidelines recommend two months). For acne in pregnancy: topical benzoyl peroxide, topical erythromycin, or azelaic acid.

Caribbean Practice Note: Isotretinoin requires a strict pregnancy prevention programme (iPLEDGE in the US, PPP in the UK/EU). These programmes may not be consistently implemented in Caribbean practice. Any woman prescribed isotretinoin must be on two forms of effective contraception and must have a negative pregnancy test before each prescription refill.

Section 3: During Pregnancy — Drugs to Avoid or Adjust

These drugs are encountered during pregnancy — either because the woman was already taking them or because a new condition arises that requires treatment.

3.1 NSAIDs (Ibuprofen, Diclofenac, Naproxen)

Risk in pregnancy: Third trimester: premature closure of the ductus arteriosus, oligohydramnios, delayed labour. First trimester: some studies suggest increased miscarriage risk, though data is inconsistent. The FDA issued a warning in 2020 against NSAID use after 20 weeks of gestation.

Trimester of concern: Third trimester (established). First trimester (possible). Avoid throughout if possible.

Safer alternative: Paracetamol (first-line analgesic in pregnancy — see dose limits in Report 2 for hepatic impairment).

Caribbean Practice Note: Ibuprofen and diclofenac are available over the counter across the Caribbean. Pregnant women may self-medicate without knowing the risk. Clinicians should ask specifically about NSAID use at every antenatal visit.

3.2 Tetracyclines (Doxycycline, Tetracycline)

Risk in pregnancy: Permanent staining of fetal teeth (yellow-brown discolouration), inhibition of bone growth, and maternal hepatotoxicity with IV administration. Crosses the placenta freely.

Trimester of concern: Second and third trimesters (after week 16, when teeth begin to calcify).

Safer alternative: Amoxicillin, azithromycin, or erythromycin depending on the infection.

3.3 Fluoroquinolones (Ciprofloxacin, Levofloxacin)

Risk in pregnancy: Cartilage damage in weight-bearing joints (demonstrated in animal studies). Contraindicated in pregnancy by most guidelines.

Trimester of concern: All.

Safer alternative: Amoxicillin, co-amoxiclav, cephalosporins, azithromycin — depending on the infection and susceptibility.

Caribbean Practice Note: Ciprofloxacin is one of the most commonly prescribed antibiotics in the Caribbean. It is the default for UTIs in many settings. In pregnancy, nitrofurantoin (except near term) or a cephalosporin should be used instead.

3.4 Trimethoprim

Risk in pregnancy: Folate antagonist — increased risk of neural tube defects with first-trimester exposure. Avoid in the first trimester; use with caution thereafter.

Trimester of concern: First trimester.

Safer alternative: Nitrofurantoin (for UTIs — avoid near term due to haemolytic anaemia risk in the neonate), cephalexin, or amoxicillin based on culture and susceptibility.

3.5 Benzodiazepines (Diazepam, Lorazepam)

Risk in pregnancy: First-trimester exposure associated with cleft palate in some studies (risk is small but documented). Third-trimester/peripartum use causes floppy infant syndrome — neonatal hypotonia, respiratory depression, and withdrawal symptoms.

Trimester of concern: First trimester (cleft palate). Third trimester (floppy infant).

Safer alternative: For anxiety: SSRIs (sertraline is the preferred SSRI in pregnancy — most safety data). For insomnia: sleep hygiene, short-term promethazine (low risk in pregnancy despite other concerns). For seizure: levetiracetam.

3.6 Misoprostol

Risk in pregnancy: Potent uterotonic — causes uterine contractions, cervical ripening, and abortion. Used therapeutically for induction of labour and management of postpartum haemorrhage, but absolutely contraindicated for any other indication during pregnancy.

Trimester of concern: All.

Caribbean Practice Note: Misoprostol is available in some Caribbean pharmacies for its gastric indication (prevention of NSAID-induced ulcers). Its abortifacient properties are well-known and it is sometimes obtained for this purpose outside clinical settings. Clinicians should be aware of the possibility of self-administration and should ask about misoprostol use if a pregnant woman presents with vaginal bleeding or uterine pain.

3.7 Metformin in Pregnancy

Status: Metformin is increasingly used in pregnancy for gestational diabetes and pre-existing type 2 diabetes. It crosses the placenta. The MiG trial (2008) and subsequent studies have shown no increase in major congenital malformations, but long-term follow-up studies of exposed children are ongoing.

Current guidance: Metformin is an acceptable second-line agent for gestational diabetes when diet and exercise are insufficient and insulin is declined or unavailable. Insulin remains the gold standard for glycaemic control in pregnancy.

Caribbean Practice Note: In Caribbean settings where insulin access, storage (cold chain), and patient education may be challenging, metformin offers a practical alternative for gestational diabetes management. Its use should be documented with a clear rationale, and the patient should be counselled that insulin may still be needed if glycaemic targets are not met.

Section 4: During Breastfeeding — Drugs to Watch

Most drugs enter breast milk to some degree. The question is not whether a drug is present in breast milk but whether the amount the infant receives is clinically significant. For most drugs, the infant dose via breast milk is less than 1–2% of the maternal dose — well below the threshold for clinical effect.

The drugs listed below are exceptions — they either enter breast milk in significant amounts or carry specific risks for the nursing infant.

4.1 Codeine

Risk: Codeine is metabolised to morphine by CYP2D6. Ultra-rapid metabolisers (approximately 1–2% of the Caribbean population, higher in some ethnic groups) produce excessive morphine, which enters breast milk and can cause infant sedation, respiratory depression, and — in rare cases — death. A case of neonatal death attributed to codeine in breast milk was reported in 2006.

Safer alternative: Paracetamol, ibuprofen (safe in breastfeeding), or tramadol at low doses (with monitoring).

4.2 Lithium

Risk: Enters breast milk at 30–50% of maternal serum levels. Risk of neonatal hypothyroidism, cyanosis, and hypotonia. Breastfeeding is generally not recommended during lithium therapy.

Safer alternative: If mood stabilisation is required during breastfeeding, quetiapine or lamotrigine have more favourable breast milk profiles.

4.3 Amiodarone

Risk: Extremely long half-life (40–55 days). Enters breast milk and exposes the infant to iodine load — risk of neonatal hypothyroidism and thyroid dysfunction. Breastfeeding is contraindicated during amiodarone therapy.

4.4 Methotrexate

Risk: Immunosuppressive and cytotoxic. Contraindicated during breastfeeding — risk of immune suppression and neutropenia in the infant.

4.5 Ergot Alkaloids (Ergotamine, Bromocriptine)

Risk: Ergotamine (for migraine) can cause vomiting, diarrhoea, and seizures in the breastfed infant. Bromocriptine suppresses lactation — it is used therapeutically for this purpose but should not be prescribed if the mother intends to breastfeed.

Safer alternative for migraine: Sumatriptan (considered compatible with breastfeeding — express and discard milk for 8 hours after dose if concerned).

4.6 Combined Oral Contraceptives

Risk: Oestrogen-containing contraceptives reduce milk supply, particularly in the first 6 weeks post-partum. They do not harm the infant, but the reduction in milk volume can compromise breastfeeding.

Safer alternative: Progestogen-only pill (POP), progestogen-only injectable (medroxyprogesterone acetate), levonorgestrel IUD, or condoms. The POP can be started immediately post-partum without affecting lactation.

Caribbean Practice Note: Combined OCs are the most commonly used contraceptive method in many Caribbean territories. Women planning to breastfeed should be counselled before delivery to use progestogen-only methods for the first 6 months, switching to combined methods only after breastfeeding is well established.

4.7 Ciprofloxacin

Risk: Enters breast milk. Theoretical risk of cartilage toxicity and disruption of infant gut flora. Generally avoided during breastfeeding; short courses may be acceptable if no alternative exists.

Safer alternative: Amoxicillin, co-amoxiclav, or cephalexin for most infections.

Section 5: The Pre-Pregnancy Medication Review Checklist

Print this and use it at every consultation with a woman of childbearing age on long-term medications.

One rule: Any woman of childbearing age on a teratogenic medication should be on effective contraception and should have a documented plan for what happens if she becomes pregnant.

Section 6: About ElesRx

ElesRx includes pregnancy and lactation safety profiles for drugs in the clinical database. When a clinician indicates that a patient is pregnant or breastfeeding, the system flags medications with known pregnancy or lactation risks, identifies the trimester of greatest concern, and suggests safer alternatives where they exist.

The pre-pregnancy medication review is one of the most underused features in clinical practice — and one of the most impactful. A single review before conception can prevent a teratogenic exposure that no amount of prenatal monitoring can reverse.

elesrx.com — free tier available. Full access $9.99/month.

ElesRx is a product of PIPPS Smart Apps, a division of J.C. Epiphany Limited (Jamaica, est. 1998).

Section 7: Methodology and References

7.1 Data sources

Pregnancy and lactation safety data is drawn from the ElesRx clinical database, verified against DailyMed (FDA-approved labelling), the UK Teratology Information Service (UKTIS), LactMed (NIH/NLM), the European Medicines Agency, and published clinical guidelines. The source hierarchy and licensing constraints are the same as Reports 1–4.

7.2 FDA pregnancy categories

This report references the legacy FDA pregnancy categories (A, B, C, D, X) where they aid clinical understanding, while acknowledging that the FDA replaced this system with narrative labelling (the Pregnancy and Lactation Labeling Rule, PLLR) in 2015. The categories remain in widespread clinical use in the Caribbean.

7.3 Limitations

This report profiles twenty drugs across pregnancy and lactation. The ElesRx database contains pregnancy and lactation profiles for a broader set. The twenty were selected for their prevalence in Caribbean prescribing and the clinical significance of their risks.

Prescribing in pregnancy requires individualised risk-benefit assessment. This report provides general guidance, not patient-specific recommendations.

7.4 Author and conflict of interest disclosure

This report was authored by Juliet Duncan, BPharm, founder of J.C. Epiphany Limited and developer of ElesRx. The author has a commercial interest in ElesRx. This report is published freely as a contribution to Caribbean clinical education. No external funding was received.

7.5 Citation

Duncan J. Two Patients in One: The Drugs We Prescribe to Pregnant and Breastfeeding Women in the Caribbean. ElesRx Clinical Reports, Report 5. Published 2026 at elesrx.com/reports/two-patients-in-one/. J.C. Epiphany Limited, Jamaica.

References

1. Bromley RL, et al. Treatment for epilepsy in pregnancy: neurodevelopmental outcomes in the child. Cochrane Database Syst Rev. 2014;(10):CD010236. doi:10.1002/14651858.CD010236.pub2

2. Bullo M, Tschumi S, Bucher BS, Bianchetti MG, Simonetti GD. Pregnancy outcome following exposure to angiotensin-converting enzyme inhibitors or angiotensin receptor antagonists: a systematic review. Hypertension. 2012;60(2):444–450. doi:10.1161/HYPERTENSIONAHA.112.196352

3. Rowan JA, Hague WM, Gao W, Battin MR, Moore MP. Metformin versus insulin for the treatment of gestational diabetes (MiG trial). N Engl J Med. 2008;358(19):2003–2015. doi:10.1056/NEJMoa0707193

4. Koren G, et al. A multicenter, prospective study of fetal outcome following accidental codeine exposure in early pregnancy. Reprod Toxicol. 2006;21(4):383–389.

5. UKTIS. Use of Valproate in Pregnancy. UK Teratology Information Service Monograph. Updated 2024.

6. LactMed. Drugs and Lactation Database. National Library of Medicine. Accessed 2026. toxnet.nlm.nih.gov/lactmed