Drugs in Pregnancy and Lactation are of different categories than drugs are used in general ill health to normal woman but special caution is required in prior category.
Significance:
- Drugs that crosses the placental barrier effects the foetus directly
- Drugs that do not cross placental barrier effects foetus by constricting placental blood vessels, altering maternal physiology.
Effect of drugs on foetus depends on
- Foetal age at the time of exposure to drug.
- Potency and dosage of the drug
- Before 20th day after fertilization – all / nothing effect
- 20-56 days after fertilization – teratogenicity
- 2nd and 3rd trimester – altered functioning, growth of organs.
FDA Classification of drugs in pregnancy:
Category | Examples | Effect on fetus |
A | Diphenhydramine, Heparin, Paracetamol, Insulin | No effects |
B | Metformin Corticosteroids | Hypoglycaemia Orofacial clefts |
C | Fluoroquinolones | Bone growth retardation and pain |
D | Aspirin Aminoglycosides Habit forming agents Thyroid medicines | Abortion , delayed labour Ototoxicity Congenital malformations Goiter |
X | Warfarin Danazol Isotretinoin | Thrombocytopenia Female fetul masculinization Abortion |
Goal:
- Is to reduce the foetal risks
Prescription contains:
- Antiemetics – vomiting
- Antacids – acidity
- Antihistamine – allergy
- Analgesics – pain
- Antimicrobials – infection
- Diuretics – peripheral edema
- Hypnotics – sleep inducers
- Tranquilizers – anxiety, psychosis
- Social and illicit drugs – Smoking, Alcohol, cocaine
- Vaccines
Contraindications:
- All antihypertensives except methyldopa
- Isotretinoin
- Warfarin
- Methotrexate
- Live vaccines
- Antidepressants (paroxetine)
- All live vaccines except influenza vaccine but vaccinations for cholera, hepatitis A and B, measles, mumps, plague, poliomyelitis, rabies, tetanus-diphtheria, typhoid, and yellow fever may be given if risk of infection to foetus is minimal
- Vitamin A > 10,000 IU/day
- Higher intake of aspartame (dietary sugar)
Counselling on side effects
- Antidepressants – tapering
- Antihypertensives – rebound hypertension
