When it comes to preparing obstetrics for the NEET PG exam, drugs in pregnancy are one of the most important and high-yielding topics. Through this blog, we have tried to cover all the vital details about the topic so that you recall and revise it quickly.
Make your NEET PG exam preparations of obstetrics simpler and more productive through our medical notes blogs. Keep reading.
FDA CATEGORIES - 5 CATEGORIES
FDA has classified the different drugs used in pregnancy into five letter risk categories. Each category represents the potential of that category drug to cause risk during pregnancy.
Category A
Safe in pregnancy
Thyroxine
Multi Vitamins
Folic Acid
Category B
Have adverse effects in animals
All studies in human are safe
Penicillin
Cephalosporins
Didanosine
Metronidazole
Nitrofurantoin
Category C
Teratogenic in animals
Inadequate human studies, safe in the few studies done
Most commonly used drugs in Obstetrics
Mebendazole
Albendazole
Acyclovir
Chloroquine
Lamotrigine (Category C Anti-Epileptic drug: DOC for Epilepsy in pregnancy)
Category D
Known human teratogens
Given when Benefits > Risk
Antiepileptics (Phenytoin, Carbamazepine)
Quinine
Category X
Known Teratogens
Totally contraindicated (Risk > Benefits)
Alcohol
Androgens
Vitamin A
Lithium
Warfarin (in early pregnancy)
Radio Iodine
Cancer Chemotherapeutic Drugs
Tetracyclines
ALCOHOL IN PREGNANCY
Alcohol intake during pregnancy can cause the baby to develop serious conditions and increase the risk of miscarriage. Let’s learn about the risks of alcohol in pregnancy.
Alcohol Related Birth Defects
Cardiac: ASD or VSD
Skeletal: Radio ulnar synostosis, joint contractures
Renal: Aplastic or hypoplastic kidneys
Eyes: Strabismus, Ptosis, Optic nerve hypoplasia
Ear: Conductive or Neuro-sensory hearing loss
Minor: Hypoplastic nails, Clinodactyly, Pectus carinatum or excavatum, Camptodactyly, Hockey stick Palmar crease, RailRoad Track Ears)
Fetal Alcohol Syndrome
All are required for diagnosis
Dysmorphic Facial features (all 3 required)
Small palpebral fissures
Thin vermilion border
Smooth Philtrum
Prenatal and / or postnatal growth impairment
CNS abnormalities (1 required)
Structural: Head size < 10th percentile, significant brain abnormality on imaging
Global cognitive or intellectual deficits
WARFARIN EMBRYOPATHY
Warfarin is a Vitamin K antagonist & a potent anticoagulant
Low molecular weight: Readily cross placenta
Causes Embryotoxic & Fetotoxic effects
6-9 weeks exposure: Warfarin Embryopathy
Features
Stippling of vertebrae & femoral epiphysis
Nasal hypoplasia
Depression of Nasal bridge
LEFLUNOMIDE
A Pyrimidine synthesis inhibitor
Used for Rx of Rheumatoid arthritis
C/I in pregnancy because it is a/w multiple abnormalities like
Hydrocephalus
Eye abnormalities
Skeletal abnormalities
Embryo death
Detectable in plasma for upto 2 years following it’s discontinuation
Cholestyramine Treatment/Washout
Cholestyramine binds with Leflunomide & helps in early excretion of drug
Cholestyramine Rx is F/b verification of serum levels of Leflunomide (Serium levels of Leflunomide should be undetectable on 2 tests performed 14 days apart)
FETAL HYDANTOIN SYNDROME
D/t intake of Antiepileptics like Phenytoin, Carbamazepine
Facial features include
Upturned nose
Mild mid facial hypoplasia
Long upper lip with thin Vermilion border
Distal digital hypoplasia
Important Information
At least 3 months washout period for phenytoin is required before planning Pregnancy. If woman presents with pregnancy and is already on phenytoin → do not discontinue
Related Previous Year Questions
Q. A pregnant woman was given indomethacin for treatment of pain. Which of the following can be a likely outcome in the baby? (NEET 2021)
A. Patent ductus arteriosus
B. Premature Closure of ductus arteriosus
C. Patent ductus venosus
D. Premature closure of ductus venosus
Answer: Premature Closure of ductus arteriosus
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