Drug Use During Pregnancy

Terms associated with pregnancy:

  • Gravida:  # of times a woman experiences pregnancy (twins is still counted as one pregnancy)
  • Parity:  # of a women’s pregnancies that exceed 20 weeks gestation
    • G4P3
      • May also relate info about the outcome in the following order:  full term deliveries, preterm deliveries, abortions, living children
        • G4P2113
  • Term:  37-42 weeks of gestation
  • Preterm:  contractions with cervical changes prior to the 37th week
    • Most common cause of early neonatal mortality
    • Infant mortality increases dramatically w/ delivery prior to week 28
    • The goal is postpone delivery by 24-48 hours
    • Treatment for preterm labor:  bed rest, fluids, antibiotics for Group B strept prophylaxis (Pen G, ampicillin), corticosteroids (betmethasone, dexamethasone), tocolytics (terbutaline, MgSO4, NSAIDs, CCBs)
      • Terbutaline (Beta-2 agonist) dose generally exceeds that used for asthma
        • SE:  tachycardia, arrhythmias, tremor, hypotension, pulmonary edema
        • Only use in patient for at most 72 hours
      • MgSO4 has SE of pulmonary edema
      • NSAIDs (indomethacine & ketorolac) have SE including premature constriction of the ductus arteriosus
      • CCBs:  Nifedipine is usually used
    • Prevention of premature labor:   supplement w/ progesterone or a progesterone analog as early as week 20 of labor b/c miscarriages & pre-term labor have been associated with low levels of progesterone
  • Pre-eclampsia:  pregnancy induced HTN (&/or proteinuria, blurred vision, abdominal pain, HA, thrombocytopenia (< 100,000), elevated LFTs)
    • Elevation in BP occurring after 20 weeks of pregnancy resulting in an elevation above 140/90 (either parameter)  or an elevation of 30 mmHg systolic or 15 mmHg diastolic above baseline
    • Prophylactic treatment:  ASA 50-150 mg/day, Ca supplementation
    • Treatment:  methyldopa (aldomet) is the drug of choic
      • Alternatives:  hydralazine (apresoline), labetalol, nifedipine
        • A lot of times IV labetalol & hydralazine are given to control the BP but if there isn’t a response within 24-48 hours then the baby should be delivered
      • Contraindications:  ACE-I, diuretics
    • Mild to moderate pre-eclampsia may be treated with bed rest
    • Hospitalization may be required for moderate to severe
      • Give MgSulfate 2-4 g IV bolus followed by 1-3 g IV/hr to maintain a serum concentration of 4-7 mEq/L
        • Respiratory depression may occur at concentrations of > 13 mEq/L & Cardiac arrest may occur at > 15 mEq/L
          • Reverse these adverse reactions with CaGluconate
      • Other complications of PIH/Pre-eclampsia:  DIC, HELLP Syndrome (Hemolysis, Elevation of Liver enzymes, Low Platelets)
  • Eclampsia:  pre-eclampsia + seizures
    • Treatment:  IV bolus of MgSulfate 5-6 g
  • Teratogen:  something capable of producing congenital abnormalities
    • Organ teratogenicity:  dose & time related
    • Perinatal complications:  physical or behavioral symptoms shortly after birth
    • Neurobehavioral effects:  long-term effects
    • Greater risk of organogenesis (structural malformations) in the 2nd through 8th weeks
      • The embryo usually isn’t susceptible to teratogens during the 1st 2 weeks of development but if they are affected by a teratogen, these affects are usually fatal

2nd & 3rd trimesters are less risky

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