Sections View Full Chapter Figures Tables Videos Full Chapter Figures Tables Videos Supplementary Content ++Table Graphic Jump Location | Download (.pdf) | PrintFDA Classification of Medications during PregnancyCategory AAdequate and well-controlled human studies have failed to demonstrate a risk to the fetus in the first trimester of pregnancy (and there is no evidence of risk in later trimesters)Category BAnimal reproduction studies have failed to demonstrate a risk to the fetus and there are no adequate and well-controlled studies in pregnant womenOrAnimal studies have shown an adverse effect, but adequate and well- controlled studies in pregnant women have failed to demonstrate a risk to the fetus in any trimesterCategory CAnimal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risksCategory DThere is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience or studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risksCategory XStudies in animals or humans have demonstrated fetal abnormalities and/or there is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience, and the risks involved in use of the drug in pregnant women clearly outweigh potential benefits++Table Graphic Jump Location | Download (.pdf) | PrintAnesthetic MedicationsDosingFetal effectsInduction agentsDosing requirements are unchanged or mildly reduced for ultrashort-acting barbiturates and propofol (10–15%)Propofol TIVA: reduce dose by <10%Equilibration with fetal tissues is rapidFetal elimination strongly depends on reverse diffusion to motherIntravenous induction agents reduce fetal heart rate variabilityNarcoticsEndogenous endorphin production reduces exogenous opioid requirementPeripartum oxytocin release has been implicated in reduced narcotic requirementsRemifentanil has the shortest half-life in the newborn and has become a popular agent for labor analgesia when a neuraxial technique is contraindicated (usual starting dose is 0.03 μg/kg/min increased as needed to 0.1 μg/kg/min)Narcotics reduce fetal heart rate variabilityShort-acting rapid-onset opioids have been reported to cause fetal bradycardiaIntrathecal narcotic requirements are reduced by 30–50% when compared with nonpregnant patientsThere are no clear data for IV narcotic dose reductionSedativesBenzodiazepines are traditionally avoided in pregnant patientsDexmedetomidine has been reported for labor analgesia (insufficient data for assessment of safety of drug)Muscle relaxantsSensitivity to muscle relaxants is unchangedPseudocholinesterase activity is reduced by 30% in the pregnant patient; this has no effect on the onset and duration of succinylcholineNMBs do not cross the placenta in significant amountsMagnesium sulfate therapy may increase sensitivity to nondepolarizing NMB (no effect on succinylcholine)Neuromuscular reversal agentsDosing requirements are unchangedNeostigmine and glycopyrrolate do not cross the placentaAtropine crosses the placentaVolatile anestheticsMAC reduced by 30%Volatile anesthetics reduce fetal heart rate variabilityLocal anestheticsNerves are more sensitive to local anesthetic effect (faster block onset)Possible progesterone effect+... Your MyAccess profile is currently affiliated with '[InstitutionA]' and is in the process of switching affiliations to '[InstitutionB]'. Please click ‘Continue’ to continue the affiliation switch, otherwise click ‘Cancel’ to cancel signing in. Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Username Error: Please enter User Name Password Error: Please enter Password Forgot Username? Forgot Password? Sign in via OpenAthens Sign in via Shibboleth