Anestesia y embarazo

Local Anesthetic Use i n t h e Preg n a n t an d Postpartum Patient
Edgar P. Fayans, DDS*, Hunter R. Stuart, DDS, MS, David Carsten, DDS, Quen Ly, DDS, DMD, Hanna Kim,
KEYWORDS  Local anesthesia  Pregnant  Postpartum  Fetus
DDS

The use of systemically absorbed drugs in the gravid and in the lactating patient is of concern to the dentist. The need for interventional dental treatmentoccurs in virtually all stages of life, and during pregnancy is no exception. This article reviews concerns for the health and safety of the mother, developing fetus, and neonate involving local anesthetics. The effects of medications on successful pre- and postpartum human development and maternal health became evident in the 1960s when the drug thalidomide altered our awareness of maternal and fetaldrug complications. This article reviews available literature on the use of local anesthetics for dentistry in the pregnant and postpartum patient. In addition, the physiology of the pregnant and postpartum woman is reviewed because this is essential to understanding potential interplay with local anesthesia and the stress of a dental appointment.
FIRST TRIMESTER

Any discussion of the use oflocal anesthetics both during pregnancy and the postpartum period requires a brief explanation of teratogenicity (the capability of an agent to initiate fetal malformation) and mutagenicity. The specific definition of a mutagen involves an agent that can alter genetic material and increase the incidence of mutations compared with background levels. A teratogen is an agent that initiatesabnormalities of fetal development. The primary focus here is teratogenicity of local anesthetics. Birth defects occur in about 3% of live births each year in the United States, and have been the leading cause of infant mortality.1 Drug and chemical exposure is believed to be responsible for about 1% of these occurrences.2 Birth defects account for 20% of all infant deaths and are consequently the leadingcause of infant mortality in the United States. Extensive diagnoses or treatments of birth defects are required

Dental Anesthesiology Residency, Lutheran Medical Center, 150-55th Street, Brooklyn, NY 11220, USA * Corresponding author. E-mail address: efayans@hotmail.com Dent Clin N Am 54 (2010) 697–713 doi:10.1016/j.cden.2010.06.010 0011-8532/10/$ – see front matter Ó 2010 Published by ElsevierInc. dental.theclinics.com

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for 7% to 10% of all children,3 and approximately 65% of birth defects have no identifiable cause.4 Intrauterine vulnerability of the embryo led to the development and refinement of The Six Principles of Teratology, as found in Jim Wilson’s 1959 monograph Environment and Birth Defects. For our purposes, the principles that apply to teratogeniceffects are genotype, developmental stage, agent-specific actions, and fetal absorption.5–7 Early investigations were centered on gross deformities in animal models, but, for human studies, pregnancy registries serve as large prospective studies that record outcomes and provide information about possible risks of medications or exposures in pregnancies. Exposure to teratogens can result in a widerange of structural abnormalities such as cleft lip, cleft palate, dysmelia, anencephaly, or ventricular septal defect. In most cases, specific agents produce a specific teratogenic response. There is a long list of agents and environmental factors that has been discovered to be teratogenic, and commonly used local anesthetics have not been included. Teratogenic agents are categorized asradiation, infections, metabolic imbalances, drugs, or environmental chemicals. By the end of the first month of development following fertilization, the fetus has a closed neural tube, hematopoesis has begun, and a primitive heart is present.8 The embryonic period reaches from conception to the 10th gestational week, with the embryo then becoming a fetus and the first trimester culminating at the end of...