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Acne and Pregnancy

Acne and Pregnancy

Posted by admin on February 2nd, 2000 — in newsletter

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Acne and Pregnancy

Vol 7#5, February 2000

Kathleen O’Connell, BA; Megan Shepard, BA; Kelly Ormond, MS, CGC; Eugene Pergament, MD, PhD, FACMG

A variety of medications are prescribed for the treatment of acne, some taken orally, others topically. When assessing the possible risk of these medications during pregnancy, the route of the exposure is important to consider. Topical creams and gels are less systemically available than medicines taken orally, ultimately meaning that the fetus is exposed to less of the medication. As with any decision about medication during pregnancy, the potential risks must be weighed against its benefits for the patient. Since there are various acne medications available, it may be possible for a woman to find a combination of medications that is both effective and does not put her pregnancy at risk for major malformations. This newsletter examines various medications used in the treatment of acne.

Common medications

Benzoyl Peroxide (Benzac, Benzamycin, Beroxyl, Desquam, Triaz, Vanoxide)

Benzoyl peroxide is a topical treatment for acne that has antibacterial effects and induces skin peeling. About 5% of each topical dose is absorbed sytemically. There are not any animal or human reproductive studies on benzoyl peroxide, and therefore its potential teratogenic risk is undetermined. However, benzoyl peroxide is commonly used, and there are no case reports about benzoyl peroxide and birth defects in the literature. This, combined with its topical exposure, provides some reassurance that the risk of malformations is likely to be low.

Hydrocortisone (Vanoxide-HC; w/ benzoyl peroxide)

Hydrocortisone is a corticosteroid used topically to treat acne and other dermatologic conditions. There have been no reproductive studies on topical exposures to hysdrocortisone specifically, and as such its risk in pregnancy is undetermined.

A literature review of oral cortisol exposures during pregnancy did not find an increased risk for malformations in the exposed group, but it was found that the exposed group did have an increased risk for prematurity and other complications for the mother and fetus (Aron et al., 1990). The doses in the studies reviewed were presumably much larger than a dose from a topical exposure. Fraser et al. (1995) surveyed 468 women exposed to all corticosteroids in general, and noted no significant increase in birth defects. However, this study did note an increase in cleft palate versus that expected (2 vs. 0.2). Because an increase in clefting has been observed in mice exposed to corticosteroids (Fraser et al., 1951), this finding is of potential concern.

Most other studies of oral and inhaled corticosteroids have not found a significant increase in birth defects or in clefts specifically (Czeizel and Rockenbauer, 1997; Fitzsimons et al., 1986; Rodriquesz-Pinella and Martinez-Frias, 1998; Schatz et al., 1997). Finally, a retrospective study by Czeizel et al. (1997) followed 191 women exposed to topical cortisone during pregnancy and found no significant increase in birth defects. In summary, although there is a potential connection between oral corticosteroids and cleft palate identified in the human and animal studies by Fraser et al. (1951 and 1995), it is unlikely that a topical exposure to hydrocortisone significantly increases the risk of birth defects, including oral clefts.

Salicylic Acid (Sal Ac)

Salicylic acid is used to treat acne, warts and other dermatological problems. There are no studies specifically looking at topical salicylic acid in pregnancy. Oral salicylic acid (aspirin) has not been associated with an increase in malformations if used during the first trimester, but use in late in pregnancy has been associated with bleeding, especially intracranial bleeding (Rumack et al., 1981). The risks of aspirin late in pregnancy are probably not relevant for a topical exposure to salicylic acid, even late in the pregnancy, because of its low systemic levels. Topical salicylic acid is common in many over-the-counter dermatological agents, and the lack of adverse reports suggests a low teratogenic potential.

Antibiotics/Anti-infectives

Erythromycin (A/T/S 2% acne gel, Benzamycin, Emgel, Erycette, T-Stat, Theramycin)

Erythromycin is an antibiotic that is commonly prescribed in pregnancy. Although often taken orally to treat infection, it is also used topically for acne. Erythromycin crosses the placenta minimally; the fetal blood concentration is only 2-10% of the maternal serum concentration, and the medication is quickly metabolized by the body.Takaya et al. (1965) found no increased malformations in mice exposed to 1-20 times the human dose. Human studies on erythromycin have all examined oral exposures. Retrospective studies of 79 and 6972 women exposed in first trimester had no significant increase in birth defects (Heinonen et al., 1977; Briggs, 1998). Jick et al. (1981) examined the prescription records of women exposed to erythromycin during the first trimester and also found no increase in birth defects (n=100-200). Because of these studies and the fact that this medication is commonly prescribed, it is generally assumed that topical erythromycin does not pose a significant increased risk for birth defects.

Clindamycin (Cleocin)

Clindamycin is an antibiotic related to erythromycin and available both orally and topically for the treatment of acne. It has been studied in both mice and rats at doses up to 180 mg/kg/day without teratogenic effects (Weinstein et al., 1976; Philipson et al., 1976).The retrospective Michigan Medicaid study identified 647 women exposed to clindamycin in the first trimester (both oral and topical exposures) and did not note an increased risk for major malformations. Furthermore, a study of 104 women exposed to clindamycin in the second and third trimesters did not suggest an increased risk for prematurity or placental complications (McCormack et al., 1987). This medication is unlikely to significantly increase the risk for birth defects in either its oral or topical form.

Tetracycline

Tetracycline is an antibiotic taken orally to treat acne. This medication belongs to a family of antibiotics that includes minocycline and doxycycline. The half-life of tetracycline is 11-22 hours, so most of the medication is removed from the body in 5 days.Two retrospective studies found no increase in the incidence of major malformations when women were exposed to tetracycline in the first trimester (Heinonen et al., 1977; Briggs, 1998). However, discoloration of deciduous teeth and the crowns of permanent teeth was seen in children who were exposed to tetracycline after the fourth month of gestation. Studies performed by Cohlan et al. (1961), Kline et al. (1964) and Kutscher et al. (1966) established that infants exposed to tetracycline in utero after the fourth month of gestation may have discoloration of deciduous (”baby”) teeth, cavities, and enamel hypoplasia in their teeth. It is believed that tetracycline causes dental discoloration and bone depression because it acts on the calcification process in development. The critical period for calcification begins at four months’ gestation and ends twelve months post-partum. Therefore, tetracyline should be avoided after the sixteenth week of gestation and throughout lactation.

The degree of dental staining appears to proportional to the dose of the medication (Egerman et al., 1992). Cohlan et al. (1961) also found that tetracycline caused long bone growth depression of 40% which normalized when the use of the medication was suspended.

Doxycycline and minocycline, two medications structurally-related to tetracycline, are also used to treat acne. These medications have not been as well-studied as tetracycline; it is, however, generally assumed that doxycycline and minocycline similarly affect the fetal calcification process. Therefore, these medications should also be avoided after the first trimester of pregnancy through the breastfeeding period.

Sodium Sulfacetamide (Sulfaset, Klaron, Novacet, Sebizon)

Sodium sulfacetamide is a topical anti-infective medication used to treat acne and seborrheic skin conditions. It belongs to the class of medications termed sulfonamides, and most reproductive studies examine sulfonamides as a class and in oral dosages, making it difficult to extrapolate the potential risk for a topical medication such as sulfacetamide.

The maternal use of sulfonamides near delivery can lead to newborn toxicity, resulting in anemia and jaundice and, theoretically, kernicterus, although this has yet to be documented in the literature. (Briggs, 1998). There have been two large retrospective studies of sulfonamide exposure, which involved 1445 and 3465 women exposed in the first trimester; neither study found an increased risk for malformations from the class in general (Heinonen et al., 1977; Briggs, 1998).

In contrast, other case controlled studies raised concerns about sulfonamide use in pregnancy. A 1971 case-control study by Nelson et al. determined the pregnancy exposures of 1369 patients, 468 of whom had babies with congenital malformations. They observed that significantly more mothers of the babies with birth defects took sulfonamides than the control mothers (Nelson et al., 1971). Saxon et al. (1975) looked retrospectively at 599 children born with oral clefts. The mothers of children with malformations in addition to the oral clefts were more likely to have taken sulfonamides than mothers of children with isolated oral clefts.

Because topical sulfacetamide has never been specifically studied to determine its potential teratogenic risk, one cannot definitively conclude that it does not cause birth defects. However, because it is topical and, for the most part, sulfonamides as a class do not appear to significantly increase the risk for birth defects, it is unlikely that topical sulfacetamide causes a significantly increased risk for malformations.

Breastfeeding while using sulfonamides is probably not a risk to a healthy infant. At most 1-2% of a maternal, oral dose of sulfonamides enters the breastmilk (Adair, 1938; Hac, 1939). However, sulfonamides can potentially cause anemia and jaundice in stressed, premature or hyperbilirubinemic infants. In addition, if an infant has G-6-PD deficiency breastfeeding should be avoided while taking sulfonamides , as sulfonamides act as oxidative stressors and can result in a hemolytic crisis.

Retinoids Isotretinoin (Accutane, Roaccutane)

Isotretinoin is an oral retinoid used to treat cystic acne. A known teratogen, this medication is contraindicated during pregnancy due to the characteristic malformations it causes. The pattern includes defects of the CNS, thymus, craniofacial and cardiovascular systems, as well as conotruncal malformations. Isotretinoin is thought to affect initial differentiation and migration of cephalic neural crest cells, and the critical period for this medication is 2-5 weeks post conception. Because the teratogenicity of Accutane is fairly well-known, we have chosen to focus upon other common acne medications in this review, rather than summarizing the literature about isotretinoin (for more details, see RISK/NEWSLETTER 3/96). Despite the half-life of approximately 1 day (manufacturer insert), due to the teratogenicity of this medication it is recommended that isotretinoin be discontinued at least one month prior to attempting pregnancy (Braun et al., 1984; Benke, 1984; Rosa, 1983; McBride, 1985; Rizzo et al., 1991).

Tretinoin (Avita cream, Retin A)

Tretinoin is a component of various topical acne creams. Because this medication is related to isotretinoin, there is concern that tretinoin could potentially have similar teratogenic effects on the fetus. Two case reports have described infants born to women using topical tretinoin during the first trimester of pregnancy. The infants had malformations that mimic the birth defects associated with isotretinoin (Camera et al., 1992; Lipson et al., 1993). In contrast, a prospective cohort study failed to find an association between birth defects and 215 women exposed to tretinoin in the first trimester (Jick et al., 1993). Shapiro et al. (1997) did not find a significant increase in number of livebirths, SAB’s, low birth weight, major malformations, duration of pregnancy, and cesarean sections in 94 women exposed to tretinoin versus controls.

A dose-response relationship potentially could play a role in the effects of tretinoin; it is of note that 5-31% of tretinoin is absorbed sytemically, depending on whether the skin is healthy or dermatitic. Although prospective studies have shown no increase in congenital anomalies, the case reports and biological plausibility of the anomalies raise concern about this medication. While such risks are likely to be low given the low topical absorption, health professionals should encourage women to weigh the risk and benefits of tretinoin during pregnancy.

Adapalene (Differin Gel)

Adapalene is a retinoid used in a topical gel form for the treatment of acne. As such, there are theoretical risks for retinoid embryopathy. However, the manufacturer reports that only trace amounts of adapalene are absorbed from the skin (trace is defined as less than 0.25 ng/ml). The manufacturer’s studies on pregnant rats and rabbits using doses 120-150 times the maximum human topical dose did not show an increased risk of adverse outcome or malformations. There has been one human case report of adapalene use during weeks 4-13 of pregnancy; the fetus had IUGR, anophthalmia and agenesis of the optic chiasm, and the pregnancy was aborted at 13 weeks (Autret et al., 1997). The anomalies seen in this pregnancy are not typical of those seen with other retinoid exposures. In addition, as with any case report, the malformations could be coincidental and unrelated to the adapalene. There have not been any other human studies or case reports to date. The overall risk of adapalene is undetermined because there have not been any human studies. However, because only trace amounts of the gel are absorbed into the skin, it is unlikely that doses large enough to induce malformations could reach a fetus.

Other medications

Azelaic Acid (Azelex)

Azelaic acid is a topical cream for acne. The manufacturer’s studies in animals do not show an increase in malformations at doses much higher than the maximum human dose. There have not been any human reproductive studies to date. While it is reassuring that animal studies do not show teratogenicity and that the fetal dose is small because the medication is topical, the risk of azelaic acid is undetermined because there have been no human studies.

Conclusions/Summary

In summary, acne medications present a range of risks during pregnancy. Because of its proven teratogenicity, it is well known that isotretinoin (Accutane) should not be taken during pregnancy. Additionally, tetracycline and its derivatives should not be used after 16 weeks gestation due to its effects on calcium-containing tissue, particularly teeth. The risks of other medications such as tretinoin are less certain, while some commonly used medications, like benzoyl peroxide, do not appear to pose a significant risk for malformations. Because of the widely known teratogenic effects of isotretinoin, many women are wary of acne medications in general during pregnancy. However, there are a wide variety of medications available for the treatment of acne, many of which pose a minimal risk if applied topically during pregnancy.

References

Adair (1938). JAMA. 111:766-70.Aron et al. (1990)

Autret et al. (1997). Lancet. 350:339.

Benke PJ (1984). JAMA. 251:3267-9.

Braun JT et al. (1984). Lancet 1:506-7.

Briggs et al. (1993). Drugs in Pregnancy and

Lactation 5th Ed. Williams and Wilkins, 1998.

Camera, G et al (1992). Lancet, 339:687.

Cohlan SQ et al. (1961). Antimicrobial Agents and

Chemotherapy. 340-7.

Czeizel and Rockenbauer (1997). Teratology. 56(5): 335-40.

Egerman et al. (1992). Obstet Gynecol Clin NA. 19(3):551-61.

Fitzsimons et al. (1986) J Allergy Clin Immunol 78:349-53.

Fraser et al. (1951). Pediatrics. 8:527-33.

Fraser et al. (1995). Teratology. 51(1):45-6.

Hac (1939). Am J Obstet Gynecol. 38:57-66.

Heinonen et al., Birth Defects and Drugs in Pregnancy.

Littleton, MA:Publishing Sciences Grp, 1977

Hill RM (1984). Lancet. 1:1465.

Jick H. et al. (1981). JAMA. 246(4):343-6.

Jick S et al. (1993). Lancet, 341:1181-1182.

Kline et al. (1964). JAMA. 188:178-80.

Kutscher et al. (1966). Am J Obstet Gynecol. 96:291-2.

Lipson AH et al (1993). Lancet, 341:1352-3.

McBride WG. (1985). Lancet. 1:1276.

McCormack et al. (1987). Obstet Gynecol. 69:202-7.

Nelson et al. (1971). BMJ. 1:523-7.

Philipson et al. (1976). Clin Pharm Ther. 19:68-77.

Rizzo R et al. (1991). Teratology. 44:599-604.

Rodriquez-Pinella and Martinez-Frias (1998)

Teratology 58:2-5.

Rosa FW. (1983). Lancet. 2:513.

Rumack et al. (1981). Obstet Gynecol. 58(Sup):52S-6S

Saxon et al. (1975). Int J Epidem. 4:37-44.

Schatz et al. (1997) J Allergy Clin Immunol 100:301-6

Shapiro L et al (1997). Lancet, 350:1143-4.

Takaya (1965)

Weinstein et al. (1976) Am J Obstet Gynecol. 124:688-91

Additional Useful Review Articles:

Duff, P. (1992). “Antibiotic use in Obstetrics andGynecology.” Obstet Gynecoly Clin NA 19(3).

Reed BR. (1997). Dermatologic drug use during pregnancy and lactation. Derm Clinics, 15(1):197-206.

Robert E and Scialli A (1994). Topical medications during pregnancy. Reproductive Toxicology 8(3):197-202.

Surgery and Pregnancy

Posted by admin on February 1st, 2000 — in newsletter

PDF Version

Surgery and Pregnancy

Vol 7#5, February 2000

Kim Kitson, BA; Kelly Ormond, MS, CGC; Eugene Pergament, MD, PhD, FACMG

Up to two percent of all pregnant women undergo surgery during pregnancy. Each year, thousands more women of reproductive age chronically inhale trace amounts of anesthetic gas while working in operating rooms and dental offices. The risks and benefits of possible surgery or occupational exposure must be carefully considered in any pregnancy. This RISK//NEWSLETTER will review the potential reproductive risks in women acutely exposed to anesthesia during surgery or chronically exposed to anesthetic gases in their occupation.

Surgery and anesthesia in pregnancy

Knowledge regarding the safety of surgery and anesthesia during pregnancy is based primarily on animal studies and retrospective human surveys conducted mostly in the 1970’s and early 1980’s. These studies have a number of confounding variables. Women are generally given multiple anesthetic agents and other agents (including analgesics, antiemetics and sedatives), making it difficult to discern the effects of individual agents. When surgery is combined with anesthesia, it is not possible to determine whether adverse outcomes are due to the operative procedure, the underlying maternal condition, maternal stress, fever or the anesthetic agent. While animal studies make it possible to separate the procedural risks from risks associated with the anesthesia exposure, even in animal studies, it remains difficult to determine if the observed effect is due to the anesthetic or to the physiological changes caused by anesthesia. Variations in genetic susceptibility also make it difficult to generalize these studies to humans because of interspecies variation.

Most human studies have not found a significant difference in the overall rate of congenital anomalies among women receiving general anesthesia while undergoing surgery (Knill Jones, 1972; Duncan et al., 1986; Mazze et al., 1989). Further analysis of the Mazze et al. study did note a significant increase in the incidence of neural tube defects (NTDs); six NTDs were observed while only 2.5 were expected. There were no indications that any one anesthetic was the cause of the NTDs, and researchers could not rule out other factors such as the underlying disease, the neuroendocrine events associated with the stress of surgery, or the trauma of the operation as the cause of the increased incidence NTDs. The authors report that the association could be a random finding because the observation developed as a result of searching a large data base, rather than as a consequence of testing a hypothesis regarding the effect of surgeries on NTDs. No other studies have found similar increases in NTD incidence, and as such, the association between NTDs and maternal surgery during the period of neural tube formation must be regarded as unproven (Kallen et al., 1990).

For women undergoing general anesthesia and surgery during pregnancy, aside from malformations, several studies have noted an increase in spontaneous abortions (Brodsky et al. 1980; Duncan et al., 1986), in infants with very low (<1500 gm) or low (<2500 gm) birth weights and in infant mortality (Mazze et al., 1989).

Occupational expsoure to anesthestic agents

Not unlike the confounding factors associated with surgery, occupational exposure studies are confounded by a number of factors, particularly that the control groups in these studies often consisted of non-working women. One study found that employed women had higher levels of education and income, earlier prenatal care, greater weight gain during pregnancy, and they were slightly less likely to be heavy smokers. Employed women were also had fewer previous births and more spontaneous abortions and stillbirths than their unemployed counterparts (Savitz et al., 1990). Factors such as standing, heavy lifting, long work hours and changing shift work may also contribute to the confounding biases of these studies.

Finally, it is important to note that these studies were performed in the 1970’s, when ventilation and scavenger systems in hospitals and dental operating rooms were not as efficient as those produced today; women in these studies were probably exposed to significantly higher levels of anesthetic gas than current workers. Nevertheless, a report in 1994, warning exposed workers of the potential harmful effects of nitrous oxide, was published by the United States National Institute for Occupational Safety and Health (NIOSH) (Boivin, 1997).

Common General Anesthetic Agents

Most human data available on individual anesthetic agents comes from the Collaborative Perinatal Project (Heinonen et al., 1977). Data are reported individually for each agent despite the fact that women in this study were probably given more than one anesthetic at surgery in every case. Consequently, the information available is difficult to interpret. Unfortunately, for many of these agents reproductive risk assessment is limited to this retrospective human data, coupled with minimal animal data. Friedman (1988) provides a comprehensive review of the available literature on a larger number of anesthetic agents.

Parenteral anesthesia

Thiopental

Thiopental is a rapidly acting barbiturate that has been used since the 1930s. In studies with rats and mice treated with 1.5-3 times the human dose, thiopental was not found to be teratogenic (Persaud, 1965). In a retrospective study of 152 women treated with thiopental during the first four months of pregnancy, there was no increase in congenital anomalies (Heinonen et al., 1977).

Methohexital

Methohexital is a short acting barbiturate. A manufacturer study using pregnant rabbits and rats found no increase in fetal abnormalities. Forty-one women treated with methohexital during the first four months of pregnancy did not result in a significant increase in the number of congenital anomalies (Heinonen et al., 1977).

Thiamylal

Thiamylal is an ultra-short acting barbiturate, similar to Thiopental. Treating pregnant mice with thiamylal resulted in an increase in limb anomalies, which sometimes are a sign of maternal toxicity (Friedman, 1988). Among the children of 21 women treated with this agent during the first four months of pregnancy, the frequency of congenital anomalies was not increased (Heinonen et al., 1977).

Etomidate

Etomidate is an imidazole hypnotic used for the induction of general anesthesia. In rats exposed to up to forty times the recommended human dose, the frequency of malformations was no greater than expected (Friedman, 1988). No epidemiological studies have been reported of women treated with etomidate during pregnancy having children with congenital anomalies, and therefore the risk associated with etomidate in human pregnancy remains unknown.

Ketamine

Rats exposed to ketamine at doses more than ten times those used in humans were not found to have an increased incidence of malformations (Friedman, 1988). No epidemiological studies have been reported of congenital anomalies in children born to women treated with ketamine during pregnancy, and therefore the risk associated with ketamine in human pregnancy remains unknown.

Inhaled anesthetics

Nitrous oxide

Growth retardation and malformations have been observed in the offspring of pregnant rats exposed to high or chronic doses or nitric oxide (Mazze et al., 1984). In contrast, other studies found that increased rates of resorptions (analogous to spontaneous abortion) but no increase in malformations in exposed rats (Mazze et al., 1982; 1984; 1986). The incidence of congenital anomalies among children of 76 women anesthetized with nitrous oxide during the first four months of pregnancy was no greater than expected (Heinonen et al., 1977). One study reports an association between use of this agent during the first trimester and an increased incidence of spontaneous abortion (Brodsky et al. 1980). A subsequent larger study did not confirm an increased incidence of spontaneous abortion among women treated with nitrous oxide (Mazze et al. 1989).

Halothane

Halothane is a halogenated hydrocarbon. Rodent studies initially found exposure to high or prolonged halothane concentrations to be associated with an increase in birth defects specifically involving the skeleton (Basford et al., 1968). Subsequent studies have not found an association between moderate doses of halothane in pregnant rodents and birth defects (Mazze et al 1986), and it is possible the malformations noted by Basford were due to maternal toxicity. The Collaborative Perinatal Project found that the frequency of congenital anomalies was not significantly increased among children of 25 women who received halothane during the first 4 months of pregnancy (Heinonen et al., 1977).

Enflurane

Among the offspring of rabbits treated with enflurane during pregnancy, limb and abdominal wall defects were observed more often than expected (Freidman, 1988). Pregnant mice exposed to anesthetic concentrations of enflurane had an increased frequency of cleft palate, ventriculomegaly, and hydronephrosis (Wharton et al., 1979). Other studies have not found enflurane during pregnancy to be associated with increased risk for birth defects (Mazze et al., 1986; Freidman, 1988). There are no epidemiological studies of congenital anomalies in children of women treated with enflurane during pregnancy, and therefore the risk associated with enflurane in human pregnancy remains uncertain.

Isoflurane

Pregnant mice exposed to light doses of isoflurane were found to have an increased frequency of cleft palate, skeletal variations and fetal growth retardation (Mazze et al., 1985). At doses similar to those used in humans, other investigators have not observed teratogenic effects among the offspring of pregnant rats or rabbits treated repeatedly with isoflurane (Kennedy et al., 1977; Mazze et al., 1986). There are no epidemiological studies reporting congenital anomalies in children born to women exposed to isoflurane during pregnancy. Therefore, its risk in human pregnancy remains undetermined.

Methoxyflurane

Offspring of rats and mice treated with methoxyflurane had an increase in skeletal anomalies in one study (Schwetz 1970). A subsequent study found no increase in the number of malformations among the offspring of mice treated with this agent during pregnancy, although fetal growth retardation and delayed skeletal development occurred (Wharton, 1980). No epidemiological studies of congenital anomalies in children born to women exposed to methoxyflurane during pregnancy have been reported, and its risk remains undetermined.

Local Anesthetics

Because local anesthetics are used by topical application or injection, their systemic absorption is often limited. In situations where systemic absorption by the mother is virtually absent, no significant teratogenic effect would be expected regardless of the potential teratogenic activity of the agent. The Collaborative Perinatal Project is the primary source of epidemiological data on possible teratogenic effects of local anesthetic agents. In addition to the previously discussed limitations, this study does not distinguish medicaitons by route of exposure. Therefore, topical application, local injection, regional infiltration and spinal infusion are all considered together. This study evaluated the possible teratogenicity of several local anesthetic agents including procaine, lidocaine, mepivacaine, benzocaine, propoxycaine, and tetracaine. Based on the limited information available, it seems unlikely that these topical agents are associated with a high risk of teratogenic effects in humans (Friedman, 1988).

Summary

Information regarding the safety of anesthesia and surgery during pregnancy is limited and confounded by many factors. In the case of surgery, it is important to weigh the risks and benefits of the procedure against any possible risks. Based on the information reviewed in this newsletter, there does not appear to be an increased risk for congenital malformations associated with anesthetic use. The possible association between anesthesia/surgery and a risk for neural tube defects is unclear and warrants further study. Occupational exposure to anesthetics has been shown to increase the risk of spontaneous abortion by 1.5 to two times the background risk. Given the methodological weakness of these studies, there is a possibility that this increase is coincidental. With all exposures, particularly occupational ones, it is best to limit the exposure as much as possible.

References

Basford A, Fink B (1968). Anesthesiology 29:173-4.

Boivin JF (1997). Occup Environ Med 54:541-548.

Brodsky JB et al (1980) Am J Obstet Gynecol 138:1165-7.

Cohen ENet al. (1971) Anesthesiology 34:343-347.

Duncan PG et al (1986) Anesthesiology 64:790-4.

Friedman, JM (1988). Teratology 37:69-77.

Källén B, Mazze RI (1990) Teratology 41:717-20.

Kennedy GL et al (1977). Drug Chem. Toxicol. 1:75-88.

Knill-Jones RP et al. (1972) Lancet 1:1326-1328.

Mazze RI, Källén B (1989) Am J Obstet Gynecol 161:1178-85.

Mazze RI et al (1986). Anesthesiology 64:339-44.

Mazze RI et al. (1982). Teratology 26:11-16.

Mazze RI et al. (1984). Teratology 30:259-265.

Savitz DA et al. (1990) Am J Epidem 132:933-45.

Tannenbaum TN, Goldberg RJ (1985) J Occup Med 27:9659-668.

Wharton RS et al. (1979)Teratology 19:53A.

Wharton RS et al. (1980) Anesth. Analg. 59:421-425.