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Warfarin Pregnancy and Breastfeeding Warnings

Warfarin is also known as: Coumadin, Jantoven

Warfarin Pregnancy Warnings

Warfarin has been assigned to pregnancy category X by the FDA. Problems associated with perinatal administration of warfarin have included central nervous system defects, spontaneous abortion, stillbirth, prematurity, hemorrhage, and ocular defects when given anytime during pregnancy, and a fetal warfarin syndrome when given during the first trimester. Warfarin is considered contraindicated during pregnancy.

Limited data suggest warfarin fetal complications may be dose dependent. A study of 58 pregnancies with 31 healthy babies revealed an increased incidence of complications at dosages greater than 5 mg daily. Fetal warfarin syndrome is characterized by nasal hypoplasia, hypoplasia of the extremities, and developmental retardation. In a review of 418 reported pregnancies during which warfarin was administered, one-sixth resulted in fetal abnormalities, one-sixth resulted in abortion or stillbirths, and two-thirds resulted in normal infants. Nasal hypoplasia, varying in severity, is the most common feature of warfarin embryopathy. Epiphyseal stippling, primarily in the axial skeleton, proximal femurs, and the calcanei is present in the majority of cases. In addition, hypoplasia of the extremities, low birth weight, eye abnormalities (i.e. optic atrophy, microphthalmia, and blindness), and developmental retardation may be present. In one review, the common time of exposure was from the sixth to the ninth week of gestation in all 24 cases of warfarin embryopathy. Central nervous system abnormalities include dorsal midline dysplasia with agenesis of the corpus callosum, Dandy-Walker malformation, midline cerebellar atrophy, and ventral midline dysplasia with optic atrophy. Exposure time does not appear to play a role in the development of CNS anomalies. Cases have been reported in the absence of first trimester exposure. However, in one review, all cases of CNS anomalies involved second and/or third trimester exposure. Hall, et al (1980) reviewed and analyzed published cases involving coumarin use during pregnancy. A total of 418 pregnancies were evaluated. In 156 pregnancies, coumarin derivatives were used throughout pregnancy. Of these, 76% resulted in normal liveborn infants. Fetal complications, including spontaneous abortion, stillbirth, prematurity, CNS anomalies, embryopathy, and fetal hemorrhage, occurred in the remaining 24% of cases. In another literature review, Ginsberg and Hirsh (1989) documented 45 cases of warfarin embryopathy and 26 cases of CNS abnormalities out of 970 pregnancies in which warfarin was used. After excluding pregnancies with maternal comorbid conditions, analysis of cases in which oral anticoagulants were used alone revealed a 26.5% incidence of adverse pregnancy outcome. Again, use of warfarin between weeks six and twelve of gestation appeared to be associated with warfarin embryopathy. Forty-three women with mechanical heart valves, maintained throughout pregnancy on warfarin, and carrying out 58 pregnancies were observed. In the group of 25 pregnancies taking greater than 5 mg warfarin daily, 22 fetal complications and 3 full term pregnancies occurred. Complications included 18 spontaneous abortions, 2 warfarin embryopathies (spontaneously aborted in the 6 month), 1 stillbirth, and 1 ventricular septal defect (closed in the first year of life). The group of 33 pregnancies receiving less than 5 mg warfarin daily delivered 27 full term babies and 1 premature baby. Five fetal complications in this group included 4 spontaneous abortions and 1 infant with growth retardation (no skeletal, mental, or neurologic retardation, and now fully developed).

See references

Warfarin Breastfeeding Warnings

Orme, et al (1977) evaluated the excretion of warfarin into breast milk of 13 women treated with warfarin 5 to 12 mg per day. Warfarin was undetectable (< 0.08 mmol/L) in all milk samples. Seven women elected to continue breast-feeding their infants. Warfarin was undetectable in plasma samples from all seven infants. In addition, all seven infants had normal prothrombin times. McKenna, et al (1983) reported similar results. Two women who required warfarin anticoagulation after delivery and their infants were followed, in one case for 56 days and in the other for 131 days. Both women elected to continue to breast-feed. At no time was warfarin detected in the milk of either mother nor were any changes in prothrombin activity in either infant.

Based on limited data, warfarin has not been detected in human milk. However, changes in prothrombin time in breast-feeding infants of mothers treated with warfarin have been reported. The manufacturer recommends that caution be used when administering warfarin to nursing women.

See references

References for pregnancy information

  1. Ginsberg JS, Hirsh J "Use of antithrombotic agents during pregnancy." Chest 108 Suppl (1995): s305-11
  2. Sheikhzadeh A, Ghabusi P, Hakim S, Wendler G, Sarram M, Tarbiat S "Congestive heart failure in valvular heart disease in pregnancies with and without valvular prostheses and anticoagulant therapy." Clin Cardiol 6 (1983): 465-70
  3. Harrod MJ, Sherrod PS "Warfarin embryopathy in siblings." Obstet Gynecol 57 (1981): 673-6
  4. Chan WS, Anand S, Ginsberg JS "Anticoagulation of pregnant women with mechanical heart valves - A systematic review of the literature." Arch Intern Med 160 (2000): 191-6
  5. Koren G, Pastuszak A, Ito S "Drugs in pregnancy." N Engl J Med 338 (1998): 1128-37
  6. Ginsburg JS, Hirsh J "Use of anticoagulants during pregnancy." Chest 95 (1989): s156-60
  7. Hall JG, Pauli RM, Wilson KM "Maternal and fetal sequelae of anticoagulation during pregnancy." Am J Med 68 (1980): 122-40
  8. Ruthnum P, Tolmie JL "Atypical malformations in an infant exposed to warfarin during the first trimester of pregnancy." Teratology 36 (1987): 299-301
  9. Baillie M, Allen ED, Elkington AR "The congenital warfarin syndrome: a case report." Br J Ophthalmol 64 (1980): 633-35
  10. Normann EK, Stray-Pedersen B "Warfarin-induced fetal diaphragmatic hernia. Case report." Br J Obstet Gynaecol 96 (1989): 729-30
  11. Lecuru F, Desnos M, Taurelle R "Anticoagulant therapy in pregnancy - report of 54 cases." Acta Obstet Gynecol Scand 75 (1996): 217-21
  12. Kaplan LC, Anderson GG, Ring BA "Congenital hydrocephalus and Dandy-Walker malformation associated with warfarin use during pregnancy." Birth Defects Orig Artic Ser 18 (1982): 79-83
  13. Barker DP, Konje JC, Richardson JA "Warfarin embryopathy with dextrocardia and situs inversus." Acta Paediatr 83 (1994): 411
  14. Wong V, Cheng CH, Chan KC "Fetal and neonatal outcome of exposure to anticoagulants during pregnancy." Am J Med Genet 45 (1993): 17-21
  15. Iturbe-Alessio I, Fonseca MC, Mutchinik O, Santos MA, Zajarias A, Salazar E "Risks of anticoagulant therapy in pregnant women with artificial heart valves." N Engl J Med 315 (1986): 1390-3
  16. Cotrufo M, De Feo M, De Santo LS, et al. "Risk of warfarin during pregnancy with mechanical valve prostheses." Obstet Gynecol 99 (2002): 35-40
  17. Chong MK, Harvey D, DeSwiet M "Follow-up study of children whose mothers were treated with warfarin during pregnancy." Br J Obstet Gynaecol 91 (1984): 1070-3
  18. DiSaia PJ "Pregnancy and delivery of a patient with a Starr-Edwards mitral valve prosthesis." Obstet Gynecol 28 (1966): 496-71
  19. "Product Information. Coumadin (warfarin)." DuPont Pharmaceuticals, Wilmington, DE.
  20. "Product Information. Coumadin (warfarin)." DuPont Pharmaceuticals, Wilmington, DE.

References for breastfeeding information

  1. McKenna R, Cole ER, Vasan U "Is warfarin sodium contraindicated in the lactating mother?" J Pediatr 103 (1983): 325-7
  2. Committee on Drugs, 1992 to 1993 "The transfer of drugs and other chemicals into human milk." Pediatrics 93 (1994): 137-50
  3. De Swiet M, Lewis PJ "Excretion of anticoagulants in human milk." N Engl J Med 297 (1977): 1471
  4. Roberts RJ, Blumer JL, Gorman RL, et al "American Academy of Pediatrics Committee on Drugs: Transfer of drugs and other chemicals into human milk." Pediatrics 84 (1989): 924-36
  5. "Product Information. Coumadin (warfarin)." DuPont Pharmaceuticals, Wilmington, DE.
  6. Orme LE, Lewis PJ, Swiet M, Serlin MJ, Sibeon R, Baty JD, Breckenridge AM "May mothers given warfarin breast-feed their infants?" Br Med J 18 (1977): 1564-5

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