Abstract
There are many potential mechanisms of action for the intrauterine device (IUD), which
vary by type of IUD (inert, copper, or hormonal). This paper reviews the evidence
for each potential mechanism of action. On the basis of available data for fertilization
rates and clinical pregnancy rates, the relative contribution of mechanisms acting
before or after fertilization were quantitatively estimated. These estimates indicate
that, although prefertilization effects are more prominent for the copper IUD, both
prefertilization and postfertilization mechanisms of action contribute significantly
to the effectiveness of all types of intrauterine devices. (Am J Obstet Gynecol 2002;187:1699-708.)
Keywords
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References
- Biologic effects of intrauterine devices.Am J Obstet Gynecol. 1968; 100: 448-459
- The intrauterine device: contraceptive or abortifacient?.Minn Med. 1974; 57: 493-501
- Mechanisms of action of intrauterine devices.Obstet Gynecol Surv. 1996; 51: S42-S51
- The mode of action of IUDs.Contraception. 1987; 36: 37-53
- IUDs are contraceptives, not abortifacients: a comment on research and belief.Stud Fam Plann. 1989; 20: 355-359
- IUD mechanisms of action.in: Proceedings of the Fourth International Conference on Intrauterine Contraceptive Devices; 1994. Butterworth Heinemann1994
- Mechanism of action of intrauterine contraceptive devices and its relation to informed consent.Am J Obstet Gynecol. 1997; 176: 503-506
- Mechanism of action of intrauterine contraceptive devices [letter].Am J Obstet Gynecol. 1997; 177: 718-719
- Action of intrauterine contraceptive devices [letter].Am J Obstet Gynecol. 1997; 177: 720-721
- Mechanism of intrauterine device contraceptive action [letter].Am J Obstet Gynecol. 1997; 177: 976
- No evidence to support intrauterine contraceptive device and embryo destruction [letter].Am J Obstet Gynecol. 1997; 177: 980
- Intrauterine devices: mechanisms of action, safety, and efficacy.Contraception. 1998; 58: 45S-53S
- The intrauterine contraceptive device: an often-forgotten and maligned method of contraception.Am J Obstet Gynecol. 1999; 181: 1-5
- The mechanism of action of hormonal contraceptives and intrauterine contraceptive devices.Am J Obstet Gynecol. 1999; 181: 1263-1269
- The levonorgestrel intrauterine system in contraception.Steroids. 2000; 65: 693-697
- The potential postfertilization effect with use of the IUD.Am Fam Physician. 1999; 60: 761-763
- Informed consent: are we there?.J Perinatol. 1999; 19: 401-402
- Mechanisms of action, safely and efficacy of intrauterine devices.World Health Organization, Geneva1987
- Premature onset of menstrual bleeding during ovulatory cycles in women with an intrauterine contraceptive device.Am J Obstet Gynecol. 1973; 117: 957-971
- The biological actions of endouterine copper.Contraception. 1975; 11: 209-225
- Intrauterine contraception with the copper-T device, 3: effect upon endometrial morphology.Contraception. 1972; 6: 207-218
- Ovarian function after seven years' use of a levonorgestrel IUD.Adv Contracept. 1995; 11: 85-95
- The menstrual cycle in women using an intrauterine device.Fertil Steril. 1980; 34: 427-430
- Effect of levonorgestrel-releasing intrauterine device on hormonal profile and menstrual pattern after long-term use.Contraception. 1995; 51: 359-365
- Ovarian function in amenorrheic and menstruating users of a levonorgestrel-releasing intrauterine device.Fertil Steril. 1984; 41: 52-55
- Pituitary and ovarian function and clinical performance during the use of a levonorgestrel-releasing intracervical contraceptive device.Contraception. 1984; 29: 31-43
- Levonorgestrel-releasing IUD as a method of contraception with therapeutic properties.Contraception. 1995; 52: 269-276
- Effects of various IUDs on the composition of cervical mucus.Contraception. 1991; 43: 447-458
- Intrauterine contraception with the copper-T device: effect on trace elements in the endometrium, cervical mucus and plasma.Contraception. 1972; 6: 37-54
- Sperm migration in the female reproductive tract in the presence of intrauterine devices.Am J Obstet Gynecol. 1964; 88: 963-964
- Mode of action of the copper IUD: effect on endometrial copper and cervical mucus sperm migration.in: Proceedings of the Third International Conference on Intrauterine contraception; 1974 Dec 12-14; Cairo, Egypt Elsevier, New York1974
- The effect of a synthetic progestogen, ethylnorgestrienone, on hypothalamic-pituitary-ovarian function, cervical mucus, vaginal cytology, and endometrial morphology.Fertil Steril. 1981; 35: 284-288
- Cervical mucus and contraception.Semin Reprod Endocrinol. 1986; 4: 383-386
- Studies on copper release from copper-T devices (T-CU 200) and its influence on sperm migration in vitro.Contraception. 1974; 10: 651-666
- Progestin releasing intrauterine contraceptive device.in: Proceedings of the Fourth International Conference on Intrauterine Contraceptive Devices; 1994 Butterworth Heinemann, 1994
- Studies on the intrauterine contraceptive device.South Med J. 1966; 59: 589-592
- Effect of Lippes loop on sperm recovery from human fallopian tubes.Contraception. 1980; 22: 549-555
- Observations on spermatozoa in the human uterus and oviducts in the chronic presence of intrauterine devices.Am J Obstet Gynecol. 1966; 96: 114-118
- Proportions and their differences.in: 2nd ed. Statistics with confidence. MJ Books, Bristol (UK)2000: 45-56
- Effect of intrauterine devices on sperm transport in the human being: preliminary report.Am J Obstet Gynecol. 1975; 123: 734-735
- Sperm distribution and degradation in the human female reproductive tract.Obstet Gynecol. 1970; 35: 831-840
- Searches for ova in the human uterus and tubes, I: review, clinical methodology, and summary of findings.Am J Obstet Gynecol. 1966; 96: 157-167
- Effects of non-medicated and copper IUDs on sperm migration.Contraceptive Delivery Systems. 1983; 4: 203-206
- Studies on sperm migration in the human female genital tract.in: Hafez E Thibault C The biology of spermatozoa: transport, survival and fertilizing ability, Proceedings of the INSERM International Symposium, Nouzilly, November 4-7, 1973 Karger, Basel1975
- Studies on the duration of egg trasport in the human oviduct, I: the time interval between ovulation and egg recovery from the uterus in normal women.Fertil Steril. 1972; 23: 447-458
- Studies on the duration of egg transport by the human oviduct, II: ovum location at various intervals following luteinizing hormone peak.Am J Obstet Gynecol. 1978; 132: 629-634
- Studies on the duration of ovum transport by the human oviduct, III: time interval between the luteinizing hormone peak and recovery of ova by transcervical flushing of the uterus in normal women.Am J Obstet Gynecol. 1980; 137: 116-121
- New insights on the mode of action of intrauterine contraceptive devices in women.Fertil Steril. 1988; 49: 768-773
- Searches for ova in the human uterus and tubes, II: clinical and laboratory data on nine successful searches for human ova.Am J Obstet Gynecol. 1971; 109: 313-334
- Detection of fetal wastage.Fertil Steril. 1982; 37: 655-660
- Early pregnancy factor as a monitor for fertilization in women wearing intrauterine devices.Fertil Steril. 1982; 37: 201-204
- A study of early pregnancy factor activity in preimplantation.Am J Reprod Immunol. 1997; 37: 359-364
- Early pregnancy factor.Semin Reprod Endocrinol. 1992; 10: 72-82
- Rosette inhibition test: a multicentre investigation of early pregnancy factor in humans.J Reprod Immunol. 1982; 4: 251-261
- An update on the identity of early pregnancy factor and its role in early pregnancy.J Assist Reprod Genet. 1997; 14: 492-495
- Identification of early pregnancy factor as chaperonin 10: implications for understanding its role.Rev Reprod. 1996; 1: 28-32
- Detection of the early pregnancy factor (EPF) in the serum of patients with questionable pregnancy.Zentralbl Gynakol. 1987; 109: 968-973
- Early pregnancy factor (EPF) as a marker for the diagnosis of subclinical embryonic loss.Exp Clin Endocrinol. 1992; 99: 123-128
- The early pregnancy factor (EPF) in pregnancies of women with habitual abortions.Early Hum Dev. 1991; 26: 83-92
- Early pregnancy factor as a marker for assessing embryonic viability in threatened and missed abortions.Gynecol Obstet Invest. 1994; 37: 73-76
- Early pregnancy factor as a marker for the earliest stages of pregnancy in infertile women.Hum Reprod. 1988; 3: 113-115
- Early pregnancy factor (EPF) as a marker for detecting subclinical embryonic loss in clomiphene citrate-treated women.Am J Reprod Immunol. 1995; 33: 350-353
- Fertilization and early pregnancy loss in healthy women attempting conception.Clin Reprod Fertil. 1982; 1: 177-184
- Early chorionic activity in women bearing inert IUD, copper IUD and levonorgestrel-releasing IUD.Contraception. 1987; 36: 217-226
- Urinary human chorionic gonadotropin among intrauterine device users: detection with a highly specific and sensitive assay.Fertil Steril. 1987; 47: 265-269
- Incidence of early loss of pregnancy.N Engl J Med. 1988; 319: 189-194
- Mechanism of action of intrauterine devices: biochemical changes.Contraception. 1987; 36: 11-22
- Progesterone contraceptive system.in: Proceedings of the Fourth International Conference on IUDs; 1994 ···. ··· Butterworth Heinemann, 1994
- Endometrial morphological changes in IUD users: a review.Contraception. 1987; 36: 1-10
- Effect of intrauterine contraceptive devices on cytokine messenger ribonucleic acid expression in the human endometrium.Fertil Steril. 1995; 63: 773-778
- Interleukin-6 and tumor necrosis factor-alpha concentrations in the intrauterine cavity of postmenopausal women using an intrauterine delivery system releasing progesterone: a possible mechanism of action of the intrauterine device.Contraception. 1999; 59: 175-179
- Expression of 4B1 and vB3 integrins in the endometrium of women using the T200 copper intrauterine device.Fertil Steril. 2000; 74: 1102-1107
- IUD use and the risk of ectopic pregnancy: a meta-analysis of case-control studies.Contraception. 1995; 52: 23-34
- Extrauterine pregnancies and intrauterine devices reasessed.in: Proceedings of the Fourth International Conference on IUDs; 1994 ···. ··· Butterworth Heinemann, 1994
- Ovarian pregnancy and the intrauterine device.Am J Obstet Gynecol. 1970; 108: 1005-1009
- A multinational case-control study of ectopic pregnancy.Clin Reprod Fertil. 1985; 3: 131-143
- Grossesses extrauterines sur sterilet: caracteristiques et fertilite ulterieure.J Gynecol Obstet Reprod. 1991; 20: 1069-1073
- Ectopic pregnancy despite intrauterine contraception: a clue to mode of action of IUCDs.BMJ. 1975; 3: 467
- The effect of a levonorgestrel-releasing intrauterine device on human endometrial oestrogen and progesterone receptors after one year of use.Hum Reprod. 1999; 14: 970-975
- Morphological and functional features of endometrial decidualization following long-term intrauterine levonorgestrel delivery.Hum Reprod. 1998; 13: 1218-1224
- A morphometric study on the endometrial activity of women before and after one year with LNG-IUD in situ.Contraception. 1995; 52: 57-61
- Levonorgestrel-releasing intrauterine device-wearing women express contraceptive glycodelin A in endometrium during midcycle: another contraceptive mechanism?.Hum Reprod. 1997; 12: 2671-2675
- Endometrial morphology of women using a d-norgestrel-releasing intrauterine device.Fertil Steril. 1978; 29: 397-401
- Intrauterine devices.Curr Ther Endocrinol Metab. 1997; 6: 285-292
- The Copper T 380 IUD.in: Proceedings of the Fourth International Conference on IUDs; 1994 ···. ··· Butterworth Heinemann, 1994
- Prolonged intrauterine contraception: a seven-year randomized study of the levonorgestrel 20 μg/day (LNg 20) and the Copper T380 Ag IUDS.Contraception. 1991; 44: 473-480
- Risk factors for intrauterine device failure: a review.Contraception. 2001; 64: 33-37
- Contraceptive efficacy of the Copper T380A and the Multiload Cu250 IUD in three developing countries.Adv Contracept. 1994; 10: 137-149
- Contraceptive efficacy of the Copper T 380A and Copper T 200 intrauterine devices: results from a comparative clinical trial in six developing countries.Contraception. 1994; 49: 231-243
- Levonorgestrel-releasing intrauterine device.Ann Med. 1990; 22: 85-90
- Timing of sexual intercourse in relation to ovulation: effects on probability of conception, survival of the pregnancy, and sex of baby.N Engl J Med. 1995; 333: 1517-1521
- Day-specific probabilities of clinical pregnancy based on two studies with imperfect measures of ovulation.Hum Reprod. 1999; 14: 1835-1839
- A description of 34 human ova within the first 17 days of development.Am J Anat. 1956; 98: 435-494
- Intrauterine devices [letter].JAMA. 1990; 263: 235-236
- Intrauterine devices [letter].JAMA. 1990; 263: 236
- Action of intrauterine contraceptive devices [reply].Am J Obstet Gynecol. 1997; 177: 721
- Epidemiology of ectopic pregnancy.Epidemiol Rev. 1987; 9: 70-94
- Long term effects of injected progestogens on the morphology of human oviducts.J Reprod Med. 1972; 8: 288-292
- Sources of bias in studies of time to pregnancy.Stat Med. 1994; 13: 671-681
Article info
Publication history
Accepted:
July 2,
2002
Received in revised form:
January 2,
2002
Received:
October 24,
2001
Footnotes
☆Reprint requests: Joseph B. Stanford, MD, MSPH, Department of Family and Preventive Medicine, University of Utah Health Research Center, 375 Chipeta Way, Suite A, Salt Lake City, UT 84108. E-mail: [email protected]
Identification
Copyright
© 2002 Published by Elsevier Inc.
