Contraceptive Efficacy and Comparative Side Effects of a Mini Copper Intrauterine Device

Courtney A. Schreiber; Kavita Nanda; David Hubacher; David K. Turok; Jeffrey T. Jensen; Mitchell D. Creinin; Katharine O. White; Ila Dayananda; Stephanie B. Teal; Pai Lien Chen; Beatrice A. Chen; Alisa B. Goldberg; Jennifer L. Kerns; Clint Dart; Anita L. Nelson; Michael A. Thomas; David F. Archer; Jill E. Brown; Paula M. Castaño; Anne E. Burke; Bliss Kaneshiro; Diana L. Blithe

doi:10.1056/EVIDoa2400480

Contraceptive Efficacy and Comparative Side Effects of a Mini Copper Intrauterine Device

Courtney A. Schreiber, Kavita Nanda, David Hubacher, David K. Turok, Jeffrey T. Jensen, Mitchell D. Creinin, Katharine O. White, Ila Dayananda, Stephanie B. Teal, Pai Lien Chen, Beatrice A. Chen, Alisa B. Goldberg, Jennifer L. Kerns, Clint Dart, Anita L. Nelson, Michael A. Thomas, David F. Archer, Jill E. Brown, Paula M. Castaño, Anne E. BurkeBliss Kaneshiro, Diana L. Blithe

Gynecologic Surgery and Obstetrics

Research output: Contribution to journal › Article › peer-review

1 Scopus citations

Abstract

BACKGROUND Intrauterine devices (IUDs) are highly effective, yet acceptability and continuation differ by user and device characteristics. We evaluated the efficacy of the NTCu380 Mini, a 380-mm² copper IUD available in Europe and Canada, and compared safety and continuation with the TCu380A IUD, the 380-mm² copper IUD available in the United States. METHODS We randomly assigned participants between 16 and 40 years of age in a 4:1 ratio to the NTCu380 Mini or TCu380A and assessed over 37 months. The primary outcome was NTCu380 Mini efficacy measured by the Pearl Index (defined as the number of pregnancies per 100 woman-years) in participants 35 years of age and under. Additional outcomes included NTCu380 Mini time to pregnancy by survival analysis, and comparative adverse events (AEs) and continuation rates of NTCu380 Mini versus TCu380A. RESULTS We randomly assigned 887 participants to NTCu380 Mini (744 [83.9%] nulliparous) and 218 to TCu380A (183 [83.9%] nulliparous), of whom 875 (98.6%) and 213 (97.7%), respectively, had successful placement. The NTCu380 Mini IUD 3-year cumulative Pearl Index was 1.86 (95% confidence interval [CI], 1.20 to 2.74) pregnancies per 100 women-years; the cumulative rate of pregnancy through year 3 was 4.8% (95% CI, 2.8 to 6.9%). Serious AEs occurred in 31 (3.5%) NTCu380 Mini and 4 (1.9%) TCu380A users (P=0.28). Discontinuation occurred in 449 (51.3%) NTCu380 Mini and 122 (57.3%) TCu380A users (P=0.07). AEs led to discontinuation less frequently among NTCu380 Mini (152 [20.8%]) than TCu380A users (57 [33.2%]) (P=0.001), particularly bleeding or pelvic pain AEs (103 [14.5%] vs. 46 [27.3%], respectively; P<0.001). CONCLUSIONS In this predominantly nulliparous population, the NTCu380 Mini IUD had an approximate 5% pregnancy rate over 3 years, with fewer side effects leading to discontinuation than observed among TCu380A users.

Original language	English
Journal	NEJM Evidence
Volume	4
Issue number	8
DOIs	https://doi.org/10.1056/EVIDoa2400480
State	Published - Aug 2025

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10.1056/EVIDoa2400480

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Schreiber, C. A., Nanda, K., Hubacher, D., Turok, D. K., Jensen, J. T., Creinin, M. D., White, K. O., Dayananda, I., Teal, S. B., Chen, P. L., Chen, B. A., Goldberg, A. B., Kerns, J. L., Dart, C., Nelson, A. L., Thomas, M. A., Archer, D. F., Brown, J. E., Castaño, P. M., ... Blithe, D. L. (2025). Contraceptive Efficacy and Comparative Side Effects of a Mini Copper Intrauterine Device. NEJM Evidence, 4(8). https://doi.org/10.1056/EVIDoa2400480

@article{ee3c1831eed1415e9bff92ab2d5b65df,

title = "Contraceptive Efficacy and Comparative Side Effects of a Mini Copper Intrauterine Device",

abstract = "BACKGROUND Intrauterine devices (IUDs) are highly effective, yet acceptability and continuation differ by user and device characteristics. We evaluated the efficacy of the NTCu380 Mini, a 380-mm2 copper IUD available in Europe and Canada, and compared safety and continuation with the TCu380A IUD, the 380-mm2 copper IUD available in the United States. METHODS We randomly assigned participants between 16 and 40 years of age in a 4:1 ratio to the NTCu380 Mini or TCu380A and assessed over 37 months. The primary outcome was NTCu380 Mini efficacy measured by the Pearl Index (defined as the number of pregnancies per 100 woman-years) in participants 35 years of age and under. Additional outcomes included NTCu380 Mini time to pregnancy by survival analysis, and comparative adverse events (AEs) and continuation rates of NTCu380 Mini versus TCu380A. RESULTS We randomly assigned 887 participants to NTCu380 Mini (744 [83.9%] nulliparous) and 218 to TCu380A (183 [83.9%] nulliparous), of whom 875 (98.6%) and 213 (97.7%), respectively, had successful placement. The NTCu380 Mini IUD 3-year cumulative Pearl Index was 1.86 (95% confidence interval [CI], 1.20 to 2.74) pregnancies per 100 women-years; the cumulative rate of pregnancy through year 3 was 4.8% (95% CI, 2.8 to 6.9%). Serious AEs occurred in 31 (3.5%) NTCu380 Mini and 4 (1.9%) TCu380A users (P=0.28). Discontinuation occurred in 449 (51.3%) NTCu380 Mini and 122 (57.3%) TCu380A users (P=0.07). AEs led to discontinuation less frequently among NTCu380 Mini (152 [20.8%]) than TCu380A users (57 [33.2%]) (P=0.001), particularly bleeding or pelvic pain AEs (103 [14.5%] vs. 46 [27.3%], respectively; P<0.001). CONCLUSIONS In this predominantly nulliparous population, the NTCu380 Mini IUD had an approximate 5% pregnancy rate over 3 years, with fewer side effects leading to discontinuation than observed among TCu380A users.",

author = "Schreiber, {Courtney A.} and Kavita Nanda and David Hubacher and Turok, {David K.} and Jensen, {Jeffrey T.} and Creinin, {Mitchell D.} and White, {Katharine O.} and Ila Dayananda and Teal, {Stephanie B.} and Chen, {Pai Lien} and Chen, {Beatrice A.} and Goldberg, {Alisa B.} and Kerns, {Jennifer L.} and Clint Dart and Nelson, {Anita L.} and Thomas, {Michael A.} and Archer, {David F.} and Brown, {Jill E.} and Casta{\~n}o, {Paula M.} and Burke, {Anne E.} and Bliss Kaneshiro and Blithe, {Diana L.}",

year = "2025",

month = aug,

doi = "10.1056/EVIDoa2400480",

language = "English",

volume = "4",

journal = "NEJM Evidence",

issn = "2766-5526",

publisher = "Massachussetts Medical Society",

number = "8",

}

Schreiber, CA, Nanda, K, Hubacher, D, Turok, DK, Jensen, JT, Creinin, MD, White, KO, Dayananda, I, Teal, SB, Chen, PL, Chen, BA, Goldberg, AB, Kerns, JL, Dart, C, Nelson, AL, Thomas, MA, Archer, DF, Brown, JE, Castaño, PM, Burke, AE, Kaneshiro, B & Blithe, DL 2025, 'Contraceptive Efficacy and Comparative Side Effects of a Mini Copper Intrauterine Device', NEJM Evidence, vol. 4, no. 8. https://doi.org/10.1056/EVIDoa2400480

TY - JOUR

T1 - Contraceptive Efficacy and Comparative Side Effects of a Mini Copper Intrauterine Device

AU - Schreiber, Courtney A.

AU - Nanda, Kavita

AU - Hubacher, David

AU - Turok, David K.

AU - Jensen, Jeffrey T.

AU - Creinin, Mitchell D.

AU - White, Katharine O.

AU - Dayananda, Ila

AU - Teal, Stephanie B.

AU - Chen, Pai Lien

AU - Chen, Beatrice A.

AU - Goldberg, Alisa B.

AU - Kerns, Jennifer L.

AU - Dart, Clint

AU - Nelson, Anita L.

AU - Thomas, Michael A.

AU - Archer, David F.

AU - Brown, Jill E.

AU - Castaño, Paula M.

AU - Burke, Anne E.

AU - Kaneshiro, Bliss

AU - Blithe, Diana L.

PY - 2025/8

Y1 - 2025/8

N2 - BACKGROUND Intrauterine devices (IUDs) are highly effective, yet acceptability and continuation differ by user and device characteristics. We evaluated the efficacy of the NTCu380 Mini, a 380-mm2 copper IUD available in Europe and Canada, and compared safety and continuation with the TCu380A IUD, the 380-mm2 copper IUD available in the United States. METHODS We randomly assigned participants between 16 and 40 years of age in a 4:1 ratio to the NTCu380 Mini or TCu380A and assessed over 37 months. The primary outcome was NTCu380 Mini efficacy measured by the Pearl Index (defined as the number of pregnancies per 100 woman-years) in participants 35 years of age and under. Additional outcomes included NTCu380 Mini time to pregnancy by survival analysis, and comparative adverse events (AEs) and continuation rates of NTCu380 Mini versus TCu380A. RESULTS We randomly assigned 887 participants to NTCu380 Mini (744 [83.9%] nulliparous) and 218 to TCu380A (183 [83.9%] nulliparous), of whom 875 (98.6%) and 213 (97.7%), respectively, had successful placement. The NTCu380 Mini IUD 3-year cumulative Pearl Index was 1.86 (95% confidence interval [CI], 1.20 to 2.74) pregnancies per 100 women-years; the cumulative rate of pregnancy through year 3 was 4.8% (95% CI, 2.8 to 6.9%). Serious AEs occurred in 31 (3.5%) NTCu380 Mini and 4 (1.9%) TCu380A users (P=0.28). Discontinuation occurred in 449 (51.3%) NTCu380 Mini and 122 (57.3%) TCu380A users (P=0.07). AEs led to discontinuation less frequently among NTCu380 Mini (152 [20.8%]) than TCu380A users (57 [33.2%]) (P=0.001), particularly bleeding or pelvic pain AEs (103 [14.5%] vs. 46 [27.3%], respectively; P<0.001). CONCLUSIONS In this predominantly nulliparous population, the NTCu380 Mini IUD had an approximate 5% pregnancy rate over 3 years, with fewer side effects leading to discontinuation than observed among TCu380A users.

AB - BACKGROUND Intrauterine devices (IUDs) are highly effective, yet acceptability and continuation differ by user and device characteristics. We evaluated the efficacy of the NTCu380 Mini, a 380-mm2 copper IUD available in Europe and Canada, and compared safety and continuation with the TCu380A IUD, the 380-mm2 copper IUD available in the United States. METHODS We randomly assigned participants between 16 and 40 years of age in a 4:1 ratio to the NTCu380 Mini or TCu380A and assessed over 37 months. The primary outcome was NTCu380 Mini efficacy measured by the Pearl Index (defined as the number of pregnancies per 100 woman-years) in participants 35 years of age and under. Additional outcomes included NTCu380 Mini time to pregnancy by survival analysis, and comparative adverse events (AEs) and continuation rates of NTCu380 Mini versus TCu380A. RESULTS We randomly assigned 887 participants to NTCu380 Mini (744 [83.9%] nulliparous) and 218 to TCu380A (183 [83.9%] nulliparous), of whom 875 (98.6%) and 213 (97.7%), respectively, had successful placement. The NTCu380 Mini IUD 3-year cumulative Pearl Index was 1.86 (95% confidence interval [CI], 1.20 to 2.74) pregnancies per 100 women-years; the cumulative rate of pregnancy through year 3 was 4.8% (95% CI, 2.8 to 6.9%). Serious AEs occurred in 31 (3.5%) NTCu380 Mini and 4 (1.9%) TCu380A users (P=0.28). Discontinuation occurred in 449 (51.3%) NTCu380 Mini and 122 (57.3%) TCu380A users (P=0.07). AEs led to discontinuation less frequently among NTCu380 Mini (152 [20.8%]) than TCu380A users (57 [33.2%]) (P=0.001), particularly bleeding or pelvic pain AEs (103 [14.5%] vs. 46 [27.3%], respectively; P<0.001). CONCLUSIONS In this predominantly nulliparous population, the NTCu380 Mini IUD had an approximate 5% pregnancy rate over 3 years, with fewer side effects leading to discontinuation than observed among TCu380A users.

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U2 - 10.1056/EVIDoa2400480

DO - 10.1056/EVIDoa2400480

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JO - NEJM Evidence

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