Contraception
Volume 75, Issue 1 , Pages 16-22, January 2007

Efficacy and safety of a new 24-day oral contraceptive regimen of norethindrone acetate 1 mg/ethinyl estradiol 20 μg (Loestrin® 24 Fe)

This work was presented in abstract form in two publications [Abstract P-53 (Fertil Steril 2005;84:S169–S170) and Abstract P-56 (Fertil Steril 2005;84:S171)] at the 61st Annual Meeting of the American Society for Reproductive Medicine, Montreal, Quebec, Canada.

  • Steven T. Nakajima

      Affiliations

    • Division of Reproductive Endocrinology and Infertility, Department of Obstetrics, Gynecology and Women's Health, University of Louisville, Louisville, KY 40202, USA
    • Corresponding Author InformationCorresponding author. Tel.: +1 502 629 2441; fax: +1 502 629 2444.
    • ,
  • David F. Archer

      Affiliations

    • CONRAD Clinical Research Center, The Jones Institute for Reproductive Medicine, Eastern Virginia Medical School, Norfolk, VA 23507, USA
    • ,
  • Herman Ellman

      Affiliations

    • Warner Chilcott Inc., Clinical Development, Rockaway, NJ 07866, USA

Received 15 May 2006; received in revised form 1 July 2006; accepted 2 August 2006. published online 21 September 2006.

Abstract 

Background

New low-dose formulations of combination oral contraceptives (COCs) are safe and effective, but they may be associated with an increased risk of breakthrough bleeding. Extending the duration of active hormonal treatment may reduce the frequency of intracyclic bleeding/spotting while maintaining efficacy and tolerability.

Methods

This 6-month, open-label, randomized, active-controlled study involved healthy women aged 18–45 years who were at risk for pregnancy. Women were randomized 4:1 to a 24-day regimen of norethindrone acetate 1 mg/ethinyl estradiol 20 μg (NETA/EE-24) or to a 21-day regimen of the same combination (NETA/EE-21). The outcomes assessed included pregnancy and incidence, duration of bleeding and intensity of bleeding.

Results

The cumulative risk of pregnancy in the NETA/EE-24 group (n=705) was 0.9% during six cycles of treatment. Compared with NETA/EE-21 (n=181), NETA/EE-24 was associated with significantly fewer intracyclic bleeding days (0.95 vs. 1.63; p=.005), fewer days of withdrawal bleeding (2.66 vs. 3.88; p<.001) and fewer total bleeding/spotting days for Cycles 2–6 (18.6 vs. 23.2; p<.001). NETA/EE-24 was well tolerated, and side effects were generally mild to moderate in severity.

Conclusions

NETA/EE-24 is an effective well-tolerated COC that is associated with a bleeding profile more favorable than that of NETA/EE-21.

Keywords: Combination oral contraceptives, Ethinyl estradiol, Norethindrone acetate, Withdrawal bleeding, Intracyclic bleeding

To access this article, please choose from the options below

Login to an existing account or Register a new account.

  • Purchase this article for 31.50 USD (You must login/register to purchase this article)

    Online access for 24 hours. The PDF version can be downloaded as your permanent record.

  • Subscribe to this title

    Get unlimited online access to this article and all other articles in this title 24/7 for one year.

  • Claim access now

    For current subscribers with Society Membership or Account Number.

  • Visit SciVerse ScienceDirect to see if you have access via your institution.
 

PII: S0010-7824(06)00317-9

doi:10.1016/j.contraception.2006.08.004

Contraception
Volume 75, Issue 1 , Pages 16-22, January 2007

Article Tools

* Image Usage & Resolution