Comparison of Serum Contraceptive Hormone Levels Between Normal Weight and Obese Users of the NuvaRing®

Not Applicable

Completed

Conditions: Pharmacokinetics

Interventions: Drug: NuvaRing

Registration Number: NCT00710606

Lead Sponsor: Columbia University

Brief Summary: There are over 60 million women of reproductive age in the U.S. and a majority of these women qualify as overweight or obese. Evidence suggests that there is an association between increased body weight and decreased contraceptive efficacy. Studies with the combined hormonal contraceptive patch (Evra®) and the subdermal contraceptive implant (Norplant®) demonstrate higher failure rates in heavier versus lighter women.

Weight related differences in the effectiveness of NuvaRing® need further study. A single secondary analysis of pooled data from Phase III clinical trials of NuvaRing® noted no difference in pregnancy rates among women in the highest weight decile (\>166#) versus the rest of the study population using the ring. (Westhoff, 2005) The finding of no difference, however, was influenced by too few obese subjects in the analysis which contributed to wide confidence limits. Additional studies are needed to explore how well the contraceptive ring functions to maintain effective serum steroid concentrations to suppress ovarian activity in obese women.

This investigation focused on evaluating mean serum concentrations of hormones released in obese and normal weight women using the NuvaRing® . This study was a prospective clinical trial. Normal weight women are defined as women with a BMI 19-24.9 and obese women are those with a BMI 30-39.9. We recruited forty adult women interested in initiating the combined hormonal contraceptive ring to two months of use to complete analysis of at least 34 subjects (17 normal weight, 17 obese). We compared mean serum concentrations of ethinyl estradiol (E2) and etonogestrel (ENG) along with additional markers for ovarian suppression. These markers included sonographic evidence of follicular development and ovulation as well as circulating E2 levels which strongly correlate with follicular development and endometrial proliferation during the second month of NuvaRing® use. Assessment of these parameters will translated to understanding contraceptive-mediated suppression of ovarian function in these two groups. Subjects also logged patterns of ring use and bleeding patterns during the study period.

Detailed Description: Not available

Recruitment & Eligibility

Status: COMPLETED

Sex: Female

Target Recruitment: 40

Inclusion Criteria

18-35 yo
Meet BMI requirements
Weight stable
English speaking
Desire contraception
History of regular menses with normal uterus and ovaries
Medically eligible for combined hormonal contraception
Tolerates phlebotomy/TVS

Exclusion Criteria

Exclusion:
Heavy smokers
Users of medications that alter hormone levels

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
1- Obese Women /Nuvaring	NuvaRing	Obese subjects (BMI 30-39.9)received two contraceptive hormonal rings. During the second cycle of ring use, subjects returned to the study site for serial serum hormone measurements and transvaginal ultrasound twice weekly during four weeks of continuous use.
2- Normal Weight / Nuvaring	NuvaRing	Normal weight subjects (BMI 19-24.9) received two contraceptive hormonal rings. During the second cycle of ring use, subjects returned to the study site for serial serum hormone measurements and transvaginal ultrasound twice weekly during four weeks of continuous use.

Primary Outcome Measures

Name	Time	Method
Mean Serum Concentrations of Etonogestrel and Ethinyl Estradiol	Measurements at Week 3 and Week 6 continuous ring use	Serum concentrations were obtained from thirty-seven women completed follow-up.

Secondary Outcome Measures

Name	Time	Method
Mean Endometrial Proliferation	Transvaginal ultrasound measurements of endometrial proliferation will be completed over continuous ring use, an average of 3 weeks	The mean endometrial proliferation from week 1, week 2 and week3
Number of Participants Achieving a Maximum Follicle Diameter > 13mm During the 3 Weeks of Follow-up	continuous ring use, an average of 3 weeks	Follicular development was minimal in both groups, with only five women achieving a maximum follicle diameter \> 13mm at any time during the 3 weeks of follow-up (3 normal weight and 2 obese women).