Contraceptive efficacy with NuvaRing vs two combined oral contraceptives-data from a pooled analysis 

Contraceptive efficacy with NuvaRing vs two combined oral

contraceptives-data from a pooled analysis 

H-J Ahrendt1, M Nap2, MZ


1Private Practice, Magdeburg, Germany, 2NV Organon, Medical

Services, Oss, Netherlands, 3NV Organon, Biometrics Department, Oss, Netherlands 

Background NuvaRing has previously been shown to be a highly effective

contraceptive (intent-to-treat [ITT] Pearl Index of 0.65) in a non-comparative

study [Roumen et al, Hum Reprod 2001; 16: 469-75]. Since then, NuvaRing’s

contraceptive efficacy has been studied in two comparative randomised trials vs

two different combined oral contraceptives (COCs) containing 30 mcg

ethinylestradiol (EE)-30 mcg EE/150 mcg levonorgestrel (Microgynon) and 30 mcg

EE/3 mg dropspirenone (Yasmin). 

Objective To further characterise contraceptive

efficacy in women using NuvaRing vs the COCs by performing a pooled data

analysis of two large randomised comparative trials. 

Design and methods Data

were pooled from the two randomised controlled trials comparing NuvaRing to

Microgynon and Yasmin, both of which had treatment durations of 13 (28-day)

cycles. The analysis comprised women from the ITT and the per protocol (PP)

cohorts (NuvaRing = 1011 ITT and 890 PP; Microgynon = 518 ITT and 459 PP; Yasmin

= 484 ITT and 450 PP). Inclusion and exclusion criteria and clinical report

forms used for data collection were similar for the two studies. 

Results A

total of 21,396 cycles (1640 woman-years) were available for the ITT analysis.

In total, six pregnancies were observed in the NuvaRing users, five pregnancies

in the Microgynon users and four pregnancies in the Yasmin users. The ITT Pearl

Index based on the pooled analysis of the two trials was 0.74 (95% CI:

0.27-1.60) for NuvaRing, 1.19 (95% CI: 0.39-2.79) for Microgynon and 0.99 (95%

CI: 0.27-2.53) for Yasmin. For the PP analysis of the pooled data (based on

17,921 cycles and 1374 woman-years), the Pearl Indexes were 0.64 (95% CI:

0.17-1.63) for NuvaRing, 0.53 (95% CI: 0.06-1.90) for Microgynon and 0.55 (95%

CI 0.07-1.98) for Yasmin. 

Conclusions The results of the pooled analysis of two

randomised comparative trials show that NuvaRing has comparable contraceptive

efficacy to two COCs containing 30 mcg EE (Yasmin and Microgynon)-even when both

imperfect and perfect use are taken into consideration. These results support

previous findings from a noncomparative study that show NuvaRing to be a highly

effective contraceptive.

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