Day-specific pregnancy probability estimation in barrier contraceptive effectiveness trials

Area of Science:

• Reproductive health
• Contraception research
• Statistical modeling in clinical trials

Background:

• Understanding per-cycle day pregnancy risk is crucial for contraceptive efficacy.
• Previous models often lack precise ovulation timing, limiting accuracy.
• Female barrier contraceptives require robust efficacy evaluation.

Purpose of the Study:

• To estimate the probability of pregnancy per cycle day using barrier contraceptives.
• To evaluate the contraceptive effect of barrier methods, specifically the diaphragm.
• To adapt and apply a statistical model from fertility research to contraceptive trials.

Main Methods:

• Extension of a statistical model from fertility research.
• Application to data from a randomized trial of female barrier contraceptives.
• Estimation of pregnancy probability per cycle day, with and without barrier use.

Main Results:

• The per-cycle day pregnancy curve in the barrier trial mirrored previous fertility study findings.
• A strong contraceptive effect was observed for diaphragm use.
• The model successfully estimated pregnancy risk in relation to barrier contraceptive use.

Conclusions:

• The adapted statistical model provides reliable estimates of pregnancy probability.
• The diaphragm demonstrates significant efficacy as a barrier contraceptive.
• This modeling approach can be used to evaluate coitus-specific exposures in future fertility and contraceptive studies.