Objective:

To measure the impact of an intervention on adolescents’ knowledge of the phase of the menstrual cycle with more likelihood of pregnancy and identify its associated factors.

Materials and methods:

A quasi-experimental study in two rural communities. Difference-in-differences analyses was performed.

Results:

There was a 22.1% average reduction in wrong answers on the phase of the menstrual cycle with more likelihood of pregnancy in the intervention group versus the control group (p<0.001). We founded six factors associated with this knowledge: marry and have children, right to receive education and information on sexual and reproductive health; gender equity; use of the condom; condom self-efficacy; emergency and contraceptive pills.

Conclusion:

There is a prevailing need to improve -among sexuality topics- basic knowledge of reproductive biology, while at the same time insisting on the benefits of using birth control methods provided for practicing responsible sexuality.