Continued....
JoanK - thank you....TonyV argues from a non-scientific ideological meme position.  

Two other points:
a) many women do take BC for medical conditions e.g. endrometreosis
b) studies have proven that BC measures that are most effective actually can be expensive for low income folks.  E.G. implants work best but cost.  https://www.nytimes.com/2015/07/06/science/colorados-push-against-teenage-pregnancies-is-a-startling-success.html
Critical evaluation - another reputable, objective source:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4000282/

btw - posting one study from UK means little but it does actually support the reality that birth control (correctly used, implants for example, etc.) are necessary rather than the tired meme that we just skip BC because folks mis-use it.  Geez - sounds like the other failed UK stunt around vaccines and autism gambit.