My Girlfriend got Pregnant when i was 15 and she was 16. We used protection. I was not completely surprised to find out as we had an active sex life (yes, i realise i was underage, but this has only been in the past 6 months, and police in the UK overlook anyone above 15) and had been together roughly 6 months ourselves. Unluckily for me I had just moved 35 miles away and so saw her less often. I told her that the kindest thing to do for all three of us (baby included) was to have an abortion. Yes, I would love to be a father someday, however today, this year, or even the next 10 years is not the time for me. My stepdad had his first child in his mid 40's and it still completely stuffed up his life.
The point I'm trying to make, is that me and this girl have broken up now. I realised that with me moving the relationship probably wouldn't last very long. At first she was adamant at keeping it, she eventually saw sense and had an abortion. It was tough on us both to do it, but also the kindest thing to do.
I believe most teenage girls in the UK have this romantic notion in their heads of having this child and all the nice stuff that go's with it, and non of the responsability. I know the reality being the eldest of five and the second eldest being 3.
It doesn't help that (and I hate to say this), a vast majority of pregnant teenage girls are fairly promiscious and believe that "If you pull out before you cum" or "if i'm due on my period" or "if i just came off my period" you arn't going to get pregnant. The threat is still there (admittedly less so) and protection should always be used, moreso to stop the risk of STI's. Also doesn't help that usually pregnant teenagers have parents that just don't care and probably will look after the baby themseleves and leave the teenager to go out drinking on the streets the day after.
And before people go off on rants. All these are based upon people I know/have known personally and discussed this with.