You say sex
ed is poor in the uk, I don't have the exact figures but I'm sure teen pregnancy rates have dropped in England over the past few years. They are working on improving sex education and teaching it from a younger age.
I know what you mean, a girl who went to my school had a baby last year. She broke up with the guy not long after and this year got pregnant again and got it aborted. I don't usually judge but all she seems to do is go out and get drunk. I never hear her talk about anything else. Ofcourse I'm not saying all teen moms are like this though some are actually a credit to themselves and work hard to make something of themselves despite becoming a young mum.
Edit: No amount of sex
ed will ever stop teenagers getting pregnant. It may make some more aware therefore safer in regards to sex. But there will always be a minority who will do what they want regardless of what you tell them.