The birth control pill, or as often refered to as the pill, is just a pill. Although there are multiple brands and dosages, they are all just estrogen and progesterone. Except of course the mini-pill which is just progestrone and used for people
who can't take estrogen. Alesse, one of the lowest dosages available is still just as effective as the higer doses.
There can be side effects to the pill such as morning sickness, and lack of sex drive. Keep in mind that being on a lower dosage pill will prevent these symptoms.
And yes, as jennypaul said, no technically plan b is not an abortive because if you're pregnant you're pregnant, if taken under 72 hours after unprotected sex it will prevent the fertilization of the egg. So although it doesn't abort it
is in the same mindset of it - just preventing before it happens. It can also prevent an egg from sticking to the uterine lining, so there is a possibility that you could have a fertilized egg but the pill won't let it implant. (Which is why
although plan B says it's no abortive some people argue it's still classified as one).