You cannot expect a woman to allow every pregnancy to result in a baby if you are unwilling to help large families afford basic housing, utilities, food, healthcare, and other supplies required for an acceptable standard of living.
If women cannot afford reproductive health services and sex education, and they are expected to only have children they will be able to support financially, these services should be provided for them.
Increasing access to contraception and sex education will not encourage sex among teens. It will encourage sexually active teens to practice safe sex. Young people do not usually realize the consequences of unprotected and unsafe sex until they are forced to face them, so they will be sexually active whether or not they have contraceptives. Why not provide ways to prevent unplanned pregnancy and give women more control over their own bodies and futures?