Teresa from Concord said:
Apparently if a woman has sex she a) immediately falls in love, and b) she’s pregnant. Than god I never lived in Westeros. I wouldn’t be Mother of Dragons but the Old Motherwho lived in a Shoe
6 syllables: She did not want to die.
Birth control of some form or another has existed throughout time. No doubt it exists in Westeros. Not that we've seen anyone use it!