She seems to have a strange attitude to it, never explicitly said she is against it.
But she got pregnant with Pearl seemingly by accident. Her and Liam were on/off when she found out she was pregnant, it was very early days.
And I think someone else posted earlier in the thread that Darcy was conceived in a sort of accidental way. Like not trying, but also actively not using birth control responsibly.
Though I feel like I can recall her making a video talking about using the morning after pill once. Though I might be wrong on that. So she isn't totally against birth control.