Hi mama! From what I know, you need to be a member muna to claim maternity benefits, pero yes, you can open an SSS account kahit walang work, ask kung pwede ka mag-voluntary member since you're planning to get pregnant or expecting na. I'd suggest mag-visit ka sa nearest SSS branch or check their website directly para sa exact requirements ngayon kasi medyo nag-update na sila dati, but a few of us moms did manage to get in as voluntary members para ma-secure ang benefits, so definitely doable!