Does separation anxiety cause sleep regression?

Yes, these two are directly linked. Between 8-14 months, the development of object permanence — understanding "the thing I can't see still exists" — is the root of separation anxiety. When you leave during the day, she cries; when she wakes at night and doesn't find you, the same fear kicks in: "Mom left, will she come back?"

This is a developmental period, not a setback. Usually lasts a few weeks. Daytime short separations (step into another room, come back immediately, gradually extend) plus brief, matter-of-fact goodbyes — "I'm going, I'll be back" rather than dramatic exits — build trust. At night, instead of rushing to pick her up every time, use your voice to signal presence and wait 1-2 minutes for her to self-soothe. If it lasts over 3 weeks or daytime anxiety and appetite drop noticeably, check with your pediatrician.