Zella Mamasana Live In Maternity Ankle Leggings in Black - they're a size XS and are NWOT. Still for sale for $69 at Nordstrom.

A stretchy, supportive panel expands with your growing bump in these lean, ankle-skimming leggings. Ideal for working out or wearing out and about, they're cut from a moisture-wicking Zeltek fabric and sewn with flatlock seaming for incredible comfort.

Over the belly
Zeltek moisture-wicking fabric dries quickly to keep you cool and comfortable
Smooth flatlock seaming won't rub or irritate
Body: 88% Polyester, 12% Spandex
Waistband: 77% Polyester, 23% Spandex
XS=0-2
Style: NR382159MI