Hindi po siya fit, mama, Pigeon and Avent nipples have different collar sizes, kaya di sila compatible kahit paano mo icocouple. Maraming kaibigan ko na nag-try ng ganitong workaround and laging failed dahil hindi sila snug, plus may spillage pa, so better stick with Avent nipples na lang if you're going with Avent bottles. Pero if your LO is already happy with Pigeon, honestly try the Pigeon 9oz bottles instead para sure na walang adjustment period, mas makakatipid ka pa ng hassle, trust me!