Flexible Pregnancy Belly Button Ring. Body Jewelry made with a pregnant women in mind. Keep your piercing intact with this flexible pregnancy PTFE belly ring. The adjustable length pregnancy barbell will allow you adjust the piercing to your size.. Specifications: Flexible Self Threading 14 Gauge (1.6mm) PTFE Shaft, 2" Length, 316L Surgical Grade Stainless Steel Balls. Black Add on Charm Pregnancy Belly Ring