Some women have a flat or inverted nipple. The nipple is also inverted if it retreats when the woman tries to express milk by hand. If a woman intends to breastfeed, the doctor will examine the breasts during an antenatal visit, and if the nipples are flat or inverted, a nipple shield may be worn to correct the problem. The shield fits over the nipple drawing it out gently, making it protrude enough for the baby to feed. Stimulating the nipple by rolling it between finger and thumb, and exposing the breasts to fresh air (but not direct sunlight) may also help.