Simpson forceps are surgical forceps that are used during childbirth. They are comprised of two metal handles for the physician to grip, a pelvic blade, a cephalic blade and the shank, where the blades meet the handles. Simpson forceps are often used when the child's head becomes elongated as he or she passes through the birth canal.
The blades of Simpson forceps are classified as either left or right blades. The left blade, also referred to as the pelvic curve, provides traction and conforms to the birth canal. The right blade is long and rounded. It is also referred to as the cephalic curve, and it conforms to the shape of the child's head.
At the point of articulation, where the blades cross, Simpson forceps have either a fixed lock mechanism or sliding lock mechanism. Simpson forceps feature an English lock that can be fully engaged only when the right shank overlies the left shank. Forceps with a fixed lock typically are used when the child's head requires little to no rotation. When the baby's head must be rotated, forceps with a sliding lock mechanism typically are used.
During the birthing process, an unborn child's head might change shape or become elongated as it moves through the birth canal. This is called molding. In this situation, the unborn child's head might become trapped within the birth canal and might not be able to fully emerge. Forceps, primarily Simpson forceps, can be used to guide the baby fully out of the birth canal.
When applying the forceps, the left blade usually is inserted before the right. The physician secures the blades around the unborn child's head, and the blades will lock into place. The physician is then able to guide the child down the birth canal. The physician might remove the forceps when the child is emerging or after the head has fully emerged. After delivery, the mother might require an episiotomy to repair tearing, and the child might have bruises on his or her head because of pressure from the forceps.