What is Forceps Delivery?
Forceps delivery is a form of assisted delivery or operative delivery where active measures are taken to accomplish vaginal delivery by means of an instrument known as the obstetric forceps. Simply, the forceps are used to help with the delivery of the baby through the vagina. This form of delivery has been an important part of obstetric practice for nearly 400 years. This procedure is best used by a skilled obstetrician only when there is a clear indication for its use. It aims to avoid a difficult vaginal delivery which may be harmful to the mother or baby.
The Obstetric Forceps
The obstetric forceps is an instrument designed to assist with the delivery of the baby’s head. It can either help to expedite delivery by providing traction, or by rotation of the head it may correct the position of the baby’s head in relation to the mother’s pelvis so as to facilitate easy delivery.
Parts of the Forceps
The obstetric forceps consists of 2 matched parts that when articulated or locked together can hold the baby’s head so as to provide traction without harming the baby. Each part of the metal forceps is made up of a blade, shank, lock and handle.
- Blade. The blades are spoon-shaped with the central portion missing in most types of forceps. The tip of the blade is called the toe. Each blade has 2 curves – the inner or cephalic curve is so designed as to fit comfortably around the side of the baby’s head, while the outer or pelvic curve can be aligned to the maternal pelvis. Kielland’s forceps have a reduced pelvic curve and are suitable for rotation.
- Shank. The shanks connect the blades to the handles and may vary in length in different types of forceps. They may lie parallel to each other or may cross when they lock. Wrigley’s forceps are short-shanked and are used to lift out the baby when the head is on the perineum. Long-shanked Neville Barnes forceps are used for higher deliveries.
- Lock. The lock is where the right shank comes atop the left so that the forceps articulate or lock together.
- Handle. The operator holds the forceps by the handle, which may have a finger guard on each side to prevent slipping when traction is applied.
Types of Forceps
Many different types of forceps have been designed, with various modifications in one or more of the basic parts. The ones most commonly in use are :
- Simpson forceps
- Elliot forceps
- Kielland forceps
- Piper forceps
- Wrigley’s forceps
- Neville Barnes forceps
- Bailey-Williamson forceps
- Tucker-McLane forceps
- Barton forceps
Methods of Forceps Delivery
The frequency of forceps deliveries has decreased in recent times since it is often safer for both mother and child to do a cesarean section than undertake a difficult forceps delivery. Failed forceps indicates an unsuccessful attempt at forceps delivery which ultimately leads to a cesarean section. Trial forceps is a cautious attempt to deliver with forceps if possible, but with the intent of abandoning the procedure if undue resistance is encountered.
The classification of forceps delivery approved by The American College of Obstetricians and Gynecologists (ACOG) was adopted in 1988 and uses the leading bony part of the baby’s head and its relationship to the mother’s ischial spines in centimeters as the point of reference. Accordingly, the methods of of forceps delivery includes :
Outlet forceps is the application of forceps when :
- The scalp is visible at the introitus (vaginal opening) without separating the labia.
- The fetal skull has reached the pelvic floor.
- The sagittal suture (the joint between the 2 skull bones in the center of the head) is in the anterior-posterior diameter, or in the right or left occiput anterior or posterior position.
- The fetal head is at or on the perineum.
- The rotation does not exceed 45 degrees.
Forceps delivery under these conditions may be done to shorten the second stage of labor – the time taken from full dilatation of the cervix till delivery of the baby.
Low forceps is the application of forceps when the leading part of the baby’s head is at station (relationship of the presenting part to an imaginary line drawn between the 2 ischial spines of the maternal pelvis) +2 cm or more and not on the pelvic floor. These are of 2 types :
- Rotation 45 degrees or less.
- Rotation more than 45 degrees.
Mid forceps is the application of forceps when the baby’s head is engaged (the widest diameter of the baby’s head passes through the brim of the pelvis) but the leading part of the skull is above station +2 cm.
Mid forceps delivery should only be attempted in case of sudden development of severe maternal or fetal complications, while at the same time preparing for a cesarean section should forceps delivery fail. Forceps delivery should not be attempted under any circumstances if the cervix is not fully dilated or the presenting part is not engaged.
High forceps is the application of forceps before engagement of the fetal head. High forceps delivery is rarely done nowadays and has been replaced by the use of cesarean section.
Conditions of Forceps Use
Forceps should only be used if the following conditions have been met with :
- The head must be engaged to a station below +2 cm.
- The membranes have been ruptured.
- There should not be significant cephalopelvic disproportion (the head too large to come out of the pelvis).
- The cervix is fully dilated and the uterus contracting.
- The position of the head is known.
- Suitable presentation, such as vertex or face.
- Adequate anesthesia, such as pudendal block, depending upon the type of forceps delivery.
- The bladder must be empty before application of forceps.
Indications for Forceps Use
Delay in Second Stage of Labor
Forceps are most commonly used when there is delay in the second stage of labor, such as in :
- Uterine inertia.
- Failure in maternal effort due to exhaustion.
- Epidural analgesia, causing diminished urge to push.
- Malposition of the fetal head.
Other Second Stage Complications
- Fetal distress.
- Cord prolapse.
To Avoid Undue Maternal Effort
- In cardiac disease.
- In respiratory disease.
- For the after-coming head in breech deliveries.
- Assisted delivery of preterm baby.
- Delivery of the head during a cesarean section.
- Assisted delivery with face presentation.
Contraindications for Forceps Use
- If the head is not engaged.
- Membranes not ruptured.
- Cervix is not fully dilated.
- Cephalopelvic disproportion.
Forceps Delivery Procedure
The mother is placed in lithotomy position (lying on the back, with the hips and knees flexed, thighs apart and the legs supported in stirrups) over the edge of the delivery bed. The vulva and perineum are cleaned with an antiseptic fluid and the bladder is emptied by a catheter.
The position of the head is confirmed by a pelvic examination and then the pudendal block is administered. The blades are assembled to verify that it fits. The lubricated left blade is inserted first and then the right, following the fetal and pelvic curve. The handles should lock easily. Traction should be given at the time of uterine contractions but it should not be excessive. A large episiotomy should be given when the head is at the vulva. Initially the pull should be downwards, and then gradually upwards and out as the head passes out of the vulva.
Video of Forceps Delivery
Complications and Risks of Forceps Delivery
- Injury to the mother’s pelvis.
- Vaginal tear.
- Cervical tear.
- Excessive bleeding.
- Extension of the episiotomy, leading to perineal tears.
- Rupture of uterus.
- Rupture of bladder.
- Late complications, such as fistula, and fecal and urinary incontinence.
- Facial bruising.
- Injury to the facial nerve.
- Facial nerve paralysis but this is usually temporary.
- Brachial plexus injury, leading to brachial plexus palsy or Erb’s palsy. It may arise from compression of the forceps blade in the fetal neck.
- Cephalohematoma (collection of blood under the periosteum covering the skull).
- Skull fractures.
- Intracranial damage.
- Intracranial hemorrhage.
- Cerebral palsy.
When applied properly, forceps rarely causes permanent injury to the baby. Many of the maternal and fetal complications may be avoidable with proper assessment of the case and recognizing the essential conditions for forceps delivery. It is always preferable to abandon a difficult forceps and resort to cesarean section and thus prevent avoidable complications of forceps delivery.
Article reviewed by Dr. Greg. Last updated on December 4, 2011