Obstetrical forceps are a medical instrument designed to assist in a vaginal delivery when a mother requires help completing the second stage of labor. The instrument consists of two curved, spoon-shaped metal pieces positioned around the baby’s head to provide gentle guidance and traction. This tool has been recognized as a means to assist in childbirth for centuries. Modern forceps expedite birth when spontaneous delivery is not progressing safely, often acting as an alternative to a cesarean section.
Indications for Assisted Delivery
The decision to use forceps is based on specific clinical criteria. A major reason is a prolonged second stage of labor, which is the period from full cervical dilation until the baby is born. This stage is considered prolonged when a nulliparous woman, or a first-time mother, fails to deliver after three hours of pushing with a regional anesthetic, or two hours without one.
Maternal health conditions or exhaustion also necessitate an assisted delivery using forceps. Women with certain cardiac or pulmonary diseases may need to limit the physical strain of prolonged pushing to protect their own health. When a mother is too exhausted for effective pushing, forceps shorten the second stage and ensure a timely birth.
Fetal indications center on concern for the baby’s well-being in the final stages of labor. A non-reassuring fetal heart rate pattern, suggesting the baby is under stress and may not be receiving enough oxygen, is a common indication. If the baby’s head is low in the birth canal, a forceps delivery achieves a rapid birth more quickly than a surgical procedure. The procedure is only considered after the cervix is fully dilated, the membranes have ruptured, and the baby’s head is engaged in the pelvis.
Instrument Anatomy and Application
Obstetrical forceps are articulated metal instruments, each consisting of a blade, a shank, and a handle, connected by a lock. The blades grasp the fetal head and feature a cephalic curve to conform to the baby’s skull shape without undue compression. They also have a pelvic curve, which aligns the instrument with the natural arc of the maternal birth canal to facilitate smooth traction.
The shanks connect the blades to the handles and meet at a lock, which secures the two halves together once they are positioned around the fetal head. Some forceps, like the Kielland type, have a sliding lock to allow for small adjustments, which is particularly useful for correcting fetal head positioning. The handles allow the obstetrician to grip the instrument securely and apply controlled force during the delivery.
The application of forceps is classified based on how far the baby’s head has descended into the birth canal, measured by its station relative to the mother’s ischial spines. The clinician first assesses the exact position of the baby’s head, then carefully inserts each blade individually along the sides of the head, ensuring a proper fit. Once the blades are locked, controlled, gentle traction is applied in sync with the mother’s contractions and pushing efforts to guide the baby through the final stage of birth.
Types of Forceps Delivery
An outlet forceps delivery is the least difficult, used when the fetal scalp is visible at the vaginal opening and the head is on the pelvic floor. Low forceps delivery is performed when the leading bony point of the fetal head is at a station of +2 centimeters or lower. Mid-forceps delivery involves application when the head is positioned higher than +2 station, though this is now performed less frequently than the lower classifications.
Potential Maternal and Fetal Outcomes
A successful forceps delivery can avoid the need for an emergency cesarean section, thereby reducing the risks associated with major abdominal surgery. However, the use of forceps carries a specific set of potential outcomes for both the mother and the baby.
For the mother, the most common outcomes are perineal injuries, including vaginal or cervical lacerations that may be more severe than those from a spontaneous vaginal delivery. There is an increased risk of third- and fourth-degree perineal tears, which involve the anal sphincter muscles. Less common maternal complications include injuries to the urinary tract, such as the bladder or urethra, and an increased chance of postpartum hemorrhage.
For the baby, transient effects are the most frequent outcome, such as temporary bruising or marks on the face and scalp where the blades were applied. Some babies may experience a temporary facial nerve palsy, causing a slight drooping or weakness on one side of the face; this generally resolves spontaneously within days or weeks. More serious fetal complications are rare but include skull fractures, intracranial bleeding, or nerve injuries. These severe outcomes are typically associated with difficult deliveries or improper application, which is why prerequisites and operator training are highly emphasized before the procedure is attempted.