A cervical block is a local anesthetic injection that numbs a specific area of the body, either around the cervix during gynecological procedures or around the neck nerves before surgery on that region. The term most commonly refers to a paracervical block, which targets the nerves surrounding the cervix and uterus to reduce pain during IUD insertions, biopsies, and other in-office procedures. Less commonly, it refers to a cervical plexus block, used to numb the neck area for surgeries like carotid artery repair.
Paracervical Block: The Gynecological Type
A paracervical block is the type most people encounter. It involves injecting a local anesthetic (typically lidocaine at a 1% concentration) into the tissue right next to the cervix, targeting a cluster of nerves that relay pain signals from the cervix and uterus. These nerves sit on either side of the cervix, and numbing them effectively blocks the sharp, cramping pain that many procedures cause.
During the injection, a thin needle is inserted at two points along the cervix, roughly at the 4 o’clock and 8 o’clock positions, to a depth of only about 10 millimeters. Most people feel a brief pinch or sting with each injection, followed by a spreading numbness. The actual injection takes under a minute, and providers typically wait a few minutes afterward for the anesthetic to fully take effect before starting the procedure.
Procedures That Use a Paracervical Block
Paracervical blocks are used across a range of gynecological procedures, particularly those performed in an office setting rather than an operating room. Common uses include:
- IUD insertion: especially for patients who haven’t previously given birth, where the cervix may be tighter
- Uterine aspiration: including early pregnancy procedures, where the block has strong evidence for reducing pain
- Endometrial biopsy: sampling the uterine lining for diagnostic purposes
- Cervical dilation procedures: such as placement of laminaria (cervical dilators) before a second-trimester procedure
- Hysteroscopy: inserting a small camera into the uterus
The American College of Obstetricians and Gynecologists recognizes paracervical blocks as effective for reducing procedural pain, particularly for uterine aspiration.
How Well It Works
Paracervical blocks meaningfully reduce pain for most patients, though they don’t eliminate it entirely. In a randomized controlled trial of adolescents receiving an IUD, those who got a lidocaine paracervical block reported a median pain score of 30 out of 100, compared to 71.5 out of 100 in the group that received a sham injection. Only 13% of the block group reported severe pain (above 80 on the scale), versus 40% in the sham group.
That difference is significant. A paracervical block roughly cuts perceived pain in half, turning what many describe as intense cramping into something more like mild to moderate discomfort. The block works best on the deep, cramping pain from the uterus and cervix. It does less for the initial discomfort of having instruments placed or the pressure of cervical manipulation.
What It Feels Like as a Patient
If your provider offers a paracervical block, here’s what to expect. You’ll be in the same position as a standard pelvic exam. A speculum is placed, and the cervix is stabilized. You’ll then feel one or two quick needle sticks on either side of the cervix. Some people describe this as a sharp pinch, others as a brief cramp. Within a few minutes, the area goes numb.
The numbness typically lasts long enough to cover the procedure itself, generally 30 to 60 minutes depending on the anesthetic used. As it wears off, you may feel mild cramping similar to period pain. Most providers recommend taking an over-the-counter pain reliever beforehand as a complement to the block.
Risks and Side Effects
Paracervical blocks are considered low-risk. The most common side effects are temporary: slight bleeding at the injection site, brief dizziness, or a sensation of warmth. Serious complications are rare but can include an allergic reaction to the anesthetic or, if too much medication enters the bloodstream, symptoms like ringing in the ears or a metallic taste in the mouth.
In obstetric settings, paracervical blocks have historically been associated with temporary changes in fetal heart rate. This concern, first documented decades ago, is one reason the block is used more cautiously during active pregnancy compared to other gynecological contexts. For non-obstetric procedures like IUD placement or biopsies, fetal heart rate is not a concern.
People with a known allergy to local anesthetics or an active infection at the injection site would not be candidates for the block.
Cervical Plexus Block: The Neck Type
A cervical plexus block is an entirely different procedure that shares only a name. It targets the cervical plexus, a network of nerves in the neck that originates from the second through fourth vertebrae. By injecting anesthetic around these nerves, surgeons can numb the front and side of the neck without putting a patient under general anesthesia.
The most common use for a cervical plexus block is carotid endarterectomy, a surgery to remove plaque buildup from the carotid artery in the neck. Keeping the patient awake during this procedure allows the surgical team to monitor brain function in real time by simply talking to the patient. Other uses include lymph node removal, thyroid surgery, and some plastic surgery procedures on the neck.
There are two variations: a superficial block that numbs the skin and surface tissues, and a deep block that reaches the nerves closer to the spine for more complete numbness. Recent applications have also extended to treating cervicogenic headaches, which are headaches originating from the neck. In these cases, the block serves both as a treatment and a diagnostic tool, helping distinguish neck-related headaches from migraines.
Why Your Provider May or May Not Offer One
Whether you receive a cervical block depends on the procedure, the clinical setting, and your provider’s practice. For gynecological procedures, not all providers routinely offer paracervical blocks, even though evidence supports their effectiveness. Some rely instead on topical numbing agents applied to the cervix or oral pain medication alone. If you’re having an in-office procedure and are concerned about pain, it’s reasonable to ask whether a paracervical block is an option. For neck surgeries, the anesthesia team will determine the best approach based on the specific operation and your medical history.