Cervical Priming - Methods, Advantages, Contraindications and Complications

Introduction

Surgical abortions are done at a later stage of pregnancy. Fetal health problems, congenital malformations, and health problems of the mother are the leading causes of such procedures. Maternal death during such procedures is the leading cause of death worldwide. Around 13 % of maternal death occurs due to post-operative complications. Also, such conditions are associated with post-abortion bleeding and severe cramps after the procedure. Similar complications can also be seen during other uterine surgical procedures. That is why reducing such complications is important to increase patients' comfort. Cervical priming is a procedure that decreases post-operative complications.

What Is Cervical Priming?

Cervical priming or cervical preparation is when the cervix is prepared for surgical procedures. In this technique, the dilation and softening of the cervix are done. This is done before the following procedures:

• Before surgical abortion at 20 to 24 weeks of pregnancy.

• Before surgical hysteroscopy for examination of the uterus and intrauterine structures.

• Before the myomectomy procedure to remove uterine fibroids.

• For retrieval of retained or embedded intrauterine devices.

What Are the Different Methods of Cervical Priming?

The cervical priming can be done through the following methods:

1. Mechanical Dilation: These are the early methods of cervical dilation. These methods are not much help, but they increase the chances of mortality and reduce post-operative complications. Devices like Pratt (a vaginal dilator) are used.

2. Osmotic Dilators: These are medical devices that are inserted into the cervix to dilate the uterine cavity. These devices absorb moisture from surrounding tissue and swell up. These devices are of three types:

• Laminaria: These are composed of seaweed stems. These substances absorb fluid, gradually expand, and help release endogenous steroids. These devices take 12 to 24 hours to attain full dilation.

• Dilapan: These are rod-shaped devices made up of hydrophilic polymers. These devices act faster than laminaria. One of the disadvantages of such materials is they are prone to fracture.

• Lamice: These materials are made up of polyvinyl sponge with magnesium sulfate. They act faster than any other osmotic dilator and dilate the cervix within 30 minutes. Apart from mechanical dilation, they also act via chemical dilation.

3. Ripening Agents: These drugs dilate the uterine cavity and soften uterine muscles. These agents are:

• Prostaglandins: Misoprostol is used as the first choice of drug in such cases. This is a prostaglandin E1 analog that is used in gastric ulcers. These drugs act on the smooth muscle cells in the uterine cavity. As a result, the frequency of contractions is increased. Also, this drug causes collagen degradation in the stroma's connective tissue and reduces the cervical tone.

• Anti-Progesterone: Mifepristone is the drug of choice in these cases. These synthetic steroids compete with progesterone and bind to the progesterone receptors much faster. This drug archives cervical dilatation and softening of uterine muscles without initiating contraction. The chances of initiation of labor with this drug are less.

What Are the Different Modes of Application?

Misoprostol can be administered via various routes. These are present in oral, sublingual, and vaginal gel forms.

• 400 micrograms of Misoprostol can be used sublingually or orally 3 hours before the procedure.

• 25 micrograms of Misoprostol can be administered vaginally every 4 to 6 hours for a maximum of 4 doses.

• A single dose of 400 micrograms can be applied vaginally.

• 200 milligrams of Mifepristone can be taken 24 to 48 hours before the surgery.

What Is Cervical Ripening?

Softening the cervix before the delivery is known as cervical ripening. This is a process of induction labor. This process is done through the application of the following methods:

• Prostaglandin E2: This increases the collagenase activity in the cervix. This is also responsible for the increased glycosaminoglycan, dermatan sulfate, and hyaluronic acid in the cervix. As a result, the intracellular concentration of calcium is increased. These factors are responsible for the relaxation of uterine smooth muscles. Dinoprostone is the only drug used in this case. 10 milligrams of the vaginal insert of this medication can be used. Apart from this, 0.5 milligrams in 2.5 milliliters of gel can be applied vaginally every 6 to 12 hours.

• Oxytocin: Injection of this hormone activates the phospholipase C-inositol pathway and increases intracellular calcium levels. This increases the contractile ability of the uterine smooth muscles. For this purpose, 2.5 units of oxytocin are mixed with 500 milliliters of dextrose solution and infused at the rate of ten drops per minute.

• Relaxin: Relaxin is another hormone helpful for the induction of labor. It decreases myometrial activity and helps to loosen the pelvic girdle (enclosing structure of the bony pelvis). As a result, the loosening of cervical muscles causes labor induction.

What Are the Advantages of Cervical Priming?

The advantages of cervical priming are:

• This procedure reduces post-operative pain.

• The chances of blood loss during and after the procedure is reduced.

• If cervical priming is done under local anesthesia, the amount of anesthesia can be kept low, which can be helpful to the patient and helps to reduce anesthesia-related complications.

What Are the Contraindications of Cervical Priming?

The contraindications of cervical priming include:

• It cannot be used in known cases of Misoprostol allergy.

• The ongoing case of a wanted pregnancy.

What Are the Complications of Cervical Priming?

• Mild abdominal pain.

• Mild vaginal bleeding.

The precautionary steps taken before the application of such medications are:

• Prior hospitalization is needed before consumption of oral Misoprostol. However, the vaginal application does not require this.

• Patients with a previous history of cesarean section should be treated cautiously.

Conclusion

Complications like excessive pain after abortion can be serious. Every 1 out of 8 women is losing life because of such complications. Cervical priming is an effective measure to soften uterine muscles. This procedure reduces peri and post-operative complications. Cervical ripening does not appear to have any long-term effects on your uterus and can assist in speeding up labor.