Dilation and curettage (also referred to as a D&C) is one of the most common procedures performed in the United States. The procedure can be applied to a pregnant or non-pregnant female and be either diagnostic or therapeutic. Sometimes the circumstances lead to the two overlapping, and the diagnostic procedure becomes therapeutic. The pregnant patient seeking a first trimester (< 14 weeks) elective termination or management of a missed, incomplete or inevitable abortion would be offered this surgical procedure or medical management. D&E (dilation and evacuation) refers to the procedure performed on a second-trimester pregnancy (>14 weeks) and is outside of the scope of this article. Three out of ten women will have an abortion by age 45, with the majority of these in an outpatient setting.
Medication abortions have increased in the last several years, but first-trimester aspiration procedures are still most common at 74%. History documents the first cervical dilators available in the early 19th century. Recamier is credited with the invention of the first curette in 1843, which resembled a small scoop or spoon with a long handle. The instruments have remained similar to the original dilators and curettes with small modifications through history. As the name implies, the 2 part procedure involves dilation of the cervix and curettage of the uterine cavity.
Anatomy and Physiology
The D&C removes tissue from the uterine cavity. In a non-pregnant female, the endometrial lining is sampled and sent for pathological evaluation. Standard of care recommends that hysteroscopy be performed with directed uterine sampling but if resources are unavailable, then perform the D&C with the submission of the tissue to pathology for diagnosis. Anatomically the cervix is the gateway to the uterine cavity. It is 3 to 4 cm long. The external os (the one visible in the vagina) and the internal os must be dilated to gain access to the uterine cavity.
The uterine cavity will vary in size depending on distorting features like fibroids and polyps and how far along the pregnancy is in gestation. There are 2 layers to the non-pregnant endometrial lining the stratum basalis and stratum functionalis. Removal of the stratum functionalis is the goal of the D&C, but it will not affect the hypothalamic-pituitary-ovarian axis in regard to ovulation and future menses.
The pregnant patient will have the pregnancy or products of conception removed from the endometrial cavity trying to avoid removing tissue beyond the decidua basalis layer. The decidua is formed with the transformation of the endometrial lining by steroid hormone. The decidua is divided into 3 layers. The decidual basalis is where implantation takes place, and the basal plate is formed; it’s also where the placenta will detach after birth. When performing the pregnant D&C, the surgeon will try to avoid the removal of tissue beyond this layer to prevent the potential for adhesion formation.
There are diagnostic indications as well as therapeutic indications for the D&C. Many diagnostic indications for the D&C have been replaced with office endometrial biopsy (EMB). D&C and EMB have been shown to reveal similar rates of cancer detection; however, there remain clinical scenarios where that is insufficient. Hysteroscopy (with directed sampling) followed by D&C is recommended but not required.
The patient’s intolerance of the EMB or tissue sample that returned insufficient for diagnosis would prompt the surgeon to perform a D&C. Cervical stenosis, and persistent abnormal bleeding or postmenopausal bleeding after a benign office biopsy warrants a D&C. D&C is indicated to exclude endometrial cancer in women diagnosed with endometrial intraepithelial neoplasia on office EMB. Finally, D&C should be used for the evaluation of chorionic villi in a patient who has a pregnancy of an unknown location. Therapeutically the D&C may be used in the non-pregnant patient with excessive bleeding who has failed medical management or become hemodynamically unstable. The D&C alone is inadequate for a full evaluation of the uterine disorder but provides a temporary reduction in bleeding.
Indications for the D&C in the pregnant patient include elective termination of pregnancy, early pregnancy failure, evacuation of a molar pregnancy, or suspected retention of products of conception. The pregnant D&C is usually performed with either manual or electric vacuum aspiration.
The only absolute contraindication to a D&C is the desire to maintain a viable intrauterine pregnancy. There are relative contraindications that should be contemplated to determine if the procedure should be performed in the outpatient clinical setting or the operating room. Patients with bleeding diathesis or that take anticoagulant medications could potentiate a problem in the outpatient setting, depending on your facility.
In general first trimester abortions performed on patients who are anticoagulated are considered safe and incur similar amounts of bleeding vs. patients not on anticoagulants. Holding these medications must be weighed with the severity of the patient’s disease state and why she is on the medication. Patients who have a clotting deficiency should have their clotting factors replaced prior to the procedure.
If the pregnancy is a suspected molar pregnancy, this should be performed in the operating room in order to control anesthesia complications and the potential for severe hemorrhage. A scheduled or elective D&C should be delayed in a patient with a known active pelvic infection. However, in the circumstance of a septic abortion or endometritis with possible retained products of conception, the surgeon should proceed with uterine evacuation.
Every provider needs dilators, curettes, and a type of aspiration instrument- either manual or electric.
The three most common types of dilators are steel Pratt dilators, Hank dilators, and Hegar dilators. Pratt dilators tend to be preferred as they have long tapered tips that allow the least amount of force. They come in sizes 9-79 F (French unit). Pratts are measured by French scale, and Hegars use the diameter of the dilator in millimeters as the size markings. The French unit is the diameter of the dilator in millimeters. If you divide the Fench unit by 3 (Pi), then you will have the diameter of the dilator in millimeters.
Hank dilators visually look like Pratt dilators with a cuff on them. They use French units, but the taper from the tip to dilation is sharper than Pratt dilators. There is an increased risk of perforation with this dilator set as many providers use the cuff as a stopping point and each cervix and even uterine cavity is different. Hegar dilators are short and have a blunt end. They increase in size rapidly, and more force must be used to dilate, which increases the risk of perforation. Overweight women or women with longer vaginal canals can be difficult to use this set of dilators as they won't sufficiently reach the entire cervical canal. There are no trials that have compared the safety or efficiency of these different dilator sets.
Curettes are both metal or plastic. The diagnostic D&C typically will utilize the sharp metal curette. They have a long handle with an open teardrop shape at the tip. They are available in a variety of sizes measured by the largest diameter at the tip. The curette with teeth is sometimes used in the postmenopausal patient for aggressive tissue sampling of the endometrium. Plastic curettes or cannulas are more commonly used in pregnant patients. These cannulas can be straight or curved and rigid or flexible. These cannulas are measured in millimeters, and typically, in the first trimester, abortion sizes between 7-12 mm are sufficient. The rigid plastic cannulas are slightly more difficult to place, so if the provider is using a Pratt dilator, they will dilate just past the chosen cannula size. In other words, if using an 8 mm cannula, then dilating to 25-26 Pratt dilator would be sufficient for placement.
Aspirators are either electric or manual vacuum aspirators (MVA). Where this procedure is performed, and space availability may determine which the provider will choose. The electric suction aspirator produces a negative pressure to quickly and efficiently empty the uterus and decrease bleeding. These machines tend to be loud and can increase anxiety in the patient. The MVA's are a handheld device that uses a large attached syringe to create the negative pressure. These can be very effective in the office but tend to take longer as multiple passes may be required as suction is absent when the syringe is filled and must be emptied.
If the patient requires IV sedation, then anesthesia personnel would be required. The provider with a single assistant is adequate for both electric aspiration or manual vacuum aspiration. The assistant may be used to collect the aspiration contents or provide ultrasound guidance if the clinician wants to utilize the ultrasound. A single provider can accomplish this procedure, but all providers must be supervised by a second party due to the nature of the exam.
Cervical preparation for the D&C can be considered. In general, some form of cervical preparation is recommended for any second-trimester procedure, also known as the D&E or dilation and evacuation but not necessarily with the first trimester D&C. There are traditionally 2 methods that can be considered, the osmotic dilators or the chemical ripening agents. Osmotic dilators, such as Laminaria and Dilapan-S, are established, safe, effective ways to dilate a cervix but require overnight placement. These agents are placed in the cervical os and absorb moisture from the cervix, slowly expanding and dilating the cervical os. Chemical agents used are prostaglandin analogs or progesterone antagonists, which soften or prime the cervix. Misoprostol, a prostaglandin analog, is the most common vaginally administered medication that is a safe and effective form of cervical preparation and can be administered the same day.
The progesterone antagonist, mifepristone, is as effective as misoprostol; however, its high cost and limited availability prohibit routine use. The Society of Family Planning does not recommend any cervical preparation for first-trimester abortions unless the woman is at increased risk of complications: cervical lacerations, inadequate cervical dilation, or uterine perforation. Cervical priming is timely and can have uncomfortable side effects. Later first trimester abortions (12 to 14 weeks), adolescents and in women whom cervical dilation may be challenging, such as one who has had a LEEP procedure, should, however, consider a priming agent.
The patient should be placed in a dorsal lithotomy position. A bimanual exam is done to assess the uterine size and position.
Vaginal preparation with an antiseptic solution is generally performed to reduce the risk of post-abortion infection. There is limited evidence that preparation with chlorhexidine or providone-iodine is superior to saline alone, but studies are inadequate. There is data to support that vaginal bacterial load is reduced when using the chlorohexidine solution, but this study was not powered to examine clinical outcomes.
Preoperative antibiotics lower the risk of post-surgical abortion in pregnant patients but have not been proven in non-pregnant patients. Routine procedures such as endometrial biopsies and hysteroscopy do not recommend antibiotic prophylaxis; therefore is not recommended for the non-pregnant D&C. Preoperative doxycycline is a safe and effective prophylactic for surgically induced abortions, whether used as a single dose or short perioperative course.
A bivalve or weighted speculum is placed in the vagina. If local anesthesia is being used, then injection of the cervix and lower uterine segment should be performed. Most commonly, 1% lidocaine is adequate. A tenaculum is used to grasp the anterior lip of the cervix and pulled towards the introitus with the non-dominant hand. The traction will stabilize the uterus and reduce the cervicouterine angle to decreases the risk of uterine perforation. Routine use of uterine sound for cavity length does not benefit the procedure unless the uterus was unable to be palpated on the initial exam.
If performing a diagnostic D&C in a non-pregnant patient, then an endocervical curettage is done and sent as a separate specimen prior to endometrial sampling so as not to contaminate the cervical specimen with endometrial cells. Otherwise, in all D&C’s initiate dilation of the cervix with the smallest dilator that will pass and sequentially increase dilator size. The dilator must pass through the external and internal os. Surgeons learn to identify this landmark with loss of mild resistance with gentle pressure. The dilator should be held with two fingers in the surgeon’s dominant hand as pressure should not be excessive; otherwise, the risk of uterine perforation. The extent of dilation will be determined by the amount of tissue to be removed and the size of the curette. After adequate dilation, then inserts the metal or plastic curette.
If suction is used, then apply manual or electric suction once the curette is inserted into the fundus of the uterus. The curette is applied to the walls of the uterus and pulled from the fundus to the cervix. Stay inside the uterine cavity while suction is applied to limit any cervical damage. Rotate the curette 360 degrees while proceeding with the repetitive vertical pass motion from the fundus to the level of the internal os covering the entire uterine cavity. A gritty texture indicates complete removal of the pregnancy or, in non-pregnant procedures, adequate sampling of the endometrium. In the pregnancy D&C, there should be limited to no bleeding from the os with total removal of the pregnancy, indicating completion.
If a gritty texture is present, but bleeding is seen, consider bimanual massage to treat possible atony, retention of products, or uterine or cervical injury. Ultrasound can be used to directly visualize the uterus while performing the procedure. In patients with an abnormal uterine cavity or difficulty dilating the cervix, the ultrasound may provide a safety measure to prevent injury.
The overall mortality rate associated with D&C is low. The rate is 0.6 per 100,000 legal induced abortions. To put this in perspective, the risk of death associated with childbirth is 14 times this rate. The risk of morbidity and mortality increases with increasing gestational age. Infection, hemorrhage, cervical lacerations, uterine perforation, and post-op uterine adhesions are complications associated with D&C in pregnant and non-pregnant patients. Overall infection rates are low at 1% to 2 %, and prophylactic antibiotic use is recommended in pregnant patients.
Infection rates are even rarer in non-pregnant patients, and prophylactic antibiotics are not recommended. Uterine perforation is the most common immediate complication in pregnant or non-pregnant D&Cs. Uterine perforation is more likely to occur at the fundus of the uterus, and risk factors are post-partum hemorrhage, post-menopausal status, nulliparity, and retroverted uterus. Uterine perforations rates increase in pregnant patients with increasing gestational age. Management of uterine perforation depends on when it occurred in the procedure. If there was a bowel present in the suction device and evidence of intrauterine bleeding, then completion of the procedure may need to be with direct visualization using laparoscopy or ultrasound.
Laparoscopy should be performed if there is suspicion for bowel injury or significant hemorrhage and suspicion of lateral wall perforation. Cervical injury or lacerations to the lip of the cervix typically occur when too much traction is applied to the cervix with dilation or manipulation. Most lacerations can be managed with pressure, silver nitrate, or ferric subsulfate. Occasionally suture ligation is needed. If there is an injury to the internal cervix canal again, pressure or suture should be used first. If there is no response, then consideration for balloon tamponade or embolization with further evaluation possible for abdominal or retroperitoneal bleeding.
Hemorrhage is extremely rare in the non-obstetric patient D&C. The surgeon should consider uterine perforation or cervical injury as the most likely cause in this setting and manage it appropriately. Hemorrhage is more common in the pregnant patient D&C and increases with increasing gestational age or being post-partum. Multiple etiologies must be considered when evaluating post abortion hemorrhage. Retained products of conception, uterine atony, abnormal placentation, and injury to the cervix or uterus can potentially cause significant hemorrhage.
Management should be specific to the etiology. Post-op uterine adhesions, Asherman syndrome, is rare but more common after a septic D&C. The patient may have symptoms of infertility, changes to her menstrual cycle, or pain associated with menses, and a diagnostic hysteroscopy is used to visualize the adhesions. Treatment can be difficult depending on the severity of the adhesions.
The dilation and curettage is a surgical procedure that provides an alternative for both pregnant and non-pregnant patients. If the pregnant patient desires an abortion, either elective or not, she has both medical and surgical options. (Medical options are generally limited to 10 weeks.) The surgical option with a D&C can control bleeding and pain more effectively. It will provide a timelier therapy than medical abortions. The results are similar, but the risks and benefits depend on individual patient risks and desires.
The non-pregnant patient can alternatively have a D&C or an office endometrial biopsy and an associated ultrasound to evaluate the uterine cavity and tissue. The latter can be falsely reassuring therefore concealing cancer until it is more aggressive or extensive in nature but allowing the patient to avoid the operating room. The D&C is a common procedure that has been a part of the OBGYN’s armament in their patients' care for over 100 years. This procedure will continue to provide similar answers and care for patients for years to come.
Enhancing Healthcare Team Outcomes
Effective clear communication with your patient and your team will improve patient outcomes. This procedure has clear risks and benefits to pregnant and non-pregnant patients. These must be made transparent in an informed consent process that allows the patient an opportunity to ask questions about all alternative options and associated issues.
Understanding these risks does not diminish the complications but allows the patient and physician to engage in shared-decision making. Abortion is a controversial topic; physicians and their staff must be aware of legal implications where they practice as well as discuss any ethical dilemmas that the physician and staff may face. These discussions should be held well in advance of any patient care, and no one should be asked to participate in any patient encounter if they are not comfortable with the care being provided. This is where interprofessional communication and collaboration in D&C cases are essential, both for the patient's benefit and the members of the healthcare team. [Level 5]
Hefler L,Lemach A,Seebacher V,Polterauer S,Tempfer C,Reinthaller A, The intraoperative complication rate of nonobstetric dilation and curettage. Obstetrics and gynecology. 2009 Jun; [PubMed PMID: 19461421]