A number of surgical methods can be used to induce abortions. To end a pregnancy before it reaches eight weeks, a doctor typically performs a preemptive abortion or an early uterine evacuation. In both procedures a narrow tube called a cannula is inserted through the cervix (the opening to the uterus) into the uterus.
The cannula is attached to a suction device, such as a syringe, and the contents of the uterus, including the fetus, are extracted. Preemptive abortion uses a smaller cannula and is performed in the first four to six weeks of pregnancy. Early uterine evacuation, which uses a slightly larger cannula, is performed in the first six to eight weeks of pregnancy. Both types of abortions typically require no anesthesia and can be performed in a clinic or physician's office. The entire procedure lasts for only several minutes. In preemptive abortions the most common complication is infection. Women who undergo early uterine evacuation may experience heavy bleeding for the first few days after the procedure.
Vacuum aspiration is a procedure used for abortions in the 6th to 14th week of pregnancy. It requires that the cervix be dilated, or enlarged, so that a cannula can be inserted into the uterus. Progressively larger, tapered instruments called dilators may be used to dilate the cervix. During the procedure, the cannula is attached to an electrically powered pump that removes the contents of the uterus. In some cases, the lining of the uterus must also be scraped with a spoonlike tool called a curette to loosen and remove tissue. This procedure is referred to as curettage. Vacuum aspiration may require local anesthesia and can be performed in a clinic or physician's office. Minor bruising or injuries to the cervix may occur when the cannula is inserted.
Dilation and curettage (D&C), performed during the 6th to 16th week of pregnancy, involves dilating the cervix and then scraping the uterine lining with a curette to remove the contents. A D&C often requires general anesthesia and must be performed in a clinic or hospital. Possible complications include a reaction to the anesthesia and cervical injuries. Since the development of vacuum aspiration, the use of D&C has declined.
After the first 16 weeks of pregnancy, abortion becomes more difficult. One method that can be used during this period is dilation and evacuation (D&E), which requires greater dilation of the cervix than other methods. It also requires the use of suction, a large curette, and a grasping tool called a forceps to remove the fetus. D&E is a complicated procedure because of the larger size of the fetus and the thinner walls of the uterus, which stretch to accommodate a growing fetus. Bleeding in the uterus often occurs. D&E must be performed under general anesthesia in a clinic or hospital. It is typically used in the first weeks of the second trimester but can be performed up to the 24th week of pregnancy.
An induction abortion can also be performed in the second trimester, usually between the 16th and 24th week of pregnancy. In this type of abortion a small amount of amniotic fluid, the fluid that surrounds the fetus, is withdrawn and replaced with another fluid. About 24 to 48 hours later, the uterus begins to contract and the fetus is expelled. When this method was first developed, physicians used a strong saline (salt) solution to abort the fetus; today they may also use solutions containing prostaglandins or pitocin, a synthetic form of a chemical produced by the pituitary gland that induces labor. Heavy bleeding, infection, and injuries to the cervix can occur. This procedure is performed in the hospital and requires a stay of one or more days.
Abortions performed at the end of the second trimester and during the third trimester require major surgery. Two such late-term procedures include hysterotomy and intact dilation and extraction. In hysterotomy, the uterus is cut open and the fetus is removed surgically in an operation similar to a cesarean section, but a hysterotomy requires a smaller incision. Hysterotomy is major abdominal surgery performed under general anesthesia.
Intact dilation and extraction, also referred to as a partial birth abortion, consists of partially removing the fetus from the uterus through the vaginal canal, feet first, and using suction to remove the brain and spinal fluid from the skull. The skull is then collapsed to allow complete removal of the fetus from the uterus.