There has been considerable controversy over which method of second trimester abortion is safest, least stressful to patient and provider, and most cost effective. However, evidence demonstrates that dilatation and evacuation (D&E) performed by a physician experienced in gestations up to 16 weeks is safer than instillation abortion, and that both are safer than hysterotomy and hysterectomy.
Surgical Abortion: Dilatation and Evacuation
For gestations of less than 18 weeks, several osmotic dilators should be placed on the day before the procedure.
Beyond 18 weeks, serial sets of dilators (10 to 13) should be inserted over two days. A uterosacral block or paracervical block can be used at the time of insertion to decrease pain and facilitate the insertion of more dilators.
Misoprostol is an attractive agent because it is inexpensive, stable at room temperature, and easily applied either orally or vaginally. At 14 to 16 weeks’ gestation, buccal misoprostol (600 ìg) two to four hours prior to D&E can provide dilatation and softening for vacuum aspiration with a 14 mm curette or further dilatation.If misoprostol is administered vaginally more than four hours before the procedure, there is potential for unexpected delivery (greater than with osmotic dilators).
D&E can be performed safely under local anaesthesia (paracervical block) with intravenous conscious sedation and analgesia; however, a full range of anaesthetic options should be available. An outpatient setting may be preferable as this adds more individualized care, greater confidentiality, and fewer bureaucratic issues. The most important requirements for safe D&E are the speciality training, skill, and experience of the surgeon. If multiple or serial osmotic dilators are used it is usually unnecessary to dilate the cervix further. Up to 17 weeks’ gestation, the uterus can generally be evacuated with a number 16 curette or extraction forceps. After 17 weeks’ gestation, the amniotic fluid should be carefully and slowly emptied with a suction curette following which the POC should be removed with extraction forceps.
Various forceps have been designed to extract POC at late gestations. The type of forceps depends on the length of the gestation and the degree of cervical dilatation obtained. It is suggested that during forceps extraction the physician keep one hand on the fundus as a splint to reduce the risk of perforation. The procedure may also be performed under ultrasound guidance in an attempt to minimize the incidence of perforation.
The fetal tissue should not be removed forcibly through the cervix, as bone spicules may lacerate the cervix. Crushing and rotating techniques lessen cervical trauma.
After forceps extraction, the uterine cavity should be gently explored with a large curette to ensure complete evacuation.
The products of conception need to be examined for completeness.
Intravenous oxytocin (≥ 40 units/L) during the procedure or after uterine evacuation, as well as intracervical injection of vasopressin prior to the procedure (2 - 4 units mixed with local anaesthetic or diluted with 10 - 12 ml of saline), can reduce bleeding.
If bleeding seems to be heavier than expected, bolus oxytocin (intravenously) or intra-cervical vasopressin should be given alone or in combination.
Summary of Recommendations
Victoria Jane Davis, MD
These guidelines were reviewed by the Clinical
Practice - Gynaecology Committee and the Social and Sexual
Issues Committee and approved by the Executive and Council of
the Society of Obstetricians and Gynaecologists of Canada.