2nd trimester induced abortion

(also known as termination of pregnancy)

The full guidance on 2nd trimester induced abortion has been published in the International Journal of Gynecology and Obstetrics 2007;99(supp 2):S178-81, and is available as a read-only pfd file here.

Recommended dosage for 13-22 weeks: 400 mcg vaginally 3-hourly (x5)

Regimens

A. 13-22 weeks: 400μg of vaginal misoprostol every 3 hours up to 5 doses. Studies have shown that the additional use of mifepristone shortens the induction-abortion interval and reduces the amount of prostaglandins required for the abortion. A randomized trial showed that when the women were given mifepristone, and the first dose of misoprostol was given vaginally, the subsequent doses could be given orally without affecting the efficacy. It has also been shown that 200 mg of mifepristone is as effective as 600 mg in termination of pregnancy in the second trimester. When mifepristone is available, 200 mg of mifepristone is given orally and 36-48 hours later 800 μg of misoprostol is administered vaginally followed by 400μg orally every 3 hours up to 4 doses. Further doses do not need to be given after complete expulsion of fetus and placenta.

Route: Randomized trials comparing oral versus vaginal misoprostol showed that vaginal misoprostol is more effective than oral misoprostol in inducing abortion. The incidence of side effects is also lower though more women prefer the oral route. It is not yet known whether subsequent doses of misoprostol can be given orally without affecting its efficacy if a higher dose of vaginal misoprostol is given as the first dose. The sublingual administration of misoprostol has also been compared with vaginal misoprostol but it appeared to be less effective for this indication. Therefore, vaginal administration of misoprostol is more effective than other routes of administration and the incidence of side effects is lower.

Dose: A randomized trial compared three regimens of misoprostol-alone administration: (a) 400 µg misoprostol 6-hourly (b) 200 µg misoprostol 6-hourly and (c) 600 µg misoprostol followed by 200 µg misoprostol 6-hourly. Results showed that 6 hourly vaginal administration of 400µg misoprostol is better than 200µg 6 hourly or 600µg followed by 200µg 6 hourly, as it is more effective than 200µg regimen and the incidence of side effects is less than that of 600µg regimen.

Interval: Two randomized clinical trials showed that the induction-abortion interval with 3-hourly vaginal administration of 400µg of misoprostol is significantly shorter than 6-hourly administration without significant increase in side effects.

There are many regimens of misoprostol reported in the literature with apparently good results. The regimens listed above have been found to be effective without excessive side effects or complications. Lower doses of misoprostol or less frequent administration are also acceptable though the induction-abortion intervals may be longer.

B. 23-26 weeks

It should be noted that most of the studies for this indication were conducted at the gestational age of 13 to 22 weeks. There is inadequate data to make any recommendations on the dosage and regimen for termination of pregnancy between 23 to 26 weeks. Since the uterus becomes more sensitive to prostaglandins with increasing gestational age, it would be wise to reduce the dosage and frequency of administration.

Course of treatment

Because of the potential for heavy vaginal bleeding and serious complications, it is advisable to conduct second trimester terminations of pregnancy in health care facilities where blood transfusion and access to emergency surgery (including laparotomy) are available.

At the initial evaluation, the woman should undergo a clinical assessment including history and clinical examination. The blood group including ABO and Rhesus typing should be checked. If the woman is Rhesus negative, 250-500 mcg of anti-D immunoglobulin should be given intra muscularly. Ultrasound examination is not necessary in the majority of women. It should be done when there is uncertainty about the diagnosis or gestational age.

Abortion may take place after any dose of misoprostol. With the regimen of a combination of oral mifepristone and vaginal misoprostol described above, the median induction-abortion interval is 5.9-6.6 hoursand 97% of the women will abort within 24 hours.

With the misoprostol alone regimen, the median induction abortion interval is 10-15 hours and 80-90% of the women will abort within 24 hours.

Before each dose the woman should be examined to see if she has already aborted. If not, assess the frequency and strength of uterine contractions. The next dose may be deferred if there are strong and frequent uterine contractions (>3 contractions in 10 minutes).

After the fetus is aborted, the placenta is usually expelled within a short time. If the placenta is not delivered within two hours, an infusion of 10 units oxytocin in 500ml of normal saline at a rate of 20-30 drops/min may be given to help the expulsion of the placenta. After expulsion, the placenta should be examined to see whether it is complete. If the placenta is incomplete, evacuation of the uterus may be needed. If the placenta is not delivered after infusion of oxytocin, or the woman starts bleeding excessively, evacuation of the uterus may be required.

After abortion, the woman should be observed in the hospital for at least 4 hours to monitor the vital signs and the amount of vaginal bleeding. If there is heavy vaginal bleeding, a careful speculum and pelvic examination should be performed to exclude the possibility of lacerations of the cervix. If there is no evidence of lacerations in the lower genital tract but the uterus is not contracting well, an oxytocin infusion may be given to stimulate the uterus to contract. If the bleeding persists despite the use of oxytocin infusion, the uterine cavity should be explored to see whether there are any retained products of conception.

During the recovery period in the hospital after the abortion, the woman may be provided with information on follow-up and contraception. All women should be followed up about two weeks after the abortion. The patient should be assessed for the amount of vaginal bleeding, and any signs of infection. The opportunity should be taken to discuss and advise on future methods of contraception. The contraceptive methods should be started as soon as possible.

If the woman fails to abort within 24 hours after the first dose of misoprostol and there are no significant side effects, a second course of misoprostol can be given beginning at least 12 hours after the last dose.

If the woman still fails to abort after the second course of misoprostol, other prostaglandins available in the center may be tried to induce the abortion. Alternatively infusion of a high dose of oxytocin or dilatation and evacuation may be considered. Caution should be exercised in using a combination of prostaglandins and infusion of high doses of oxytocin as over stimulation of the uterus may lead to rupture of the uterus.

These recommendations are produced by an expert group on misoprostol brought together by WHO in Bellagio, Italy in Feb 2007. These recommendations do not reflect official WHO guidelines, but have been released early so as to provide guidance to clinicians worldwide. The excerpt above is taken from:

PC Ho, PD. Blumenthal, K Gemzell-Danielsson, R. Gómez Ponce de León, S Mittal, OS Tang. Misoprostol for the termination of pregnancy with a live fetus at 13 to 26 weeks. International Journal of Gynecology and Obstetrics 2007;99(supp 2):S178-81.

Alternative guidelines for 2nd trimester abortion are available here.