Diaa M. El-Mowafi - Zagagig University, Egypt

Dilapan versus Prostaglandin E1 in Induction of Midtrimester Abortion

Diaa El-Mowafi, Nabil EL-Orabi, Ibtesam El-Arousi
Department of Obstetrics and Gynecology, Benha Faculty of Medicine, Egypt

Correspondence and reprints request: Diaa El-Mowafi M.D., 4 Ghazza St., El-Hosania, El-Mansoura 35111, Egypt. Tel. + 2 050 363308 Fax+ 2 050 332771

Abstract

This study included 30 patients with indications for second trimester abortion admitted to El-Galaa Hospital at a time between September 1996 and September 1997. Patients had been randomly classified into 2 groups, each containing 15 women. Dilapan dilators (one or two at most) were inserted into the cervical canal of patients in the first group. Vaginal Misoprostol (one tablet of 200 m g every 6 hours) was inserted in patients of the second group. The two methods were effective in induction of cervical ripening. Cervical dilatation was sufficient in all cases of the first group, but further dilatation was needed in 2 cases (13.3%) in the second group. Surgical evacuations were done in 10 patients out of 15 (66.7%) in the first group, and in 5 patients (38.5%) in the second group. Spontaneous uterine contractions were experienced in 6 patients (40%) in the first group and oxytocin administration was indicated in 5 patients (33.3%). In the second group, contractions experienced in 13 patients (86.7%) and oxytocin was used in 5 patients (33.3%). No side effects or complications were encountered in group I, while in group II vomiting, nausea, and fever were detected as one case of each.

Introduction

About 30 million abortions are performed worldwide each year (Henshaw, 1990), therefore the safety of the procedure is of global public importance. Midtrimester medical methods require further refinement in order to reduce the associated psychological and physical distress.

Dilapan synthetic dilator is composed of hydrophilic polyacrylonitrile which absorbs moisture through hygroscopic action drawing fluid from the cervical stroma with a resultant softening of the canal (Blumenthal, 1988). In addition to the mechanical effect, intracervical expansion may encourage the synthesis of endogenous prostaglandins (Kazzi et al, 1982).

The most recent cervical ripening compound tested for induction of labor and abortion is a prostaglandin E1 analogue misoprestol (15 deoxy-16 hydroxy methyl PGE1) which is manufactured for the treatment of peptic ulcer and marketed under the trade name «Cytotec». The first indication for its powerful uterotonic properties came from Latin America when it was utilized to terminate pregnancy (Toppozada et al, 1997).

Materials and Methods

The present study included 30 patients admitted to EL-Galaa Hospital from September 1996 to September 1997 for induction of midtrimester abortion.

Inclusion Criteria :

• Any age and parity.
• Sure indication of abortion.
• Estimated gestational age between 12-24 weeks as calculated from last normal menstrual period (LNMP) and confirmed by abdominal ultrasound.
• No uterine scar. · Intact membranes.
• No medical disorder prevents the usage of any of the medications in the study.

Exclusion criteria :

• History of cervical surgery or presence of cervical scarring.
• Uterine scar.
• Serious intercurrent illness as diabetes, hypertension, cardiac, renal, chest, liver, or blood diseases.

Complete history taking and examination were performed including measurement of blood pressure, pulse and temperature. Skin was examined for petichae or ecchymosis to exclude coagulation defects or blood diseases. The abdominal examination included detection of the size of the uterus (in cm above symphysis pubis), presence of scar of previous laparotomy, tenderness or rigidity. The local examination included detection of uterine size by bimanual examination, cervical dilatation, consistency, effacement, and position.

Each patient was investigated for hemoglobin content, Rh-typing, blood sugar level, Coagulation profile, renal function tests, and liver function tests.

Our 30 patients were divided into 2 groups, each containing 15 patients : In the first group, induction of abortion was started with Dilapan. In the second group, induction of abortion was carried out by prostaglandin E1 methyl analogue, Misoprestol (Cytotec 200 microgram tablet, Searle Company). It was given by vaginal route.

The vagina was prepared with Povidine iodine as an antiseptic, which was also used to moisten the dilators. A sterile speculum was inserted and after inspection of the cervix, the anterior lip was stabilized with ring forceps. Using gentle traction on the cervix, the Dilapan dilator was inserted into the cervical canal, the upper vagina was then packed with a sterile gauze to maintain the dilator in place. The dilators were left for a period not less than 6 and not more than 24 hours. After removal of the gauze, the Dilapan handle was grasped with forceps and removed with gentle steady downward traction on Dialpan loop itself. The cervical dilatation was measured by Hegar’s dilators and recorded. Surgical evacuation was then carried out under general anesthesia. In cases with gestational age more than 16 weeks, an oxytocin infusion was added to induce uterine contractions and expulsion of the contents. Failure was considered if dilatation of the cervix was not achieved, or if there was no response to oxytocin within 36 hours.

In the second group, the initial Bishop score was recorded and the minimal dose of one tablet (200 m g) was inserted deep in the posterior fornix. The dose was repeated every 6 hours till the products of conception are expelled. If remnants of conception were retained for more than 30 minutes, oxytocin drip was initiated starting with a minimal dose of 2.5 U in 500-ml glucose 5%. Failure of induction was considered if uterine contractions and start of expulsion had not occurred within 36 hours from initiation of therapy.

Clinical data were recorded in an investigative report form and Sudent’s (t) test was used to compare means. P value of < 0.05 was considered significant.

Results

There was no significant difference in the criteria of our patients in both groups (table 1). The commonest indication for induction of abortion was missed abortion in both groups (table 2). Intrauterine fetal death (IUFD) was considered when gestational age was 20 weeks or more. Multiple congenital malformations (MCMF) included meningocele, short limbs, fetal ascitis and other congenital anomalies. In group I, Dilapan was inserted in 15 patients for 12.5 hours (range, 8-22) (table 3). Cervical dilatation was measured by Hegar’s dilators, but when it exceeds 20 mm, cervicometry was done using abdominal ultrasound. Dilatation of the cervix was measured in 14 patients out of 15, because in one case an immediate expulsion of the uterine contents as an intact sac was noticed during bimanual examination after removal of the Dilapan, while the cervix was rapidly reformed again. Five patients in group I were pregnant more than 16 weeks, so oxytocin was used to accomplish expulsion of the contents. In group II, the mean Misoprostol dose was 666.7± 258.2 m g (range, 400-1200). The maximum dose to be given in 36 hours is 1200 m g as one tablet 200 m g every 6 hours, but it is not the maximum dose to induce abortion. The main time from start of the induction to the expulsion of the contents was 14.4± 5.1 hours (range,8-26) in group I, and 14.35± 3.1 hours (range,9.3-20). These include the time for cases required oxytocin infusion. There was no significant difference between the mean time in both groups (P > 0.05).

Table 4 shows that there was no need for further dilatation in the first group. Ten cases ended by surgical evacuation and 5 cases needed oxytocin with total of 14 cases (one case received both oxytocin and surgical evacuation while another case aborted spontaneously after dilatation without surgical evacuation or oxytocin). Complete and incomplete abortions were not criteria for the first group, as these are not expected to be an effect of the Dilapan. In the second group, if expulsion of the fetus was not followed by expulsion of the placenta and membranes for 30 min. Or still there were remnants, oxytocine drip was used but if failed or severe hemorrhage occurred, surgical evacuation of placenta or membranes was carried out. Uterine contractions were observed in 6 out of 15 patients (40%) in the first group and in 13 out of 15 (86.7%) in the second group. Cervical dilatation failed in 2 cases of group II where the cervix failed to respond within 36 hours of Cytotec application. One case responded after 48 hours with a dose of 1600 m g (8 tablets) while the other case failed to respond with the Cytotec treatment and Prostein E2 vaginal suppository was used for the induction after 120 hours We didn’t experience failure of dilatation in the first group with Dilapan. Side effects were seen in group II only in the form of vomiting in one case, nausea in another, and a fever of 38oC in a third one.

Discussion

It has been demonstrated that mechanical dilatation of the cervix for induction of abortion can cause cervical lacerations and uterine perforation (Moberg, 1996), leading to permanent alteration of the internal os of the cervix (Johnstone et al., 1974).

This study was done aiming to find out an effective method to induce second trimester abortion within a reasonable time and with the least possible cost and complications. Two different methods were tried ; Dilapan for cervical dilatation and ripening followed by surgical evacuation in one group and Misopristol (Cytotec) for induction of cervical dilatation and ripening as well as expulsion of pregnancy contents in the second group.

The ripening effect of Dilapan on the gravid cervix may be attributed to its osmotic effect on the cervix, affection of the collagen contents of the cervix (Blumenthal et al., 1990), and local prostaglandin release form the cervix (Bokström and Wiqvist, 1995). Prostaglandin might bring ripening by one of two mechanisms. Firstly, they could induce collagen breakdown due to increase collagenase enzyme. Secondly, they could alter collagen binding and tissue hydration by altering the glycosaminoglycans (GAG)/proteoglycan composition (Calder, 1980).

The main diameter of cervical dilatation by Dilapan in our study was 16± 6.3 mm which was enough to introduce the ovum forceps without resistance. This was consistence with other studies. Wells and Hulka (1989), found that the mean cervical dilatation with Dilapan was 16.5± 3.2 mm. Bokström and Wiqvist (1989), found that treatment of the cervix with 4 mm Dilapan during 3-4 hours or 3 mm Dilapan during 16-20 hours produced a cervical dilatation that allowed an easy evacuation of the uterus with minimal complications. In our study, spontaneous expulsion of the uterine contents as an intact sac occurred in one case of 14 weeks gestational age. The patient was a nullipara with no previous history of abortion, diagnosed as missed abortion. This may be explained by the release of endogenous prostaglandins which induced contractions as reported in the studies of Ölund et al., (1984) and Bokström and Wiqvist (1995). Borgida et al., (1995), studied termination of abnormal second trimester pregnancy using one of the natural prostaglandins (PG E2 suppositories) versus a PG analogue (15 M PG F2a ).Both drugs were given every 3 hours through vaginal and intramuscular route respectively. The mean time from start of treatment till delivery of the placenta was 13.5± 4.7 in PG E2 group and 22.6± 10.7 in 15 M-PG F2a group in that study. In the mean time, side effects experienced by the patients in both groups were relatively high in comparison with PG E1 in our study (table 5).

The mean time for induction of abortion with Misoprostol in our study was 14.35± 3.1 hours with a mean dose of 584.6± 15.9 m g (range, 400-800). The study of Bugalho et al., (1993) showed that the mean duration from application to expulsion was 11.8± hours with an initial dose of 800 m g, while the total dose ranged from 1200-1600 m g. In the study done by Rodger and Baird (1990), Gemeprost pessaries (another PG E1 analogue) were applied every 3 hours for termination of mid trimester pregnancy. The mean time needed for that was 15.8 hours, and in the study done by Thong et al., (1992) was 16.9 Hours.

In the present study, 5 cases (40%) in the Dilapan group had a gestational age between 18 and 24 weeks. Oxytocin infusion with a relatively high dose (30-40 iu/500 ml glucose 5%) succeeded in fetal expulsion within 4.5± 2.1 hours without water intoxication or other complications. In the Misoprostol group, 2 cases (13.3%) failed to abort within the designed time (36 Hours). One case of them (6.7%) aborted within 48 hours while the other one failed to respond even after 120 hours of sequential treatment with Misoprostol. In the study of Bugalho et al., (1993), 80.3% aborted within 36 hours, 11.4% aborted within 56 hours and 8.3 % failed to respond after 56 hours.

The total cost of Misoprostol treatment may be higher than Dilapan treatment due to the need for hospitalization in case of Misoprostol while Dilapan can be applied on an out patient basis.

Conclusion

Dilapan and Misoprostol, used through vaginal route, are effective methods for achieving cervical dilatation in the process of induction of midtrimester abortion. Both have minimal side effects and the complications of mechanical dilatation can be avoided.

References

1. Blumenthal P.D. (1988) : Prospect comparison of Dilapan and Laminaria for pretreatment of the cervix in second trimester induction of abortion. Obstet Gynecol 72 : 243-246.
2. Bokström H. and Wiqvist N. (1989) : Preoperative dilatation of the vervix at legal abortion with a synthetic fast-swelling hygroscopic tent. Acta Obstet Gynecol Scand 68 :313-318.
3. Bokström H. and Wiqvist N. (1995) : Prostaglandin release from human cervical tissue in the first trimester of pregnancy after preoperative preparation with hygroscopic tents. Prostaglandins 50 : 179-188.
4. Bugalho A., Bique C., Almeida L., and Bergström S., (1993) : Pregnancy interruption by vaginal Misoprostol. Gynecol Obstet Invest 36 :226-229.
5. Calder A.A.(1980) : Pharmacological management to the unripe cervix in the human. In Naftolin, F. and Stubblefield, P.G. (eds.) Dilatation of uterine cervix, New York, Roven Press, P. 317.
6. El-Refaey H. and Templeton A. (1995) : Induction of abortion in the second trimester by a combination of Misoprostol and mifepristone : A randomized comparison between two Misoprostol regimen. Hum Rep 10 :475-478.
7. Henshaw R.C. (1990) : Induced abortion : A world review, Fam. Plann. Prespect. 22 :76-89.
8. Johnstone F.D., Boyd I.E., Mc Arthy T.G., Mc Clire Brown T.G.(1974) : The diameter of the uterine isthmus during the menstrual cycle, pregnancy and the puerperium. J Obstet Gynecol Br Common Wealth 81 :558-562.
9. Kazzi G.M., Bottoms S.F., and Rosen M.G. (1982) : Efficacy and safety of Laminaria digitata for preinduction ripening of the cervix. Obstet Gynecol 60 :4-10.
10. Moberg P.J.(1996) : Uterine perforation in connection with vacuum aspiration for legal abortion. Int J Gynecol Obstet 14 :77-80.
11. Ölund A., Jonasson A., Kindahl H., Fianu S., and Larsson B.(1984) : The effect of cervical dilatation by Laminaria on the plasma level of 15-Keto 13,14-Dihydro- GF2a . Contraception 30 :23-27.
12. Rodger M.W., and Baird D.T.(1990) : Pretreatment with mifepristone (RU 486) reduces interval between prostaglandin administration and expulsion in the second trimester abortion. Br J Obstet Gynecol 97 :41-45.
13. Tong K.J., Robertson A.J. and Baird D.T.(1992) : A retrospective study of second trimester termination using Gameprost. Prostaglandins 44 :65-74.
14. Toppzada M.K., Anwer M.Y.M., Hasan H.A., El-Gazaerly W.S.(1997) : Oral or vaginal Misoprostol for induction of labour. Intern J Gynecol Obstet 56 :135-139.
15. Wells E.C., Thompson B.H> and King T.M. (1989) : Cervical dilatation : A comparison of Laminaria and Dilapan. Am J Obstet Gynecol 161 :1124-1126.

Table (1): Clinical Criteria of the Studied Groups. N.S= Not significant.

Criteria	Group I	Group II	P Value	Significance
Age (Years)	27.8± 5.8 (range,19-37)	30± 6.5 (range,19-39)	0.336	N.S
Parity	2.4± 2.19 (range,0-9)	2.5± 1.6 (range,0-5)	0.849	N.S
History of Abortion	0.33± 0.8 (range,0-3)	0.67± 0.98 (range,0-3)	0.319	N.S
Gestational Age (Weeks)	16.7± (range,14-24)	17.3± 3.1 (range,14-22)	0.591	N.S

Table (2): Pre-induction Diagnosis

Diagnosis	Group I		Group II
	No.	%	No.	%
IUFD	1	6.7	3	20
Missed Abortion	13	86.7	10	66.7
Anencephaly	1	6.7	1	6.7
MCMF	0	0	1	6.7
Total	15	100	15	100

Table (3): Descriptive Statistics of Group I.

	No.	Mean± SD	Range
No. of Dilapan used	15	1.2± 0.4	1-2
Duration of Insertion (Hours)	15	12.5± 3.7	8-22
Diameter of Cervical Dilatation (mm)	14	16.7± 6.3	11-30
Duration from Oxytocin Infusion to Expulsion	5	4.5± 2.2	2-7

Table (4): Follow up of both Groups.

	Group I			Group II
	Total No.	No.	%	Total No.	No.	%
Need for Further Dilatation	15	0	0	15	2	13.3
Surgical Evacuation	15	5	33.3	15	5	33.3
Uterine Contractions	15	10	66.7	15	5	33.3
Need for Oxytocin	15	6	40	15	13	86.7
Complete Abortion	_	_	_	15	7	46.7
Incomplete Abortion	_	_	_	15	6	40

Table (5): Complications of PGs in Induction of Abortion.