Int J Gynaecol Obstet 15: 177-183, 1977

Menstrual Regulation: Risks and "Abuses" William E. Brenner1 and David A. Edelman2 ^Department of Obstetrics and Gynecology, University of North Carolina, Chapel Hill, North Carolina, USA ¿International Fertility Research Program, Research Triangle Park, North Carolina, USA

ABSTRACT Brenner, W. E. and Edelman, D. A. (Dept. of Obstetrics and Gynecology, University of North Carolina, Chapel Hill, North Carolina, USA, and International Fertility Research Program, Research Triangle Park, North Carolina, USA). Menstrual regulation: risks and "abuses". Int J Gynaecol Obstet 15: 177-183, 1977 The definitions, methods, and techniques of menstrual regulation (MR) are presented. The risks and abuses of performing MR by vacuum aspiration to terminate pregnancies of less than 7 menstrual weeks are reviewed.

INTRODUCTION Menstrual regulation (MR) is defined as any procedure which disrupts the intrauterine environment so that embryonic implantation either cannot occur or cannot be maintained. MR can be performed using drugs, physical agents, and surgical techniques. Of the drugs investigated, it appears that prostaglandins (PGs) are the most practicable. Vaginal administration of the 15(S) 15 me PGF20/ analogue in slow release suppositories (4) or silastic devices (3) usually results in abortion within a few days. Unfortunately, vomiting and diarrhea are frequent unpleasant side effects of PG administration (3, 4). Although the PG method may be useful in the future, the only currently useful method is vacuum aspiration (VA). VA of the uterus has been used for many Í purposes: inducing a therapeutic abortion; obtain! ing endometrium for diagnostic purposes; alleviating dysmenorrhea; and insuring that a woman is not or does not remain pregnant prior to IUD insertion, oral contraceptive therapy, sterilization, or diagnostic pelvic x-rays. It has also been useful for managing incomplete, inevitable, threatened, and artificial abortions throughout the first trimester. This discussion will be limited to the use of VA performed within 6 weeks of the last normal menstrual period to insure that a woman does not remain pregnant. Equipment Since at 6 menstrual weeks the uterine contents are of small volume, the uterus is minimally

enlarged and cervical dilatation is rarely necessary, simple equipment can be used (5). Except under very unusual circumstances, the uterus can be adequately evacuated with a flexible, disposable, plastic 4, 5, or 6 mm diameter catheter without cervical dilatation (Fig. 1). A specially adapted 50 cc plastic syringe provides adequate vacuum and volume for the evacuated uterine contents and blood. The catheter has two whistle tip apertures and bends easily but does not collapse with the vacuum developed by the syringe. When the plunger of the syringe is adequately withdrawn to form the vacuum, the two arms of the plunger engage the edge of the barrel, thereby maintaining the vacuum by not allowing the plunger to return. Some syringes have a simple pinch valve to obstruct the rubber tube that connects the syringe with the cannula. Analgesia is rarely needed, but paracervical blocks are frequently used.

Fig. 1. The 50 cc hand syringe and 4, 5, and 6 mm cannulae. The syringe is distributed by International Pregnancy Advisory Services, Chapel Hill, N. C , USA; the cannulae are products of Burnette Instruments, Lawrence, Kan., USA.

Procedure The procedure and the patient's decision are thoroughly discussed with the patient. She is told what to expect during VA and informed of the possible complications. She is also counseled about contraceptive measures. The procedure is simple. After a bimanual examination of the patient in the dorsal lithotomy

Int J Gynaecol Obstet 15

178 W. E. Brenner and D. A. Edelman

position, the cervix is visualized using a speculum. The cervix and vagina are wiped with an antiseptic solution. The cervix is stabilized with an atraumatic tenaculum. A paracervical block is performed with 10 ml of a suitable anesthetic such as 1% lidocaine. Using the "no touch" technique, the operator inserts the cannula to the uterine fundus and measures the length from the fundus to the external os. If there is a valve on the syringe, the valve is closed, and vacuum is created by retracting the barrel until it locks. The syringe is then attached to the cannula before the valve is opened. If the syringe has no lock, it is attached to the cannula before the vacuum is created in the syringe. The cannula is simultaneously rotated about its axis and slowly withdrawn to the cervical canal, then returned to the fundus. These motions are continued until bubbles appear and a gritty sensation occurs, indicating complete evacuation of the uterine contents. The length of the uterine cavity is noted. If the cannula becomes obstructed and/or the vacuum is lost, the cannula is removed from the uterus. The arms of the plunger are collapsed, the plunger is pushed (emptying the uterine aspirate into a container), vacuum is reestablished by pulling the plunger until it locks, and the procedure is repeated. After the patient receives adequate postoperative and contraceptive counseling and her cramps have subsided, she may return home or to work with no sexual or physical restrictions. Although VA during early pregnancy can be performed with the larger flexible or rigid metal or plastic cannulae using high volume vacuum pumps in operating rooms with the patient under general anesthesia, it is doubtful that these measures are as efficient or as safe as using the simpler equipment with a small cannula in a treatment room.

Risks of remaining pregnant Overall, 99.1% of the pregnant patients are aborted by the VA procedure (Table I). Only patients whose pregnancies were documented (through the discovery of placental parts in the uterine aspirate or finding that pregnancy is continuing despite VA) were considered in calculating abortion rates. The proportion who were pregnant varied in different clinics. Table I. Failure rate of menstrual regulation, by type of vacuum source and size of cannula No.

%

Vacuum source Syringe Vacuum pump

63 22

0.8 1.2

Size of cannula (mm) 4 5 6

42 29 9

1.1 0.7 0.5

Overall failure rate

0.9

Source: Unpublished data f r o m the International Fertility Research Program, Research Triangle Park, North Carolina, USA.

MR should be performed by experienced physicians who have demonstrated a high success rate. Success rates vary from 90.1% to 100% in different clinics (10). Although the procedure is relatively simple, the failure rate is often high until physicians have acquired the necessary experience to perform the procedure proficiently (Fig. 2). 40n a>

30-

O

RESULTS The results given here are based on the first author's personal experience with the technique and on the analysis of 10117 cases reported on standardized forms to the International Fertility Research Program, Research Triangle Park, North Carolina, USA. Some of the data have been previously reported (1, 2, 5, 8). Some of the tables and figures used to illustrate this manuscript were abstracted from these previous reports; therefore, the number of cases analyzed in these tables and figures will differ. Two types of risks are associated with MR: continuation of pregnancy and complications. For the sake of discussion, any use of MR in a situation that is less than ideal will be considered "abuse".

Ini J Gynaecol Obstet 15

rr 2 OH a>

= I OH o

JZZL 1-25

2 6 - 5 0 51-75 76-113

Patient Order Number N =

10

II

13

20

Fig. 2. Menstrual regulation failure rates for one selected clinic. The failure rate in % (100 x no. of patient continuing to be pregnant after vacuum aspiration/total no. of pregnant patients) over the study period by consecutive patient order numbers. N=number of patients documented to be pregnant (i.e., identified by chorionic villae in the uterine aspirate) in each group. Source: Brenner, W E, et al. (1).

Menstrual regulation

The modified syringe and a 5 or 6 mm cannula should be used. Failure rates are lower with the syringe than with the vacuum pump and with the 5 and 6 mm cannulae than with the 4 mm cannula (Table I). No differences in failure rates were noted when the type of anesthesia (none or paracervical) or the patient's parity was controlled for (10). Thus, under ideal circumstances, the risk that pregnancy will continue after VA is less than 1% when the best techniques are used in properly selected patients. When the method is "abused" (i.e., performed by physicians with no training or with high failure rates, or performed with a high volume pump and a 4 mm cannula), failure rates increase markedly. Risks from complications Risks from complications other than continued pregnancy are related to the patient's pregnancy status, her gestational age, her past obstetrical history, the type of anesthesia used, and the cannula size, but not to the vacuum source. Rates of potentially serious complications are low (Table II). Total complication rates and rates of uterine injury and prolonged bleeding are higher in patients documented to be pregnant. Complication rates are higher in nulliparas than in multiparas and higher when the 6 mm rather than the 5 mm cannula is used. The 6 mm cannula should be used only when necessary.

general anesthesia is routinely used (Fig. 3) (2). MR should be performed as soon as practical after 31 days of amenorrhea. After 42 days of amenorrhea, the complication rate increases (Fig. 4) (8). The abortion should not be delayed until after 6 weeks' amenorrhea when the cervix often has to be dilated and a larger cannula and high volume vacuum source (for VA) used. The incidence of complications increases at least threefold after 6 weeks' amenorrhea (Fig. 4) (8). Thus, in properly selected gravidas, the risks of MR are small when the appropriate equipment is used.

6-

~

4

^ General Anesthesia

Paracervical B l o c k / A n a l g e s i a / N o Anesthesia I I Electrical Vacuum Pump I 50cc Syringe

N * 598

Table I I . Rates of specific complications w i t h menstrual regulation, by pregnancy status Pregnant (N = 7031)

Not Pregnant (N = 3086)

%

No.

%

No

Uterine perforation Suspected Confirmed

0 0

0.0 0.0

1 2

Menstrual regulation: risks and "abuses".

Int J Gynaecol Obstet 15: 177-183, 1977 Menstrual Regulation: Risks and "Abuses" William E. Brenner1 and David A. Edelman2 ^Department of Obstetrics...
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