Ectopic pregnancy after tubal sterilization.
JP Shah, SV Parulekar, IN Hinduja
Department of Obstetric and Gynecology, Seth G.S. Medical College, Parel, Bombay, Maharashtra.
J P Shah
Department of Obstetric and Gynecology, Seth G.S. Medical College, Parel, Bombay, Maharashtra.
We report 13 cases of ectopic pregnancy following tubal ligation out of 287 ectopic pregnancies seen during a six year period (1984-1989). These findings suggest that tubal sterilization does not invariably confer infertility. Ectopic pregnancy must not be disregarded in women who have undergone tubal ligation, especially if two or more years have elapsed since the sterilization.
|How to cite this article:|
Shah J P, Parulekar S V, Hinduja I N. Ectopic pregnancy after tubal sterilization. J Postgrad Med 1991;37:17-20
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Shah J P, Parulekar S V, Hinduja I N. Ectopic pregnancy after tubal sterilization. J Postgrad Med [serial online] 1991 [cited 2021 Jan 16 ];37:17-20
Available from: https://www.jpgmonline.com/text.asp?1991/37/1/17/811
Ectopic pregnancy continues to be an important cause of maternal deaths. There has been a trcmendous increase in recent years in the number of elective sterilisation. Although the incidence of pregnancy after sterilisation is relatively small, a significant proportion of such pregnancies are ectopic and tubal in location . As a consequence, post-sterilisation ectopic pregnancies are beginning to account for over 12% of all ectopic pregnancies.
The present study was undertaken to evaluate in detail the occurrence of ectopic tubal gestation after sterilisation operations.
Two hundred and eighty seven exploratory laparotomies were performed for ruptured or un-ruptured ectopic pregnancies between 1984 and 1989 at the King Edward Memorial Hospital, Mumbai 400 012. Of these, 13 (4.53%) cases had undergone tubal sterilisation in the past. A detailed evaluation was done in these 13 cases as to the type of ligation procedure performed, the time interval between the sterilisation and the occurrence of ectopic pregnancy, and whether the sterilisation had been done in the immediate puerperium, simultaneously with a medical termination of pregnancy (MTP) or with a cesarean section, or as an interval procedure. The mean age of the patients was 25.8 years and the mean parity was 2.8.
The analysed data are depicted in [Table:1]. Six of the thirteen patients came with ruptured ectopic pregnancy, five came with un-ruptured ectopic pregnancy and two with a chronic ectopic gestation.
The incidence of failure of voluntary sterilisation is relatively small; however, if pregnancy does occur, 15-20% of such pregnancies are likely to be ectopic,,,,,,.
Post- sterilisation ectopic pregnancies are beginning to account for over 10% of all ectopic gestations,,. Never the less the absolute risk of developing ectopic pregnancy after sterilisation is lesser than that observed for normal women. Among women who undergo tubal ligation, the risk is about 1/7th the expected risk had they continued their previous contraception. Ectopic pregnancy continues to be an important cause of maternal deaths, and it is important to realise that many of these maternal fatalities are preventable, as they usually occur because of failure to consider ectopic gestation as part of the differential diagnosis.
Ectopic tubal pregnancies after tubal ligation accounted for 4.5% of all the ectopic pregnancies in this study. In the largest reported series to date, 7 of 100 consecutive ectopic pregnancies occurred in sterilised women. When a patient with previous tubal ligation develops the signs and symptoms of pregnancy, the diagnosis of extra-uterine pregnancy has to be considered, as the ratio of ectopic to intrauterine pregnancy is higher among pregnancies occurring after sterilisation failure than in the general population .
Chi et a1 found that of the 194 confirmed pregnancies conceived after sterilisation procedures, 15 were ectopic. Uncorrected incidence rates of 0.64 per 10,000 sterilisation procedures and 7.7 per 100 pregnancies conceived after tubal sterilisation were derived.
The probable explanation for these ectopic gestations after tubal ligation is recanalization or formation of a tubo peritoneal fistula; sperm may pass through, but the fertilised ovum cannot, so implantation occurs classically in the distal tubal segment,. It has also been suggested that in the process of recanalization there is "an abnormal reconstitution of the tubal lumen with the formation of blind pouches and slit like spaces" and that this is responsible for the greater likelihood of ectopic implantation . Rock et al suggested that the development of tubo peritoneal fistulas subsequent to sterilisation was associated with the development of endometriosis, especially when the ligation site was within 4 cm of the cornua. The focal endometriosis might then be considered as a probable point for implantation. Histological studies have indicated that implantation after failure of tubal sterilisation is influenced by probable fluid movcments within the remaining tubal segments.
Ectopic pregnancy occurred more than a year after sterilisation in 84.6% of the cases in this study. In another study, the ectopic versus intrauterine pregnancy ratio was 1:14.2 at one year after sterilisation and was 1:2 at more than 2 years after sterilisation. Hence physicians should raise their index of suspicion for ectopic pregnancy when they encounter signs of pregnancy in a woman who has undergone sterilisation especially if 2 or more years have elapsed since sterilisation.
Furthermore, 92.3% of the patients in this study had undergone sterilisation in conjunction with a pregnancy event such as medical termination of pregnancy or puerperium or The incidence of ectopic pregnancy after sterilisation is higher when sterilisation is performed during the postpartum period because the oedematous, friable and congested fallopian tubes following pregnancy increase the chances of incomplete occlusion of the tubal lumen. The silastic band has a outer diameter of 3 mm, inner diameter of 1 mm and a width of 2 mm. Although these dimensions are ideally suited for occlusion of the fallopian tube in the non-pregnant state, they may not successfully occlude the lumen of a tube, which is thick and edematous as a result of pregnancy. Such failure of band application can be avoided if the fallopian tube is milked several times by drawing it in and out of the applicator sheath before application of the band. Also, one must carefully look for a vertical crease between the two limbs of the loop and blanching of the banded tubal segment to ensure complete occlusion of the fallopian tube at the end of laparoscopic sterilisation.
Furthermore, bilateral salpingectomy should be performed at the time of an exploration for an ectopic pregnancy, which has occurred after a sterilisation procedures.
For whatever reason, be it simply the increasing number of sterilisation or a change in the nature of the procedure, it is apparent that the entity of ectopic gestation following tubal sterilisation is becoming more common. Hence, whenever tubal sterilisation is to be performed in conjunction with a pregnancy event such as a MTP or the puerperium, extra caution and meticulous technique are required to avoid failure. Furthermore, it is important that the gynecologist becomes more cognisant of this fact, and that the woman who is about to be sterilised be counselled as to both the possibility and the risk of extra-uterine as well as intrauterine gestation subsequent to all methods of sterilisation.
We are grateful to the Dean, Seth GS Medical College and King Edward Memorial Hospital for allowing us to publish hospital data.
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