Medical Journal

Published by

Faculty of Medical Sciences,
University of Sri Jayewardenepura,
Nugegoda,
Sri Lanka.

Original Articles

When to “Think Ectopic”– Case report on a heterotopic pregnancy in a patient with spontaneous conception with no risk factors

Meegoda V J1*, Nimana K V H1, Hewawitharana K G2, Fernando A3,4

1Intern Medical Officer, Obstetrics & Gynaecology Professorial Unit – Colombo South Teaching
2Senior Registrar, Obstetrics & Gynaecology Professorial Unit – Colombo South Teaching
3Senior Lecturer, Department of Obstetrics & Gynaecology, Faculty of Medical Sciences, University of Sri Jayewardenepura
4Consultant Obstetrician & Gynaecologist, Obstetrics & Gynaecology Professorial Unit – Colombo South Teaching Hospital
*jithmalmeegoda@gmail.com

Abstract

Background: Heterotopic pregnancy (HP) is a rare and potentially fatal condition where simultaneous gestations occur at multiple implantation sites. It rarely occurs in spontaneous conception.

Case presentation: Primigravida with no risk factors for ectopic pregnancy presented at 5+2 weeks with abdominal pain. TVS revealed an intra-gestational sac with free fluid in the pelvis which raised the suspicion of HP. Serum beta-HCG rose by 88% within 48 hours. Diagnostic laparoscopy revealed a right tubal ectopic and a salpingectomy was performed. Post-operative TVS in two weeks revealed a growing intra-uterine pregnancy (IUP).

Discussion and Conclusions: Early diagnosis of HP is difficult due to the lack of clinical symptoms and in the presence of an IUP, HP is easily misdiagnosed as a luteal cyst. The difficulty of an accurate clinical and sonographic diagnosis can justify laparoscopy as a diagnostic & therapeutic tool. After diagnosis, the ectopic component is usually treated surgically, whereas the intrauterine component is expected to develop normally.

Introduction

Heterotopic pregnancy (HP) is a rare condition in which simultaneous gestations occur at two or more implantation sites (1). It rarely occurs in spontaneous conception cycles (1:30,000) but with assisted reproductive techniques (ART), the incidence has increased to 1:100-1:500(2,3).

It can be life-threatening but can be easily missed, with the diagnosis being overlooked. Here we report a case of simultaneous intrauterine and extrauterine tubal pregnancy in a natural conception cycle, in a woman with no risk factors for ectopic pregnancy.

Case Presentation

This 22-year-old, recently married primigravida presented at 5 weeks and 2 days following spontaneous conception. During the initial sonographic examination, suspicion of a tubal pregnancy was raised and was admitted for further evaluation. She had no history of utilization of ART or contraception with no history of pelvic inflammatory disease, abortions, or prior abdominal surgery.

Pregnancy was confirmed by urine beta-HCG & was asymptomatic except for lower abdominal pain. Serum beta-HCG was 1326 mIU/ml on day one & repeated value in 48h was 2388 mIU/ml, leading to an increase of 88%, thus confirming a viable pregnancy. TVS revealed a gestational sac at the fundus of the uterus (6mm) with no foetal pole nor adnexal masses but minimal free fluid in the pouch of Douglas. The suspicion of heterotrophic pregnancy or ectopic pregnancy was raised. TVS repeated 48h later revealed an expanding sac of 7mm confirming IUP.

A laparoscopy was arranged and right tubal ectopic was identified & salpingectomy was performed, with extra effort taken not to manipulate the uterus. Post-operative TVS confirmed a viable IUP.

Discussion

HP is a form of multiple pregnancies with one embryo viably implanted in the uterus and the other being implanted as an ectopic pregnancy. Factors predisposing to ectopic pregnancy and/or multiple gestations may contribute to HP (4). These include tubal damage following pelvic inflammatory disease, intrauterine devices, ART, endometriosis, sexually transmitted diseases, and tubal surgeries (5).

Tal et al (2) reported that 70% of the heterotopic pregnancies were diagnosed between 5-8 weeks of gestation, 20% between 9-10 weeks, and only 10% after the 11th week. The early diagnosis of heterotopic pregnancy is difficult because the clinical symptoms are lacking. Usually, signs of extrauterine pregnancy predominate. Our case was diagnosed at 5 weeks, when the EP was not producing any suggestive symptoms, purely based on meticulous sonographic examination. Once an IUP is diagnosed, symptoms including abdominal pain & bleeding are usually attributed to a threatened miscarriage rather than an HP.

The method of definitive diagnosis has shifted from a surgical approach to ultrasonography. However, the sensitivity of TVS in diagnosing HP is only 56% at early pregnancy (5–6 weeks). A transabdominal scan is complimentary and Doppler studies can be helpful as the trophoblastic tissue in the adnexa shows increased flow with a significantly reduced resistance index. However, in the presence of an IUP, HP is easily misdiagnosed as a luteal cyst, especially if the concurrent IUP is reassuring. Excessive production of beta-hCG by the placenta in intrauterine pregnancy can mask subnormal ß-hCG production as in ectopic pregnancy. Therefore, serial beta -hCG estimation is not useful in HP. If beta-hCG levels are higher for the period of gestation with an IU pregnancy, one must look for a coexistent EP (2). In our patient, the beta-hCG levels were only risen by 88% over 48h. Given the viable IUP and EP, theoretically, it should have risen more than 100%. In many reported cases beta-hCG was found to be misleading. Difficulty in accurate clinical and sonographic diagnosis in asymptomatic patients can justify laparoscopy (1) as a diagnostic & therapeutic tool.

The management of heterotopic pregnancy remains controversial. Surgical therapy has been the traditional mainstay but involves risks to both the mother and IUP. Laparoscopic management is preferable over laparotomy in HP as it involves minimal manipulation of the uterus. When patients are hemodynamically unstable, laparotomy is the treatment of choice. A recent review demonstrated no difference in rates of IUPs after conservative (salpingostomy) or radical (salpingectomy) surgery for tubal EP. A conservative approach includes ultrasound-guided local infiltration of methotrexate, mifepristone, prostaglandins, KCl, and also aspiration of ectopic gestation via the transvaginal route. But most of the material used is teratogenic to the IUP

In heterotopic pregnancy, maternal mortality is recorded as 1% and intrauterine foetal mortality rate is 45-65%, therefore early interventions are necessary.

Conclusions

In conclusion, this rare case of heterotopic pregnancy in a woman with no known risk factors illustrates the importance of the dictum “think ectopic” even when an IUP is present. Detection of an IUP should not exclude the existence of a simultaneous EP. A high index of suspicion followed by an early surgical laparoscopic intervention can minimize maternal morbidity and preserve the development of IUP.

References

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