Study Finds Routine HSG After Medical Treatment for Ectopic Pregnancy Does Not Alter Initial Management
Ectopic pregnancy (EP) is defined as the abnormal implantation of the blastocyst outside the uterine endometrium. It affects 2% of all pregnancies and is associated with significant maternal morbid mortality, being the main cause of maternal death during the first trimester of gestation.
The most common site of implantation is the Fallopian tube (in the fimbrial end, ampullary section, or isthmus) but can also be interstitial, ovarian, abdominal and cervical, or on the site of a previous cesarean section scar. Females with abnormal Fallopian tubes are at increased risk of developing an EP. Thus, the risk factors for developing EP include pelvic inflammatory disease (PID), history of EP, infertility, history of pelvic or abdominal surgery, endometriosis, sexually transmitted diseases, previous tubal surgery (namely tubal sterilization), smoking, older maternal age, and in uterus exposure to diethylstilbestrol.
Despite the fact that the treatment is classically surgical, early diagnosis allows the implementation of a medical treatment, thus avoiding the surgery-associated morbidity and maintaining the patient’s anatomy. Several medical treatments have been used such as prostaglandins, dactinomycin, etoposide, hyperosmolar glucose, anti-hCG antibodies, potassium chloride, or mifepristone. However, the treatment with methotrexate (MTX) has shown better results and is presently considered the first option for medical therapy.
MTX is chemotherapeutic drug, antagonist of folic acid and acts as an antimetabolite, by combining with the enzyme tetrahydrofolate reductase. It inhibits the synthesis of puric and pyrimidic bases, essential for the formation of DNA and RNA. Its action is exerted on cells with fast replication, including the trophoblast.
The medical treatment with methotrexate may be applied systemically (intramuscular administration of MTX) or by direct injection inside the gestational sac, whether guided by ultrasound or by a laparoscopic approach. MTX destroys cells in fast replication (in this case the trophoblast). However, this process may result in residual lesion to the Fallopian tube. Fertility after a conservative treatment for an EP can be attested indirectly through a hysterosalpingography (HSG) or directly by diagnosing a new gestation.
HSG is the radiographic evaluation of the uterine cavity and fallopian tubes after the administration of a radioopaque medium through the cervical canal. Properly performed HSG can detect the contour of the uterine cavity and the width of the cervical canal. Further contrast medium injection will outline the cornua isthmic and ampullary portions of the tubes and will show the degree of spillage.
The aim of this study was to assess the usefulness of HSG following medical treatment of EP in order to counsel patients willing to have future gestations about the most appropriate method of conception. The secondary aims of the study were to evaluate the clinical effectiveness of the different modalities of treatment and fertility rates following a medical treatment of EP.
Between 1998 and 2008, 144 patients were submitted to medical treatment for an EP and performed HSG 3 months after the event. 72.2% of normal HSG, 18.8% with unilateral obstruction, 6.3% tubal patency with defect, and 2.8% bilateral obstruction.
This data showed that findings on HSG were different according to the therapeutic approach, with the intramuscular treatment carrying an increased ratio of normal exams, when compared to the intrasacular injection. Two reasons could explain these findings: the inclusion criteria for intrasaccular treatment allow higher initial levels of β-HCG. The increase in β-HCG levels is related to an enhancement in tubal obstruction risk, probably because in patients with high levels of β-HCG there is more invasion of the trophoblast
tissue at the serosa of the tube, which increases the dam- age. Additionally, the intrasacular treatment requires direct tubal puncture, possibly injuring the Fallopian tube with consequent increased scarring and additional peritubal peritoneal adhesions.
Findings on HSG carry a prognostic value when considering future fertility, following medical treatment of EP. However, initial management is affected only in 2.8% of the women.
Further studies should be undertaken in order to confirm the present results that suggest that routine HSG following medical treatment for an EP does not seem necessary but might be considered in selected risk cases, permitting timely referral of patients to in vitro fertilization.
Source: Hindawi Publishing Corporation Obstetrics and Gynecology International Volume 2011, Article ID 547946 ndoi:10.1155/2011/547946
