Ectopic pregnancy is a very common diagnosis (2% of pregnancies), and implantation location varies. Although 97% of ectopics are implanted within the fallopian tube, associated with commonly recognized risk factors, ectopic implantation can occur in other pelvic and abdominal locations that may not have such predisposing risk factors. After an extensive review of the literature, along with the author’s personal experience, implantation frequency, etiologic possibilities, and treatment options for each ectopic pregnancy location are presented. When ectopic pregnancy is diagnosed early, before rupture, regardless of location, conservative, fertility-sparing treatment options can be successful in terminating the pregnancy. Predisposing risk factors and treatment options can vary and can be ectopic-location specific.
Ectopic pregnancy, the implantation of a fertilized ovum outside the uterine cavity, has been increasing in number and now accounts for 2% of all pregnancies in the United States. Nearly all ectopic pregnancies (97%) are implanted within the fallopian tube, and a common factor for the development of such ectopics is the presence of a pathologic fallopian tube. Causes of such pathology include genital tract infection caused by gonorrhea and chlamydia, tubal surgery including tubal sterilization, previous ectopic pregnancy, and in utero exposure to diethylstilbestrol. Other risk factors for tubal ectopic pregnancy include conception with an intrauterine device (IUD) in place and conception while using a progesterone only contraceptive method.
Tubal ectopic pregnancy within the tubal ampulla ( Figure 1 ) , 70% of all ectopics, and fimbriae, 11% of all ectopics, when treated laparoscopically, are amendable to salpingectomy, linear salpingostomy, or fimbrial expression with only a small risk of residual trophoblastic tissue left behind (persistent ectopic pregnancy), and the need for rescue therapy. With the use of the published recommendations for the medical treatment of ectopic pregnancy, many such pregnancies can be treated nonsurgically. Any ectopic with a pretreatment mass diameter greater than 3.5 cm , a human chorionic gonadotropin level above 5000 mIU/mL, and/or an embryo present is more likely to fail medical therapy and may be more successfully treated surgically. Special consideration to pregnancies at risk of failure with single-dose methotrexate may be successfully treated with a multidose methotrexate protocol.
Ectopic implantation can also occur outside of the fallopian tube, within the cervix, ovary, abdomen, uterine cornua, and cesarean scars. These extratubal implantations may not be associated with tubal pathology or the expected preexisting risk factors for tubal ectopic implantation, and there are no prospective studies published to guide management. Regardless of location, however, when diagnosed early, before symptoms of rupture, many ectopic pregnancies can be successfully treated conservatively.
Cervical pregnancy
Less than 1%, and the rarest, of ectopics are implanted within the cervical canal below the level of the internal cervical os. The cause of such implantations is unknown but predisposing factors include prior uterine curettage, induced abortion, Asherman’s syndrome, leiomyomata, presence of an IUD, in vitro fertilization, and prior in utero exposure to diethylstilbesterol.
Raskin suggested that the diagnosis by ultrasound examination of cervical pregnancy required 4 criteria: enlargement of the cervix, uterine enlargement, diffuse amorphous intrauterine echoes, and absence of an intrauterine pregnancy. Timor-Tritsch et al, refined the criteria to include the placenta and entire chorionic sac containing the pregnancy must be below the internal cervical os and the cervical canal must be dilated and barrel shaped. If necessary to exclude the diagnosis of a spontaneous abortion in progress, the presence of embryonic cardiac activity, and/or Doppler ultrasound indicating vascular attachment confirm a living pregnancy.
Before the now common use of early pregnancy transvaginal ultrasound, cervical pregnancies were frequently diagnosed at the time of spontaneous abortion or reached the second trimester, both associated with life-threatening hemorrhage frequently requiring hysterectomy as treatment. Usually, the first complaint is painless vaginal bleeding and speculum examination may reveal an open external cervical os with a fleshy type endocervical mass presenting. With early transvaginal ultrasound, these implantations are easily identified ( Figure 2 ) and can, thus, be treated with conservative fertility sparing options. Although there are neither large published series nor consensus on the preferred treatment for cervical pregnancy, and no standard recommendations are available, several conservative treatment options have been reported.
