Findings:

1) Empty endometrial cavity showing fluid

2) Presence of gestational sac below the level of internal os as well as caesarean scar.

3) Presence of echogenic decidual reaction with peritrophoblastic flow from cervical tissue.

4) Internal os is closed.

 ISUOG DEFINITION:

Cervical ectopic pregnancy refers to an abnormal implantation of a fertilized ovum within the myometrium below the level of the internal os with a reported incidence of less than 1% of all ectopic pregnancies.

Risk factors

    • variant anatomy 10

    • fibroids 10

    • IUCD

    • Asherman syndrome

    • IVF

    • repeated dilatation and curettage 

Ultrasound is the primary diagnostic modality, using a transvaginal approach supplemented by transabdominal imaging if required. The following ultrasound criteria may be used for the diagnosis of cervical pregnancy [9]: 

(1)    An empty uterus

(2)    A barrel -shaped cervix

(3)    A gestational sac present below the level of the internal os 

(4)    The absence of the “sliding sign”, 

(5)    Blood flow around the gestational sac using colour Doppler.

Magnetic resonance imaging (MRI) can be used as a second-line investigation if the diagnosis is equivocal and there is local expertise in the MRI diagnosis of caesarean scar pregnancies [9]. The typical MRI finding of a cervical pregnancy is a heterogeneous hemorrhagic mass with densely enhancing papillary solid components [10].

A suboptimal rise in serial human chorionic gonadotropin (ß-hCG) allows to suggest the diagnosis of an ectopic pregnancy but does not help to confirm the diagnosis of a cervical pregnancy.

Differential diagnosis

    • it is important to consider miscarriage in progress as a differential when the gestational sac is located within the endocervical canal; features suggestive of a miscarriage include:

        ? absent embryonic cardiac activity

        ? open internal os: lack of typical hourglass appearance

        ? sac shape and location often changes on serial scans and it may be possible to alter the location of the sac with gentle probe maneuvering (“sliding sac sign”)

        ? subsequent loss of the fetal sac on a repeat ultrasound confirms miscarriage

Table 1. Differentiation of a cervical pregnancy from cervical phase of spontaneous abortion / miscarriage

Cervical pregnancy may be misdiagnosed as a Cesarean scar pregnancy. The difference is that cervical pregnancy is located below the internal os, while scar pregnancy is located above, at the level of the cesarean scar incision. All pregnancies implanted into the posterior cervix should be described as cervical pregnancies regardless of women’s previous history of delivery by Caesarean section. In cases of anterior implantation in women who have had a caesarean in the past, the differential diagnosis includes Caesarean scar ectopic pregnancy. In terms of management, they differ very little from Caesarean scar pregnancies [1]