The cervix is the cylindrical portion of the uterus which enters the vagina and lies at right angles to it. It is well documented in the literature that pregnancy following assisted reproductive technologies (ART) has a higher risk of adverse outcomes. A meta-analysis comparing in-vitro fertilization (IVF) with spontaneous conceptions showed that IVF singleton pregnancies had significantly higher odds of perinatal mortality. Cervical funneling is described as dilatation of the internal os so that the cervical canal changes in shape, with bulging of the bag of membranes through the dilated cervix into the cervical canal. Vasa previa is diagnosed by transvaginal or transabdominal ultrasound, and with Doppler flow studies. Cervical pregnancy is a rare ectopic pregnancy defined as implantation of the gestational sac in the endocervix. Due to its difficult diagnosis, cervical pregnancy should be differentiated from the cervical stage of spontaneous abortion, nabothian cyst, and cervical choriocarcinoma.

With the advancement of ultrasound (US) technology with introduction of 3D technology as well, detailed examination of the uterine cervix, anatomy, and accurate measurements have become possible. Benign gynecologic conditions seen by US in non-pregnant state include nabothian cysts, cervical polyps, fibroids and Mullerian anomalies. The importance of transvaginal US in diagnosing placenta previa lies also in the ability by transvaginal US to determine exact distance of placental edge from internal os, which will consequently determine mode of delivery. US is the main diagnostic tool for cervical pregnancy. Doppler is a very important tool as well, due to its difficult diagnosis, it should be differentiated from the cervical stage of spontaneous abortion and nabothian cyst and cervical choriocarcinoma. The risks of cervical pregnancy are mainly severe hemorrhage, necessitating hysterectomy in many situations, and it usually occurs in nulliparous or low-parity women, adding to the dilemma of management.