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.

Transrectal ultrasound (TRUS) evaluates the distal components of the ejaculatory duct system including the ampullae of the vas deferens, the seminal vesicles, ejaculatory ducts, and the prostate. Patients with complete distal ejaculatory obstruction and partial distal obstruction are ideal candidates for TRUS evaluation. The examination can be performed with the patient in the lithotomy, knee-chest, or lateral decubitus position. Lateral decubitus position is the preferred position as this provides easy access for the operator and less discomfort for the patient. On TRUS examination, the seminal vesicles appear as hypoechoic areas with fine septations. Anteroposterior diameter up to 15 mm is considered normal. Importantly, TRUS can reveal the anatomical relationship between ejaculatory channels and calcifications. It can also detect proximal dilatation of the ejaculatory tract, which indirectly implies the presence of a distal obstruction. TRUS can also be used for therapeutic aspiration and reduction in the size of obstructive cysts.