Interstitial (cornual) pregnancy

Definition

• Interstitial pregnancy is an ectopic pregnancy in the interstitial segment of the fallopian tube, the part of the tube that crosses the uterine wall.
• Interstitial and cornual pregnancy are clinically difficult to separate and are regarded as the same by many authors.

Classification

Interstitial and cervical pregnancy

• An interstitial (cornual) pregnancy is located in the intramural portion of the fallopian tube and, compared to an ampullary pregnancy, ruptures later and with massive bleeding.

Clinical features

Clinical features and complications

• The intramural tubal segment can expand considerably before rupture, so the pregnancy may remain asymptomatic until 7–16 weeks of gestation.
• Because the region is highly vascular, rupture causes life-threatening haemorrhage with haemoperitoneum; mortality is reported as 2.0–2.5%.

Diagnosis

• Typical ultrasound findings are the interstitial line sign (an echogenic line between the eccentrically located gestational sac and the uterine cavity) and a sac surrounded by myometrium.
• 3D ultrasound localises the pregnancy even more precisely; MRI helps to distinguish it from an angular pregnancy.

Keep learning in the app

Further reading (selection)

1. Gynecol Minim Invasive Ther 2023: Cornual Pregnancy (PMC, open access)
2. MSD Manual Professional Edition: Ectopic Pregnancy (Pregnancy of Unknown Location)
3. DocCheck Flexikon, Zervixgravidität

Cross-references