Cornual pregnancy is implantation of a pregnancy in one horn of a bicornuate or septate uterus, or in the cornual part of the uterine cavity. It is rare, and presents like interstitial ectopic with late rupture and heavy bleeding. It matters because it is easily mistaken for a normal intrauterine pregnancy and carries a high risk of uterine rupture.

Risk factors: uterine anomaly, previous tubal surgery, assisted reproduction.
Diagnosis is often late, at 8 to 16 weeks.
Classically associated with a rudimentary horn.

Patients have amenorrhoea and lower abdominal pain with minimal bleeding, and rupture causes collapse. The uterus is asymmetrical.

Pain on one side of the uterus.
Often misdiagnosed as early intrauterine pregnancy.
Differential diagnosis: interstitial ectopic, intrauterine pregnancy in a bicornuate uterus, fibroid, tubal ectopic, molar pregnancy.
Complications: rupture, haemoperitoneum, shock, hysterectomy, death.

The principle is to remove or terminate the pregnancy before rupture.

Supportive: admission; two large-bore cannulae; blood available; resuscitation as needed.
Pharmacological: methotrexate 50 mg/m2 IM single dose for stable women with hCG below 5000 IU/L and no fetal heart; hCG days 4 and 7 then weekly; alternatively 4 dose regimen of methotrexate 1 mg/kg IM days 1, 3, 5 and 7 with folinic acid 0.1 mg/kg IM days 2, 4, 6 and 8; analgesia with paracetamol 1 g oral 6-hourly (maximum 4 g in 24 hours).
Procedures: laparoscopic resection of the rudimentary horn or cornual wedge resection with suturing; laparotomy and hysterectomy for rupture.
Special groups: Rhesus negative women give anti-D immunoglobulin 250 IU IM within 72 hours; later pregnancies need elective caesarean delivery at 36 to 37 weeks.
Red flags: acute pain, collapse, rising pulse, falling haemoglobin.
Follow-up: hCG weekly until negative; haemoglobin check; early scan in subsequent pregnancy.

Cornual Pregnancy

Overview

Clinical Features

Diagnosis

Management