Angular pregnancies is a type of pregnancy that is located within the endometrial cavity at the lateral upper angle. It is one of the eccentrically located pregnancies in the fundal region of the uterus.
Given the intrauterine location of angular pregnancies and the enveloping myometrium, these patients are likely to present with symptoms later than patients with ectopic pregnancies.
The embryo is implanted in the lateral angle of the endometrial cavity medial to the uterotubal junction and round ligament. In contrast, an interstitial ectopic pregnancy is located in the muscular layer of the Fallopian tube and is surrounded by the myometrial layer. The critical differentiating feature is that the fertilised ovum of an interstitial pregnancy develops in the uterine wall, whereas in an angular pregnancy, it develops towards the endometrial cavity. Anatomically the angular pregnancy is implanted medial to the round ligament.
- 3D ultrasound can be helpful in the precise location of sac
- pregnancy is eccentrically high in location; the gestational sac is located within the endometrial cavity at the lateral upper angle on the spectrum between normal pregnancy and interstitial cornual pregnancies
- should always have normal myometrial coverage, which is thick and usually more than 5 mm
- grows towards the endometrial cavity and requires close follow-up to document the gestational sac growing into the cavity
Treatment and prognosis
Many of these pregnancies result in live birth but have an increased complication rate.
The true complication rate not known as cases reported as angular may have actually been interstitial but complications include:
- spontaneous abortion (~40%)
- uterine rupture (~15%)
interstitial ectopic pregnancy
- located in the intramural portion of Fallopian tube
- also eccentrically located with respect to endometrial cavity but seen separately >1 cm from the endometrial cavity
- interstitial line sign: an echogenic line in continuity from the ectopic to the endometrial echo complex
- covered by myometrium but thinned to <5 mm
- can grow to a larger size than the tubal ectopic pregnancy
- presents in settings of a uterine anomaly such as unicornuate, bicornuate, or septate uterus with a rudimentary horn
- gestational sac is located medial to the Fallopian tube including the anomalous part