Refining Angular Pregnancy Diagnosis in the First Trimester: A Case Series of Expectant Management

To describe the natural history and outcomes of a large cohort of expectantly managed angular pregnancies diagnosed in the first trimester by specific ultrasound criteria.

We conducted a prospective case series of women with prenatally diagnosed angular pregnancy at a single academic tertiary care center from March 2017 to February 2019. Participants were identified at first-trimester ultrasound scan using specifically proposed diagnostic criteria for angular pregnancy and followed prospectively. Maternal and fetal data were gathered from the medical record.

Forty-two cases of angular pregnancy were identified at first-trimester ultrasound scan. At presentation, 33 patients (79%) were asymptomatic, eight (19%) had vaginal bleeding, and two (5%) had pain. The mean gestational age at diagnosis was 7.4±1.0 weeks; the mean myometrial thickness was 5.1±1.6 mm (95% CI 4.6-5.6). At initial follow-up about 2 weeks later, 23 patients (55%) had ultrasound scans that normalized, 13 (31%) cases persisted as angular pregnancies, and six (14%) resulted in early pregnancy loss. After each gestation had been followed until completion, 33 (80%) pregnancies resulted in live birth and eight (20%) in early pregnancy loss. One patient was lost to follow-up. Of the 33 live births, 24 (73%) were vaginal deliveries, nine (27%) were cesarean deliveries, 27 (82%) were term deliveries, and six (18%) were preterm deliveries. There were no cases of uterine rupture, maternal death, abnormal placentation, or hysterectomy.

In 42 cases of angular pregnancy diagnosed by first-trimester ultrasound examination, outcomes were largely positive, with an 80% live-birth rate and a 20% early pregnancy loss rate. Early diagnosis of angular pregnancy using the described criteria may represent an entity that more closely resembles a normal, noneccentric intrauterine pregnancy rather than an ectopic pregnancy. Therefore, most cases can be closely observed and efforts made to expectantly manage pregnancies while awaiting viability.