What type of abortion is a 33-year-old female at 7 weeks of gestation, presenting with mild vaginal bleeding and a closed cervix, with an ultrasound confirming a viable intrauterine pregnancy, most likely experiencing?

Threatened Abortion

This patient is experiencing a threatened abortion, characterized by vaginal bleeding in early pregnancy with a closed cervix and confirmed viable intrauterine pregnancy on ultrasound. 1

Clinical Classification

The key distinguishing features that define this as threatened abortion include:

• Viable intrauterine pregnancy confirmed by ultrasound showing fetal cardiac activity at 7 weeks gestation 1
• Closed cervix on examination, indicating the pregnancy has not progressed to inevitable abortion 1
• Mild vaginal bleeding without passage of tissue 1

Why Other Options Are Incorrect

Missed abortion (Option A) is definitively excluded because ultrasound demonstrates a viable pregnancy with cardiac activity, whereas missed abortion requires absence of embryonic cardiac activity in a gestational sac ≥25 mm mean sac diameter or absence of cardiac activity 11+ days after a yolk sac was seen without an embryo. 1

Inevitable abortion (Option B) requires an open or dilating cervix, which this patient does not have. 1 The closed cervical os is the critical distinguishing feature that rules out inevitable abortion.

Incomplete abortion (Option D) occurs after partial passage of products of conception with an open cervix and ongoing bleeding, which is inconsistent with this patient's presentation of a viable intrauterine pregnancy. 1

Clinical Significance and Prognosis

Bleeding in the first trimester occurs in 7-27% of pregnancies, with an overall miscarriage risk of approximately 12%. 1 However, when fetal cardiac activity is confirmed on ultrasound as in this case, the prognosis improves significantly.

Important counseling points include:

• First trimester bleeding increases risk of preterm delivery, placental abruption later in pregnancy, and small for gestational age infants if the pregnancy continues 2, 3
• Follow-up ultrasound should be scheduled in 1-2 weeks to monitor progression 2, 4
• The presence of fetal cardiac activity is a reassuring prognostic sign 1

Management Approach

The American College of Radiology recommends transvaginal ultrasound as the primary diagnostic tool for first trimester vaginal bleeding, which has already been appropriately performed in this case. 1, 2, 4

Appropriate next steps include:

• Schedule follow-up ultrasound in 1-2 weeks to confirm continued viability and appropriate growth 2, 4
• Assess for subchorionic hematoma on the ultrasound images, as this is a common associated finding 1, 2
• Obtain blood type and Rh status if not already on file, as Rh-negative patients require anti-D immunoglobulin administration 4
• Reassurance and activity modification as clinically appropriate, though bed rest has not been proven beneficial 5