Differential Diagnosis
- Single most likely diagnosis
- Anembryonic pregnancy (also known as a blighted ovum): This diagnosis is the most likely due to the presence of a gestational sac and yolk sac without a fetal pole on two separate ultrasound examinations, despite adequate β-hCG levels. The decrease in β-hCG levels also supports this diagnosis.
- Other Likely diagnoses
- Missed abortion: Although the cervix is closed and there is no vaginal bleeding, a missed abortion is still possible, especially given the lack of fetal development and decreasing β-hCG levels.
- Ectopic pregnancy: Although the ultrasound shows an intrauterine gestational sac, an ectopic pregnancy cannot be completely ruled out, especially if there is a possibility of a heterotopic pregnancy (a simultaneous intrauterine and ectopic pregnancy).
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Ectopic pregnancy with rupture: This is a life-threatening condition that requires immediate attention. Although the patient does not have any symptoms of rupture, such as severe abdominal pain or vaginal bleeding, it is essential to consider this possibility.
- Molar pregnancy: Although the ultrasound does not show the characteristic "snowstorm" appearance of a molar pregnancy, it is still possible, especially if the β-hCG levels are higher than expected.
- Rare diagnoses
- Twin pregnancy with one demised fetus: This is a rare possibility, especially if one fetus has demised and the other is still viable.
- Pregnancy with a chromosomal abnormality: Some chromosomal abnormalities, such as triploidy, can cause abnormal fetal development and a lack of fetal pole on ultrasound. However, this would typically be associated with other ultrasound findings and is a less likely diagnosis.