Up to one in three women experience vaginal bleeding during the first few months of the pregnancy, and many wonder how they can make sure the pregnancy is viable. In a study published in the Obstetrics & Gynecology journal, the authors reviewed records of patients with first-trimester vaginal bleeding who were evaluated with serum beta hCG levels and ultrasound.
Higher hCG levels were associated with a greater proportion of ultimately viable pregnancies.
The authors found that 90% of the time in viable pregnancies one would expect to see the gestational sac at 1,918 mIU/ml, the yolk sac at 5,412 mIU/ml and the fetal pole at 24,599 mIU/ml.
They found that 99% of the time one would expect to see the gestational sac at 3,510 mIU/ml, the yolk sac at 17,716 mIU/ml and the fetal pole at 47,685 mIU/ml.
The "threshold value" the lowest value at which one would expect to see something on ultrasound was:
- Gestational sac: 390 mIU/ml
- Yolk sac: 1,094 mIU/ml
- Fetal pole: 1,394 mIU/ml
This study showed that a viable pregnancy can be diagnosed at lower beta hCG levels and with better ultrasound equipment than previously published.