Can an Empty Sac Still Have a Baby?

In short, Yes.

This is dependent upon the size of the sac. There are three options in this scenario:

1) If the pregnancy is very early, the gestation sac may be visible but the baby is still developing. In viable pregnancies, a transvaginal (internal) scan should be able to detect a gestation sac from 5 weeks of pregnancy. A yolk sac can be seen at 5 1/2 weeks and a fetal pole (small embryo) may be seen at approximately 6 weeks. Ultrasound scans can detect a fetal heartbeat at approximately 6-7 weeks of pregnancy. Transabdominal (external) scans may be less accurate at this early stage.

Bhcg (pregnancy hormone) levels should indicate whether or not a sac should be seen. At levels >2000, we would hope to see a gestation sac on ultrasound.

2) A very large gestation sac (average diameter >25mm) with no baby is called an an-embryonic pregnancy (the old term is blighted ovum).

Sadly, this is a type of miscarriage when a very early embryo stops developing. The cause is unknown. The placenta and gestation sac can continue to support itself for a short time and will continue to produce Bhcg. Therefore, pregnancy symptoms and positive pregnancy tests will continue, even though the pregnancy is failing. You may suffer pain or bleeding or it can happen with no symptoms.

3) Very rarely an empty sac can be associated with ectopic pregnancy (pregnancy implanted outside the womb).

This is a dangerous complication of pregnancy requiring hospital treatment. If your sonographer is concerned, they will discuss this with you.