As an IVF specialist, it's very gratifying when patients conceive after IVF treatment. However, like any other pregnancy, 10% of all IVF pregnancies are also destined to have medical problems. The commonest problem is a miscarriage; and in some of these, the reason is because the embryo/fetus does not develop properly. This means that even though the woman is pregnant, and the pregnancy tests are all positive, there is no baby. This is a non-viable pregnancy, and many women get very confused - How can I be pregnant when there is no baby, doctor ?
It's important for the doctor to sit down and explain exactly what the problem is, so that they don't lose hope for the future. A pregnancy consists of two tissues - the embryonic tissue, which gives rise to the baby; and the extraembryonic tissue, which gives rise to the placenta. In these pregnancies, only the tissue from which the placenta arises is formed properly. The tissue which gives rise to the embryo does not develop at all. This appears as an empty gestational sac on ultrasound scanning. This is called a "missed abortion" - presumably because the embryo is missing. The technical term is an anembryonic pregnancy. The commonest reason for this is a genetic problem in the embryo, which prevents it from developing properly. This is a random event, and the risk of recurrence is low, which means patients can be reassured that their chances of having a healthy pregnancy for the future are actually excellent !