Vanishing Twin

As fertility providers we have become victims of our own success with the rate of twin pregnancies rising to very high levels as IVF laboratory techniques improve. I view twins as an OK outcome but honestly, if I was never responsible for another twin pregnancy I would be ecstatic. The problem with twins is that the rate of preterm labor, preterm delivery and pregnancy related problems are not insignificant. Not all twins end up as cute little Santas on the family’s Christmas card. Some twin pregnancies end in the mid trimester or in the early 3rd trimester. The babies can do well if delivered at a hospital with a good NICU but we would all prefer term, healthy, 7 pound babies.

Sometimes twin pregnancies “auto-reduce” to singleton pregnancies and that is the topic of today’s “Question of the Day.”

79. When I went in for my first ultrasound after IVF, my RE saw two gestational sacs at 6.5 weeks, but only one had a fetal pole with a heartbeat. What will happen to the other pregnancy sac?

Such events are not uncommon following IVF. The incidence of a clinical twin pregnancy after IVF is 10% to 25%, with the exact likelihood depending on the number of embryos transferred and the age of the patient. In 30% to 40% of these pregnancies, one gestational sac will be empty, a situation called a blighted ovum pregnancy. Often, these pregnancies will simply disappear. At other times, the woman may experience cramping and bleeding. In such a case, there is a 40% to 50% risk that the healthy gestational sac and fetus will also abort. There is no way to predict the outcome, and there is no medical intervention that can be implemented to preserve the normal sac and fetus. During this difficult time, patients are well advised to rest and decrease their stress as much as possible. Supplemental progesterone may help quiet uterine contractions, but it is not curative. In women who suffer a twin early pregnancy loss, a medical investigation may be indicated to search for any organic causes that may have contributed to the early pregnancy loss. Unfortunately, such evaluations usually do not produce any definitive answers.