A blighted ovum is a fairly common type of early miscarriage. In some cases, the woman doesn't even know that she is pregnant yet when she miscarries. In the case of a blighted ovum, a placenta develops, but the embryo doesn't develop and the fetus is never visible on an ultrasound. Doctors think that chromosomal abnormalities cause blighted ovums. Here's how a blighted ovum is diagnosed.
Check the appearance of the gestational sac with an ultrasound. In cases of a blighted ovum, the gestational sac may be small for gestational age and it may have irregular borders. The gestational sac may also be incomplete.
See if a fetus or embryo is present in the gestational sac. As early as 5 1/2 weeks of pregnancy, an embryo can be visualized using a transvaginal ultrasound. If no embryo is seen, the diagnosis of a blighted ovum may be made.
Determine if the uterus is growing as expected. In women who have a blighted ovum, the size of the uterus appears small for the particular week of pregnancy. A doctor can determine the size of the uterus with an examination.
Monitor levels of the pregnancy hormone, human chorionic gonadotropin (hCG). In early pregnancy, hCG levels rise, doubling approximately every 48 hours. However, in cases of a blighted ovum, hCG levels may decrease early on. Having blood work to determine hCG levels over a several day time period can aid in the diagnosis of a blighted ovum.
Watch out for spotting or bleeding. Women with blighted ovums will usually experience spotting or bleeding as hCG levels begin to drop. Cramping can also accompany the bleeding or spotting. If you begin bleeding or spotting in early pregnancy, contact your doctor to see if your bleeding is related to a blighted ovum.
Keep track of your pregnancy symptoms. Women with a blighted ovum often notice a decrease in their pregnancy symptoms such as nausea, fatigue and breast tenderness. This decrease results from the decreasing level of the pregnancy hormone, hCG. Noticing a decrease in pregnancy symptoms can help your doctor possibly diagnose a blighted ovum.