Ectopic pregnancies occur when a fertilized egg grows outside the uterus. Ectopic pregnancies are not viable for the fetus and can be dangerous and even fatal for a woman if the ectopic pregnancy is not diagnosed in time. About 2% of all pregnancies are ectopic. Another condition, known as “blighted ovum,” the fertilized egg also fails to develop into an embryo, leaving an unviable pregnancy.
Finding a relatively simple and reliable way to detect these abnormalities as early as possible in pregnancy would help women and clinicians, while also enabling researchers to search for possible genetic factors involved in ectopic pregnancy and blighted ovum.
In healthy pregnancies, the fertilized egg develops into a mass of cells, known as the blastocyst, which is encased in a layer of specialized cells called trophoblasts, which that aid in attaching the blastocyst to the wall of the uterus. The trophoblast cells eventually develop into the placenta that connects the developing embryo and then fetus to the mother for nourishment and oxygen.
In a recent pilot study, investigators in the Division of Intramural Research gently collected cells from cervical canal, which leads into the uterus, from women in early stages of pregnancy and from non-pregnant women. Using a specific staining technique, they found significantly fewer trophoblast cells, which are shed by the developing placenta, in pregnant women diagnosed with blighted ovum or ectopic pregnancy compared with women with healthy pregnancies and non-pregnant women.
This procedure could lead to a simpler, less-invasive technique than those currently available for diagnosing abnormalities in pregnancy and furthering genetic studies of pregnancy abnormalities (PMID: 19497946).