Vanish

Purpose: The main goal of this research study is to collect blood samples and health information from women who are known or at risk for carrying a vanishing twin pregnancy, as well as a cheek swab from the newborn baby, in order to see if Natera’s investigational non-invasive prenatal test, Panorama, can distinguish between the living twin and the twin who has miscarried, and can provide information about possible chromosomal conditions for the living twin.  The results of this study may enable the Panorama test to be used for vanishing twin pregnancies in the future.

In the case of a vanishing twin pregnancy, there is a spontaneous loss of one of the babies resulting in a singleton (single baby) pregnancy. During pregnancy, the fetus contributes some cell-free DNA to the cell-free DNA that can be detected in the mother’s bloodstream. The percentage of fetal cell-free DNA in the mother’s bloodstream is called fetal fraction. When the miscarried twin starts to reabsorb, the fetal fraction for the miscarried twin decreases over time. At the same time, the living twin continues to grow and there is a progressive increase in the fetal fraction for the living twin. Being able to expand the ability of the Panorama test to tell the difference between the fetal fraction of the miscarried twin from the living twin could allow for an accurate detection of chromosomal conditions for the living twin.

In order to expand the ability of the Panorama test for this purpose, we need to collect blood samples and medical information from women with known vanishing twin, or from women who have received a Panorama test result suggesting they may be at risk for a vanishing twin pregnancy, and a cheek swab sample from the newborn baby.

About 200 subjects are expected to take part in this research.

We expect that participation in this research will last from the time of consent to approximately 2 months after the expected due date (approximately 1 year).