Data and sample collection
Couples received saliva sample and buccal swab kits to collect cells for
DNA sampling with instructions along with a brief questionnaire for
demographic data collection. Research team and obstetricians examined
patient clinical and demographic data and entered the data in REDcap.
Couples provided spit saliva and buccal saliva from their live-born
children. Placenta samples from pregnancies that resulted in fetal
demise were processed by pathology within three days of delivery. One
family with a known aneuploid stillbirth (Family 3) was included since
they had five unexplained losses (Table S1 ). Placentas were
processed using clinical protocols for placental pathology, and samples
were obtained from formalin fixed and paraffin embedded (FFPE) blocks
and stored at room temperature. In some cases, samples were collected
for research only. In these cases, placentas were washed and dissected
from fetal villi and maternal decidual tissue to ensure sampling of
fetal tissue. Tissue from these samples were divided into aliquots and
stored at -80 oC.