student research day - Case Western Reserve University School of ...

Anna Strohl
Newly developed methodology to test adherence of the fetal membranes (amnion to choriodecidua)
Anna Strohl, Ryan Novince, Jill Novak, Deepak Kumar, MD, Joe Mansour, Brian Mercer, MD, Robert Moore and John
Moore, MD.
Pediatrics, Mechanical and Aerospace Engineering and Reproductive Biology
CWRU, Metro Health
We have previously shown that separation of the fetal membranes (FM), amnion from
choriodecidua, occurs as an integral part of the process of FM rupture. We have also
reported that some spontaneous separation of FM at delivery is nearly universal and is
associated with increased gestation, SROM, shorter duration of contractions, and SVD.
The etiology of this spontaneous FM separation is unknown. If biochemical degradation
at the amnion-choriodecidua interface is a factor, decreased adhesive force between
the FM components prior to complete separation would be expected. The purpose of
this project was to develop and validate machinery and procedures to measure the
adhesive force between amnion and choriodecidua.
Commercial tensile testing equipment was adapted to perform a standard T-peel test
(ASTM D1876) to measure FM adhesive force. FM test strip dimensions, peel speed,
and orientation of test strips with respect to the placental disc were optimized for
reproducibility. Test system validation was performed using Shurtape CP 60 (slow
release painters masking tape) as the standard. FM were from term Caesarean or term
SROM vaginal deliveries.
Equipment and procedures for a standard T-peel test on FM were developed. The
adhesive force between FM ranged from 0.01 lb/in to 0.15 lb/in. A 0.5 lb load cell
(sensitivity of 0.0001) was incorporated into the design and the system adjusted was
so that the load cell operated in its mid-range. Reproducibility was optimal with FM test
strips of 4 cm width by 6 cm length, peel speed of 10 in/min, and FM test strips
oriented parallel to the placental disk. Shurtape CP 60 of decreasing widths showed
reproducible, linear changes (r2 = 0.96) in adhesive force over the adhesive force
range of FM. FM showed greater adhesive force adjacent to the placental disc than
distal from the disc (p