Biomechanics of cervical function in pregnancy : case of cervical insufficiency

The uterine cervix is a passive organ in the female body. Its normal function in pregnancy is to stay firm and closed for the duration of the gestation. At term, under the action of coordinated contractions from the myometrium the cervix dilates sufficiently to allow for the delivery of the fetus. Cervical insufficiency refers to a condition in which the cervix dilates asymptomatically and painlessly in the absence of contractions from the uterine smooth muscle and results in a spontaneous pregnancy loss between the second and third trimester of pregnancy. An elusive and often misdiagnosed condition, cervical insufficiency accounts for a significant percentage of extremely premature deliveries with high incidence of infant mortality and morbidity. Accurate diagnostic criteria and treatment guidelines for this condition are not established and remain a clinical and research challenge. In an attempt to better understand the biomechanics of cervical insufficiency, a fully three-dimensional constitutive model for the large strain, time dependent mechanical behavior of the cervical stroma is proposed. The constitutive model is implemented numerically and integrated with a three dimensional solid model of the lower pelvic region of a pregnant patient into a finite element framework. The resulting finite element model provides a tool to study the effects of different clinical features on the biomechanics of the pregnant cervix and uterus, and allows to investigate the conditions that lead to a premature dilation in the case of cervical insufficiency. New findings on the mechanical behavior of the stroma emphasize the complexity of the stress-strain and volume change behavior of the stroma as well as the intricate correlation between the two. The challenges involved in prescribing a constitutive behavior for the cervical tissue include characteristics such as nonlinearity, viscoelasticity, anisotropy, inhomogeneity and preconditioning.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2007

Author dc:creator

• Paskaleva, Anastassia

Advisor dc:contributor.advisor

• Simona Socrate.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/42287

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/42287