Method and probe for predicting spontaneous preterm delivery

1 . A method for predicting spontaneous preterm delivery, the method comprising the steps of:

a) providing a cervix probe with a head equipped with a plurality of tactile sensors forming together a flat tactile sensor array, and an ultrasound transducer, said head positioned at an angle to a probe shaft, thereby said probe is configured for an orthogonal contact of the entire flat tactile sensor array with an external cervix surface of a pregnant woman,

b) inserting said cervix probe into a vagina to contact said external cervix surface,

c) applying cervix deformation at an external cervical wall facing the vagina and adjacent to an external cervical os with said cervix probe, while simultaneously acquiring cervix stress data using all of said plurality of tactile sensors and cervix strain data using said ultrasound transducer,

d) calculating cervix elasticity and cervix length using said cervix stress data and said cervix strain data, wherein said cervix elasticity is calculated as a ratio of (i) cervix stress derived from said cervix stress data to (ii) cervix strain derived from changes in ultrasound echo time-of-flight during said cervix deformation, wherein said steps (c) and (d) are performed on four radial sectors of cervix, and e) calculating a probability of spontaneous preterm delivery using a predictive model having as inputs respective cervix elasticity and respective cervix length of four radial sectors of cervix.

2 . The method as in claim 1 , wherein said steps (b) through (e) are performed on the same pregnant woman repeatedly beginning from about 22 weeks of pregnancy.

3 . The method as in claim 1 , wherein said step (d) further comprising calculating cervix length from ultrasound pulse time-of-flight from the head of the probe located in contact with said cervix surface at the cervical wall facing the vagina and adjacent to an external cervical os to an internal os surface of said cervix, wherein said time-of-flight is determined from a receive-side ultrasound echo reflected from said internal os surface.

4 . The method as in claim 1 , wherein said step (e) further comprising calculating said cervix elasticity based on a finite element model simulation for cervix.

5 . The method as in claim 1 , wherein said step (d) further comprising compiling of a cervix map with a set of sectors each showing said respective cervix elasticity and said cervix length.

6 . The method as in claim 1 , wherein in said step (e) said predictive model is derived using a clinical validation study.

7 . A probe for predicting spontaneous preterm delivery, said probe comprising: a head equipped with a plurality of solely cervix-facing tactile sensors forming together angle to a probe shaft, thereby said probe is configured for detecting cervical wall pressure distribution during an orthogonal contact with and deformation of an external cervical wall adjacent an external cervical os and facing a vagina, while avoiding contact with adjacent vaginal walls, said ultrasound transducer is positioned adjacent to said plurality of tactile sensors on said head, said tactile sensor array is configured to acquire stress data from four radial sectors of cervix, and said ultrasound transducer is configured to emit an ultrasound pulse and to acquire a scattered ultrasound waveform from four radial sectors of cervix during deformation by said head at the external cervical os facing the vagina and without deforming adjacent vaginal walls, a control unit operably connected to said tactile sensor array and said ultrasound transducer and configured for acquiring said stress data from four radial sectors of said cervix using said tactile sensors and said scattered ultrasound waveform from four radial sectors of said cervix using said ultrasound transducer, and a data processor operably connected to said control unit and configured for calculating cervix elasticity and cervix length of four radial sectors of said cervix using said stress data from four radial sectors of said cervix and said ultrasound waveform from four radial sectors of said cervix, wherein (i) cervix length is calculated from receive-side echo time-of-flight to an internal os reflection, and (ii) cervix elasticity is calculated as ratio of (i) cervix stress derived from stress data to (ii) cervix strain derived from changes in ultrasound eco time-of-flight during said cervix deformation, said processor is further configured to calculate a probability of spontaneous preterm delivery using a predictive model having as inputs of respective cervix elasticity and respective cervix length of four radial sectors of said cervix.

8 . The probe as in claim 7 , wherein said head further comprises an elastic layer covering said tactile sensor array and said ultrasound transducer to allow reversible stress transmission therethrough and multiple disinfections of said probe.

9 . The probe as in claim 7 , wherein said ultrasound transducer is made using a piezoceramic composite material with a mylar film with a predetermined thickness as an acoustic matching layer.

10 . The probe as in claim 7 , wherein said ultrasound transducer has an elastic backing layer to allow attenuation of acoustic backscattering from a support base housing thereof.

11 . The probe, as in claim 7 , wherein the angle between the head and the probe shaft is between 130 degrees and 150 degrees.

12 . The probe, as in claim 7 , wherein the plurality of tactile sensors are positioned around the ultrasound transducer and in the same plane therewith at the head of the probe.

13 . The probe, as in claim 12 , wherein both the head and the probe shaft are straight and form a V-shape in between thereof.

14 . The probe, as in claim 13 , wherein the probe shaft is no larger than the head of the probe to allow applying of cervix deformation without deforming adjacent vaginal walls at the same time.