After several years of research and development, the device is currently being evaluated in clinical trials at the Nepean Hospital branch of the University of Sydney Medical School in Australia. This device is not currently FDA or TGA approved and is not available for sale.
The Materna device will be used during the first stage of labor, in a hospital or birthing center, under the supervision of trained clinical professionals. The device design is a mechanical dilator which penetrates the first 4 cm, or 1/3rd of the vaginal canal, and gradually expands the vagina from a resting diameter of 2.6 cm to the fully expanded size of the delivering fetus, roughly 8-10 cm. Expansion will be precisely controlled by a very easy to use semi-automatic force- controlled actuation system, and the device can be removed quickly at any time the mother wishes.
How does it work?
The device works by gently pre-stretching both the vaginal wall and the deeper pelvic support structures during the often lengthy first stage of labor. By stretching the soft tissue slowly and under precise control, we believe maternal injuries can be significantly reduced or even prevented.
We know from research done in sports medicine that muscle injuries are most likely to occur when the stress and strain on the tissue are highest. The faster the rate at which a muscle is stretched, the more stress it experiences. The injuries associated with childbirth are a clear example of this observation. During vaginal delivery, the intense stretching of the vaginal wall and pelvic support structures occurs over a relatively brief period of time, i.e. minutes, not hours. Thus, the tissues do not have enough time to adjust to the massive loads placed upon them. When the muscle is stretched too quickly, it can and will fail and tear.
Conversely, if muscles and ligaments are stretched more slowly, using a modest, controlled force, then the likelihood of injury may be lessened. This is how the Materna Medical device promises to reduce injuries. By slowly stretching, we have on opportunity to maximize the stretch of the tissues. The device will stretch the tissue sufficiently, but it will do so very slowly by exerting precise control over the force and the rate at which that force is applied. The Materna device will exert significantly lower force and pressure on the soft tissue compared to an unassisted vaginal delivery.
In essence, the Materna Medical Device can be thought of as a sophisticated, controlled dilator of the vaginal wall and pelvic soft tissues. A timeline showing the proposed procedure related to labor is shown below:
Walking through what we envision the procedure would look like, the average women spends 14 hours in the hospital from the time she is admitted until the time the baby is delivered. The Materna device intends to take advantage of the time a woman spends in labor to slowly prepare the tissues of the vaginal canal and pelvic floor.
During labor, the dilation of the cervix (green line) is used as the guideline for the progression of labor. The green cervical curve shows the slow dilation of the cervix over the course of 12 hours. However, the orange curve shows the diameter profile for the tissues of the vagina and pelvic floor. The opening of the vagina stays closed through most of labor, however it quickly expands over the course of seconds to minutes as the baby is being delivered. Perhaps there is a way to make the orange pelvic tissue curve look more like the gradual green cervical curve.
The Materna Device, indicated by the purple curve, will begin dilation at some point during the 1st phase of labor and slowly dilate over approximately 1-3 hours. The device would then be removed before the 2nd phase of labor, and the baby would be delivered normally and without any device present.
After several experiments in animal models, Materna has been able to demonstrate that by slowly dilating pelvic tissues we are able to achieve higher diameters, with less force, and less damage to the tissue as compared to more rapidly dilated tests. These animal experiments validate that by stretching slowly, perhaps the stretching can be optimized, and prevent tissue damage. Results for these animal studies have been reviewed by many physicians, and include a histology and pathology analysis to validate the device's safety.
How is the device placed?
During the first stage of labor, before the cervix is fully dilated and effaced, the device is gently inserted into the vagina in the closed position. It never touches the cervix. By utilizing sensitive load and locations sensors, the device initiates a slow, controlled dilation, and cannot exceed a predetermined force. The tissue contacting pads are made of a soft elastomeric material to improve comfort and reduce the chances of trauma. The force exerted by the device is designed to be much lower than the force exerted by the baby's head during the second stage of a normal vaginal delivery. The device dilates the vaginal wall over approximately one to two hours until the device diameter reaches approximately 8 cm (2 cm less than the average baby's head). The device is then removed and the remainder of the labor and delivery proceeds normally.
The device could be inserted any time during the 1st stage of labor, and dilation could occur in short 5-15 minute increments. In between dilations, the mother could remove the device and ambulate if needed. The progression of the cervix could be used as a guideline of the progression of labor. In order to reduce or eliminate any discomfort, the device could be used under epidural analgesia or local anesthesia on the vagina. Based on preliminary work, it is anticipated that this device will need approximately 1-3 hours of dilation time to successfully reduce the internal stresses in the tissue in preparation for the 2nd phase of labor.
Is it safe for the baby?
The device is perfectly safe for the baby, because it is not used during the second stage where the head is normally entering the vaginal canal. The timing for use the device is designed to prevent contact with the baby. However, in the rare situation where the second stage of labor occurs more rapidly than planned, the device has a safety mechanism that collapses the device if it ever touches the baby's head.
The device incorporates several other safety features as well. A switch located on the handle serves as a quick release mechanism. If for any reason the device needs to be quickly removed, the switch is flipped and the device contracts back to an almost closed position. Furthermore, since the device requires active energy to dilate, if any mechanism breaks or malfunctions, the device will naturally want to collapse.
Other Potential Benefits of the device
Since the device will be reducing the tension of the pelvic floor tissues, it is possible that the device may also speed up delivery times. If the device did speed up delivery times, this could mean less stress on the baby during delivery. This could also mean a reduction in the use of forceps or instruments for delivery, which significantly increase the risk of tissue damage. Additionally, many women are choosing elective C-sections because of fear of damage to their pelvic anatomy. If this device is successful, it could possibly lead to a reduction in C-sections.
Why are the first studies being done in Australia?
The Materna device is currently being evaluated with a formal clinical trial at the University of Sydney Medical School in Australia. The Principal Investigator, Dr. Hans Peter Dietz, is a recognized expert in childbirth related injuries and has published widely on the subject.
In fact, Dr. Dietz has discovered these injuries can be visualized using ultrasound, and his group has the largest database of pre- and post-delivery ultrasounds in the world. Dr. Dietz’s experience, research interests, trial infrastructure, research team, and his esteem as an expert in this research area make him the ideal investigator for the Materna device.
In short, Materna has chosen to perform their initial studies with Dr. Hans Peter Dietz, who happens to be in Australia. Materna also has IRB approval to conduct studies within the United States, however at this time, have chosen to focus resources on the study with Dr. Dietz.
These trials begin in July 2011 and will conclude in early 2012.