Intrauterine Contraceptive Device

Abstract

A three-dimensional intrauterine contraceptive device which conforms in an infinite manner to the internal geometric shape of the uterine cavity. The device is comprised of a plurality of resilient interconnected rib-like members which define a generally cylindrical-type shape. The device is inserted into the uterine cavity in a compressed condition. Upon release from a holder the device expands outwardly engaging the walls of the uterine cavity to provide an effective contraceptive device.

Description

BACKGROUND OF THE INVENTION

One of the most effective methods of contraception is the use of intrauterine devices (IUD). Although many theories have been presented describing the mode of action of IUDs, the most popular is that recently proposed by Sagiroglu. This theory states that a foreign body in the uterus produces a foreign body reaction, with subsequent accumulation of a high concentration of leukocytes in the uterine cavity. The leukocytes in turn prevent fertilization of the ovum by the spermatozoa. One of the essential elements of this theory is that it requires maximum contact between the foreign device and the uterine lining. Furthermore, in order to allow maximum reaction time between the leukocytes, spermatozoa, and blastocyst, in case of fertilization, the device should be as close as possible to the uterotubal junction and make maximal contact with the posterior and anterior walls of the uterine cavity.

Numerous intrauterine devices have been designed and are currently in use. These are for the most part two dimensional in configuration and do not conform to the size or shape of the uterine cavity. They usually suffer either from a high expulsion rate, a high pregnancy rate, or a high rejection rate due to pain or bleeding. These three factors are the most important criteria used today for evaluating the performance of all intrauterine devices. In general, it has been found that if one device has a low rate of pregnancy it may fail in one or both of the other properties. Another important property which in this case will facilitate the wide spread use of the intrauterine device, is the need for dilatation of the cervical os. Some devices, although quite efficacious, require chemical dilatation of the cervical os for insertion. This highly specialized operation, however, must be performed only by a physician who is trained in the procedure of controlled administration of drugs having the desired local dilatatory properties. A similar operation may also be required when the device is withdrawn from the uterine cavity. The dilatation procedure places a certain constraint on the ease of application of the device and the time required for its insertion and removal. It limits its widespread use, especially in places where only paramedical personnel are available. Furthermore, it adds to the total cost of inserting the device. From this, it is obvious that an intrauterine device which does not require the additional step of dilatation during insertion and withdrawal is superior to another that requires it.

SUMMARY OF THE INVENTION

The ideal intrauterine device is one which satisfies all the above criteria. It should produce a very low pregnancy rate, expulsion rate, and rejection due to pain and/or bleeding. Furthermore, it should not require pretreatment of the patient with other drugs. The device I have developed is three dimensional and conforms to the size and shape of the uterine cavity. It also does not require dilatation of the cervical os for insertion or removal. Based on results obtained with other intrauterine devices which have some of the elements of this device, it is expected that the three dimensional device will have a very low pregnancy rate, expulsion rate and rejection rate due to either pain and/or bleeding.

Its three dimensional configuration conforms in an infinite manner to the internal geometrical shape of the uterine cavity. Its low resistance or elastic design permits continuous flexing and bending with changes in the uterine size and shape during menstruation. It is thus capable of compression under the lateral forces of the uterus. This ability to conform in a three dimensional manner to the uterine lining is especially important since the human uterus also varies in size and shape from one individual to another.

The device may be inserted with the popular straw-type introducer and is released in a uni-directional fashion. This eliminates the need for dilatation of the cervical os before insertion, insures its symmetrical location in the uterus and uniform distribution of the pressure against the walls of the cavity. The upper open end of the device produces direct contact between the device and the uterotubal junction. This is important for producing minimal pregnancy rates.

The lower end of the device is also open and does not have the usual tail. Its broad, cervical base makes expulsion of the device very difficult since it does not come in contact with the cervical os, a zone which is known to be sensitive and which responds to foreign objects by producing contractile motions, which in the past have been the primary cause of expulsion of other intrauterine devices. Both the open upper and lower ends of the device greatly facilitate the passage of menstrual fluids during the monthly cycle. The device is thin and has minimal volume. Its smooth, contoured surface especially when coated with a medical grade soft tissue substitute material such as medical grade silicone rubber, will produce minimal pain and bleeding reactions. Further, the device is easily removed by pulling a filament attached to its lower end. This operation reduces the diameter of the lower opening of the IUD to that of the cervical os, which allows the device to pass through the cervix into the vaginal cavity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the invention;

FIG. 2 is a front view of the device in the uterine cavity;

FIG. 3a is a side view of FIG. 2;

FIG. 3b is the device in view of FIG. 3a in the uterine cavity during the menstrual cycle;

FIG. 4 is a schematic illustration of an alternative embodiment of the invention;

FIG. 5 is a schematic illustration of a still further embodiment of the invention;

FIGS. 6a and b are variations of a still further embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The device is shown generally in perspective view in FIG. 1 at 10 and is formed from a resilient material, such as spring stainless steel wire. In order to minimize endometritis, the wire may be coated with a synthetic, inert polymer, such as silicone rubber, polyethylene, Teflon, a fluoronated hydrocarbon, polypropylene, etc. Alternately, it can be constructed from a hydrocarbon material, such as a parafin, for example polyethylene. Referring to FIGS. 2 and 3, the device or daisy 10 as shown is inserted in the uterine cavity 12. The device comprises a plurality of continuously joined elongated loops 14. As previously stated, the device may be inserted with the straw-type introducer as is well-known and is released in a uni-directional fashion. The device or daisy when inserted into the uterine cavity prior to its release from the introducer is about 3 millimeters in diameter in its compressed condition. When released, it will expand from about 25 to 55 millimeters depending upon the size of the uterine cavity. This expansion allows the device to expand with varying diameters along its axial length to intimately conform to the surface of the cavity walls.

The upper open end 16 of the device 10 produces direct contact between the device and the uterotubal junction 18. The broad cervical base 20 defined by the lower loop ends 22 of the device insures that the device does not come into contact with the cervical os 24. The volumetric area defined by the device and its upper and lower ends as shown in FIG. 2 provides a funnel-shaped zone to facilitate the passage of menstrual fluids during the monthly cycle. Because of the flexibility and resiliency of the device 10, it is easily removed by pulling a filament 26 secured thereto. The filament 26 is interwoven through the bottom loops such that when the filament is pulled the lower loops are drawn together diminishing the circumferential area. This reduces the diameter of the lower opening 20 of the device 10 to that of the cervical os 24 which allows the device to pass through the cervix into the vaginal cavity 28. Referring to FIGS. 3a and b, the efficiency and compatibility of the device are shown in that in the lateral cross section as portrayed the device through its three-dimensional aspect and resiliency conforms to the shape of the uterine cavity during the menstrual cycle.

In FIG. 4, an alternative embodiment of the preferred embodiment is shown wherein a fabric, either nonwoven or woven, for example, a screen-like or lace fabric material, such as lace 30, covers the lower end 20 and upper end 16 of the device 10. This provides for the passage of menstrual fluids therethrough while limiting the diameter of the device at this end which helps reduce the expulsion and penetration of the device into the walls of the cervix. The upper end of the device is shown as being covered with a fabric or lace 30 to provide contact with the fundus thus helping enhance the foreign body reaction and subsequent accumulation of leukocytes. The combination of the device with the fabric provides maximum and positive contact with the uterine cavity in all directions. For example, to increase the foreign body (surface area of the device) contact with the uterine walls the fabric may be disposed entirely on the inner portion of the device, entirely on the outer portion of the device, or threaded through the elongated loops 14 as shown in FIG. 1. The fabric may also be secured between the rib-like members to form a web-like surface. The fabric may cover all or a portion of the device in any geometric arrangement thereon. Further, the fabric used on the walls of the device may be more sheer than that which covers the top and bottom opening, that is, the interstices may be of a smaller dimension. Natural or synthetic elastomers may be used in combination with the materials to form the fabric or they may be used in lieu thereof.

A modification of the device of FIG. 4 would be to envelop the whole device with a fabric such as a lace fabric. This would aid significantly in nurturing the accumulations of leukocytes in the interstices of the fabric structure. For the type of lace fabrics which may be employed with the device, either at one end or the other end or both ends of the device or completely enveloping the device in the lace fabric or covering a portion thereof, the lace fabric of course must be medically acceptable for incorporation into the body cavity.

A further embodiment of the invention relating to its structure is shown in FIG. 5 wherein a plurality of flexible members 34 intersect and are secured at 36 to define two cone-shaped zones 38 and 40.

Referring to FIGS. 6a and b, still further embodiment of the invention is shown wherein a cage-type structure 42 having a plurality of rib-like members 44 define a globe-like volume having upper and lower open ends 46 and 48. A modification of this embodiment is shown in FIG. 6b wherein the rib-like members extend completely from one to the other end of the central axis about which the member 42 is formed.

In addition to the components of construction mentioned above, if the device is composed of metals, the metal may be composed of copper or copper alloys or similar metals known to reduce significantly the incidence of pregnancy. The fabric, whether woven or nonwoven, should preferably be screen-like to allow for the passage of fluids therethrough. The fabric, as the device, may be formed from metallic materials, such as steel, copper and their alloys, platinum, etc., nonmetallic materials, such as from a variety of organic polymers and also from inorganic compounds which offer the advantages of intertness, complete stability and a wide range of surface properties. For example, organic materials, such as polymeric materials which would include silicones, fluorinated polymers, cellulose and its derivatives, polyesters, polyolefins, vinyls, polyamides, etc., may be used.

Further, any of the devices shown may be constructed of these materials or coated in whole or in part with a fabric such as a lace-type fabric or a flock or nonwoven flock in order to increase the surface area of the device which is exposed to the uterine wall, thus increasing the formation of leukocytes.

Claims

Having described my invention, what I now claim is:

1. A three-dimensional intrauterine contraceptive device, which device comprises:

a plurality of elongated members forming an elongated loop, successive members joined at alternate ends to form said elongated loop, the members adapted to engage and conform in a resiliant manner to the wall of the uterine cavity, the members defining therebetween a fluid-flow zone open at each end, and comprising an upper and a lower zone, the zone facilitating the passage of menstrual fluids during the monthly cycle, the members of the upper fluid zone adapted to engage and contact directly the area of the uterotubal junction, while the members of the lower fluid zone are adapted to avoid contact with the cervical os.

2. The device of claim 1 wherein said members form a continuous sinusoidal wall about the periphery of the three-dimensional device.

3. The device of claim 1 wherein the loop members of the device form a funnel-shaped fluid-flow zone.

4. The device of claim 1 wherein the loop members are arcuate in form and define a globe-like fluid-flow zone.

5. The device of claim 1 which includes means to remove the device from the uterine cavity.

6. The device of claim 1 which includes loop members comprising an inert synthetic polymeric material.

7. The device of claim 1 wherein said loop members comprise a metal known to reduce the incidence of pregnancy.

8. The device of claim 1 which includes a screen-like fabric material secured to at least a portion of the device.

9. The device of claim 8 which includes a screen-like fabric material secured across the upper or lower opening of the fluid-flow zone.

10. The device of claim 8 wherein the screenlike fabric material is secured to the loop members to form all or a portion of the peripheral wall of the device.

11. A three-dimensional intrauterine device which comprises a plurality of elongated loop members in generally sinusoidal form, said members adapted to engage and conform in a resilient manner to the walls of the uterine cavity, the loop members defining a generally funnel-shaped fluid-flow zone open at each end and comprising an upper and a lower zone, said members of the upper zone adapted to engage and to contact directly the area of the uterotubal junction, while the members of the lower fluid zone are adapted to avoid contact with the cervical os.

12. The device of claim 11 which includes a screen-like inert fabric material secured to at least a portion of the device.

13. The device of claim 11 which includes a screen-like fabric secured across the upper or lower ends of the funnel-shaped fluid-flow zone.

14. The device of claim 11 which includes a screen-like fabric secured to the loop members in a continuous manner about the wall of the device as defined by said members.

15. The device of claim 11 wherein the members comprise an inert synthetic polymeric material or stainless steel.

16. The device of claim 11 which includes a filament means to remove the device, the filament means interwoven between the lower loop members and adapted to reduce the diameter of the lower portion of the device when tension is applied to said filament, thereby permitting the removal of the device from the intrauterine cavity.

17. The method of preventing pregnancy by the employment of an intrauterine contraceptive device, which device includes a plurality of resilient loop members, which method comprises:

a. inserting the device in a compressed condition into the uterine cavity;

b. expanding the device in the uterine cavity to provide a plurality of elongated members forming an elongated loop, successive members joined at alternate ends to form said elongated loop, the members forming a fluid-flow zone open at each end comprising an upper zone and a lower zone, the upper zone having the same or a greater flow size than the lower zone; and

c. contacting the area about the uterotubal junction with the loop members defining the upper end of the fluid zone while avoiding contact with the cervical os of the lower and of the loop members defining the lower fluid-flow zone, thereby permitting the passage of menstrual fluid through the fluid-flow zone between said members, the members on expansion engaging and conforming in a resiliant manner to the wall of the uterine cavity.

18. The method of claim 17 which includes the step of removing the device from the uterine cavity by reducing the diameter of the lower portion of the members in the lower fluid-flow zone by the application of tension.

19. The method of claim 17 which includes inserting a screen-like fabric material across at least a portion of the fluid-flow zone, the fabric providing for the passage of menstrual fluid therethrough by limiting the diameter of the loop members at the lower end of the fluid-flow zone.

20. The method of claim 17 which includes securing a screen-like fabric material about the wall of the device as defined by the loop members.

21. The method of claim 17 which includes the step of providing a funnel-shaped fluid-flow zone formed by the loop members.

22. The method of claim 17 which includes forming the loop members into a globe-like structure wherein the upper and lower ends of the fluid-flow zone are similar in flow diameter and the loop members are arcuate in form.