U.S. patent number 3,918,443 [Application Number 05/391,625] was granted by the patent office on 1975-11-11 for method for birth control.
This patent grant is currently assigned to Ethyl Corporation. Invention is credited to William O. Vennard, Jack C. Wright.
United States Patent |
3,918,443 |
Vennard , et al. |
November 11, 1975 |
Method for birth control
Abstract
A method and apparatus for birth control utilizing an
intrauterine contraceptive device which includes a preformed,
hollow body with thin, flexible walls, the hollow body having the
approximate size and shape of the uterine cavity. A flexible,
compressible, filler material substantially completely fills the
hollow body so that the walls of the hollow body make contact with
a major portion of the walls of the uterine cavity when the device
is in position within the uterine cavity. In a preferred form, the
hollow body is filled with a polymerizable organosiloxane material
after being placed in the uterine cavity and the material is then
polymerized to produce a device having substantially the size and
shape of a normal uterine cavity.
Inventors: |
Vennard; William O. (Baton
Rouge, LA), Wright; Jack C. (Baton Rouge, LA) |
Assignee: |
Ethyl Corporation (New York,
NY)
|
Family
ID: |
26886441 |
Appl.
No.: |
05/391,625 |
Filed: |
August 27, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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190780 |
Oct 20, 1971 |
3779241 |
|
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Current U.S.
Class: |
128/836; 424/432;
128/839; 604/57; 604/515 |
Current CPC
Class: |
A61F
6/16 (20130101) |
Current International
Class: |
A61F
6/00 (20060101); A61F 6/16 (20060101); A61F
005/46 () |
Field of
Search: |
;128/127,128,129,130,131,260,268 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Medbery; Aldrich F.
Attorney, Agent or Firm: Johnson; Donald L. Sieberth; John
F. Mays; E. Donald
Parent Case Text
This is a division of application Ser. No. 190,780, filed Oct. 20,
1971, now U.S. Pat. No. 3,779,241.
Claims
What is claimed is:
1. The method of birth control which includes: positioning an
inflatable, non-irritating, flexible, hollow body substantially
within the uterine cavity, said body being formed from a material
selected from the group consisting of polyvinyl pyrrolodone,
polycellulosics, and polyvinyl alcohol, which material is soluble
in fluids normally present in the uterine cavity; filling said
hollow body with a liquid polymerizable prepolymer or monomer to
produce a flexible, compressible intrauterine contraceptive device
having the shape of the uterus; and dissolving said hollow body
with uterine fluids.
2. The method of claim 1 including foaming said prepolymer or
monomer prior to polymerizing to produce a cellular intrauterine
contraceptive device.
3. A method of birth control including: positioning an empty,
preformed, intrauterine contraceptive device within the uterine
cavity, said device comprising a preformed hollow body having a
shape approximating an equilateral triangle with a continuous,
imperforate top wall joined at its periphery to a continuous,
imperforate bottom wall, said walls being formed of a thin,
flexible material and being connected to each other by connector
stem means at one or more points intermediate their peripheries to
limit expansion of said body; means defining an opening in one of
the apices of said hollow body for filling and emptying said hollow
body; means closing said opening; and expanding said device by
substantially filling said hollow body with a flexible,
compressible, filler material whereby the walls of said body will
make contact with a major portion of the walls of said uterine
cavity when said device is positioned in said uterine cavity.
4. The method of claim 3 wherein said filler material is selected
from the group consisting of water, mineral oil, silicone fluids
and saline solutions.
5. The method of claim 3 wherein said filler material contains a
member selected from the group consisting of bacteriostats,
medicaments, and fragrances.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates, in general, to a method and apparatus for
birth control utilizing a novel intrauterine contraceptive
device.
2. Description of the Prior Art
Intrauterine contraceptive devices are well known in the art and
have been in wide use for many years. The devices are fabricated
from many different materials and take the form of spirals, loops,
bows, rings, etc., as exemplified by devices known as the Lippe's
loop, Margulie's spiral, Birnberg bow and the Grafenberg ring. Very
early devices were made from silver metal; however, their use has
declined and thermoplastic material has replaced the former metal
structures.
Many of the prior art intrauterine contraceptive devices suffer
from two principal deficiencies which have prevented their
widespread adoption by the medical profession. In very early work
with intrauterine contraceptive devices, it was discovered that the
natural contractions of the uterine cavity would expel the earlier
devices from the uterus and lead to unwanted pregnancies when the
female was unaware that the device had been expelled. This lead to
designing the intrauterine devices into very elaborate
configurations in order to permit compression and collapse for
insertion through the cervix into the uterus and subsequent
expansion in the uterus to assume a form which would not be easily
expelled by the natural muscle contractions. The second problem
associated with the prior art intrauterine contraceptive devices
has been the tendency of these devices to produce physiological
complications in the patient. Many women are unable to accommodate
intrauterine contraceptive devices because of inflammation and
irritation and sometime bleeding which occurs in certain
patients.
A recent study of IUD's by E. J. David, M.D., and John Lesinski,
M.D., has been published in Volume 36, No. 3, September 1970 issue
of Obstetrics and Gynecology entitled "Mechanism of Action of
Intrauterine Contraceptives in Women." The conclusion is reached in
this article that the contraceptive efficacy of devices molded of
plastic materials of similar composition correlates with the total
surface area of the plastic article coming in contact with the
endometrium, irrespective of the variations in geometric design.
Further, the authors observed that chemical composition of the
device significantly influences pregnancy rates when the rates
accompanying devices of identical size, shape and surface area are
compared. In the studies conducted, it was found that an IUD
constructed in the form of a shield had the lowest percent
pregnancy rate of any of the comparative devices tested, e.g., a
"B" loop and a double coil. Efficiency for this shield-shaped IUD
was 98.9 percent pregnancy prevention. While the device disclosed
in the foregoing study is an improvement over prior art IUD's,
nevertheless, there exists the problem of placing the device within
the uterus. Because of its size and configuration, it is difficult
to collapse the device into a sufficiently small size to permit
convenient insertion through the dilated cervical canal. Further,
after entry, opening the device and positioning it properly between
the walls of the uterus presents significant problems.
Therefore, there is a need in the IUD art to provide a device which
can contact as much of the uterine wall area as possible and yet
permit easy placement within the uterus and easy withdrawal
therefrom, if it is desired to remove the device.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an intrauterine
contraceptive device which provides maximum surface area contact
between the walls of the device and the walls of the uterus.
It is a further object of the present invention to provide an
intrauterine contraceptive device which may be readily placed in
the uterus and also readily removed therefrom.
It is also an object of the present invention to provide an
intrauterine contraceptive device which has a shape substantially
the same as that of the uterine cavity.
It is still another object of the present invention to provide an
intrauterine contraceptive device which is flexible and
compressible so as not to produce significant irritation of the
walls of the uterus.
The foregoing objects are realized in an intrauterine contraceptive
device which includes a preformed hollow body having thin, flexible
walls which have the approximate size and shape of the uterine
cavity. A flexible, compressible, filler material substantially
completely fills the hollow body, whereby the walls of the hollow
body will make contact with a major portion of the walls of the
uterine cavity when the device is positioned in the uterine
cavity.
The method aspects of the present invention are realized in a
method of birth control comprising the steps of positioning a
preformed, hollow body having thin, flexible walls within the
uterine caivty and expanding said body to substantially fill the
cavity.
The intrauterine contraceptive device of the present invention
overcomes the disadvantage found in prior art devices by providing
maximum contact between the IUD and the walls of the uterus. The
IUD of the present invention also overcomes the difficulty of
fitting IUD's to various women having uteri of significantly
different sizes. By preparing the IUD of the present invention in
the form of a flexible, thin wall, hollow body shaped like the
uterus, the device, when placed in the uterus and filled, is made
to substantially fit the contours of the uterus and substantially
fill the same. By forming the hollow body portion of the IUD of the
present invention out of thin wall, flexible, soft, collapsible,
polymeric material, e.g., natural rubber or silicone rubber, the
hollow body can be folded or collapsed for easy insertion into the
uterus through the cervical passage. By utilizing either a
removable filler material, such as air or water, or a solid filler
material which is easily compressed, such as a foamed elastomeric
material, the IUD of the present invention can be easily withdrawn
from the uterus.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a side, elevational, sectional view of the human female
reproductive organs showing one embodiment of the IUD of the
present invention in place in the uterus;
FIG. 2 is a plan, sectional, partially broken view of FIG. 1 taken
along the line 2--2;
FIG. 3 is a perspective, elevational, partially broken view of
another embodiment of the IUD of the present invention;
FIG. 4 is a perspective, elevational, partially broken view of
still another embodiment of the IUD of the present invention;
FIG. 4A is a cross-sectional view of FIG. 4 taken along line
4A--4A;
FIG. 5 is a plan view of a further embodiment of the IUD of the
present invention;
FIG. 5A is a cross-sectional view of FIG. 5 taken along line
5A--5A;
FIG. 5B is a cross-sectional view of FIG. 5 taken along line
5B--5B;
FIG. 6 is a plan view of a still further embodiment of the IUD of
the present invention;
FIG. 6A is a cross-sectional view of FIG. 6 taken along line
6A--6A;
FIG. 7 is a plan view of a different embodiment of the IUD of the
present invention; and
FIG. 7A is a cross-sectional view of FIG. 7 taken along line
7A--7A.
Description of the Preferred Embodiments
Referring now to FIGS. 1 and 2, one embodiment of the intrauterine
contraceptive device of the present invention includes a hollow
body, designated generally by the numeral 10, which is shown in its
expanded or inflated position in the uterus 11. When inflated by
filling with a fluid medium, the hollow body substantially
completely occupies the uterine cavity 11a and makes contact with
the walls 11b of the uterus. The hollow body 10 includes a thin,
flexible top wall 19 and a bottom wall 20. When inflated, the
hollow body generally has the shape of an equilateral triangle
having generally parabolic sides. The hollow body includes two
spaced apart, substantially equal length, left and right leg
portions 12 and 13 which project into the "horns" or the respective
left and right Fallopian tube entrances 14 and 15. The lower neck
portion 16 of the hollow body is elongated and is received in the
cervical canal 17. The lower end of the neck portion terminates in
the cervical canal just short of its entrance into the vagina 18. A
plug 21 made of soft elastomeric material, which may be integrally
formed on the end of neck 16, closes the open end of neck portion
16 and permits the collapsed, hollow body to be inflated by means
of a hypodermic needle and syringe.
Another embodiment of the IUD of the present invention is shown in
FIG. 3. The hollow body 10 in this embodiment is filled with a
liquid material 22 in place of a gaseous medium used in the
embodiment shown in FIGS. 1 and 2. The liquid filling material may
be any suitable sterile liquid such as water, mineral oil, medical
grade silicone fluids, saline solutions, or any other non-toxic
sterile liquid.
In another embodiment of the invention, the fluids used to fill the
hollow body have dissolved or suspended therein suitable
concentrations of bacteriostatic agents or medicants, and the
hollow bodies are made of a liquid-permeable film so that a very
gradual release of the fluid from the hollow body to the uterus
occurs. Among suitable bacteriostatic materials are
2,2'-thiobis-(4,6-dichlorophenol) (sold under the trademark
"Actomer" by Monsanto Chemical Company) and
2,2'-methylenebis(3,4,6-trichlorophenol) (sold under the trademark
"Hexachlorophene" by Sindar Corporation). Suitable medicants are
the penicillins and the sulfa drugs. Other bacteriostatic agents
and medicants may also be used.
In a further embodiment of the present invention, the
bacteriostatic agents or medicants may be incorporated into the
film-forming material of the hollow bodies, e.g., by mixing with
the plastic material prior to forming the hollow body (see U.S.
Pat. No. 2,919,200) or by impregnating the hollow body after being
formed.
A still further embodiment of the present invention is to
incorporate natural and synthetic fragrances in the fluids
contained within the liquid-permeable hollow body.
Still another embodiment of the IUD of the present invention is
shown in FIGS. 4 and 4A. The preformed body 10 is first collapsed
or folded and inserted into the uterus. The body is then filled by
means of a hypodermic syringe and needle with a liquid-curable or
polymerizable material, such as a prepolymer or a monomer
containing a curing agent or polymerization catalyst. The material
is then allowed to cure or polymerize to provide a solid or
cellular, flexible, compressible filler insert having the exact
shape of the uterus. As seen in FIG. 4A, the filler insert 23 is
formed of a cellular material produced by adding any suitable
foaming agent to the liquid material used to form the filler
insert. Preferred are foaming agents which have boiling points
slightly below the normal temperature of the human body, i.e.,
below 98.2.degree.F, such as isopentane, n-butane, dimethyl ether,
diethyl ether, ethyl chloride,
2,2'-azobis(2,4-dimethylvaleronitrile), and others.
The upper wall 19 and the lower wall 20 of the hollow body may be
joined by an integrally formed connector stem or rib 24 as seen
more clearly in FIG. 4A. This stem or rib prevents excessive
thickening of the IUD so that the entire IUD may be removed from
the uterus through the cervical canal 17 when dilated. It has been
observed that the muscle tone of the upper and lower wall sections
of the uterus is weakened in women who have experienced multiple
childbirth. This condition results in the filler material assuming
an undesirable, semi-spherical, cross-sectional shape rather than
the desired elliptical, cross-sectional shape, as shown in FIG. 4A.
The stem or rib 24 prevents undue thickening of the IUD in those
uteri having poor muscle tone.
As seen in FIGS. 1-4A, the IUD of the present invention, when
expanded with a filling material, will have its maximum thickness
at the mid-portion thereof where the uterus has its normal maximum
diameter. The depiction of the IUD of the present invention, as
seen in FIGS. 1-4A, represents an average of the shape that the
device is expected to assume; however, it is understood that the
final shape of the IUD of the present invention will be determined
solely by the shape of the individual uterus in which the device is
placed, or in part by the length of the stem 24 when this form of
the IUD is utilized.
In FIGS. 5, 5A and 5B, another embodiment of the IUD of the present
invention is depicted. The hollow body, or envelope, 25 is formed
from a thin wall, flexible material and has a top wall 26 and a
bottom wall 27. The top and bottom walls are welded together, as by
being integrally formed, in a plurality of spaced apart, generally
rectangular sections 28 which extend inwardly from the side edges
29--29 of the body 25. Top, intermediate and bottom, hollow,
transverse channels 30, 30a and 30b are provided in body 25 between
the fused top and bottom wall areas. These transverse channels
intersect a longitudinal channel 31 which is an extension of the
bore defined by the stem 32 of the hollow body. The stem is closed
by plug 33.
The hollow body 34, as seen in FIGS. 6 and 6A, has the same general
shape as that of hollow body 25, but is provided with a centrally
located area 39 which has the shape of an equilateral triangle
wherin the top and bottom walls 35 and 36 are fused together. A
triangularly shaped, hollow channel 37 surrounds the fused area 39
and joins the bore provided in stem 38.
In FIGS. 7 and 7A, another embodiment of the hollow body 40 is
shown wherein top wall 41 and bottom wall 42 are joined together
along spaced-apart, parallel lines 43--43 which extend inwardly
from the top edge 44 of the body.
In all of the embodiments shown in FIGS. 5-7A, the fused portions
of the top and bottom walls limit transverse expansion of the
hollow body when the hollow body is expanded in the uterus by
filling with the selected filling material, e.g., water, air,
silicone rubber. However, the constructions still provide for a
substantial contact between the wall areas of the IUD's and the
walls of the uterus which has been determined to be directly
related to the efficiency of an IUD in preventing pregnancy. The
top and bottom walls of the IUD's of the present invention may be
joined by any suitable means at any number of points.
The hollow body portion of the IUD may be made from any suitable
material which is non-toxic, flexible, and capable of forming a
reasonably strong, thin film. Among suitable materials for forming
the hollow body are silicone rubbers (organosiloxane polymers),
synthetic rubbers, natural rubbers, polyethylene, polypropylene,
plasticized polyvinyl chloride, plasticized polyvinylidene
chloride, polyvinyl alcohol, polyesters, polyethers, polyvinyl
acetate, polyethylene oxide, polyurethanes, polyvinyl pyrrolidone,
and water soluble polystarches and polycellulosics.
The hollow body can be formed by fusing thin sheets of the material
precut in the desired shape of the hollow body. A preferred method
for forming the hollow body when using elastomeric type materials
is by dipping a mold having the desired shape into a latex solution
and curing the latex which adheres to the mold. Rotational molding
using hollow molds of the desired shape can also be used. Resin
monomers and prepolymers may also be used to form the hollow body
by coating a mold having the shape of the walls of the uterus and
then polymerizing the monomer or prepolymer.
When it is desired to use a solid or semi-solid filler material for
the IUD, these filler materials may be formed in situ in the hollow
body after placing the hollow body within the uterus by curing any
curable material which produces a soft, elastomeric polymer. It is
preferred that the filler material be formed of a non-irritating,
flexible, elastomeric material, particularly one prepared from a
polyorganosiloxane material. Among the preferred materials are the
medical grade silicone rubber prepolymers marketed by Dow-Corning
under the trade name "Silastic." In certain applications,
Dow-Corning medical adhesive Type A may be used as the prepolymer
and catalyzed to provide the polymerized, finished IUD device. The
preferred material for forming the filler material of the IUD of
the present invention is Dow-Corning's Silastic RT-382 which is a
room-temperature-curing silicone rubber or prepolymer. The
viscosity of Silastic RT-382 can be reduced by mixing with
Dow-Corning RTV thinner (dimethyl silicone fluid) to achieve the
desired viscosity for injecting the prepolymer into the hollow body
using a hypodermic syringe.
In the method of the present invention, the deflated hollow body 10
is rolled into a tubular conformation or otherwise folded into a
compact tubular shape. It is then placed in a hollow insertion
device for insertion into the uterus through the vagina and
cervical canal. U.S. Pat. No. 3,509,877 discloses a suitable
insertion device and its disclosure is hereby incorporated by
reference. After placement in the uterus, the hollow body 10 is
inflated by piercing plug 18 with a hypodermic needle and forcing
the selected filler material through the needle from a filled
hypodermic syringe. To remove the device when it is filled with a
gas or a liquid, the operation described above is reversed to empty
the hollow body and permit its collapse for easy withdrawal. The
neck 16 can then be grasped with a suitable instrument and the
device removed through the cervix, which may be dilated if
necessary. When a solid or semi-solid filler is used, it is
recommended that the cervix be dilated before removing the IUD.
Another embodiment of the IUD of the present invention is prepared
using water soluble polymers such as polyvinyl pyrrolidone (PVP),
polystarches, polycellulosics, and polyvinyl alcohol (PVA) to
fabricate the hollow body. These materials are soluble in the
uterine fluids and a hollow body made from these polymers, when
placed in the uterus and filled with a filler that polymerizes in
situ, e.g., silicone prepolymer, will dissolve and leave the
polymerized silicone material in the uterus to serve as the
IUD.
From the foregoing examples of exemplary embodiments of the
invention, it is seen that numerous modifications and changes will
readily occur to those skilled in the art. Thus, the exact
construction and operation described hereinbefore is not to be
taken to limit the invention, and all embodiments coming within the
scope of the claims are intended to be covered herein.
* * * * *