Menstrual cup
A menstrual cup is a menstrual hygiene device which is inserted into the vagina during menstruation. Its purpose is to collect menstrual fluid. Menstrual cups are made of elastomers. A properly fitting menstrual cup seals against the vaginal walls, so tilting and inverting the body will not cause it to leak. It is impermeable and collects menstrual fluid, unlike tampons and menstrual pads, which absorb it.
Menstrual cups come in two types. The older type is bell-shaped, often with a stem, and has walls more than thick. The second type has a springy rim, and attached to the rim, a bowl with thin, flexible walls. Bell-shaped cups sit over the cervix, like cervical caps, but they are generally larger than cervical caps and cannot be worn during vaginal sex. Ring-shaped cups sit in the same position as a contraceptive diaphragm; they do not block the vagina and can be worn during vaginal sex. Menstrual cups are not meant to prevent pregnancy.
Every 4–12 hours, the cup is emptied. After each period, the cup requires cleaning. One cup may be reusable for up to 10 years, making their long-term cost lower than that of disposable tampons or pads, though the initial cost is higher. As menstrual cups are reusable, they generate less solid waste than tampons and pads, both from the products themselves and from their packaging. Bell-shaped cups have to fit fairly precisely; it is common for users to get a perfect fit from the second cup they buy, by judging the misfit of the first cup. Ring-shaped cups are one-size-fits-most, but some manufacturers sell multiple sizes.
Reported leakage for menstrual cups is similar or rarer than for tampons and pads. It is possible to urinate, defecate, sleep, swim, do gymnastics, run, ride bicycles or riding animals, weightlift, and do heavy exercise while wearing a menstrual cup. Incorrect placement or cup size can cause leakage. Most users initially find menstrual cups difficult, uncomfortable, and even painful to insert and remove. This generally gets better within 3–4 months of use; having friends who successfully use menstrual cups helps, but there is a shortage of research on factors that ease the learning curve. Menstrual cups are a safe alternative to other menstrual products; risk of toxic shock syndrome infection is similar or lower with menstrual cups than for pads or tampons.
Terminology
The terminology used for menstrual cups is sometimes inconsistent. This article uses "menstrual cup" to mean all types, and for clarity, distinguishes the two main types as "bell-shaped" and "ring-shaped".The thick-walled bell-shaped cups are the older type, and the term "menstrual cup" is sometimes used to refer only to bell-shaped cups. But in modern formal contexts, such as academic research and regulations, "menstrual cup" usually refers to both types.
The US Food and Drug Administration holds that "A menstrual cup is a receptacle placed in the vagina to collect menstrual flow." The EU legislated that "The product group 'reusable menstrual cups' shall comprise reusable flexible cups or barriers worn inside the body whose function is to retain and collect menstrual fluid, and which are made of silicone or other elastomers."
Ring-shaped cups are also called "menstrual discs" and sometimes "menstrual rings", to distinguish them from bell-shaped cups. Bell-shaped cups are sometimes called "menstrual bells".
Because bell-shaped cups are commonly depicted as being placed in the vaginal canal, well below the cervix, they are also called "vaginal cups", with the ring-shaped cups called "cervical cups". This may not clearly reflect their position in the body. MRI imaging suggests that, contrary to some manufacturer's depictions, the bell-shaped cups called "vaginal cups" are placed over the cervix, in a position similar to a cervical cap. Ring-shaped cups, called "cervical cups", also cover the cervix, but have one edge next to the cervix, and the other located further down the vagina, so that the cup is nearly parallel to the long axis of the vagina.
In the 1800s, menstrual cups were called "'catamenial sacks", and were similar external catamenial sacks of "canoe-like form", which in turn were similar to catamenial sacks which were waterproof rubber undersheet supports for absorbent pads. These were made from india-rubber or gutta-percha, forms of latex.
Use
Menstrual cups are favoured by backpackers and other travellers, as they are easy to pack and only one is needed.Thorough washing of the cup and hands helps to avoid introducing new bacteria into the vagina, which may heighten the risk of UTIs and other infections. Disposable and reusable pads do not demand the same hand hygiene, though reusable pads also require access to water for washing out pads.
If the hands have come into contact with any chemical that directly trigger sensory receptors in the skin, such as menthol or capsaicin, all traces of the chemical should be removed before touching the mucous membranes.
A UN spec recommends that cups should not be shared; they should only ever be used by one person.
Insertion
The vagina is narrowest at the entrance and becomes wider and easier to stretch further in. Menstrual cups are folded or compressed to insert them, and then opened out once inside. The innermost portion of the cup typically goes into the vaginal fornix. Menstrual cups cannot pass through the cervix into the uterus.The muscles of the pelvic floor, which surround the vaginal entrance, are relaxed to let the cup pass. Involuntarily tensing the vaginal muscles can make it impossible for anything to enter the vagina without causing pain. Many initially find insertion difficult, uncomfortable, and even painful, but learn to do it within a few cycles. There is little publicly available research on learning to use menstrual cups which compares types of cup or instructions.
A bell-shaped cup is folded or pinched before being inserted into the vagina. There are various folding techniques for insertion; common folds include the "C" fold, the "7" fold, and the punch-down fold. Once inside, the cup will normally unfold automatically and seal against the vaginal wall. In some cases, the user may need to twist the cup or flex the vaginal muscles to ensure the cup is fully open.
In practice, the rim of a bell-shaped cup generally sits in the vaginal fornix, the ring-shaped hollow around the cervix. Some fornixes are much deeper than others. Those with deeper fornixes may use insertion techniques such as inserting the cup partway, opening it before the rim passes the cervix, and then pushing it up into place; or they may press the cup to one side and let it open slowly, the rim slipping over the cervix. If correctly sized and inserted, the cup should not leak or cause any discomfort. The stem should be completely inside the vagina. If it can't be positioned inside, the cup can be removed and the stem trimmed.
Ring-shaped cups are inserted differently than bell-shaped cups: by squeezing opposite sides of the rim together until they touch, sliding the inner end of the folded cup to the end of the vaginal canal, and tucking the outer end behind the pubic bone. They can be less bulky than a bell-shaped cup, no bulkier than a tampon. Inserting a ring-shaped cup requires more knowledge of anatomy, to get the cup under and around the cervix, not rucked up in front of it. Ring-shaped cups with non-circular rims are designed to be inserted with the widest, deepest part going in first. If they are inserted the wrong way around they may leak. If there are stems or other removal aids, they should be on the end inserted last.
If lubricant is used for insertion, it should be water-based, as silicone lubricant can be damaging to the silicone.
Wear
A bell-shaped cup may protrude far enough to be uncomfortable if it is too long. It may press too firmly against the bladder, causing discomfort, frequent urination, or difficulty urinating, if it is too firm, or the wrong shape. A bell-shaped cup may leak if it is not inserted correctly, and does not pop open completely and seal against the walls of the vagina. Some factors mentioned in association with leakage included menorrhagia, unusual anatomy of the uterus, need for a larger size of menstrual cup, and incorrect placement of the menstrual cup, or that it had filled to capacity. However, a proper seal may continue to contain fluid in the upper vagina even if the cup is full.While many diagrams show bell-shaped menstrual cups very low in the vagina, with the vagina gaping open, in-vivo imaging shows that the cups sit high, with their rim around the cervix, and the vagina squishes shut below the cup, sealing it inside the body.
If a ring-shaped cup pops out at the outermost edge, either the innermost edge got caught on near side of the cervix rather than tucked into the fornix behind it, or it is too big, or the outermost edge hasn't been tucked behind the public bone firmly enough. In either any case it will leak. If it comes loose and starts to slide out when using the toilet, or leaks on exertion, it is too large or too small. Some deliberately choose a ring-shaped cup which will leak when they deliberately bear down on it, but not at any other time.
Emptying
It is possible to deliberately empty a ring-shaped menstrual disc by muscular effort, without removing it. This is done in a suitable location, such as when sitting on a toilet. Bell-shaped cups must be removed to empty them.The cup is emptied after 4–12 hours of use. Leaving the cup in for at least 3–4 hours allows the menstrual fluid to provide some lubrication.
If sewers are available, menstrual cups can be emptied into a flush toilet, or sink, bath, or shower drain, and the drain rinsed with water. They can also be emptied into a pit latrine.
When using a urine-diverting dry toilet, menstrual blood can be emptied into the part that receives the feces. If any menstrual blood falls into the funnel for urine, it can be rinsed away with water.
In the absence of other facilities, menstrual fluid can be emptied into a cathole. This is a single-use hole deep, more than from water, ideally dug in organic soil, in an area where the waste will break down fast. Water used to rinse the cup can also be disposed of in the cathole, which is then refilled and concealed.