Cervical Factors to Infertility

The cervix is the opening at the bottom of the uterus. It sits at the top of the vagina, and it has a small canal that allow the menstrual blood out of the uterus during a period and allows the sperm into the uterus during intercourse. The canal is filled with mucus, which is made by the cells that line the canal. This mucus is important for conception. It acts as both a reservoir and barrier to sperm. During intercourse, sperm is deposited into the vagina. The pH of the vagina is too low for sperm to survive long, so they must make it into the mucus in the cervix fairly quickly (within 30 minutes or so) or they will perish. Within the mucus of the cervix, however, they can last for several days.

The mucus in the cervix varies during the menstrual cycle. During ovulation, it is thin, watery and stretchy, but at other times it can be thick and hard for sperm to get through. Even at ovulation when the mucus is stretchy, 99.9% of the sperm will not be able to travel from the vagina, through the mucus, and into the uterus. Some women have conditions that make the cervix even harder to penetrate.

The most common cause of cervical infertility is a previous surgery on the cervix. If a woman has an abnormal PAP smear (a test that looks at the cells of the cervix for cancer), then sometimes surgical treatment is necessary. Cryosurgery (freezing the cells of the cervix), a cone biopsy (removing a cone-shaped piece of the cervical canal), or a LEEP procedure (using an electrofied loop to remove abnormal parts of the cervix) can all affect the canal of the cervix and its ability to make good mucus. Severe infections can also damage the mucus producing cells. Some procedures can even block the canal or turn it into just a pinpoint opening. The most common of these would be a D&C (opening up the cervix and scraping out the contents of the uterus). This is done for miscarriages, terminations of pregnancy, and abnormal bleeding. All of these may keep the sperm from being able to get through the cervix and to the egg.

There are birth defects that can also affect the cervix. Some women will be born with an abnormal cervix or canal. This is common in women whose mothers took a medication called DES to try to prevent miscarriages. Women with cystic fibrosis will also not be able to produce the watery, stretchy mucus needed for optimal fertility. Sometimes we never find the reason why the cervix does not make the right kind of mucus, and sometimes it is a side-effect of the fertility medication they are given (Clomid is the most common culprit).

Even when the mucus appears thin and stretchy, it can still be toxic to sperm. High levels of nicotine can be found in the cervical mucus of women who smoke. A blood pressure medication called Propanolol can also be found in the mucus at four times the blood concentrations and will affect sperm’s motility. Lubricants used for intercourse can also be toxic to sperm. I would recommend using no lubricants, if possible. If you do need a lubricant, there are ones designed to be “sperm-friendly” like Preseed and ConceiveEase.

Unfortunately, there isn’t a good test for looking at the interaction of sperm in the cervical mucus. The Post-Coital Test (PCT) was used for many years. For this test, a couple was asked to have intercourse at a specific time on the day of ovulation. Later, the doctor or nurse removes some of the mucus from the cervix and looks at it under the microscope. If there are lots of live sperm moving around, that was thought to be a good sign. If all of the sperm were dead, that was not good. However, it turned out that this was not true. Lots of live sperm did not always predict pregnancy and vice versa. I have personally seen lots of cases were all of the sperm were dead, but the patient still conceived that cycle. So the PCT is not done much anymore.

Many different treatment have been tried with varying success as well. Cough medications containing guaifenesin are often recommended. The theory is that they loosen up respiratory secretions and they may do the same thing in the cervix. This has never really been proven, though, and my experience with them has been disappointing. It is the estrogen that is made near ovulation that causes the cervix to make that thin, stretchy mucus; so sometimes estrogen is tried. Giving estrogen before and around ovulation can affect ovulation, however, so it is not usually done unless in combination with fertility medication. Estrogen in combination with the fertility medication Clomid (which thickens cervical mucus), for instance, has not really been shown to improve mucus either. This may be because Clomid blocks estrogen receptors so that the estrogen cannot work. The failure of these medications can also be a result of the original cause of the mucus problem. If most of the cells that make the cervical mucus have been removed or destroyed with surgery, for instance, then medication is not likely to be successful.

For most cervical factors, bypassing the mucus and getting the sperm into the uterus is the treatment of choice. This is called intra-uterine insemination (IUI). Basically this is a procedure done on the day of ovulation. Sperm is washed and concentrated down into just a small amount (about 0.5 ml) of fluid. A speculum is then placed into the vagina, and the cervix is cleaned off with swabs. A small tube containing the sperm is threaded through the cervical canal and into the uterus. The sperm is deposited at the top of the uterus and the tube and speculum are removed. It feels a lot like a PAP smear and only takes a few minutes to do unless your cervical canal is very twisty. Most fertility centers are open 365 days a year, so that it can be done even if you are ovulating on a weekend or holiday. IUI gets millions more sperm to the egg, even when there isn’t a cervical issue.

If you haven’t been able to conceive and you have had a procedure on your cervix, then it may be helpful to go see a fertility specialist called a Reproductive Endocrinologist (R.E.). In places where there are no R.E.’s, there are oftentimes OB/GYN’s who know how to wash sperm and perform IUI’s. That simple little procedure may be all it takes to get you pregnant!


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