Fertility monitors are chosen by many women to help in getting pregnant, while others use them to assist in natural family planning as a contraceptive. This article will review how fertility monitors (also called ovulation predictor kits) work, the various brands and the costs associated with using them.

The main purpose in using a fertility monitor is to pinpoint the day of ovulation in a woman's menstrual cycle. This is because while sperm can survive inside a woman for 3-5 days, an unfertilized egg only has a small window of opportunity to be fertilized before it's too late to implant in time to grow a baby. Thus couples either planning to conceive or trying not to conceive must be aware of that window. This is where the fertility monitors come in. If a woman has a regular cycle, usually is aware of the day of her ovulation by observing her body and keeps track on a calendar of her fertile periods, a fertility monitor only confirms for her the fact of ovulation. However, many women do not have regular cycles or they need to know the exact time of ovulation to attempt procreation or natural contraception. A fertility monitor in this case becomes a necessity.  One note before the review:  many manufacturers of fertility monitors do not recommend them as a "safe" contraceptive because user compliance varies widely.  However, equivalent rates of contraceptive effectiveness are claimed by other companies, IF the couple uses them as directed and either abstains on fertile days or use another form of contraception like a condom.

Fertility Monitor Review

There are 3 main methods used to track the day of ovulation. These are hormonal testing in urine, electrolyte testing in saliva and body temperature measurement. The monitors vary in how much help is given to keep track of fertility, price up front and over long-term use and accuracy levels across the menstrual spectrum.

Hormone Level Testing

There are two hormones commonly tested for in urine. A third, hCG, is tested for in pregnancy kits. Ovulation is marked by a surge in luteinizing hormone (LH), which is triggered by an upswing in levels of estrogen. Women with problems conceiving often have insufficient levels of either hormone, leading to a lack of ovulation, and an ovulation predictor kit can pinpoint this cause of infertility. Once the LH surge has occurred, the egg is released by the follicle and begins its journey towards the womb. The body excretes LH and estrogen into the urine, beginning a short period of time after ovulation (as it takes the hormones a while to get into the bladder). Thus a hormone test for the presence of LH in urine only shows that ovulation has occurred, and this is a criticism some use for LH tests. However, there should still be sufficient time for conception. Most commercially sold urine testers make up for this by also testing for estrogen; once estrogen levels begin rising, the monitor alerts the user that the days of fertility are approaching, and then shows when ovulation has occurred. While there is only a day or two of viability for the egg, sperm present inside the womans' body before ovulation can also fertilize the egg, leading to a 2-3 day window of fertility before ovulation and a 1-2 window afterwards. (numbers vary depending on the motility of individual sperm)

Clearblue Easy is the largest manufacturer of "urine sticks" on the market now; Persona is sold in Europe as well. The cost of the Clearblue Easy system at this time is $150 for the monitor and a little over $10 a month (for 10 test sticks). Their computer monitor keeps track of cycle lengths as well.

Saliva Electrolyte Level Testing

When ovulation approaches, a woman's saliva changes. This change in the level of electrolytes can be monitored in two ways. The first is by licking a slide and then observing under a microscope the patterns in the dried saliva. There is a distinctive "ferning" pattern that emerges upon ovulation. This method is one of the cheapest but depends on how well a woman can read the slide. Ovulens makes a small microscope in the shape of a lipstick tube that can be reused every day. Other manufacturers include Ovulite, Fertility Scope, Fertile-Focus, Fertility Tracker, MaybeMOM, and others. Prices range from $25-$40 for one scope.

Another way of using saliva to check fertility is by monitoring the conductivity (changed by electrolytes present) of the saliva. Ovacue sells a monitoring system that just needs to be licked once a day. They also provide an optional vaginal monitor for $100 extra. Ovacue has a high up-front cost, of about $300, $400 if bought with the vaginal accessory. The computer monitor keeps track of your cycle just like the Clearblue Easy monitor does.

Basal Body Temperature (BBT) Measurement

The third common way of testing for ovulation is by measuring the body's "basal temperature". This means the body's resting temperature, usually checked first thing in the morning. A normal thermometer can do this, although specialized ones are sold to provide extra accuracy. A woman's body temperature drops slightly before ovulation and then rises slightly afterwards, and continues to rise if she becomes pregnant until it resets at a higher base. Body temperature measurement must be accompanied by charting (writing down the temperature every day) so that patterns can be discerned. A thermometer and a paper or electronic chart are probably the cheapest method of monitoring fertility, but certainly require more work. VE Valley-Electronics makes three computerized monitors that take a lot of the work out of BBT measurement. These are Lady-Comp, Baby-Comp and Pearly. Baby-Comp is the same as Lady-Comp except it comes with extra computer programming for pregnancy. Pearly is the cheapest and does not give a fertility forecast or cycle statistics. Prices for these devices are: Baby-Comp $700, Lady-Comp $565, and Pearly $360. These are all one-time up-front costs. A battery may need to be purchased in a few years. DuoFertility makes a monitor that is worn, constantly measuring body temperature to get a more accurate number of readings. Currently it is only available in the UK and is sold for approximately £495.

One note about the computerized monitors: they have high up-front costs but keep their resale value fairly well on the used market. So they can be found for cheaper used but not that much cheaper, usually. Also, women with certain body conditions like Polycystic Ovarian Syndrome may not find the urine tests as accurate as claimed.

3-in-1 Kit

Luna Fertility makes a kit, available online or at several large stores like Wal-mart, that provides a thermometer, a saliva tester (ferning observation method) and 5 LH urine strips, as well as 2 pregnancy tests and a chart.  You can buy more strips or tests online as well.  You may find it more convenient to buy everything all together.

Which One is Right for You?

Taking into account your own body (is it regular? Do you have any conditions that might affect the tests?), what you can afford and what you feel comfortable doing on a daily basis, you will find yourself leaning towards one system over another. Some of the products listed come with a satisfaction guarantee or allow monthly rentals so you can try it out risk-free. All fertility monitor systems, whether for procreation or contraception, are natural and pose no health risk to the woman. Generally, the cheaper the cost the more work the woman has to do.

Here are the manufacturers websites in order of cost, omitting BBT thermometers because they are everywhere.

DuoFertility

Lady-Comp, Baby-Comp and Pearly (Canadian site)

Ovacue

Luna Fertility

Clearblue Easy

Ovulens,

MaybeMOM (there are many other 'scope makers as well)