The very first cycle with NaturalCycles

We get a lot of questions about how many green days to expect in the beginning when using NaturalCycles, since NaturalCycles needs some data to get to know you and your body. Every woman is different, with different cycle characteristics and different body temperatures, so we cannot make any reliable assumptions about your body until you start entering your own data in your NaturalCycles account.

The number of green days a woman gets in the first ovulatory cycle depends a lot on those first data points. What cycle day did she start measuring at? Does she measure every day or does she skip a lot of days? How much is her temperature fluctuating? Which cycle day does she ovulate? Has she recently been on hormonal contraception and will this postpone ovulation? I’ve already written a separate blog entry concerning how much the pill affects your cycle, here:

http://blog.naturalcycles.com/will-quitting-the-pill-disrupt-your-cycle

NaturalCycles requires 6 low temperature values before looking for a rise due to ovulation. This means that if she ovulates around day 15, she needs to start measuring around day 10 at the latest. If she starts measuring after the temperature rise, then it is of course not possible for NaturalCycles to detect ovulation. Below is such an example, where she started measuring on day 21:

One could argue that most probably ovulation had happened there and NaturalCycles could give green days, but before the following menstruation, there is really no way of knowing whether ovulation has happened and if the temperature is high, or if ovulation is for some reason delayed and the rise is still to come. As safety comes first, these days should not be green!

Below you see another example of a user that started measuring her temperature on cycle day 11, ovulated on day 20 and then got green days on day 23. She also entered a first positive LH test (ovulation test) on day 20, which helps to get easier green days.

In some extreme scenarios, where the woman does not measure very often in combination with highly fluctuating temperatures, it can take up to two cycles to get the first post-ovulatory green days.

To summarize: on average, if a user starts measuring before ovulation, she gets 40.2% green days during her first cycle. So even though the number of green days in the first cycle varies greatly, depending on several factors, the users do on average get a significant amount of green days.

Are you ovulating? (Anovulatory cycles)

Although you might get your period, it does not necessarily imply that you ovulated.

There is something called anovulatory cycles, which are cycles where ovulation simply doesn’t happen.

This might be difficult to notice unless you are tracking your cycles and charting your temperature, but might also show up as delayed menstruation and mid-cycle spotting.  Anovulatory cycles tend to occur occasionally throughout the childbearing years and are then a rather common cause of infertility. They are however most common during adolescence and in the years before menopause.

The picture below shows a temperature chart of an anovulatory cycle of a real woman. The anovulatory cycle is often longer than usual. It does still end in a bleeding, caused by the lack of estrogen rather than progesterone, as is the case for a normal ovulatory cycle.

temperature chart for anovulatory cycles - NaturalCycles

Anovulation can arise from a number of causes, ranging from severe diet and exercise or stress to complex disruptions in the relationships between tiny glands in the brain that control our most basic functions. Hormonal imbalances are the most probable cause. An intense program of exercise can interfere with the ovulatory cycle by suppressing the output of hormones called gonadotropins from the hypothalamus in the brain. The disorder may also result from hypothalamic dysfunction, hyperprolactinemia, polycystic ovary syndrome, luteal phase defects, or tumors of the pituitary gland adrenal gland or ovaries.

Another possible contributor to anovulation is the long-term use of certain medications. Steroidal oral contraceptives (the Pill) could likely be responsible. These drugs work by intentionally disrupting the hypothalamic-pituitary-ovarian axis, suppressing ovulation and thereby preventing pregnancy and this often causes prolonged anovulation also after quitting the pill.

If you suspect you might be having anovulatory cycles, you should track your cycles and detect your ovulation by measuring your basal body temperature. NaturalCycles keeps track of your anovulatory cycles for you and NC Planning even gives you fertility advice accordingly. If you discover that you have such a problem you should consult your doctor, as there are treatments and medications that could help.

The fertile window

 

The woman’s body is really a remarkable thing. Cycle after cycle, the uterus does its job and releases another egg, expecting it to be fertilized. Today, since we have such great knowledge through medical research on what’s going on in the uterus, we can use it to our advantage to either prevent or plan a pregnancy. The time frame when a woman is fertile only occurs once per cycle and is called the fertile window.

The fertile window includes the 5 days prior to ovulation and the day of ovulation.

Fertile Window - NaturalCyclesThe 5 days period prior to ovulation is determined from the longest time sperm can survive in the uteral environment. Note, however, that most sperm have a lifetime significantly less than 5 days – more like 2 or 3 days, but to completely exclude a possibility of pregnancy one must take the longest living sperm into account. For sperm to survive any significant time at all, the uterus must contain the fertile type of cervical mucus, which helps the sperm to live longer as well as to be able to travel up the uterus and fallopian tubes. Without the presence of fertile cervical mucus sperm typically only survive about 4 hours.

The fertile cervical mucus is triggered by a rise in estrogen prior to ovulation. The amount of fertile cervical mucus does not only vary from woman to woman, but also on the age of the woman. The older you get, the fewer days you produce cervical mucus and hence the narrower your fertile window becomes.

Once released through ovulation, the egg can maximally survive up to 36h, but typically only 12-24h. Studies have shown that the quality of the egg deteriorates very quickly; causing the probability of conception to decrease rapidly every hour once the egg has been released. For optimal chances of conception, sperm should thus already be present in the fallopian tube once the egg is released. Therefore, the most fertile day of the woman’s cycle is rather the day prior to ovulation than the day of ovulation itself.

To prevent pregnancy through detecting ovulation and predicting the fertile window, one must assume the longest living sperm and egg. This sums up to 6 days in the cycle. What’s more tricky is to accurately calculate the uncertainty of the ovulation day for a woman. That is, when do we think she will ovulate and what’s the earliest possibility of ovulation to occur. Luckily this is what NaturalCycles‘ algorithm does for you. When you start measuring your temperature, NaturalCycles will be very cautious as it does not know around what time you usually ovulate. With more and more data, NaturalCycles is able to better estimate your ovulation day, the variation of your ovulation day and the uncertainty on the estimated variation of your ovulation day. All this is required for a full-proof birth control method using natural family planning. So don’t chart by hand to prevent getting pregnant ladies – it is doomed to end up in an accident. Use the mathematical tools provided for you and you’ll save both time and hassle.