Ovulation and Fertility Awareness Methods
It’s so important that we understand our bodies and what happens each cycle. Ovulation is one of my favorite topics, and I did a lot of research on it during fellowship. We will review the basic overview of the menstrual cycle and fertility awareness methods. Studies support that if you track your cycles, you have a higher chance of getting pregnant than if you don’t. If you are trying to optimize your fecundability, understanding your cycle is very important.
The Menstrual cycle
Inside your ovaries I like to think of it is a vault that holds your eggs. At the start of the month, a group of eggs are released from the vault. Each egg is microscopic and grows inside a fluid-filled structure called a follicle. The brain then sends out FSH (follicle stimulating hormone) Because the brain and ovaries are best friends, this is the perfect amount of FSH to stimulate one egg to grow. As the egg grows, it makes estrogen and the follicle gets bigger. When you have high estrogen levels, the lining of the uterus is optimized for implantation. This also triggers the brain to send out a surge of LH which allows the follicle to rupture, the egg to be released, and hopefully picked up by a fallopian tube. The follicle then reforms and becomes a cyst called a corpus luteum. The corpus luteum makes progesterone which is stimulated in pulses from LH. The corpus luteum can only live for about twelve to fourteen days. So if there is no stimulation of HCG to save it, it will die, progesterone production will stop, and you will get a period. This is the shedding of the lining induced by a drop in progesterone. If you are pregnant, the HCG will stimulate a constant progesterone exposure, and the pregnancy continues. After about nine weeks, the corpus luteum is replaced by the placenta.
Fertility Awareness Methods
If you have regular, predictable cycles, you are ovulating. That is the number one sign that you are ovulating. Can you have a period if you are not ovulating? Sometimes the lining of the uterus can overflow that constantly gets stimulating by a low dose of estrogen like a dripping faucet. You can also have irregular ovulation with things like PCOS where one month you may respond and another you may not. It may take a long duration of FSH to get response.
The Calendar Method
Long before apps, I remember patients coming into the office with their calendars or sheets of paper. The calendar method is simply a mathematic equation. The equation takes the length of your cycle and subtracts 14 days which is an average length of time from ovulation until the period starts if the corpus luteum lives a normal amount of time. So if your cycle is twenty-seven days, day thirteen would be the day that you would ovulate. The fertile window is typically five days ending with ovulation. The five days leading up to ovulation are your most fertile days because sperm can live in the reproductive track up to 5 days. Remember, if your periods are irregular, the calendar method is not for you. Also, not everyone has a perfectly set luteal phase. So sometimes you can have some symptoms of ovulation which is a cramping pain. Some people know when they ovulate because they can feel it. If your calendar or app is telling you something different, trust your body.
Cervical Mucus Monitoring
Think about the mucus inside the cervix which is like a guardian to the uterus. It’s a barrier that makes it easier or harder for sperm to get through. The cervical mucus changes based on estrogen exposure. As your body, sees more constant estrogen it changes. and your type 4 cervical mucus is the classic type that is sticky and egg-white. Stick two fingers inside, grab cervical mucus from the top of your vagina, and pull it out. If it is sticky and stretchy, that is your ovulation day. This is the day to have intercourse. If not, keep checking. Again, if your calendar or app is telling you that you are not ovulating, trust your body. When you are trying to track your cycles and using this method, know that it is a highly accurate and free way to check for ovulation.
Ovulation Predictor Kits
I like this option the best because it’s fast and easy. An OPK checks your urine for the hormone LH which is released in a high surge from the brain right before ovulation. It is causing the follicle to rupture allowing the egg to be released. The positive OPK is the day before the ovulation. This gives you two days to have intercourse. I do want to give a few thoughts about OPKs. LH is typically released in the early morning. So if you test before you go to work, it may not register yet even though you are starting to surge. I recommend checking between 10am and 2pm so you get an accurate representation. A hormone released from the brain has to go through your blood and filter through your kidneys to be in the urine. The first day you get a positive is the only day that matters. Your body makes almost no LH during the follicular phase, it starts to rise with a surge, and pulses throughout the luteal phase. You are trying to capture that first surge in order to predict ovulation. You must take them around the same time in order to capture it. Once you get a positive, stop taking tests. I prefer the digital options because it’s more clear. If you are using the ones with a line, the line needs to be as dark or darker than the control line. The digital test will tell you if you are ovulating or not.
Basal Body Temperature
Basal body temperature was so old school that we began disregarding it once OPKs came around and people got more comfortable checking cervical mucus. However, FemTech has brought it back and there are lots of different products on the market that are just used to check your temperature. The premise behind this testing is that after you ovulate your progesterone will rise. Progesterone causes an increase in your basal body temperature. So we have higher temperature in your luteal phase than you do your follicular phase. So BBT was a way to monitor your temperature and you would use graph paper to plot your temperature. However, it is not predictive. Once you get a rise in your temperature it’s too late to have sex. If you are having regular predictable periods, getting type four cervical mucus and positive OPKs, obsessing over your temperature is not helpful. Some people like the confirmation which makes sense but it’s not telling you anything about the strength of ovulation. I honestly do not love BBTs, but if you want to use it for confirmation, that is totally fine.
Luteal Progesterone
This is similar to BBT in that it tells you after you have ovulated. The test must be done well and there is no merit to certain levels of progesterone being better than others. The brain sends out LH in pulses which stimulates the corpus luteum to release the progesterone in pulses. So, we know that progesterone exposure is going to vary based on time of exposure to the pulse. In the follicular phase progesterone is low so if it’s three or higher in the luteal phase this means you ovulated. This number can range up to forty and getting a fifteen is not “better” than getting a three. It does not matter. The luteal phase is the time after you ovulate before you get pregnant. Once you get pregnant, the HCG is stimulating the corpus luteum to make more constant progesterone. You have positive pregnancy test at that time and everything is different. Studies have supported that progesterone levels in early pregnancy may be predictive of pregnancy outcomes. That is not translatable into the luteal phase. You do not have a constant stimulation of your corpus luteum nor would we expect there to be. So if you are going to your doctor to get a day twenty-one progesterone, that is something you do to confirm that you ovulated. Typically in the context of someone who is getting ovulation induction medication and is not being monitored by ultrasound, day twenty-one is supposed to represent mid luteal phase. So if you have thirty-seven day cylcles you should be checking it on day thirty. You want to check that test about a week after you ovulate. As long as it is three or higher, you ovulated.
None of these methods are right or wrong, but I want you to understand what you are checking because a lot of myths are floating around out there.
Next I am going answer some questions and debunk myths about ovulation so stay tuned!
