Can Cycle Charting Help Me Detect Miscarriage?

I got pregnant quickly at the age of 34. I’ve been tracking my cycles for a while so I knew exactly when me and my husband should get busy in the bedroom. It took us just 2 cycles of trying to get pregnant. As a fertility awareness geek, I decided to continue charting my temperature throughout the pregnancy, mostly out of curiosity.

Everything was going well until around the third month. I started spotting lightly. Doctors gave me progesterone to maintain the pregnancy. Then came the heartbreak.

When I saw the image of the 12-week ultrasound, I immediately felt uneasy. Something didn’t look right. The doctor said the fetus was no longer developing. Basically, he or she had died in my uterus. They had to induce miscarriage.

It’s been a long journey since that day four years ago. My rainbow baby boy is going to be 3 this summer. And yet I still grieve. There are days it hits me very hard.

I am one of the millions of women who have gone through pregnancy loss. It is estimated that 10 to 15 % clinically recognized pregnancies end in a miscarriage in the first or beginning of second trimester (1). Many women never realize they were pregnant and lost it because the miscarriage happened early on.

I couldn’t help but ask myself “Was there any way to prevent this”? “Have I missed something on my pregnancy chart?”. I needed to know to get some comfort. I wanted to be able to detect the early signs of miscarriage in my next pregnancy.

Basal Body Temperature indicates early pregnancy

Basal Body Temperature (BBT) is helpful in confirming a very early pregnancy. The general rule is that if your period is missing and your temps remain elevated for 18 days or longer, it is highly likely you have conceived (2). BBT rise of 18 days or longer is the first hint to make lifestyle changes, such as starting to take folic acid and giving up on alcohol.

Why 18 days? When an egg is released from the ovary, a little structure called corpus luteum is created. It may be small but its role for your fertility is huge. Thanks to progesterone produced by the corpus luteum, your uterus is preparing to welcome a fertilized egg and make sure it implants properly, making pregnancy possible.

If a cycle doesn’t end in pregnancy, the corpus luteum will live up to 16 days. In rare cases (3) it is possible to conceive with the second egg released in the same cycle (it will be no later than within 2 days after temperature rise). Add 16 and 2 and you get the magic number 18.

BBT tracking to determine chemical pregnancy

Tracking your temperature for the first few weeks of pregnancy can help you determine if you’ve had a chemical pregnancy. A chemical pregnancy is a very early type of miscarriage. It happens when fertilized egg implants in the uterus but the development of the embryo stops very early. You may get a positive test result because the body has started producing the pregnancy hormone HCG.

What usually happens is that you experience some bleeding which may not be much different from menstruation. In fact, women who don’t track their cycles may not even realize they were pregnant. They just assume the bleeding was a late period.

A BBT chart for a chemical pregnancy would look like a normal pregnancy chart with a continuous increase in temperature after ovulation. You would then see a drop in temperatures around the time of the loss. This will be accompanied or soon followed by bleeding.

Detecting first trimester miscarriages with cycle charting

When analyzing my chart for this first pregnancy I knew that miscarriage in the first trimester can be detected by a continuous drop in temperature after at least 18 days above the coverline (4). While this may be true for some women, it wasn’t the case for me.

When I looked at my chart, I didn’t notice a significant drop. What made my situation different was having a so-called missed miscarriage. I could not see symptoms of upcoming loss because my body still thought I was pregnant and did not react immediately. In fact, my HCG dropped to non-pregnancy levels only after a few weeks.

Should I track my temps while pregnant?

Does tracking temperature in early pregnancy make any sense? It’s not a foolproof way to detect the risk, so it’s up to you to decide. If it makes you feel safer, do it. On the other hand, if taking your temperature only makes you freak out more, it may not be worth it.

The only thing to keep in mind is that your body will maintain higher BBT levels only for about 3-4 months pf pregnancy. After that temperatures are likely to go down and this is not a reason to worry (5) (7).

Doctor Joseph Rötzer, creator of one of the most popular symptom-thermal methods of fertility tracking, suggests (6) his patients keep track of their temps for about 30 days from the initial rise in BBT. A sudden drop may indicate that something is wrong so you can check in with your doctor just to be on the safe side.

As for me, I got pregnant the second time about 5 months after the first loss. I continued tracking my cycle during the first trimester and beyond, up to delivery. I did have a few stressful moments, I admit, but I still think it was worth it.

Losing my first pregnancy was one of the hardest things I’ve ever experienced. By understanding my biology and wisdom of the cycles I feel reassured that my body knew what it was doing.

(1) The Johns Hopkins Manual of Gynecology and Obstetrics (4 ed.). Lippincott Williams & Wilkins. 2012. pp. 438–439. ISBN 9781451148015. Archived from the original on September 10, 2017.

(2) Raith Paula E., Frank-Hermann, P., Freundl G., Strowitzki T. Natürliche Familienplanung heute, (Heidelberg: Springer Verlag Berlin, 2013) chap. 11.7, Kindle

(3) Singer, K. The Garden of Fertility, (New York: 2004, Avery), chap.1.5, Kindle

(4) Weschler T., Taking Charge of Your Fertility, (Harper Collins, 2015), chap. 20, Kindle

(5) (7) Rötzer, J. Der persönliche Zyklus der Frau (translated into Polish). (INER, 2007). chap. 8

(6) Siegler, S., Siegler, A. Evaluation of the Basal Body Temperaturex An Analysis of 1012 Basal Body Temperature Recordings. Fertility and Sterility, Vol. 2, Issue 4, p287–30. Published in issue: July-August, 1951 [URL:  https://www.fertstert.org/article/S0015-0282(16)30600-8/pdf]

© Anka Grzywacz 2019