Basal Body Temperature Tracking: 6 Months of Data

I tracked my BBT every morning for 6 months before conceiving. The patterns were fascinating — and frustrating. Here's what the data actually showed...

I tracked my BBT every morning for 6 months before conceiving. The patterns were fascinating — and frustrating. Here's what 6 months of basal body temperature data actually showed me.

What BBT Taught Me

• My ovulation was consistent. Every cycle, my temperature rose on day 15 or 16. Like clockwork. This was reassuring — my cycles were regular.
• My luteal phase was short. 11-12 days. Borderline. Some sources say 12+ is ideal. This made me anxious, but my midwife said it was fine.
• Alcohol and illness mess with the data. One glass of wine the night before? Temperature spike. A cold? Temperature spike. The data isn't always clean.
• It's retrospective, not predictive. BBT confirms ovulation after it happens. It doesn't tell you when it's coming. For timing intercourse, you need OPKs or cervical mucus tracking.

The Frustration

Month 4, I got a beautiful biphasic chart. Perfect rise, sustained high temps. I was convinced. Tested at 12 DPO: negative. Tested at 14 DPO: negative. Period came right on time.

Month 5, same thing. Perfect chart. No baby.

Month 6, I stopped obsessing over the chart. I stopped testing early. I just tracked and waited. And that month — the month I relaxed — I got pregnant.

My Takeaway

BBT is useful for confirming ovulation and understanding your cycle. But it's not a crystal ball. It can't tell you if you're pregnant. It can't guarantee conception. And obsessing over the data can be counterproductive.

Use it as a tool, not a fortune teller.

— Sophie Miller, CNM

Sophie Miller, CNM is a Certified Nurse-Midwife in Portland, Oregon. This article reflects personal experience and clinical observations. For medical advice, consult your healthcare provider.