📖 Reference Guide
The TTC Glossary: Every Acronym Decoded
BFP, DPO, CD1, TWW — if TTC spaces feel like they're speaking another language, they kind of are. Here's the full plain-English decoder.
📅 Updated July 2026
⏱️ 7 min read
✓ Medically reviewed
Quick Answer
TTC forums and apps run on shorthand — BFP, DPO, CD1, TWW — that can feel like a foreign language the first time you encounter it. Below is a full, plain-English glossary of the terms you'll actually run into, organized from everyday cycle-tracking acronyms through fertility treatment terms.
If you've spent any time in a TTC community, you've probably seen a post like "9dpo, bfn, af due in 3 days, still poas-ing lol" and had absolutely no idea what any of it meant. You're not missing some obvious code — this is genuinely a specialized vocabulary that develops because people are tracking the same handful of concepts constantly and shorthand saves typing.
Here's the full decoder, split into everyday cycle terms and the medical/treatment terms you'll encounter if your journey goes further.
Everyday Cycle-Tracking Terms
BFP
Big Fat Positive — a positive pregnancy test.
BFN
Big Fat Negative — a negative pregnancy test.
CD1
Cycle Day 1 — the first day of your period, and the official start of a new cycle.
DPO
Days Past Ovulation — used to track where you are in the luteal phase (e.g., "8 DPO").
TWW
Two Week Wait — the roughly 14-day stretch between ovulation and when a pregnancy test becomes reliable.
O
Ovulation — the release of an egg from the ovary.
OPK
Ovulation Predictor Kit — a urine test strip that detects the LH surge before ovulation.
BBT
Basal Body Temperature — your resting temperature, which rises slightly after ovulation.
CM
Cervical Mucus — changes in texture and amount throughout your cycle signal fertility.
EWCM
Egg White Cervical Mucus — the stretchy, clear mucus that typically appears right before ovulation.
AF
Aunt Flo — your period (used when a cycle didn't result in pregnancy).
FRER
First Response Early Result — a specific brand of sensitive early pregnancy test.
LP
Luteal Phase — the time between ovulation and your next period, typically 10–16 days.
LPD
Luteal Phase Defect — an outdated term for a shortened luteal phase, now usually discussed in terms of progesterone levels.
CP
Chemical Pregnancy — a very early pregnancy loss, often before or right around a missed period.
IUI
Intrauterine Insemination — placing prepared sperm directly into the uterus around ovulation.
IVF
In Vitro Fertilization — eggs are retrieved, fertilized in a lab, and a resulting embryo is transferred to the uterus.
ICSI
Intracytoplasmic Sperm Injection — a single sperm is injected directly into an egg during IVF.
FET
Frozen Embryo Transfer — transferring a previously frozen embryo in a later cycle.
PGT-A
Preimplantation Genetic Testing for Aneuploidy — screening embryos for the correct number of chromosomes.
AMH
Anti-Müllerian Hormone — a blood marker used to estimate ovarian reserve.
FSH
Follicle-Stimulating Hormone — a hormone that stimulates egg development, also used as a fertility marker.
RE
Reproductive Endocrinologist — a fertility specialist.
PMOS
Polyendocrine Metabolic Ovarian Syndrome (formerly PCOS) — renamed by The Lancet in May 2026 to better reflect the condition's metabolic and endocrine features.
💡 A Note on "POAS"
You'll also see POAS ("pee on a stick") constantly — it just means taking a pregnancy or ovulation test. It's slang, not a formal acronym, but it's everywhere in TTC spaces.
Understanding DPO & the Two Week Wait
DPO is probably the single most-used acronym in TTC spaces, because it's the anchor for almost everything else. Ovulation is Day 0. From there:
| Timing | What's Happening |
|---|
| 1–5 DPO | Fertilization and early cell division, if it happened — no symptoms are reliable this early |
| 6–10 DPO | Implantation window for most cycles — this is where "implantation symptoms" get discussed, though many are indistinguishable from normal luteal phase symptoms |
| 10–12 DPO | Earliest a sensitive test might pick up a real positive, though a negative here doesn't rule out pregnancy |
| 14 DPO | Roughly when a missed period would occur — the most reliable time to test |
This is also why "the TWW" gets so much airtime — it's a two-week stretch where nothing you do changes the outcome, but the not-knowing is genuinely hard. It's worth reading up on managing the wait itself, not just decoding the terminology around it.
Treatment & Medical Terms
If you move from trying naturally into working with a fertility specialist, a second wave of acronyms shows up — these are clinical, not community slang, so you'll hear them from your doctor too.
IUI
Intrauterine insemination — a lower-intervention procedure, often tried before IVF.
IVF
In vitro fertilization — eggs retrieved and fertilized outside the body.
AMH / FSH
Blood markers used to estimate ovarian reserve, not a pregnancy predictor.
RE
Reproductive endocrinologist — the specialist who typically leads fertility treatment.
"Learning the acronyms isn't just about understanding forums — it's about being able to follow your own chart and your own doctor's notes without feeling lost."
The Bottom Line
None of this vocabulary is required knowledge — plenty of people conceive without ever learning what DPO stands for. But if you're spending time in TTC communities or tracking your own cycle closely, having this glossary on hand means you can actually follow the conversation instead of decoding it sentence by sentence.
This article is for educational purposes only and isn't a substitute for personalized medical advice. Always talk to a qualified healthcare provider about your specific situation.