TTC with Irregular Periods
How to track ovulation and get pregnant when your cycle is unpredictable.
Key Strategies
- Don't rely on calendar predictions: Apps can't accurately predict ovulation with irregular cycles
- Use OPKs liberally: Start testing early and test frequently
- Track cervical mucus: Your body's natural fertility signal works regardless of cycle length
- Get tested: Underlying causes like PCOS are often treatable
What Counts as an Irregular Period?
Not sure if your cycles are actually irregular? Here's the medical definition:
| Cycle Pattern | Definition | Classification |
|---|---|---|
| 21-35 days, consistent | Varies by ≤7 days cycle to cycle | Regular |
| Varies by 8+ days | e.g., 25 days one month, 38 the next | Irregular |
| Under 21 days | Very short cycles | Polymenorrhea |
| Over 35 days | Long cycles | Oligomenorrhea |
| Absent periods | No period for 3+ months | Amenorrhea |
The core problem: With irregular cycles, you can't predict when ovulation will occur. Calendar-based methods and app predictions become unreliable. This means you might miss your fertile window entirely—or have no idea when to test for pregnancy.
📊 Good News
Irregular cycles don't mean you can't get pregnant—they just mean you need to track smarter, not harder. Many women with irregular cycles conceive naturally once they learn to identify their actual fertile days.
Common Causes of Irregular Periods
Understanding the cause of your irregular cycles can help guide treatment:
Polycystic Ovary Syndrome (PCOS)
The most common cause of irregular periods and anovulation. PCOS involves hormonal imbalances that can prevent regular ovulation. Signs include long cycles, excess androgen (acne, facial hair), and polycystic ovaries on ultrasound.
Thyroid Disorders
Both hypothyroidism and hyperthyroidism can cause irregular periods. A simple blood test can check your thyroid function, and treatment often restores regular cycles.
Stress & Lifestyle Factors
High stress, extreme exercise, significant weight changes, and poor sleep can all disrupt your cycle. The hypothalamus (which controls your hormones) is sensitive to stress signals.
Perimenopause
In your late 30s and 40s, cycles may become irregular as you approach menopause. This doesn't mean pregnancy is impossible, but it may be more challenging.
Coming Off Birth Control
It can take several months for your cycle to regulate after stopping hormonal contraception. This is usually temporary.
High Prolactin
Elevated prolactin levels can suppress ovulation. This can be caused by certain medications, pituitary issues, or other conditions.
How to Track Ovulation with Irregular Cycles
Since you can't rely on calendar predictions, you need to focus on real-time fertility signs:
1Ovulation Predictor Kits (OPKs)
OPKs detect your LH surge, which happens 24-48 hours before ovulation. With irregular cycles:
- Start early: Begin testing around day 10, or earlier if you've ever ovulated before day 14
- Test daily: Don't skip days—you might miss your surge
- Consider twice daily: Some LH surges are short; testing morning and evening catches more
- Keep testing: Don't stop until you get a positive OR your period arrives
- Buy in bulk: You'll use more strips than someone with regular cycles
⚠️ OPK Caveat for PCOS
Women with PCOS may have chronically elevated LH, causing frequent false positives. If you consistently get positive OPKs, consider using a digital OPK that measures both estrogen and LH, or confirm with BBT charting.
2Cervical Mucus Monitoring
Your body produces fertile cervical mucus in the days leading up to ovulation—regardless of cycle length. This is one of the most reliable signs for irregular cycles.
- Watch for EWCM: Egg white cervical mucus (clear, stretchy, slippery) signals peak fertility
- Track the progression: Mucus typically goes from dry → sticky → creamy → egg white → dry
- Start BD when you see fertile mucus: Don't wait for a positive OPK
3BBT Charting
Basal body temperature rises after ovulation and stays elevated until your period. While BBT can't predict ovulation (only confirm it happened), it helps you:
- Confirm you ovulated: A sustained temperature rise = ovulation occurred
- Identify patterns: Over time, you may notice trends in your cycle
- Know when to test: Test for pregnancy ~12-14 days after the temperature shift
- Detect anovulation: No temperature shift may indicate you didn't ovulate
4Quantitative Hormone Monitors
For the most accurate tracking with irregular cycles, consider a monitor that measures actual hormone levels rather than just detecting a surge.
The Best TTC Strategy for Irregular Cycles
The "Frequent BD" Approach
If your cycles are very unpredictable, having sex every 2-3 days throughout your cycle ensures you won't miss ovulation. This is especially useful if:
- You can't pinpoint ovulation with tracking
- OPKs give inconsistent results
- Your partner has normal sperm parameters
The "Intensive Tracking" Approach
Combine multiple methods for the best picture:
- Start OPKs on cycle day 10 (or earlier)
- Monitor cervical mucus daily
- Track BBT to confirm ovulation
- Have sex when you see fertile mucus or approaching positive OPK
- Continue having sex through ovulation day
When to Take a Pregnancy Test
This is tricky with irregular cycles because you don't know when your period is "due." Instead:
- If you confirmed ovulation: Test 12-14 days after your BBT shift or positive OPK
- If you didn't track: Test 14 days after any unprotected sex, then again a week later if negative
- When in doubt: Use cheap strip tests and test weekly until your period arrives
💡 Pro Tip
Keep a stash of cheap pregnancy tests on hand. With irregular cycles, you may need to test multiple times before you know if this cycle was successful.
Best Products for Irregular Cycles
Easy@Home 100 Ovulation Test Strips
With irregular cycles, you'll use more OPKs than average. This 100-pack is the most economical choice. Works with the free Premom app for line-reading help.
Mira Fertility Plus System
Measures actual hormone concentrations (not just detecting a surge), making it more reliable for women with PCOS or consistently elevated LH. Tracks LH, estrogen, and progesterone.
Tempdrop Wearable BBT Sensor
Wear it on your arm overnight—no waking at the same time, no oral thermometer. The algorithm learns your patterns and provides accurate BBT readings even with irregular sleep.
Easy@Home BBT Thermometer
Affordable BBT thermometer that syncs with the Premom app. Two decimal places for accurate tracking. Great starter option before investing in a wearable.
When to See a Doctor
While many women with irregular cycles conceive on their own, you should see a doctor if:
- Cycles are consistently over 35 days or under 21 days
- You haven't had a period in 3+ months
- You've been trying for 6+ months without success (the timeline is shorter for irregular cycles)
- You're not ovulating (no BBT rise, never get positive OPK)
- You have signs of PCOS: acne, facial hair, weight gain
- You're over 35
What Your Doctor May Do
- Blood tests: Check FSH, LH, estradiol, AMH, TSH, prolactin, and androgens
- Ultrasound: Look for polycystic ovaries or other structural issues
- Prescribe medication: Clomid or Letrozole to induce ovulation
- Treat underlying conditions: Thyroid medication, metformin for PCOS, etc.
💊 Good News About Treatment
If irregular periods are caused by anovulation (not ovulating), ovulation induction medications like Letrozole or Clomid have high success rates. Many women who weren't ovulating achieve pregnancy within a few treatment cycles.
The Bottom Line
Irregular periods make TTC more challenging, but not impossible. The key is shifting from calendar-based predictions to real-time fertility tracking. Monitor your cervical mucus, use OPKs liberally, and confirm ovulation with BBT charting.
If you've been trying for 6+ months without success, or if you're not ovulating at all, see a doctor. Most causes of irregular periods are treatable, and with the right approach, many women with irregular cycles go on to conceive. 💚