Ovulation Tests vs Fertility Apps vs Temperature Tracking: Which Helps You Get Pregnant?
Urine LH ovulation tests are the only tracking method with randomized-trial evidence of more live births. Temperature charting and apps have too little trial data to say whether they help, and two apps given the same temperature data often disagreed on the fertile days.
By Kymata Health Editorial Published Last checked
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This guide
Fertility & Prenatal- Question
- Are ovulation test strips or fertility tracking apps better for getting pregnant?
- Sources
- 6 cited
- Quick answers
- 3 questions
- Clinician review
- None; sources cited inline
Key takeaways
4 points- A 2023 Cochrane review (7 trials, 2,464 women or couples) found urine ovulation tests probably increase live births (risk ratio 1.36, one trial of 844): if 16% have a live birth without them, 16% to 28% would with them1.
- For fertility awareness methods such as temperature, cervical mucus and calendar or app charting, the evidence was too limited to tell whether they change live birth rates1.
- Against ultrasound, the urine LH peak predicted ovulation early in nearly 10% of cycles and late in 23%2.
- When the same temperature data were entered into two apps, they agreed on the start of the fertile window in 57% of cycles and on its end in 36%4.
How each method works
The fertile window runs from about five days before ovulation to several hours after it1. Urine ovulation tests measure hormones such as luteinizing hormone (LH), while fertility awareness methods track basal body temperature, cervical mucus or cycle dates, often in an app1.
A 2024 review counted 23 nonprescription fertility wearables and devices sold in the US, most based on body temperature or urine hormones, and described the research validating their accuracy as scant3.
What the trials show
Cochrane reviewers found 7 randomized trials of timing sex with ovulation prediction1. Compared with no prediction, urine ovulation tests probably increased live births (risk ratio 1.36, one trial, 844 women, moderate-quality evidence) and pregnancy, counting clinical pregnancies or positive urine tests (risk ratio 1.28, four trials, 2,202 women)1. Evidence was insufficient on time to pregnancy, stress and quality of life1.
For fertility awareness methods, the reviewers were uncertain whether they change live birth rates (risk ratio 0.95, two trials, 157 women, low-quality evidence)1. No trial tested timing sex with pelvic ultrasound1. The review's authors declared no conflicts of interest, and they concluded that urine tests probably help women under 40 who have been trying for less than 12 months1.
How accurate each signal is
In 107 women followed with ultrasound and daily urine hormone tests, the average gap between the urine LH peak and ultrasound evidence of ovulation was under one day, but the LH peak pointed to ovulation too early in nearly 10% of cycles and too late in 23%2. A rise in basal body temperature was seen in 98% of cycles, and the first rise in LH, the cervical mucus peak and a urine hormone ratio each fell close to ultrasound-confirmed ovulation in more than 72% of cycles2.
Apps can disagree. When researchers entered the temperature data of 20 regularly cycling women into Natural Cycles and compared it with CycleProGo, which also uses cervical mucus, the fertile-window start matched in 57% of cycles and the end in 36%, and Natural Cycles' window averaged 12.8 days vs 15.14. The lead author works for the Couple to Couple League, the natural family planning group that makes CycleProGo4.
Natural Cycles for planning a pregnancy
Natural Cycles is a software app the FDA classified in August 2018 for women 18 and older to monitor their fertility, for preventing or planning a pregnancy6. In an observational study of 5,376 users in its pregnancy-planning mode, the estimated chance of logging a positive pregnancy test was 61% within 6 cycles and 74% within 12, with a median of 4 cycles5. There was no comparison group, the study was funded by Natural Cycles with partial support from the NIH intramural research program, and most authors were employees or founders holding company shares5.
Choosing a method, and when to get help
If your cycles are regular and you have been trying for less than a year, urine LH tests have the best trial support1. The Cochrane reviewers also note possible downsides of ovulation prediction: stress, time, and the cost of kits and app subscriptions1. Apps and temperature charts can still help you learn your cycle, but there is not enough trial evidence that they raise live birth rates1.
- Irregular or absent periods are a reason to see a clinician rather than keep testing; see the PCOS hub.
- For how long to try before getting checked, see how long it takes to get pregnant.
- An app used to avoid pregnancy is not a fertility test, and no contraceptive method is 100% effective6.
Where to buy
Natural Cycles
Paid links · we earn a commissionAn app the FDA authorized in 2018 for women 18 and older to monitor their fertility, for preventing a pregnancy or planning one; it reads your temperature and cycle data to flag fertile days. It does not make you more fertile or guarantee a pregnancy. As birth control, the FDA reported a 6.5% typical-use failure rate, and the risk is higher if you used hormonal birth control in the previous 60 days. It does not protect against STIs.
See Natural Cycles (paid link, opens in new tab)
Quick answers
Questions
3 answersAre ovulation tests worth it?
For women under 40 trying for less than a year, a Cochrane review found they probably increase live births and pregnancies compared with no prediction1.
Is a fertility app as good as ovulation strips?
There is not enough trial evidence to say: Cochrane was uncertain whether fertility awareness methods, including app charting, change live birth rates1, and two apps given identical data often disagreed4.
Do expensive fertility monitors work better?
A 2024 review found 23 consumer devices on the US market and scant research validating their accuracy3.
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- Next in this topicTrying to Conceive: Prenatal Vitamins, Fertility Supplements and What to Stop, by the EvidenceFolic acid is the one prenatal nutrient with top-grade evidence: 400 to 800 mcg a day, started before pregnancy.
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References
Every study and document cited in this guide, numbered as in the text.
Sources
6 sources- 1Timed intercourse for couples trying to conceive. Cochrane Database Syst Rev, 2023. PMID 37709293
- 2Chronological aspects of ultrasonic, hormonal, and other indirect indices of ovulation. BJOG, 2001. PMID 11510707
- 3Consumer wearables and personal devices for tracking the fertile window. Am J Obstet Gynecol, 2024. PMID 38768799
- 4A comparison of app-defined fertile days from two fertility tracking apps using identical cycle data. Contraception, 2022. PMID 35901971
- 5Time to Pregnancy for Women Using a Fertility Awareness Based Mobile Application to Plan a Pregnancy. J Womens Health (Larchmt), 2021. PMID 34495761
- 6De Novo classification order DEN170052: Natural Cycles (software application for contraception). U.S. Food and Drug Administration, 2018.
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