Table 4.
Fertility awareness-based methods and time to pregnancy in women or couples with no known subfertility trying to conceive.
| N | Population | Mean women's age (years) | Study design | Follow-up duration | FABM | Major findings | References |
|---|---|---|---|---|---|---|---|
| 5,376 | Sweden, UK, USA | 31.8 | Cohort | Up to 12 cycles | Natural Cycles | Cumulative pregnancy at 12 cycles 74%; median 4 cycles to pregnancy; for women <35 years with regular cycles, 95% and median 2 cycles to pregnancy | Favaro et al. (70) |
| 8,363 | North America, recruited online | 29.9 | Cohort | Up to 1 year | Multiple | Among women using an app together with cervical fluid, basal body temperature, and/or urine LH: fecundability ratio* 1.21–1.26 | Stanford et al. (71) |
| 785 | UK, recruited online | 30 | Randomized trial | Up to 2 cycles | Clearblue Connected Ovulation Test System® | After 2 cycles, 36.2% pregnant in FABM arm; 28.6% pregnant in control arm | Johnson et al. (72) |
| 2,874 | 84% from Sweden; online | 28.1 | Cohort | Up to 13 cycles | Natural Cycles | Recent use of hormonal contraception: mean 3.7 cycles to pregnancy; no recent hormonal contraception: mean 2.3 cycles to pregnancy | Berglund Scherwitzl et al. (73) |
| 256 | North America | 29.2 | Cohort | Up to 24 cycles | Marquette | Cumulative pregnancy rates by cycle 12 was 83% (monitor only), 72% (mucus only) and 75% (monitor and mucus) | Bouchard et al. (74) |
| 124 | Women recruited online | 29.5 | Cohort | Up to 1 year | Marquette | With intercourse on high fertile days, 87% pregnant at 1 year | Mu and Fehring (75) |
| 69 in CrM group | Women in Utah, all parous | 28.2 | Randomized trial | Up to 9 months | Creighton Model | Cumulative pregnancy 93% by cycle 7 of trying to conceive in CrM group; no significant difference from non-CrM group; randomized trial was confounded by instruction to avoid pregnancy in first cycle | Stanford et al. (76) |
| 331 | Women in North Carolina | 30% >35 years | Cohort | Up to 12 months | Cervical fluid | Among women consistently observing cervical fluid: fecundability ratio* 2.3 | Evans-Hoeker et al. (77) |
| 346 | German couples | 29.0 | Cohort | Up to 6 months | Sensiplan | Cumulative pregnancy proportion by 6 months: 92% | Gnoth et al. (78) |
*
The fecundability ratio is the relative probability of conceiving per menstrual cycle; a higher fecundability ratio results in shorter time to pregnancy.