Table 2.
Temperature shifts and diagnostic accuracy for wrist skin temperature and basal body temperature.
| Variables | Wrist skin temperature | Basal body temperature | ||||
| Ovulatory cycles | ||||||
|
|
Total number of temperature shifts detected, n | 240 | 47 | |||
|
|
Cycles with ≥1 temperature shift, n (%) | 106 (62.4)a | 39 (22.9)a | |||
|
|
|
With 1 temperature shift | 40 (37.7)b | 31 (79)c | ||
|
|
|
With 2 temperature shifts | 31 (29.2)b | 8 (21)c | ||
|
|
|
With 3 temperature shifts | 15 (14.2)b | 0 (0) | ||
|
|
|
With >3 temperature shifts | 20 (18.9)b | 0 (0) | ||
|
|
The first day of temperature shift relative to ovulation day, mean (SD) | 4.4 (2.75) | 2.69 (1.89) | |||
| Anovulatory cycles | ||||||
|
|
Total number of temperature shifts detected, n | 39 | 9 | |||
|
|
Cycles with ≥1 temperature shift, n (%) | 17 (74)d | 7 (30)d | |||
|
|
|
With 1 temperature shift | 5 (29)e | 5 (71)f | ||
|
|
|
With 2 temperature shifts | 4 (24)e | 2 (29)f | ||
|
|
|
With 3 temperature shifts | 6 (35)e | 0 (0) | ||
|
|
|
With 4 temperature shifts | 2 (12)e | 0 (0) | ||
|
|
Diagnostic accuracy (urine luteinizing hormone tests as standard reference; N=193 ) | |||||
|
|
|
True positives, n (%) | 106 (54.9) | 39 (20.2) | ||
|
|
|
True negatives, n (%) | 6 (3.1) | 16 (8.3) | ||
|
|
|
False positives, n (%) | 17 (8.8) | 7 (3.6) | ||
|
|
|
False negatives, n (%) | 64 (33.2) | 131 (67.9) | ||
|
|
|
Sensitivity (95% CI) | 0.62 (0.55-0.70) | 0.23 (0.17-0.30)g | ||
|
|
|
Specificity (95% CI) | 0.26 (0.10-0.48) | 0.70 (0.47-0.87)g | ||
|
|
|
Negative predictive value (95% CI) | 0.09 (0.03-0.18) | 0.11 (0.06-0.17)g | ||
|
|
|
Positive predictive value (95% CI) | 0.86 (0.79-0.92) | 0.85 (0.71-0.94)g | ||
aN=170.
bN=106.
cN=39.
dN=23.
eN=17.
fN=7.
gP values comparing wrist skin temperature and basal body temperature: P<.001 for sensitivity; P=.002 for specificity; P=.39 for negative predictive value; and P=.74 for positive predictive value.