Table 2

Variation within versus between women in cumulative and mean daily E2, measured during two menstrual cycles

No. of cycles (subjects)First cycle mean, pg/ml (SE)ICC95% CIa
Cumulative E2
Preovulatory (days−4 to 0)
Reverse dating18 (9)51.5 (7.5)0.790.35–0.95
Urine LH testing16 (8)55.1 (7.9)0.770.27–0.95
Rise in salivary PG20 (10)51.9 (6.8)0.740.27–0.93
Center cycle (days−6 to+8)
Reverse dating20 (10)148.8 (19.4)0.850.54–0.96
Urine LH testing16 (8)152.5 (23.7)0.920.68–0.98
Rise in salivary PG20 (10)148.1 (19.3)0.860.56–0.96
Mean daily E2 (entire cycle minus first 5 days)20 (10)9.5 (1.4)0.910.68–0.98
  • a CI, confidence interval.