Figure 8.

(A–C), show three conception cycles, (A) with a single oestrogen peak, which is the most common, and (B) and (C) with composite oestrogen peaks to show that such cycles are fertile. (C) Showed an early anovulatory oestrogen peak on Day-7. Note that all these conception cycles showed pregnanediol values exceeding 3 mg/24 h within 6 days of the oestrogen peak and all showed a fall by Day 10 as if the corpus luteum was regressing and was rescued by the developing pregnancies. (D) Shows a long cycle of 45 days with a deficient luteal phase, an oestrogen peak at the 10th percentile (40 µg/24 h) and an early anovulatory oestrogen peak on Day 24. The (pre-ovulatory) oestrogen peak day was Day 30.