Table 1.

Characteristics of 52 menstrual cycles and periods

Duration of menstrual cycle (d)	Mar through May			Jun through Sep			Oct through Dec			Jan through Feb
	Cycles (n)	Menstrual period (d)	%	Cycles (n)	Menstrual period (d)	%	Cycles (n)	Menstrual period (d)	%	Cycles (n)	Menstrual period (d)	%
19–23	0		0	0		0	4	3–4	7.69	2	1–3	3.85
24–31	0		0	0		0	12	3–7	23.08	7	1–6	13.46
32–40	1	4	1.92	0		0	3	2–4	5.77	3	1–2	5.77
41–50	3	5–6	5.77	1	8	1.92	0		0	3	5–7	5.77
51–60	1	6	1.92	3	7–9	5.77	0		0	0		0
>60	3	9–10	5.77	6		11.54	0		0	0		0
Total	8	4–10	15.38	10	7–9	19.23	19	2–7	36.54	15	1–7	28.85