Table 1 Distribution of menstrual regularity at age of 18–22 years old by year of birth
Year of birth | ||||||
|---|---|---|---|---|---|---|
1930s | 1940s | 1950s | 1960s | 1970s | 1980s | |
n (%) | n (%) | n (%) | n (%) | n (%) | n (%) | |
Menstrual regularity | ||||||
Very regular | 42 (42) | 1664 (38) | 5935 (38) | 6933 (34) | 1965 (30) | 55 (20) |
Usually regular | 32 (32) | 1772 (40) | 6090 (39) | 7855 (39) | 2468 (38) | 126 (45) |
Usually irregular | 19 (19) | 661 (15) | 2365 (15) | 3815 (19) | 1386 (21) | 69 (25) |
Always irregular | 6 (6) | 282 (6) | 1013 (7) | 1559 (8) | 622 (10) | 28 (10) |
No periods | 2 (2) | 39 (1) | 118 (1) | 193 (1) | 78 (1) | 2 (1) |