Table 6 Hazard ratio (HR) of the onset of menopause according to the studied reproductive parameters (adjusted for birth cohorts) in the Cox proportional regression modelling (95 % CI, p = 0.019, omnibus test)

Hormonal contraceptives

No^a

–

–

Yes

0.271

1.005

Cycle length in climacterium

Short

0.771

4,525

Average

1.009

3.097

Long^a

–

–

Number of gestations

0^a

–

–

1

0.219

2.038

2

0.298

2.161

3

0.187

1.971

4+

0.273

2.156