Variable Endometriosis (+) Endometriosis (-) p value
N=3249 N=85149
Maternal age, mean years (SD) 32.9 (4·5) 31·3 (4·9) <0·001a
Maternal age category, %
≦19 0·1 0·6 <0·001b
20–24 3·2 8·5
25–29 20·3 28
30–34 37·7 35·9
35–39 31·7 22·5
≥ 40 7·1 4·5
DII before pregnancy, mean (SD) -0·38 (2·51) -0·02 (2·62) <0·001a
DII category, %
Q1 (most proinflammatory group) 14·3 19·8 0·001b
Q2 19·1 20·2
Q3 21·6 20·1
Q4 22 20·1
Q5 (most anti-inflammatory group) 23 20·1
Maternal smoking, % 4·9 4·6 0·528b
Maternal education, %
<10 years 3·6 4·5 <0·001b
10–12 years 27 30·8
13–16 years 45·5 42·2
≥17 years 23·9 22·4
Household income
< 2,000,000 JPY 4·4 5·7 <0·001b
2,000,000–5,999,999 JPY 64·1 67·8
6,000,000–9,999,999 JPY 26·3 22·3
≥10,000,000 JPY 5·2 4·2
BMI, %
<18.5 15·6 16 0·031b
18.5–24.9 75·1 73·3
≥25 9·3 10·7
Uterine myoma, % 16·1 5·8 <0·001b
Adenomyosis, % 3·8 0·2 <0·001b
ART pregnancy, % 10·7 2·7 < 0·001b