This pajamas is made using milk silk fabric. It's very stretchy and soft. Since it's a unisex pattern, follow your American size for men. Women can go one size down for a tight fit or stay your size for loose fit. Please refer to the size chart.  These measurement on the chart is before stretch.  These fabric can stretch 2-3 inches out.  
SIZE
BODY LENGTH (INCHES)
BUST (INCHES)
WAIST (INCHES)
HIP (INCHES)
LEG OPENING (INCHES)
S
25.5
38.6
25.2
40.2
15.9
M
25.5
40.5
27
42.1
16
L
26
43
29
44.5
17
1XL
26.4
45.3
31.5
46.8
17.7
2XL
26.7
47.6
33
49.2
18.5