Figure 1.

Relation between female BMI and fecundability, by parity status at baseline, fitted by restricted cubic splines.

Reference level for fecundability ratio is a BMI of 22 kg/m². The dotted line segments represent ranges beyond the last knot used in the spline fitting, denoting tail ranges that have less information. The curves are adjusted for age, partner's age, cycle regularity, cycle length, partner's BMI, physical activity, smoking, alcohol intake, intercourse frequency and waist circumference.