Primary purpose of the study is to assess the concentration of bimekizumab in mature human breast milk.
Study participant must be at least 18 years of age at the time of signing the informed consent.
Study participant is being treated with commercial bimekizumab per locally approved prescribing information and in accordance with her treating physician.
Study participant is breastfeeding and intends to breastfeed throughout the Sampling Period.
The decision to treat with bimekizumab and to breastfeed is made independently from and prior to the study participant consenting to participate in the study.
Study participant has any medical, obstetrical, or psychiatric condition that, in the opinion of the Investigator, could jeopardize or would compromise the study participant's ability to participate in this study.
The infant has any abnormality noted on physical examination or medical history that, in the opinion of the Investigator, may jeopardize or compromise study participation.
Study participant has a history of chronic alcohol or drug abuse within the previous last year.
Study participant has history of breast implants, breast augmentation, or breast reduction surgery.