- 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. - Study participant plans a surgical intervention during the Screening Period and Sampling Period or anticipates having surgery while participating in the Sampling Period (does not apply to tubal ligation). - Study participant or her infant has participated in another study of an investigational medicinal product (IMP) (and/or an investigational device) within the previous 6 months or is currently participating in another study of an IMP (and/or an investigational device), unless the study is UCB PS0036 or a bimekizumab registry study. - Study participant or her infant has previously participated (ie, entered the sampling period) in this study.