Recruitment. Uppsala: Mothers were recruited among xxxxxxxxxx who delivered at Uppsala University Hospital from April 2000 to March 2001, from March 2002 to February 2003, from January to December 2004 and from January to December 2006. Women who delivered on randomly selected days during the first week of each month were asked to participate in the breast milk study. 2-3 mothers were recruited every month. In 2000-2001, 67 women were asked to participate in the study and 31 donated milk and answered the questionnaire. In 2002-2003, 49 women were asked to participate and 31 agreed. In 2004, 51 women were asked to participate and 32 agreed. In 2006, 97 women were asked to participate and 50 agreed to participate.
Recruitment. Purpose and legal basis
Recruitment. Breast milk was exclusively sampled from primipara women in order to minimise variation. Breast-feeding is the major pathway of POP excretion in women, and consequently the POP levels are usually higher in breast milk sampled after the first child is born than in breast milk sampled after subsequent deliveries (Vaz et al. 1993).