[1] Hosp Univ La Paz, Dept Nursing & Midwifery, Madrid 28046, Spain
[2] Univ Alfonso X El Sabio, Sch Hlth Sci, Madrid 28691, Spain
[3] Hosp Univ La Paz, Dept Obstet, Madrid 28046, Spain
[4] Univ Autonoma Madrid, Sch Med, Dept Obstet & Gynecol, Madrid 28029, Spain
[5] Free Univ Berlin, Educ & Psychol, D-14195 Berlin, Germany