Gynaecology & Obstetrics The one measurement of fetal maturity that is not affected by a ‘bloody tap’ during amniocentesis is: A L/S ratio B Phosphatidyl glycerol C Ξ±-fetoprotein D Bilirubin as a measured by DOD 450 π‘ Explanation The one measurement of fetal maturity that is not affected by a 'bloody tap' during amniocentesis is: β Correct Answer: B. Phosphatidyl glycerol