title: Pregnancy-associated plasma protein A (PAPP-A) to predict adverse fetal outcomes in Chinese: What is the optimal cutoff value?
abstract: A low level of PAPP-A predicts adverse fetal outcomes. As Chinese pregnant women have a higher level of PAPP-A, the predictive performance of PAPP-A and its optimal cutoff value might be different. This study aims to establish a PAPP-A cutoff value in the Chinese population that identifies adverse fetal outcomes. We retrospectively analysed 4936 spontaneous singleton pregnancies of Chinese women who underwent first-trimester combined Down's screening in our unit from March 2010 to January 2014 and had delivery information available. A composite adverse fetal outcome encompassed intrauterine fetal loss (including miscarriages and stillbirths), and live births either before 32 weeks or weighing less than -2 standard deviation (SD) for gestation. The area under the curve of the receiver-operator characteristic curve for prediction of the composite adverse outcome using PAPP-A was 0.626 (95% CI =0.612-0.640, p < 0.0001). PAPP-A ≤ 0.23 multiples of median (MoM) identified 0.6% of Chinese pregnant women to be at significant risk of adverse fetal outcome (positive likelihood ratio 11.2, positive predictive value 21.4%) despite a low sensitivity (5.1%, 95% CI =1.9-10.8). The negative predictive value was high (97.7%). The commonly used cutoff of 0.4 MoM was associated with a positive likelihood ratio of 3.7 only. A prospective study is warranted.
authors.affiliation: a Department of Obstetrics and Gynecology , Princess Margaret Hospital , Hong Kong.
authors.forename: Tsz-Kin
authors.initials: TK
authors.lastname: Lo
authors.affiliation: b Prenatal Diagnostic Laboratory , Tsan Yuk Hospital , Hong Kong.
authors.forename: Kelvin
authors.initials: K
authors.lastname: Yuen-Kwong Chan
authors.affiliation: b Prenatal Diagnostic Laboratory , Tsan Yuk Hospital , Hong Kong.|c Department of Obstetrics and Gynecology , Queen Mary Hospital , Hong Kong.
authors.forename: Anita
authors.initials: A
authors.lastname: Sik-Yau Kan
authors.affiliation: c Department of Obstetrics and Gynecology , Queen Mary Hospital , Hong Kong.
authors.forename: Amelia
authors.initials: A
authors.lastname: Pui-Wah Hui
authors.affiliation: c Department of Obstetrics and Gynecology , Queen Mary Hospital , Hong Kong.
authors.forename: Noel
authors.initials: N
authors.lastname: Wan-Man Shek
authors.affiliation: b Prenatal Diagnostic Laboratory , Tsan Yuk Hospital , Hong Kong.|c Department of Obstetrics and Gynecology , Queen Mary Hospital , Hong Kong.
authors.forename: Mary
authors.initials: M
authors.lastname: Hoi-Yin Tang
mesh_terms: D000022:Abortion, Spontaneous / Q000453:epidemiology*; D000328:Adult; D015415:Biomarkers / Q000032:analysis; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D007230:Infant, Low Birth Weight; D007752:Obstetric Labor, Premature / Q000453:epidemiology*; D011237:Predictive Value of Tests; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood / Q000175:diagnosis; D011256:Pregnancy Outcome / Q000453:epidemiology; D011266:Pregnancy-Associated Plasma Protein-A / Q000032:analysis*; D011296:Prenatal Diagnosis / Q000379:methods; D012189:Retrospective Studies; D013223:Statistics as Topic
chemical_list: D015415:Biomarkers; D011266:Pregnancy-Associated Plasma Protein-A
keywords: Chinese; Pregnancy-associated plasma protein A; intrauterine fetal growth retardation; miscarriage; prematurity; stillbirth