The relationship between the level of pregnancy-associated plasma protein A and placenta size and thickness

Authors

1 Assistant Professor of Radiology, Department of Radiology, Poursina Hospital, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran

2 Resident of Radiology, Reproductive Health Research Center, Student Research Committee, Guilan University of Medical Sciences, Rasht, Iran

3 Assistant Professor of Obstetrics and Gynecology, Reproductive Health Research Center, Department of Obstetrics & Gynecology, Al-Zahra Hospital, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran

4 Associate Professor, Department of Biostatistics‌‌‌‌, Social Determinants of Health Research Center, Guilan University of Medical Sciences, Rasht, Iran.

10.22038/ijp.2020.49676.3971

Abstract

Background: The low level of pregnancy-associated plasma protein A (PAPP-A) has a close relationship with unfavorable outcomes in neonates. We conducted this study to evaluate the association between thickness and size of placenta in 18-23 weeks and PAPP-A level at gestational age in 11 to 14 weeks in singleton pregnant women referred to Al-Zahra Hospital, Guilan. 
Materials and Methods: In this prospective cohort study, we investigated 102 women with singleton pregnancy between August 2017 to June 2018. Serum PAPP-A of pregnant women was measured in the first trimester of pregnancy. Patients who had PAPP-A ≤0.5 Multiple of the Median (MOM (were dedicated to exposed group and others to non-exposed group. Placental thickness and size were assessed during second trimester by ultrasound examination and described as abnormal high thickness if the thickness was > 4 cm or more than 50% of placental length and abnormally small size when the maximum length was < 10 cm. Placental thickness and size of the two groups were compared using the Mann-Whitney u test.
 Results:The mean age of the patients was 28.2 (SD: 5.2) years and the means of gestational age in exposed and non-exposed groups was 20.38 and 20.84 weeks, respectively (P=0.203). Sixty-eight patients had PAPP-A >0.5 and 34 patients had PAPP-A ≤0.5. Women with low levels of PAPP-A in the first trimester had an increased incidence of abnormal placental thickness in 13 cases, and small placental size in 7 cases, whereas this number in another group was 12 and 7 cases, respectively (P=0.023). We found the sensitivity and specificity of PAPP-A<0.55 were 72.3% and 56% for abnormal placental thickness, respectively. Moreover, the sensitivity and specificity of PAPP-A< 0.55 were 69.3% and 57.1% in the assessment of abnormal placenta size, respectively.

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