Is there any relationship between low PAPP-A levels and measures of umbilical vein and placental thickness during first trimester of pregnancy?

OBJECTIVE: Low pregnancy-associated plasma protein A (PAPP-A) level is associated with adverse perinatal outcomes. The purpose of this study was to evaluate relationship between umbilical cord diameter (UCD), umbilical vein and artery diameters (UVD, UAD), placental thickness, and PAPP-A level at gestational age of between 11 and 14 weeks. METHODS: UCD, UVD, UAD, and placental thickness of 246 women were assessed during ultrasound examination at between 11 and 14 weeks of gestation, as well as measurement of nuchal translucency (NT) and crown-rump length (CRL). Patients were divided into 2 groups according to PAPP-A percentile. Group 1 comprised 23 patients who had low PAPP-A (<0.44 multiple of medians [MoM], <10(th) percentile) and Group 2 was made up of 223 patients with PAPP-A of >0.44 MoM, >10(th) percentile. Calipers used for measurement were placed inner edge to inner edge of echogenic boundaries of the vessel. Largest sections of all vessels (UV and both arteries) were evaluated. Thickest part of the placenta was used for placental thickness measurement. RESULTS: Narrow UCD (<4.5±0.6 mm) was associated with low PAPP-A level (p=0.02). There was no significant difference in UVD, UAD, or placental thickness between groups. There was no significant difference in gestational age, CRL, or NT between groups. Fetal birth weight was significantly lower in Group 1 (p=0.03). CONCLUSION: Closer attention to women with low-risk, healthy pregnancies and low PAPP-A level in first trimester screening results is recommended. They should be routinely screened for background medical risk factors and umbilical cord morphology in first trimester scan.