Evaluation of indications for amniocentesis in cases of normal fetal ultrasound results

OBJECTIVES

The objective of this study was to analyze indications for amniocentesis in cases of patients with normal fetal ultrasound results between 11+0 and 13+6 weeks of gestation.

MATERIAL AND METHODS

The results of first-trimester screening tests performed between 2014 and 2018 on 6,863 patients of the Prenatal Testing Outpatient Clinic at the Clinical Department of Obstetrics and Gynecology, Pomeranian Medical University, Szczecin, Poland, were analyzed. The inclusion criteria were a singleton pregnancy and normal results of fetal ultrasound between 11+0- and 13+6-weeks' gestation. Depending on the calculated risk of fetal trisomy 21, the patients were divided into three groups (group A = RS > 1:300, group B = RS 1:300 - 1:999, group C = RS ≤ 1:1000). Subsequently, values such as PAPP-A and fβ-hCG protein levels and maternal age were analyzed for each of the groups.

RESULTS

The patients, 6,310 (91.94%) met the inclusion criteria. A high risk of fetal trisomy 21 was identified for 514 women (8.15%). Group B had 733 (11.62%) and group C 5,063 (80.23%) patients. In group A, an fβ-hCG level of ≥ 2.000 MoM was shown for 50.97% of the women. A PAPP-A level ranging from 0.001 to 0.499 MoM was observed for 38.72% of group A patients. The mean maternal age in groups A, B and C was 36.45, 36.08 and 31.64 years, respectively.

CONCLUSIONS

In the first-trimester, patients with normal ultrasound results obtained during prenatal screening tests, the main cause of an increased risk of trisomy 21 was elevated PAPP-A and fβ-hCG concentrations. According to this paper's authors, in these cases extension of diagnosis to include other gestational complications, e.g. preeclampsia, should be considered.