# Noninvasive prenatal tests for chromosomal abnormality screening in in vitro fertilisation elderly pregnant women in northwest China

## TL;DR

This study evaluates the effectiveness of noninvasive prenatal tests for detecting chromosomal abnormalities in older women undergoing IVF in northwest China.

## Contribution

The study provides insights into NIPT accuracy and influencing factors in elderly IVF pregnancies in a specific geographic region.

## Key findings

- NIPT showed high sensitivity and specificity for detecting common chromosomal aneuploidies in IVF pregnancies of women over 35.
- Mean gestational age and AFP were identified as independent risk factors for NIPT diagnostic failure.

## Abstract

The study aimed to explore the value of using noninvasive prenatal tests (NIPT) in the second trimester of pregnancy for chromosomal abnormality screening in vitro fertilisation (IVF) in elderly pregnant women and to analyse the reasons for inconsistent screening results in northwest China.

A total of 47,286 pregnant women aged 19-51 who underwent prenatal examinations were collected. NIPT detection found that the positive rate of pregnant women aged > 35 with spontaneous pregnancy was 0.78% , and the positive rate of IVF pregnancy was 0.82%. Then, the detection accuracy of NIPT for pregnant women aged >35 with IVF was further analysed.

NIPT's sensitivity, specificity, and positive predictive value in detecting common chromosomal aneuploidies (T21, T18, and T13) in pregnant women aged >35 who received IVF were 99.72% , 99.78% , and 66.45% , respectively. The mean gestational age, pregnancy number, AFP, and free b-HCG significantly differed between the positive and false positive groups (P < 0.05). Logistic analysis showed that the mean gestational age and AFP were independent risk factors for the failure of NIPT diagnosis (P < 0.05).

NIPT has a particular detection performance for common chromosomal aneuploidies IVF in pregnant women. However, factors affecting detection accuracies must be considered when using it.