Evidence of compliance with and effectiveness of guidelines for noninvasive prenatal testing in China: a retrospective study of 189,809 cases

In China, the medical guidelines recommend performing noninvasive prenatal testing (NIPT) with caution for pregnant women aged 35 years or older. However, the Mother and Child Health Care Law suggests that all primiparous women whose age is older than 35 years undergo prenatal diagnosis. These two inconsistent suggestions/recommendations have made obstetricians confused about whether to offer NIPT to these older pregnant women. To face this issue and find out the solution we performed a retrospective study of 189,809 NIPT samples collected from 28 provincial-leveled administrative units in China. Of 1,564 women with high-risk pregnancies who underwent NIPT, 459 (29.3%) did not participate in follow-up. The compound sensitivity and specificity of NIPT for trisomies 21, 18 and 13 detection was 99.1% (95% CI, 98.0%–99.6%) and 99.9% (95% CI, 98.8%–99.9%), respectively. In secundiparous women, NIPT showed high sensitivity and specificity similar to that in primiparous women. The observed risk for trisomies 21 and 18 significantly increased when the maternal age was 39 and older. After the publication of the current NIPT policy, the follow-up rate at our center was 91.9%; however, a large number of women are not in maternal and infant care networks nationwide, and that makes the follow-up rate outside our center relatively low. Our study shows that to balance the prevention of major aneuploidies and the limited resources for prenatal diagnosis, the cut-off age of 35 for invasive prenatal diagnosis might be unnecessary. Although the NIPT guidelines are well written, how to practice it effectively, especially in less industrialized areas, is worth discussing.