Fetal Tachycardia Is an Independent Risk Factor for Chromosomal Anomalies in First-Trimester Genetic Screening

The association of an abnormal fetal heart rate (FHR) and chromosomal anomalies in the first trimester of pregnancy remains unclear, probably because of the lack of control for known confounding factors. This study was designed to determine whether an increased FHR is an independent risk factor for chromosomal anomalies between 11 and 14 weeks' gestation.

This cohort study included women who underwent first-trimester genetic screening between 2011 and 2014 at a single institution. A multivariable logistic regression analysis was performed to determine whether an FHR of 170 beats per minute (bpm) or higher, derived from a receiver operating characteristic curve, is an independent risk factor for all chromosomal anomalies while controlling for known confounding factors. P < .05 was considered significant.

An FHR of 170 bpm or higher was observed in 7% (228 of 3254), and chromosomal anomalies were present in 1.0% (31 of 3254) of the population. A higher proportion of fetuses with an FHR of 170 bpm or higher had chromosomal anomalies compared to those with an FHR lower than 170 bpm. An FHR of 170 bpm or higher was an independent risk factor for chromosomal anomalies after controlling for known confounding factors. Of note, in the group of fetuses with a nuchal translucency above the 95th percentile, the frequency of chromosomal anomalies was significantly higher among fetuses with an FHR of 170 bpm or higher compared to those with an FHR lower than 170 bpm.

Fetal tachycardia is a risk factor for chromosomal anomalies during first-trimester genetic screening, independent of increased nuchal translucency, nuchal septations, and maternal age.