Noninvasive Ultrasound Monitoring of Embryonic and Fetal Development in Chinchilla lanigera to Predict Gestational Age: Preliminary Evaluation of This Species as a Novel Animal Model of Human Pregnancy

Table 4

Spearman’s correlation coefficient and significance of each embryonic parameter.

Embryonic structure	Correlation coefficient
Longitudinal sac diameter	0.765	<0.0001
Transversal sac diameter	0.683	<0.0001
Placental diameter	0.841	<0.0001
Placental thickness	0.902	<0.0001
Lens diameter	0.639	0.0014
Eye axis	0.313	0.1914
Head diameter	0.942	<0.0001
Occipital to snout length	0.923	<0.0001
Heart rate (BPM)	−0.362	0.0062
Stomach diameter	0.517	0.0114
Body diameter (long axis)	0.919	<0.0001
Crown-rump length	0.71 ± 0.33 (E31)	2.70 ± 0.78 (E70)

BPM: beats per minute.