Determination of fetal biparietal diameter without the use of ultrasound in squirrel monkeys

This study evaluated manual caliper measurement of fetal BPD in Saimiri thr ough the abdomen of the dam (TBPD) for correlation with paired ultrasound m easurements, prediction of delivery date, subspecies variation, prediction of pregnancy outcome, and correlation between postpartum BPD and TBPD. Regr ession analysis revealed a close relationship between TBPD measurements and those obtained by ultrasound (P < 0.001). TBPD for Saimiri boliviensis bol iviensis increased from a mean of 14.8 +/- 0.3 mm for 11 weeks prepartum to a delivery week measurement of 33.2 +/- 0.2 mm, Delivery-week TBPD of Saim iri boliviensis peruviensis were significantly smaller than Saimiri sciureu s sciureus (P < .05). Delivery week TBPD had a correlation coefficient of 0 .64 with paired post-patrum measurements. No complications were associated with the technique. Delivery date could be predicted within two weeks. TBPD is an inexpensive, safe, rapid method of approximating fetal growth during the last half of pregnancy in Saimiri.