Evaluation of placenta volume at 11-13+6 weeks of pregnancy by three-dimensional ultrasonography

Abstract

Objective To establish normative data for placenta volume (PV) at 11-13+6 weeks of gestation age using three-dimensional ultrasound (3DUS).Methods From June 2011 to July 2012,placental volume was prospectively measured by vitual organ computer-aided analysis(VOCAL) method in 169normal pregnancies and correlated with gestational age and crown-rump length (CRL).The maximum placental diameter(MPD) and the maximum placenta thickness(MPT) were calculated in the same maximal plane.Then,regression analysis was used to deduce the formula for the expected placenta volume.Results 1) The placenta volume ranged from 33.2 cm3 at 11 weeks to 171.3cm3 at 14 weeks with a mean of (84.9 ± 26.5 cm3),the gestational age ranged from 79 days and 100 days with a mean of (87.6 ± 3.9)day,the CRL ranged from 4.6 cm to 8.3 cm with a mean of (6.2 ± 0.8) cm.2) Linear regression yielded the following formula for the placental volumes (PV) according to gestational age(GA):PV =-190.6 + 21.8 ×GA (r =0.511,P ＜0.001) and according to CRL:PV =-17.5 + 16.5 × CRL (r =0.513,P ＜0.001).3) The placenta volume could be estimated by the formula according to MPD and MPT:PV=-30.7 + 12.6 ×MPD + 11.7 × MPT (r =0.622,P ＜ 0.01).Conclusions Placental volume of the first trimester has positive relationship with gestational age and crown-rump length during the first trimester.Placenta volume can be estimated simply by maximal placenta length and thickness through two dimensional ultrasound. Key words: Ultrasonography,three-dimensional; Placenta; Placental volume; Fetal development