title: Morphometric analysis of fetal development of Cavia porcellus (Linnaeus, 1758) by ultrasonography--pilot study.
abstract: Measurements on the growth process and placental development of the embryo and fetuses of Cavia porcellus were carried out using ultrasonography. Embryo, fetus, and placenta were monitored from Day 15 after mating day to the end of gestation. Based on linear and quadratic regressions, the following morphometric analysis showed a good indicator of the gestational age: placental diameter, biparietal diameter, renal length, and crown rump. The embryonic cardiac beat was first detected at an average of 22.5 days. The placental diameter showed constant increase from beginning of gestation then remained to term and presented a quadratic correlation with gestational age (r(2) = 0.89). Mean placental diameter at the end of pregnancy was 3.5 ± 0.23 cm. By Day 30, it was possible to measure biparietal diameter, which followed a linear pattern of increase up to the end of gestation (r(2) = 0.95). Mean biparietal diameter in the end of pregnancy was 1.94 ± 0.03 cm. Kidneys were firstly observed on Day 35 as hyperechoic structures without the distinction of medullar and cortical layers, thus the regression model equation between kidney length and gestational age presents a quadratic relationship (r(2) = 0.7). The crown rump presented a simple linear growth, starting from 15 days of gestation, displaying a high correlation with the gestational age (r(2) = 0.9). The offspring were born after an average gestation of 61.3 days. In this study, we conclude that biparietal diameter, placental diameter, and crown rump are adequate predictive parameters of gestational age in guinea pigs because they present high correlation index.
authors.affiliation: University of São Paulo, São Paulo, Sao Paulo, Brazil. Electronic address: jpasantosvet@gmail.com.
authors.forename: Juliana
authors.initials: J
authors.lastname: Santos
authors.affiliation: Federal University of Tocantins, Araguaína, Tocantins, Brazil.
authors.forename: Erika
authors.initials: E
authors.lastname: Fonseca
authors.affiliation: Institute of Biology, Unicamp, Campinas, Sao Paulo, Brazil.
authors.forename: Juliano
authors.initials: J
authors.lastname: van Melis
authors.affiliation: University of São Paulo, São Paulo, Sao Paulo, Brazil.
authors.forename: Maria Angélica
authors.initials: MA
authors.lastname: Miglino
mesh_terms: D000818:Animals; D005260:Female; D047109:Fetal Development; D005865:Gestational Age; D006168:Guinea Pigs / Q000196:embryology*; D010865:Pilot Projects; D011247:Pregnancy; D011270:Pregnancy, Animal; D016216:Ultrasonography, Prenatal / Q000662:veterinary
keywords: Embryo age; Fetal age; Guinea pig; Pregnancy; Ultrasound