Detection of twin pregnancies in ewes by pregnancy-associated glycoprotein assay and transabdominal ultrasonography

The objectives of the present study were to evaluate and compare the accuracy of transabdominal ultrasonography and pregnancy-associated glycoprotein (PAG) assay in the diagnosis of twin pregnancies in ewes and to evaluate the utility of the PAG assay for predicting fetal gender in singleton pregnancies. The animals in the study consisted of 179 pregnant ewes. The number of fetuses in the ewe was determined using transabdominal ultrasonography between days 40 and 60 (on days 40, 45, 50, 55, and 60). Blood samples were collected from all the ewes on the same day to determine the PAG concentrations. The results found were highly sensitive for the detection of twin pregnancies by transabdominal ultrasonography. The accuracy of transabdominal ultrasonography in detecting twin pregnancies was found to be higher on day 60 than on other days (P < 0.05). The sensitivities of PAG assay in detecting twin pregnancies on days 40, 45, 50, 55, and 60 were 91.67%, 66.67%, 81.82%, 88.89%, and 33.33%, respectively. The accuracies of the PAG assay in detecting twin pregnancies on days 40, 45, and 50 were found to be statistically significant higher than other days (P < 0.05). The PAG assay had low sensitivity and specificity for predicting fetal gender. It was concluded that twin pregnancies in ewes can be diagnosed with high accuracy using transabdominal ultrasonography on day 60 of pregnancy and as well as using the PAG assay during the early days of pregnancy (on days 40, 45, and 50). The PAG assay is not useful for predicting fetal gender.

Sonographische Verlaufsuntersuchungen an trächtigen Hündinnen – ein Beitrag zur Bedeutung der Fruchtresorption beim Hund

Gegenstand: Sonographische Verlaufuntersuchungen an trächtigen Hündinnen zur Evaluierung von Häufigkeit und Bedeutung des Fruchtverlustes. Material und Methoden: Bei 39 Kangalhündinnen wurden vom 15. bis zum letzten Tag der Gravidität täglich die Fruchtanlagen/Feten ultrasonographisch gezählt und die Vitalität der Embryonen/Feten beurteilt. Ergebnisse: Bei fünf Hündinnen (12,8%) war die Resorption von Embryonen nachweisbar, wobei in einem Fall eine Resorption aller Fruchtanlagen vorlag. Bei vier Hündinnen wurde ein Fetaltod dokumentiert, der mit einem Totalverlust des Wurfes einherging. Nach dem ersten Hinweis auf embryonalen Tod ließen sich noch über durchschnittlich 8,6 ± 0,5 Tage Fruchtkammern nachweisen. Die Anzahl der Embryonen differierte bei Hündinnen mit (10,8 ± 1,8) und ohne Resorption (8,2 ± 2,1) statistisch signifikant (p < 0,05). Dagegen konnte hinsichtlich der Embryonenzahl kein signifikanter Unterschied zwischen Hündinnen ohne embryonale Resorption (8,2 ± 2,1) und Tieren mit fetalem Tod (9,5 ± 1,3) festgestellt werden (p > 0,05). Eine Beziehung zwischen Wurfgröße und Trächtigkeitsdauer ließ sich nicht nachweisen (r = 0,15; p > 0,05). Schlussfolgerung und klinische Relevanz: Aufgrund der Ergebnisse wird die Hypothese aufgestellt, dass die Resorption von Fruchtanlagen ein Schutzmechanismus vor einer zu großen Wurfgröße darstellt.

[Follow-up ultrasonographic examinations in pregnant bitches - evaluation of frequency and significance of embryo resorption]

OBJECTIVE

Follow-up ultrasonographic examinations in pregnant bitches to evaluate frequency and significance of embryo resorption.

MATERIAL AND METHODS

In 39 Kangal bitches the number of gestational sacs was measured and vitality of embryos/fetuses was evaluated by real time ultrasonography daily from the 15th till the last day of gestation.

RESULTS

Five bitches (12.8%) showed embryonic resorption and one of these bitches exhibited a complete resorption. Fetal death could be observed in four females and was related to a total loss of the litter. After the first evidence of embryonic death gestational sacs remained detectable for 8.6±0.5days. The number of embryos of bitches with (10.8±1.8) or without embryo resorption (8.2±2.1) was statistically significantly different (p<0.05). On the other hand there was no statistically significant difference within the number of embryos of bitches suffering fetal death and bitches without embryo resorption (8.2±2.1) (p>0.05). A relationship between litter size and gestational length could not be verified (r=0.15; p>0.05).

CONCLUSION AND CLINICAL RELEVANCE

Due to these results the hypothesis is postulated that embryonic resorption is a kind of protective mechanism of the maternal organism against too large litter sizes.