IMR Press / CEOG / Volume 47 / Issue 1 / DOI: 10.31083/j.ceog.2020.01.5120
Open Access Original Research
Fetal acidosis in a sheep model: can we perform a second day of protocol in order to reduce the numbers of animals needed?
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1 University of Lille, EA 4489 – Perinatal Environment and Health, Lille, France
2 CHU Lille, Department of Obstetrics, Lille, France
3 CHU Lille, CIC-IT 1403, Lille, France
4 CHU Lille, Department of Pediatric Surgery, Lille, France
5 CHU Lille, Department of Neonatology, Lille, France
*Correspondence: (C. PIERRE)
Clin. Exp. Obstet. Gynecol. 2020, 47(1), 79–83;
Published: 15 February 2020
Copyright: © 2020 Pierre et al. Published by IMR press.
This is an open access article under the CC BY-NC 4.0 license

Objective: To determine if a model of acidosis caused by occlusion of the umbilical cord could be repeated in the same sheep in ethicaly order to reduce the number of animals needed. Method: To obtain fetal acidosis, 1 min of total umbilical cord occlusion (UCO) every 2.5 min was performed on fetal sheep (n=7) until pH reached 7.10. Chronic instrumentation regularly recorded arterial blood gas and hemodynamic parameters. The occlusions were repeated to compare the data between the 2 days for each animal. Results: At the end of the UCO period, fetal acidosis was obtained with a pH 7.14 on day 1 (D1) and 7.06 on day 2 (D2). At baseline, fetuses were more hypotensive at D2 (41 mmHg vs 44 mmHg on D1, p < 0.05). During the UCO period, there was no significant difference in blood gas and hemodynamic data between D1 and D2. Conclusion: To reduce the number of animals needed, performing a second experiment on the same animal appears possible even if results must be interpreted cautiously when severe acidosis is reached.

Fetal sheep
Animal experimentation
Animal ethics
Umbilical cord occlusion
Fetal acidosis
Figure 1.
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