Table 1.

Changes in pregnancy rate during ageing

Age rats (months)	4	5	6	7	8	9	10
Pregnancies (%)	69.8	92.1	85.7	69.8	50.8	22.2	4.8
Number of pups born live	8.3 ± 0.6	10.7 ± 0.42	9.7 ± 0.43	6.8 ± 0.53	4.9 ± 0.87	2.6 ± 0.63	0.5 ± 1.89

Shown is the percentage of rats that became pregnant at different ages and the number of live pups born from rats between 4 to 10 months old. Data were obtained from the animal facility of the Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile. Each point represents means ± SEM of 63 rats.