THE DURATION OF PREGNANCY IN RHESUS MONKEYS MACACA MULATTA

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Abstract

The gestation period has been estimated in 34 pregnancies which have occurred in the Birmingham colony of rhesus monkeys. The placental sign could be identified in 16 of them and the gestation periods in this group varied between the limits of 158 and 173 days. No placental sign could be recognized in the other 18 pregnancies and the records of menstrual bleeding could not be interpreted to give reasonably consistent estimates of the duration of pregnancy.

One prolonged labour is described in detail and the exceptionally heavy baby, weighing 840 g, was finally born after a normal gestation period of 165 days.

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