Merck Manual

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Gestational Age in Dogs and Cats

Gestational Age in Dogs and Cats

Dogs: Gestational Age ± 3 days

Cats: Gestational Age ± 2 days

<40 days

>40 days

>40 days

(6 × GSDa) + 20

(15 × BPb) + 20

25 × BP + 3

(3 × CRLc) + 27

(7 × BDd) + 29

11 × BD + 21

(6 × HD) + (3 × BD) + 30

Days before parturition: 64–66 minus gestational age

Days before parturition: 61 minus gestational age

a Gestational sac diameter (cm)

b Biparietal diameter (cm)

c Crown rump length (cm)

d Body diameter at the liver (cm)