Pregnancy Diagnosis In Female Dogs - Clinical Methods

Pregnancy Diagnosis In Female Dogs - Clinical Methods

  • 16 Apr 2020

Pregnancy Diagnosis In Female Dogs - Clinical Methods

On the next day, after breeding with a male. Fertilization of ova may take anywhere from 48 to 73 hours. For pregnancy diagnosis in dogs, several methods are used. Some methods like using dog pregnancy symptoms such as evaluation of teats, weight gain, and abdominal enlargement are not reliable methods of pregnancy detection. More reliable methods include abdominal palpation (30 days gestation), measuring the level of relaxin hormone in the blood (26 days gestation), ultrasonographic examination of the abdomen (starting at 21- 30 days gestation), and radiographs (after 45 days gestation). These methods vary in their ability to positively identify the number of foetuses and fetal viability.

    Small ovoid swellings can be palpated along the uterine horns 21-30 days post breeding. These swellings double in the size every week until days 35 to 38; they then become confluent and difficult to differentiate. Palpation is not as reliable as other methods for evaluating pregnancy. It is Difficult without experience to determine the exact number of foetuses and fetal viability cannot be verified with palpation.

    Relaxin is a hormone that is produced by the Placenta and found in the bloodstream of the bitch when the fertilized egg implants in the uterine wall, about 21 days post breeding (3-4 weeks). This hormone continues to circulate through the blood throughout the pregnancy, peaking around day 40 to 50. Witness Relaxin, Relaxin Pro, ReproCHEK are the current test kits in the market that measures relaxin. This test can be used to determine pregnancy and can be used continuously throughout the pregnancy to verify if total abortion has occurred. Pseudopregnant bitches do not test positive for election. This test cannot determine the number of foetuses present in the bitch. A false negative is possible if the litter size is very small. It may be cost effective in comparison to ultrasound. And relaxin based diagnostic test kit results are fast, accurate and reliable and seldom gives a false reading.

    Female dogs naturally produce higher levels of progesterone for two months after the stages of heat cycle. It is regardless of the breeding or mating. Therefore levels of progesterone in a female dog are not a reliable indicator of pregnancy.

            Ultrasound is the best method used to visualize and evaluate the pups in the womb. Ultrasound is the best done 21-30 days after breeding. Ultrasound done prior to 21 days can give false negative results. Ultrasound is a good method to differentiate between pregnancy and pyometra/ pseudopregnancy. Fetal viability can be determined by ultrasound through visualisation of fetal heart. The number of foetuses can be estimated, though it can be less accurate in bitches carrying larger litters, or when done later in gestation.

Fig: Ultrasonograph showing foetus in pregnant female dog


            At 28 days into pregnancy, the bones of the foetus begin to become calcified. At 42 -45 days of pregnancy, radiographs can be taken to visualise the pups in-utero. However, for best results, radiographs should be taken more than 47 days post-breeding, when fetal skeletons are more readily visible. Radiographs can help in determine the number of foetuses, though it is less accurate in bitches carrying larger litters. Fetal viability cannot be determined by radiograph unless advanced lesions exist in the foetus, such as skeletal collapse or gas within the foetus.


Radiograph - Showing single foetus in the uterus (Spondylosis L1-L2)

Pseudopregnancy / False Pregnancy / Canine Pseudocyesis: in this case a female dog exhibits same physiological symptoms of pregnancy like enlarged abdomen, weight gain, milk let down but foetus is not actually present. Best way is to rule out pyometra / mucometra / pseudopregnancy is ultrasound.


Que: Will a human pregnancy test kit work for dogs?

Ans: No. Pregnancy test kits designed for human are based on hCG (human chorionic gonadotropin) which is found only in women. Urine is used in such test kits while female dogs are tested for relaxin hormone which is found in blood.

Que: Are there over the counter tests / tests kits available for pregnancy diagnosis in dogs?
Ans: No, relaxin based test kits are available through resgistred vets or can be purchased online through websites / suppliers. But will need blood/serum to perform the test.


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