INTRODUCTION

Psychological pregnancy or also called pseudo-gestation, is a physiological condition that female animals (human or not) can experience approximately a month and a half after oestrus if they are not sterilised or occasionally in the case of animals that are not in oestrus as such (cats, rabbits...).

During this time, females feel all the symptoms of pregnancy, even to the point of having swollen breasts or milk secretion. It is not a disease, but psychological pregnancy can lead to serious problems affecting the health of our pets.

WHAT IS A PSYCHOLOGICAL PREGNANCY?

Psychological pregnancy is a purely normal process that can occur as a result of a failed mating or hormonal imbalance (no mating), in some animals it is recurrent and can occur every heat or every few days/weeks. 

It can also occur in females and in the case of females it is multifactorial (not only depends on hormones).

WHY DOES PSYCHOLOGICAL PREGNANCY OCCUR?

Psychological pregnancy in animals is due to a purely hormonal imbalance produced during oestrus or after an important hormonal drop in the case of those animals that are not in oestrus as such. What happens is that both the animal's body and mind act as if it is going through a real pregnancy. The bitches believe they are pregnant and develop behaviours accordingly. In the case of bitches it is considered a survival mechanism, as it is common in wolf and wild bitches (this way they can help with lactation or adopt abandoned puppies).

This is because the level of the hormone progesterone drops after oestrus in unmated bitches, causing the body to believe that there has been a birth and resulting in an increase in the hormone prolactin (the hormone responsible for the production of mother's milk).

Some dog breeds require high prolactin levels for this behaviour, others less so.

CONSEQUENCES OF PSYCHOLOGICAL PREGNANCY IN ANIMALS

Psychological pregnancy can have various consequences in animals and the severity or intensity of these depends on the animal itself. They may present one or more of the following symptoms:

• Weight gain
• Enlargement of the abdomen
• Enlargement of the vulva
• Inflammation of the breasts
• Discharge of breast milk
• Changes in behaviour (nervousness, crying...)
• Increased food and water intake
• Pulling out hair (rabbits)
• Nest making with blankets, hay, hair, rags... 
• Mastitis
• Adoption of stuffed animals, toys or objects.
• Adoption of other people's puppies (dogs and cats).
• Several psychological pregnancies in a chain can lead to:
• Mammary infections (mastitis)
• Obesity
• Pyometra (infection of the uterus)
• Uterine or mammary tumours
• Problems living together with other animals or one's own family.

CAN I PREVENT MY PET FROM HAVING PSYCHOLOGICAL PREGNANCIES?

The only solution to psychological pregnancies is castration (not tubal ligation), as the source of the excessive hormone secretion must be eliminated. It is considered normal for an animal to have one or two psychological pregnancies during its lifetime, but when this becomes excessively repetitive or the symptoms are very strong and interfere seriously with family life, it is best to opt for castration.

CONCLUSION

Pseudogestation can be annoying in all senses and the intensity of its symptoms depends on the animal. It can occur in all mammalian species (including humans) and is something that we must learn to recognise in order to help our pet, especially if we observe symptoms that require pharmacological or surgical attention.