Pregnancy Structures

ANATOMY

Mare and pig: diffuse placenta
Dog and cat: zonary placenta
Ruminants: cotyledonary placenta

• Cotyledon=area of attachment of foetal placenta (black areas of diagram).
• Caruncle=maternal endometrial attachment site (stippled areas of diagram).
• Placentome = cotyledon + caruncle.

insert the diagrams here

Normal structures found during pregnancy

1. Corpora lutea in ovaries.
2. Endometrial cups in the mare. These develop from foetal tissue, visible from day 40, pale and start to slough from day 100. They produce gonadotrophic hormones. The cups vary from 1-10cm and hold a mixture of debris and secretion which is honey-like. They are not usually found in the placenta at term as they should have disappeared by day 130. The debris from the sloughing of the cup may form allantochorionic pouches, up to 2cm in length, which can be present in the placenta at term.
3. Amniotic plaques consisting of 2-4 mm plaques of squamous epithelium.
4. Placental mineralisation, a milky deposition of calcium mid-pregnancy. May get small bony plaques in the allantochorion.
5. Calcified yolk sac remnants.
6. Hippomanes in mares.
7. Cervical star in mares (placental), an area of fibrosis where the placenta did not attach to uterus during pregnancy.

Information by permission of Professor RW Else