Maternal Recognition of Pregnancy

Question 1

Conceptus definition

Answer 1

An embryo or fetus with all its membranes and accessory structures

Embryo, conceptus, and fetus are terms often used interchangeably

Question 2

Fetus definition

Answer 2

An embryo that has completed organogenesis – recognizable as a member of its species

Embryo, conceptus, and fetus are terms often used interchangeably

Question 3

Establishment of pregnancy requires what 4 things?

Answer 3

Fertilization
Early embryonic development
Maternal recognition of pregnancy
Placentation

Question 4

Sequence of fertilization to attachment

Answer 4

Sperm fertilizes the oocyte in the oviduct
Conceptus formation and starts to descend to the uterus

Becomes blastocyst in the uterus

Blastocyst hatches and migrates in the uterus
Embryonic membrane formation

Maternal recognition of pregnancy occurs

Placentation/attachment to the endometrium

Question 5

Embryo “hatching” occurs __-__ days post ovulation

Answer 5

6-8

Question 6

_______ _______ is essential for nutrient exchange, placental attachment and maternal recognition of pregnancy

Answer 6

Uterine epithelium

Question 7

In the cow and the ewe, the embryo must be on the same side as…

Answer 7

The CL (ipsilateral)

Question 8

In the Mare the embryo must migrate between…

Answer 8

The 2 uterine horns until day 16
Continues to grow

Has NO relationship to CL

Question 9

Uterine migration and equidistant spacing between embryos is essential to embryonic survival in….

Answer 9

Litter bearing species

Question 10

Trophoblast elongation is on Day 11 or 12 in the pig or starts around Day ____ in ruminants

Answer 10

12

Question 11

Maternal Recognition of pregnancy prevents…

Answer 11

Luteolysis

Question 12

Early on the embryo will attach to the ________…

Answer 12

Endometrium by extra-embryonic membranes

Question 13

Organogenesis is the most..

Answer 13

Susceptible period of the pregnancy
1st trimester

Question 14

After attachment of embryo it will undergo placentation and…

Answer 14

Fetal growth occurs
-Sexual differentiation
-System maturation
-Specialized cell development (CNS, hair)

Ends in parturition

Question 15

Gestation length in cows

Answer 15

~9m (278-293d)

Question 16

Gestation length in mares

Answer 16

~11m (330-345d)

Question 17

Gestation length in ewes

Answer 17

~5m (144-151)

Question 18

Gestation length in the sow

Answer 18

3m, 3w, 3d (112-115d)

Question 19

Gestation length in the Bitch

Answer 19

65d
(~2m)

Question 20

Gestation length in the queen

Answer 20

58-70d
(~2m)

Question 21

Maternal Recognition happens prior to the release of ______ to prevent ________ if embryo present

Answer 21

PGF2a
prevent luteolysis

Question 22

Maternal Recognition signal comes from…

Answer 22

The embryo
May be hormone and/or protein

Question 23

Cow MRP

Answer 23

Conceptus enters uterus at ~day 5– 6

Embryo elongation by Day 13

Maternal recognition of pregnancy:
Day 15 - 18
-bovine interferon INF- tau)
-bovine trophoblastic protein 1 (bTP-1)

Question 24

Mare MRP

Answer 24

Conceptus enters the uterus Day 5 –6
-Amnionic vesicle (AV) remains spherical and diameter increases rapidly

Maternal recognition of pregnancy
-Increase embryo mobility/uterine; contractions on Days 11-16
***NO hormonal signal identified
Embryonic motility plays an IMPORTANT role
Embryo motility is lost at Day 16 when it becomes fixed

Question 25

Embryonic motility plays an important role of MRP in which species?

Answer 25

Mare Last at day 16 when attachment occurs

Question 26

Ewe MRP

Answer 26

Conceptus enters the uterus by Day 5 Maternal recognition of pregnancy: Day 12-14 Ovine interferon - oINF-tau (oTP-1)

Question 27

Sow MRP

Answer 27

Conceptus enters the uterus by Day 3 as a 4-cell Maternal recognition of pregnancy Day 11 – 12 Signal is ESTRADIOL by conceptus -Causes intraluminal vs. intravenous passage of endometrial PGF2a -FOUR EMBRYOS must be present for pregnancy to be maintained- 2 in each horn

Question 28

In the sow at least _______ embryos must be present for pregnancy to be maintained

Answer 28

Four (2 in each horn)

Question 29

Bitch/Queen MRP

Answer 29

Conceptus enters the uterus -Bitch - Day 9 – 11 -Queen – Day 4 – 5 Maternal recognition of pregnancy UNKNOWN Similar hormonal environment of the non- pregnant bitch/queen -Prolonged CL lifespan

Question 30

Endocrinology of Pregnancy- Progesterone

Answer 30

Extended production Ovarian (early) and placental (mid to late) origins Luteal-dependent species maintain ovarian production throughout pregnancy Functions: myometrial gland proliferation uterine quiescence - myometrial inhibition mammary development

Question 31

Function of progesterone during pregnancy

Answer 31

myometrial gland proliferation uterine quiescence - myometrial inhibition mammary development

Question 32

Endocrinology of pregnancy- Estrogens

Answer 32

Ovarian, placental and/or fetal origin Gradual increase with peak around the time of parturition Primer for: oxytocin - myometrial receptors progesterone, prolactin - mammary development

Question 33

In pregnancy Estrogens may originate from....

Answer 33

Ovarian, placental and/or fetus

Question 34

Estrogens during pregnancy prime for...

Answer 34

oxytocin - myometrial receptors progesterone, prolactin - mammary development

Question 35

Endocrinology of Pregnancy- gonadotropins

Answer 35

Hypothalamic source- Low levels of LH during pregnancy FSH waves may continue Progesterone negative feedback on the hypothalamus LH is luteotropic early Placental source (mare)- Equine Chorionic Gonadotropin (eCG) (previously PMSG) – from “endometrial cups” LH-like effects (FSH-like activity in other species)

Question 36

In mares eCG is produced by....

Answer 36

Endometrial cups during pregnancy

Question 37

In Mares eCG (equine Chorionic Gonadotropin) acts like....

Answer 37

LH In other species- FSH like

Question 38

In other species (not mare), eCG (equine Chorionic Gonadotropin) has activity that mimics...

Answer 38

FSH

Question 39

Luteal-Independent species

Answer 39

only needs the CL of ovulation for the first part of pregnancy followed by placental production Cow Ewe Mare

Question 40

Luteal-Dependent species

Answer 40

needs the CL of ovulation for the entire duration of pregnancy Sow Doe Bitch Queen

Question 41

Terminology used to describe pregnancy

Answer 41

Polytocous – litter bearing Monotocous – single offspring Nulliparous – never carried a pregnancy Primaparous – first pregnancy Multiparous – multiple pregnancies