Labour

Question 1

define term - how many pregnancies occur in the time frame

Answer 1

Term= 37-41 weeks;

90% of human pregnancies are delivered within this time frame.

Question 2

define pre term

Answer 2

Pre-term= 22-37 weeks

Question 3

define very pre term

Answer 3

Very pre-term= 28-32 weeks

Question 4

Term and preterm labour differ mainly in….

Answer 4

the initiating factors

Question 5

what are the key tissues involved in labour

Answer 5

Uterus and cervix

Question 6

how do these tisues change throughout pregnancy

Answer 6

undergo a substantial
change in structure and functions

transition from what is needed for pregnancy to
delivery

Question 7

define human labour

Answer 7

process of expulsion of the fetus and the placenta from the uterus.

Question 8

what main events occur leading up to deilvery of infant

Answer 8

Cervical ripening and effacement (thinning)
Co-ordinated myometrial contractions
Rupture of fetal membranes

Question 9

what main events occur after delivery of infant

Answer 9

Delivery of placenta

Contraction of uterus

Question 10

what changes occur to the cervix in labour

Answer 10

Change from rigid to flexible structure;
dilates (becomes thinner and is stretched sideways)
remodelling of extracellular matrix; recruitment of leukocytes; inflammatory process

(PG E2, Il-8).

Question 11

what is stage 2

Answer 11

delivery of infant

Question 12

describe the myometrial contractions (where they occur)

Answer 12

Fundal dominance;
increased co-ordination and power of contractions.

(increased levels and activity of MMPs)

Question 13

describe the rupture of fetal membranes (why it occurs/where)

Answer 13

Rupture of fetal membranes… Loss of strength due to changes in amnion basement component;

increased MMP activity
inflammatory changes and leukocyte recruitment;

Question 14

what factors in the cervix regulate labour

Answer 14

prostaglandin E2, IL-8, MMPs

Question 15

what factors in the myometrium regulate labour

Answer 15

increased oxytocin receptor
increased contraction associated proteins
increase prostaglandin E2

Question 16

what factors in the fetal membrane regulate labour

Answer 16

inflammatory processes, prostaglandins, IL, MMPs).

Question 17

how are cervical changes accelerated during labour

Answer 17

accelerated by increasing pressure of the fetal head on the cervix

which is caused by increasing the strength and decreasing the gaps between myometrial contractions.

Question 18

what is unique about promoters of many pro-labour genes

Answer 18

Almost all pro-labour genes have NFkB binding domains

in their promoters

Question 19

how can pro-labour genes affect cell expression

Answer 19

Modification of NFkB sites in promoter sequences leads to loss of expression in cells or in expression vectors

Question 20

what type of environment Is linked with labour

Answer 20

Inflammatory changes are strongly linked with labour and activators of inflammation are readily linked with preterm labour.

Question 21

what are the candidate initiators of human labour

Answer 21

CRH and PAF

Question 22

what do CRH and PAF do

Answer 22

up-regulate inflammatory pathways in fetal pathways

both stimulate interleukin and prostaglandin production

Question 23

where is PAF produced

Answer 23

lungs

Question 24

where is CRH produced

Answer 24

placenta

Question 25

what hormone sustains human pregnancy and how does its level change throughout pregnancy

Answer 25

Progesterone

the levels remain very high until after delivery of the placenta

Question 26

the relationship between which to molecules drives labour

Answer 26

There is a mutually negative relationship between the progesterone receptors and NFkB

if High NFkB and low Prog rc
= active NFkB
then labour continues

Question 27

why is blood lost in the uterine lumen

Answer 27

Spiral arteries are unable to vasoconstrict to decrease blood flow due to remodelling which means blood is lost into the uterine lumen

Question 28

how is blood loss limited in this stage

Answer 28

INVOLUTION

Powerful uterine contractions of involution effectively close the spiral arteries

Question 29

define involution

Answer 29

powerful contractions of the uterus, leading to a rapid decrease in overall size –

Question 30

what is the first stage labour

Answer 30

begins with the onset of uterine contractions through the period of dilation of the os uteri

Question 31

what is the second stage of labour

Answer 31

period of expulsion effort, beginning with complete dilation of the cervix and ending with the expulsion of the infant.

Question 32

what is the third stage of labour

Answer 32

begins with the expulsion of the infant and ends with the completed expulsion of the placenta and the membranes.

Question 33

how long does stage 1 of labour last

Answer 33

8h

Question 34

how long does placental delivery take

Answer 34

30 mins

Question 35

what is placental delivery associated with

Answer 35

very powerful contractions of the uterus, leading to a rapid decrease in overall size
(involution)

Question 36

what is involution linked with

Answer 36

an increase in maternal oxytocin

if it does not occur spontaneously, an injection of oxytocin is required

Question 37

What is meant by the term “effacement”?

Answer 37

The process of the cervix changing from a tubular structure to become a thinner flatter structure.