Labour, Delivery,lactation

Question 1

What is parturition ?

Answer 1

Transition for pregnant to no pregnant state

Question 2

What is labour ?

Answer 2

Physiologic process by which foetus is expelled from uterus

Question 3

What is delivery ?

Answer 3

Method of expulsion of foetus

Question 4

Which 2 physiological changes initiate labour ?

Answer 4

Uterine lining (decidua+myometrium) more excitable

Cervical ripening

Question 5

What is the birth canal composed of ?

Answer 5

Pelvic minor 
Soft tissue (uterus,cervix,vagina,vulva)

Question 6

How is the first stage of labour defined ?

Answer 6

Interval between onset of labour and full dilatation of cervix

Question 7

What are the phases of the first stage of labour ?

Answer 7

Latent phase : onset of labour , slow cervical dilatation ,softening

Active phase : faster rate of change + regular contractions

Question 8

What is the aim of the first stage of labour ?

Answer 8

Creation of the birth canal and descend of foetus

Question 9

What is stage 2 of labour ?

Answer 9

Time between full dilatation of cervix (10 cm ) and delivery

Question 10

Which changes occur during stage 2 of delivery ?

Answer 10

Changes in uterine contractions (direction) to expulsive

Descent of the foetus (crowning of head)

Question 11

What are the 2 phases of stage 2 of labour ?

Answer 11

Passive : descent and rotation of head

Active: maternal effort to expel foetus

Question 12

What is the 3rd stage of labour ?

Answer 12

Expulsion placenta and downward contraction of uterus

Question 13

Which changes must happen to start labour ?

Answer 13

• creation of birth canal (cervical ripening:effacement and dilatation )
• myometrium more excitable for initiation of contractions

Question 14

Which hormone inhibits contractions ? How ?

Answer 14

Progesterone, depresses responsiveness of uterus to oxytocin and reduces uterine prostaglandin release

Question 15

What are the effects of oestrogen on the myometrium and on other hormones ?

Answer 15

Increases gap junction : increases contractility
Also increases number of oxytocin receptors in myometrium
Induce prostaglandin synthesis

Question 16

Which changes in hormones occur near term are responsible for onset of labour ?

Answer 16

Increase in oestrogen:progesterone ration
Lead to increased excitability due to increased oxytocin receptors and contractility of myometrium Increase prostaglandin production leads to cervical ripening and aids in contraction

Question 17

What are the effects of prostaglandin and what induces its release ?

Answer 17

Promote labour :
Powerful contractor of myometrium
Involved in cervical ripening

Production by decidua,myometrium and membrane induced by increased oestrogen:progesterone ratio, oxytocin ,rupture of membrane , cervical stretching

Question 18

How is oxytocin secreted, what are its effects ?

Answer 18

Secreted by posterior pituitary , controlled by hypothalamus

Initiate uterine contraction and stimulates prostaglandin release

Question 19

Which physiological changes occur during cervical ripening ?

Answer 19

-Reduction of collagen and reduced aggregation of fibres
-increased glycosaminoglycans and hyaluronic acid : increase water content
More ground substance

Shortening and effacement

Question 20

What is the maximum size of birth canal , what determines it and how does it happen ?

Answer 20

Max size around 11cm , determined by pelvic inlet , due to softening of ligament : relaxin, oestrogen

Question 21

Which changes occur at the perineum ?

Answer 21

Stretching of fibres of levator and and thinning of perineum : almost transparent membrane

Question 22

What special properties does the myometrium have ?

Answer 22

Fibres contract and only partially relax , does not return to original size

Contraction and retraction leading to increased pressure in uterus

Question 23

How do myometrium contraction occur and how are they made more forceful and frequent during labour ?

Answer 23

Spontaneous action potential induce increase in intra cellular calcium

Prostaglandins : increase calcium per AP : increased force
Oxytocin : decreases threshold : more frequent AP

Question 24

What are the 3 types of position of the foetus ?

Answer 24

Lie : longitudinal or horizontal in relation to the long axis of the woman

Attitude : flexion or extension

Presentation : head down or breach : frank breach , full breach, footling breach

Question 25

How can we induce labour ?

Answer 25

- stimulate prostaglandin release by rupturing of membrane - artificial prostaglandins - synthetic oxytocin - anti progesterone agents

Question 26

What is the Ferguson reflex ?

Answer 26

Oxytocin stimulate uterus to contract , contraction of uterus leads to positive feedback and afferent impulse from cervix and vagina to release more oxytocin

Question 27

How can the foetus be monitored during labour ?

Answer 27

HR, maternal temperature , colour and amount of amniotic fluid , scalp capillary pH

Question 28

Describe the changes in foetal position during the second stage of labour

Answer 28

- present head down , facing sideways : Head flexes - Head rotates to face posteriorly ( due levator and contraction) - Crowning : head stretches perineal muscle and skin - Extension of head and external rotation (restitution , facing sideways) - Shoulder rotation , delivery of shoulder and body

Question 29

How can delivery be facilitated ?

Answer 29

- Cesarean section : incision through skin and uterus , delivery of baby not through birth canal - Use of forceps or vacuum extraction

Question 30

In stage 3 , how does the placenta descend and separate from the endometrium ?

Answer 30

Reduced size of uterus due to retraction decreases size of placental site : placenta is squeezed causing separation

Question 31

Which normal processes happen to limit blood loss during separation of placenta ?

Answer 31

- powerful contraction interlacing muscle fibres of uterus act as ligature of blood vessels in myometrium - pressure exerted at placenta site by contraction and retraction of myometrium - blood clotting mechanism

Question 32

Describe the first changes enabling the foetus to adapt to independent life (resp and cvs )

Answer 32

- stimuli (trauma,cold,light...) to take first breath >alveoli inflate and maintained by surfactant - clamping of umbilicus result in closure of ductus venosus First breath cause decreased resistance in lungs > blood flows to lungs and pO2 rises > net drop in pressure in RIght side and higher pressure in left atrium > closure of foramen ovale > increased pressure and pO2 cause ductus arteriosus to close

Question 33

Which changes occur in the lower genital tract after delivery ?

Answer 33

- reduction in size of vulva,vagina,cervix - decreased lubrication - transformation zone of cervix back into the endocervix and internal is closed - heavy bleeding initially : lochia rubra - then bleeding changes from dark red to pink/white : lochia Alba

Question 34

Briefly describe the haematological and hormonal changes after delivery

Answer 34

- reduction of plasma volume and increase in haemoglobin level - high WCC - low iron - prolactin remain high if lactation - thyroxine level decrease back to normal

Question 35

Briefly describe the anatomy of the breast and gland

Answer 35

Between 2n and 6th ribs , adipose tissue and glandular tissue Tubuloacinar gland , apocrine secretion in mammary ducts which join in lactiferous duct which open at the nipple

Question 36

What causes growth of breast tissue during pregnancy ? What are the changes ?

Answer 36

Progesterone,oestrogen,growth hormones and especially prolactin cause hypertrophy of existing alveola and formation of new ones with proliferation of milk ducts

Question 37

Why is there minimal lactation lactation during pregnancy ?

Answer 37

Oestrogen and progesterone inhibits effects of lactogenic hormones (prolactin)

Question 38

What is milk production and secretion dependant on ?

Answer 38

Prolactin levels induce milk production Prolactin level is dependent on frequency and duration of suckling Milk secretion also depends on adequate emptying of the breast

Question 39

What induces milk let down (delivery) ?

Answer 39

Oxytocin : contraction of myoepithelial cells around alveola cause expulsion of milk in ducts Oxytocin released in response to suckling, swing of hearing baby

Question 40

What is the name of the first product of lactation ?

Answer 40

Colostrum , high fat and immunoglobulins

Question 41

How does the milk differ between start and end of suckling ?

Answer 41

Foremilk : high water content | Hind milk : fats and iron rich

Question 42

What are the components of milk and function ?

Answer 42

Lactoferrin : binds iron to protect agains E. coli proliferation Non pathogenic flora for colonisation of gut Bacteriocidal enzymes Immunoglobulins :IgA

Question 43

What breast pbm can occur are delivery ?

Answer 43

- Nipple sensitivity and pain - engorgement - mastitis - breast abscess - lumps