Reproduction session 8

Question 1

1. Define

Partition

Labour

Delivery

Answer 1

• Parturition = transition from pregnant to non-pregnant state (birth)
• Labour = physiologic process by which a fetus is expelled from the uterus to the outside world -> uterine decidua (internal lining) and myometrium

Changes in the cervix tend to precede uterine contractions

• Delivery = the method of expulsion of the fetus, transforming fetus to neonate

Question 2

Stages of labour:

Answer 2

First stage - Creation of the birth canal

Two phases:

• Latent Onset of labour with slow cervical dilatation but softening. Lasts a variable time.
• Active Faster rate of change & regular contractions

(• Physiologically – multiple changes resulting in creation of the birth canal and descent of the fetal head into it

• Clinically – interval between onset of labour and full dilatation of the cervix)

Second Stage

• passive – descent and rotation of the head
• active –Maternal effort to expel the fetus and achieve birth
• Physiologically – changes in uterine contractions to expulsive, descent of the fetus through the birth canal and delivery. (adaptations of the fetus)
• Clinically – the time between full (10cm) dilatation of the cervix and delivery.

Third stage

• Physiologically – expulsion of the placenta and contraction of the uterus
• Clinically – third stage starts with the completed birth of the baby and ends with complete expulsion of placenta and membranes
• Usually lasts between 5 and 15 minutes; up to 30 -60 minutes may be normal depending on circumstances and management

Question 3

Draw a flow chart to show how these stages are initiated

1. In humans what promotes labour?
2. What produces this substances?
3. What stimulates its production?
4. Prostaglandins MOA:
5. Cervical ripening is due to?

Answer 3

1. Increase in O:P ratio & increase PG levels
2. PG mainly in myometrium & decidua (mother)

Placenta, decidua, myometrium and membranes can all synthesis prostaglandins

Increased synthesis of prostaglandins by amnion in third trimester

3. Increase in oestrogen: progesterone ratio and mechanical damage stimulates prostaglandin synthesis

(higher O:P more PG)

4. Powerful contractors of smooth muscle and are also involved in cervical softening
5. oestrogen, relaxin & prostaglandins breaking down the CT

Question 4

1. What factors effect contractility of the uterus?
2. Action of oxytocin is inhibited in pregnancy by?

Stimulated by?

3. What increases the no. Of receptors for oxytocin?
4. Pregnancy = increased number of gap junctions to aid communication between muscle cells (coordinates effective uterine activity)

• @ 36 weeks = increased number of oxytocin receptors in myometrium - therefore uterus can respond to pulsatile release of oxytocin from posterior pituitary gland

what allows for the inc no of receptors?

4. What increases release of oxytocin? Draw a diagram to explain. What is it called?
5. Other factors

Answer 4

1. • Progesterone inhibits contractions

• Oestrogen increases gap junctional communication between SM cells – increases
contractility

• Mechanical stretching of uterine smooth muscle increases contractility – as gestation increases

Oxytocin - Initiates uterine contractions

2. Inhibit: progesterone, relaxin and low number of oxytocin receptors

Stimulate: Afferent impulses from cervix and vagina

Ferguson reflex

3. Acts on smooth muscle receptors – More receptors if oestrogen:progesterone ratio high
4. • Cervical stretching releases prostaglandins

• Fetal effects ? – glucocorticoids – placenta – inhibits progesterone
• Fetal oxytocin?
• Infection, bleeding – feed into the central mechanisms triggering contractions

Question 5

1. When do changes in the cervix occur? What changes are made to the cervix (before & after)
2. What causes the cervix to change?
3. How does the cervix collagen in proteoglycan matrix change in ripening?
4. What is this triggered by?
5. How does increasing levels of relaxing during pregnancy effect the cervix?

Answer 5

1. Stage 1 :

Tough, thick, collagen -> dilation (10cm) , softening, ripening

2. oestrogen, relaxin and prostaglandins breaking down the connective tissue.
3. – Reduction in collagen
   – Increase in glycosaminoglycans
   – Increases in hyaluronic acid
   – Reduced aggregation of collagen fibres
4. Triggered by prostaglandins
   – PGE2 and PGF2a

in the uterus increase contractility of SM in the cervix cause dilation/relaxation

5. collagen : ground substance ratio, enzymes degrade collagen

• Occurs over a period of weeks – evident from 36/40
• Labour cervix offers less resistance to
• presenting part
• Known as effacement and dilatation

Question 6

1. Size of birth canal? (i.e. size of baby head, cervix & pelvic inlet)
2. Changes of the pelvic floor,vagina and perineum?
3. How is the myometrium specialised for stage 2

(• passive – descent and rotation of the head

• active – Maternal effort to expel the fetus and achieve birth)

4. What is the sequence of contractions in the uterus
5. The uterine capacity is progressively reduced so

Answer 6

1. • In normal presentation
   – Head biggest part
   – Diameter of presentation 9.5 cm

Cervix 10cm

• Maximum size of birth canal determined by pelvis
– Pelvic inlet typically 11 cm
– Softening of ligaments may increase it

2. stretching of levator ani & thinning of the central portion of the perineum transforms to almost transparent membranous structure
3. Myometrium -> CONTRACTION & RETRACTION (partially relax + shortening)
4. Symmetry and polarity: contractions from two poles of uterus -> fundus -> upper part of the uterus (more powerful) -> lower segment (less powerful)
5. pressure inside uterus increases

Question 7

1. How does the generating force in the myometrium start?
2. Control of contractility?

Answer 7

1. – Much thickened in pregnancy

– Force when intracellular [Ca2+] rises

– Due to action potentials

– Triggered spontaneously ‘pacemakers’

2. • Contractions made more forceful & frequent by – Prostaglandins

• More Ca2+ per action potential – Oxytocin
• More action potentials – Lower threshold

3.

Question 8

How do we describe the position of the fetus

Answer 8

Lie, attitude, presentation

LAP

Question 9

Give further detail of lie

Answer 9

Longitudinally or transverse

Question 10

Give further detail of attitude

Answer 10

Ef of - extension

flexion - fuck of

Question 11

How can a baby present?

Answer 11

Buttocks out or feet first and head is

Question 12

1. Principles of inducing labour
2. How can the physiology of the fetus be monitored during labour
3. Movements in the second stage of labour?
4. How can delivery be facilitated by intervention?

Answer 12

1. • Stimulate release of prostaglandins – membrane rupture

• Artificial prostaglandins
• Synthetic oxytocin
• Anti-progesterone agents

2. • Monitoring the fetus – compare with observations on any patient – but indirect

• Consider the whole picture – the maternal-placental-fetal unit
• Heart rate patterns
• Maternal temperature
• Colour & amount amniotic fluid
• Scalp capillary pH

SCALP = HAT on fetus SCALP H-HR A-amniotic fluid T- temp of mum

3. • Head flexes, Head rotates internally (towards sacrum), “crowning” (head stretches perineal muscle and skin) (eyes looking at ass), extension of head and external rotation/ restitution (you nose sniff the ass, you extend head away so you rotate back to normal)

• Shoulders rotate
• Shoulders deliver (right before left i think)
• Followed rapidly by the body

4. Cesarean Section, Operative delivery (forceps/ vacuum)

Question 13

A. Separation and Descent of the Placenta, how does it occur ?

1. Control of Bleeding: (3)
2. Normal blood flow through site is ? (10-15% of cardiac output)

Answer 13

A.• Baby born - marked reduction in size of uterus due to powerful contraction and
retraction (ongoing)

• Size of placental site therefore reduced (can be up to ½ before separation begins)
• Inelastic placenta is squeezed by contraction

1. • 1. Powerful contraction/retraction of uterus especially action of interlacing muscle fibres (“living ligature”) which constrict blood vessels running through the myometrium

• 2. Pressure exerted on placental site by walls of contracted uterus (apposition – once placenta and membranes delivered)
• 3. Blood clotting mechanism (sinuses and torn vessels)

2. 500-800 ml/minute

Question 14

Immediate changes in physiology enabling fetus/neonate to adapt to independent life

Answer 14

Neonate takes first breath
– Multiple stimuli
• Trauma
• Cold
• Light
• Noise

CVS:

1. Clamping the umbilical cord results in closure of the Ductus venosus
2. On taking a first breath, tissue resistance decreases in the lungs
3. Vascular resistance decreases and blood flows to lungs
4. It becomes oxygenated and pulmonary pO2 rises
5. Net drop in pressure on the right side of the heart, higher pressure in left atrium closes Foramen ovale
6. This pressure imbalance results in a temporary reversal of flow through the Ductus arteriosus and its muscle wall contracts in response to increased pO2 closing it

Respiration

• First breath causes lungs to expand
• Alveoli inflate
• Inflation maintained by surfactant
• Regular breathing enabled by neonatal brain pathways triggered at birth
• Resuscitation of newborn based on knowledge of physiology and biochemistry

Question 15

Expulsion of the fetus requires a no. Of processes

Answer 15

Question 16

Answer 16

Question 17

What is the Apgar score?

Answer 17

Question 18

Definition of post partum and importance?

Answer 18

Question 19

1. What does post natal care entail?
2. What does post natal examination entail?

Answer 19

1. midwives must visit not less than 10 days post delivery - up to 28 days post delivery

 The health visitor also has a statutory responsibility for allnot less than 10 days infants under five years of age in a given residential area and will usually visit the woman at home between day 10 and 12 postpartum and then encourage the mother to attend local baby
clinics once a week until the baby is approximately 6 weeks of age.

 The health visitor then takes over responsibility for the child until he/she is five years of age. The community midwife has a responsibility of care to the woman until 28 days postpartum and, therefore, will visit her or advise regarding care if there are any complications or concerns.

2. approx. six weeks after delivery by the GP or by the obstetrician if the antenatal period or delivery have been complicated. By six weeks postpartum most of the pregnancy-induced changes in maternal physiology have returned to normal and it is an appropriate time for assessing the mother-infant interaction.

Examination:

• woman’s mental and physical health + feeding and behaviour of the baby.
• urinary, bowel and sexual function as incontinence and dyspareunia or anxiety about sexual intercourse are issues that many women will not discuss voluntarily.
• Blood pressure, urinalysis and a general, breast, abdominal and pelvic/perineal examination is performed to ascertain that the uterus has involuted adequately and that any perineal trauma has healed.
• A cervical smear is also taken if it is due and contraception is discussed, if it has not already been initiated. The postnatal examination is an excellent opportunity to discuss with the mother her adjustment to parenthood and any anxieties she may have.

Question 20

ANATOMICAL AND PHYSIOLOGICAL CHANGES (11)

Answer 20

1. Lower genital tract- these are secondary to low oestrogen levels
   - Reduction in size of vulva, vagina and cervix
   - Poor lubrication of the vagina
   - Transformation zone of the cervix withdraws into the endocervix
   - Internal os is closed
2. Bleeding- initial heavy flow= lochia rubra
3. Changes from red-brown/red-pink-heavy white (lochia alba)
4. Duration of bleeding is variable, only 1:10 women still bleeding at 6/52 post partum
5. Passage of clots is not normal, except for the one passed on D3/4
6. Endometrium regulates
7. If no lactation, new endometrium by 3/52, 1st period due by 6/52
8. If lactation, ovarian activity suppressed, therefore menses delayed by several months
9. Skeletal muscle- devarication of the recti, resolves depending on pre-pregnancy laxity,
   parity, level of physical activity
10. Skeleton- ligament laxity resolves
11. Cardiovascular function- the increased PR (by 15bpm) at term and increased cardiac output reverses by 6/52

Question 21

What happens to haemoglobbin, serum ferritin, wbc and platelets post partum?

Answer 21

Question 22

Answer 22

Question 23

1. The early puerperium in the hours after birth may be characterised in some women by a postnatal ‘high’. A degree of elation is obviously normal, especially if the woman is satisfied with her birth experience and has a close partner and family that are supportive and congratulatory.
   Positive feelings in the puerperium include:
2. Negative feelings may include:

Answer 23

1.  satisfaction
    an increased closeness to her partner
    an increased closeness to her own mother
    a gradual ‘falling in love’ with the baby
    a feeling of protectiveness towards the baby
    changes in the relationship with the marital partner: now ‘mother
   and father’ and not just ‘husband and wife’.
2.  dissatisfaction, disappointment or distress over the delivery process
    anxiety about the baby
    rejection or ambivalence about the baby
    jealousy about the baby being the centre of attention
    fears of harming the baby
    physical discomfort and anxiety about physical damage during birth
    overwhelming responsibility
    resentment at loss of freedom
    reactivation of poor relationship with own mother leading to anxiety about repetition through generations.

Question 24

ONSET AND MAINTENANCE OF LACTATION

1.a ? cause hypertrophy in pre-existing alveolar-lobular structures in the breast. There is also formation of new alveolae by budding from the milk ducts, with proliferation of milk-collecting ducts

B. Although there are high levels of lactogenic hormones (prolactin and placental lactogen) in pregnancy, only minimal amounts of milk are formed, because

MILK PRODUCTION AND SECRETION
2a. Prolactin levels and milk production are dependent to the frequency and duration of suckling. Prolactin levels are at their highest in the early puerperium (period of 6 weeks post natal) and reduce slowly, only returning to normal after weaning.

 Milk secretion is also dependent on adequate emptying of the secreting glands. Accumulation of milk inside the alveoli will cause distention and atrophy of the glandular epithelium. Therefore, adequate milk secretion requires an intact neuroendocrine axis and
adequate emptying of the breast with infant feeding.

3. DELIVERY OF THE BREAST MILK
   A. Oxytocin, contraction of the myoepithelial cells situated around the alveolae expel the milk into the milk-collecting ducts. These ducts have longitudinal muscle cells, which are also stimulated, causing them to dilate and improve the free flow of milk towards the nipple along these dilated ducts.

b. This leads to the ‘let down’ reflex. Oxytocin is released in response to a variety of sensory inputs including suckling, seeing or hearing the baby but is also readily inhibited by emotional stress or anxiety. There also seems to be a 90 minute cycle of ‘let down’
irrespective of suckling, because oxytocin is released in a pulsatile manner from the pituitary.

As lactation is initiated, the volumes are low and colostrum is
initially produced. This has a high fat content and is also high in
immunoglobulins. As suckling continues, the amount of milk
increases until, when fully established, approximately 800 ml per
day are produced.

Answer 24

a. Progesterone, oestrogen, prolactin, growth hormone and adrenal steroids
b. oestrogen & progesterone inhibit their effects. Prolactin is released by the action of suckling at a nipple that has become exquisitely sensitive post delivery.

Question 25

COMPONENTS OF BREAST MILK
Human milk differs from other mammalian milk.
Human milk:

Answer 25

 has a much lower salt content
 has a higher energy content
 has less protein
 has more lactose
 is more digestible by the human baby.
 Even more interestingly, the constituents of human milk differ in early rather than late lactation and will also vary from feed to feed, and even from the beginning to the end of a feed.
 The so-called ‘foremilk’ that emerges at the start of suckling has a higher water content. The ‘hind milk’ is higher in fats and iron.

Question 26

Functions of breast milk

Answer 26

Question 27

IMMUNOGLOBULINS

1. The immunoglobulins that are present in large amounts in breast milk are formed by the mother in ? They are formed in response to contact with specific environmental organisms.
2. The immunoglobulin ? formed in this way is passed to the breast milk via the thoracic duct and the lymphatic system. The immunoglobulin passes into the infant gut where it remains. It attaches to the specific environmental pathogens to which it was produced in the mother and thus the infant is enabled to defend itself against endemic environmental pathogens.

Answer 27

1. Peyer’s patches in her gut
2. A

3.

Question 28

FORMULA FEEDING

1. Unless chosen by a woman herself or medically indicated – should not be given to breastfed babies. Medical indications include:
2. BREAST PROBLEMS
3. PROBLEMS OF THE PUERPERIUM- EARLY:

Answer 28

1. • Severe maternal illness
     - Maternal HIV
     - Mothers on medications that are contraindicated when breastfeeding
2. • Nipple sensitivity and pain
     - Engorgement
     - Mastitis (inflammation of mammary gland)
     - Breast abscess (Fever, tachycardia, examine the breast, abscess, needs to be drained)
      Breast lumps- benign or malignant
      Breast lump must always be investigated
      Self-examination- outside menstruation
      If malignant- requires prompt treatment, surgery+/- radiotherapy, expert oncology care
3.  Postpartum haemorrhage (PPH)- primary or secondary
    Retained placenta/placental tissue
    Uterine inversion
    Perineal trauma and sequelae
    Maternal collapse
    Cardiac arrest
    Thromboembolic disease
    Puerperal pyrexia/sepsis- sources; genital tract; urinary tract; lactation ducts.

Question 29

1. SEXUALITY AND SEXUAL FUNCTION
2. PTSD (post traumatic stress disorder)
3. Postpartum depression
    Is defined as this if the symptoms occur within 4/52 of delivery
    Affects 13% of women
    The symptoms are similar to depression outside pregnancy
    Risk of recurrence is 70%
    If lasts >1/12, is regarded as major and requires pharmacological treatment

Answer 29

1.  Altered perception of body and changes due to pregnancy
    Worried about getting pregnant again
    Perineal trauma
    Dyspareunia due to low oestrogen and other causes