ULO 8- Maternal postnatal physiology

Question 1

Explain: the timing of menstruation following birth

Answer 1

It varies from woman to woman- usually occurs after breastfeeding has ceased however can occur during BF

Question 2

What affects uterine involution

Answer 2

Breastfeeding can help speed up involution

Question 3

Whats the role of Oxytocin on involution

Answer 3

it causes uterine contractions and therefore causes involution

Question 4

Explain the role: Prolactin

Answer 4

stimulates milk production and inhibiting ovulation

Question 5

Define: Involution

Answer 5

refers to the contracting anf reducing in size of the uterus

Question 6

Define: Lochia

Answer 6

is a vaginal blood loss produced by the uterus post-birth (up to 6 wks)

• is the bodies way of eliminating waste from the lymph and blood supply

Question 7

What are the 3 forms of Lochia

Answer 7

Lochia Rubra (2-6 days)
Lochia Serosa (usually 10 days)
Lochia Alba (2-6 weeks)

Question 8

Explain: Lochia Rubra

Answer 8

bright red

- contains blood, decidual and trophoblastic debris, amnion and chorion material

Question 9

Explain: Lochia Serosa

Answer 9

Pinky red/brown

• contains blood, serum, leukocytes and tissue debris
• usually 10 days

Question 10

Explain: Lochia Alba

Answer 10

white-clear

• contains leukocytes, decidua, epithelial cells, mucus, serum and bacteria
• 2-6 weeks

Question 11

Involution of the uterus

Where would you expect to find the fundus immediately after birth

Answer 11

at the umbilicus

Question 12

Explain: purpose and physiology of afterbirth pains

Answer 12

Purpose- to contract the uterus to its pre-pregnancy state

Physiology- oxytocin causes the contraction of the uterine muscles

Question 13

Describe: what happens to the uterus following birth

Answer 13

It begins to contract and shrink, and will eventually return to its original size

Question 14

List the 4 hormones involved in the Initiation and maintenance of Lactation

Answer 14

Oxytocin
Prolactin
Oestrogen
Progesterone

Question 15

When are Prolactin levels highest

Answer 15

at night

Question 16

What hormonal change occurs at the delivery of the placenta to facilitate Lactogenesis

Answer 16

The reduction in oestrogen and progesterone lead to an increase in prolactin production leading to Lactogenesis

Question 17

Which hormone is responsible for the let down reflex

Answer 17

Oxytocin

Question 18

What are the 3 stages/types of breastmilk

Answer 18

1. Colostrum- thick, yellow, high in volume, nutrients and density (upon birth)
2. Transitional milk- produced between colostrum and mature milk (gradually changes between 7-10 days and 2 weeks after birth)
3. Mature milk- feeds the baby after 2 weeks post birth. Highly variable

Question 19

Explain: postnatal physiology of the vagina, cervix and pelvic floor

Answer 19

Cervix

• closes after 1-3 days
• external os now a slit
• lactation delays mucus production

Vagina

• pre pregnant state 6-8weeks
• rugae reappear 4 weeks

Pelvic Floor
- regains tone over 6 weeks

Question 20

Explain the 3 stages of Lactogenesis

Answer 20

Lactogenesis I- initiation of milk secretion
Lactogenesis II- the production of colostrum and transitional milk (commences 2-3 days post birth)
Lactogenesis III- the development of milk and the maintenance of established lactation (begins around day 8-9 post birth, continues for duration of breastfeeding)

Question 21

Explain: role of oxytocin in lactation

Answer 21

• stimulates contraction of myo epithelial cells

- causes milk ejection reflex (let down reflex)

Question 22

Explain: Let down reflex

Answer 22

• Oxytocin levels in the blood often rise just before a feed, either due to the baby crying or becoming restless or the mother preparing for the feed
• Levels are raised within 1 min of any breast stimulation, and during stimulation the levels remain elevated and return to baseline levels within 6 min after nipple stimulation has stopped
• Once suckling is initiated, the oxytocin response is transient and intermittent rather than sustained. The nipple and areola have a rich supply of sensory nerves.
• The afferent fibres terminate in the dorsal horn of the spinal cord, where they synapse on ascending fibres which transmit the messages received from the suckling of the baby to the brainstem.
• The messages are then relayed to the midbrain and hypothalamus, resulting in the release of oxytocin ( Fig. 54.7 ) from the posterior lobe of the pituitary gland.
• This hormone contracts the myoepithelial cells and milk is propelled along the ducts.
• Smooth muscle contraction results in shortening and widening of the ducts to allow milk to flow into the ampullae.
• Some mothers may feel pressure and a tingling warm sensation during milk ejection. The baby suckling empties the breast and stimulates the release of prolactin.

Question 23

Explain: how involution of the uterus works

Answer 23

• The uterus is well contracted at the end of the third stage and rises over the following hours to the level of the umbilicus. - The uterus reduces in size over the next few days and weeks through a process termed involution
• This is facilitated by the release of oxytocin from the posterior pituitary, which continues after the birth of the placenta and membranes.
• It stimulates strong intermittent contractions of the uterus, leading to collapse of the uterine cavity, which no longer contains the fetus, and thus to realignment of the uterine walls in apposition to each other
• This aids the process of haemostasis (stoppage of bleeding) and also reduces the size of the uterus immediately following birth.

Question 24

Define: Afterbirth pains

Answer 24

Contraction of the uterine muscles is felt as ‘afterpains’ for 4–7 days and is strongest 12–24 hours postpartum,

• These contractions facilitate the process of involution.
• Afterpains may occur in association with breastfeeding, owing to the release of oxytocin and uterine contractions, or they may occur independently of breastfeeding.