MIDW1101 Lecture Notes - Lecture 4: Lactational Amenorrhea, Enterocolitis, Thyroid Hormones
23 Jun 2018
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MIDW1101 MOD 4
POSTNATAL CARE
Puerperium
- Period of time from immediately after birth of baby, placenta and membranes, until
reproductive organs returned to non-pregnant state (6-8 weeks)
- Involves involution and lactation, and psychological, emotional and social changes
Involution of the uterus
- Return of uterus to be a pelvic organ
- Process of contraction, autolysis and epithelial regeneration and proliferation
- Oxytocin (from posterior pituitary gland) induces strong intermittent myometrial contractions
oImmediately after birth of foetus: myometrial spiral fibres compress blood
vessels supplying placenta (cause haemostasis and separate placenta from uterine
wall)
oFelt as afterpains (reduce pain through frequently voiding, oral analgesia,
gentle massage of fundus, applying heat pack or pressure to abdomen, arnica)
- Autolysis: breakdown of excess myometrial muscle fibres (induced by proteolytic enzymes
in cells)
oEnd products disposed of by phagocytosis
- After birth: uterus about halfway between umbilicus and symphysis pubis, and fundus
rises to umbilicus over next 12hrs
oHeight of fundus decreases 1cm/day
oAfter 2 weeks: uterus descended into pelvis and fundus can no longer be
palpated
- Process of involution slowed by retained placental fragments or pelvic infection
Subinvolution of uterus
- Slow, delayed or incomplete involution
- Caused by ineffective uterine contractility, retained placental products, membrane
fragments and infection
- Sigs: soft or ‘boggy’ uterus, fever, tachycardia, hypotension, abdominal tenderness and
excessive vaginal blood loss
Lochia
- Postpartum shedding of the decidual lining of the uterus
- Varies in amount and colour
oRubra (red-brown) serosa (pink-brown) alba (white-yellow)
- Can last up to 6 weeks postpartum
- Assists reduction of uterus size and process of involution
Regeneration of the endometrium
- Uterus forms new epithelium layer within 2-3 weeks
oExcept for placental site (takes around 6 weeks)
Cervix and vagina
- Vaginal walls decreased in tone and oedematous
o3-4 weeks postpartum: decrease vascularity and oedema reabsorbed
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MIDW1101 MOD 4
oGradually reduces in size and regains tone (unable to return to pre-pregnant
state)
- Cervix may appear stretched, swollen, bruised and lacerated
o48hrs postpartum: shorten and firms due to collage and proteoglycans
formation
Perineum
- Bruising around vaginal and perineal tissues likely
- Midwife to minimise perineal trauma, promote healing and effectively manage pain
- Perineal morbidity: stress and urge incontinence, flatus incontinence, sexual morbidity
and dyspareunia
Hormones
- 72hrs postpartum: placental hormones (oestrogen, progesterone and human chorionic
gonadotrophin) fall to non-pregnant levels
- Oestrogen and progesterone levels: dependant on lactational demands
- During pregnancy: progesterone inhibits effect of prolactin (inhibits lactogenesis)
oAfter birth: decreased progesterone = increased prolactin levels = inhibit
follicle stimulation hormone (FSH) and luteinizing hormone (LH) = lactational
amenorrhoea (absence of menstruation)
oBreastfeeding stimulates prolactin release
Haematologic and haemostatic systems
- Increased blood and plasma volume during pregnancy = physiological hypervolemia (can
tolerate some blood loss after birth)
- After delivery: removal of placenta increases clotting factors (hypercoagulable state)
oIncreased risk of thromboembolic disorders
Cardiovascular system
- Last weeks of pregnancy: increased fibrinogen levels = hypercoagulable blood (facilitates
rapid blood clotting at birth and reduces risk of haemorrhage)
oIncrease risk of thromboembolism (flow velocity and diameter of deep veins
change over 6 weeks)
- Transiently unstable during immediate postpartum period (birth of baby, placenta and
membranes, amniotic fluid and blood loss)
- After delivery: cardiac output increases (blood returned to systemic circulation from uterus
and placenta) and venous return improves (relief of inferior vena cava compression)
- First few days postpartum: decreased plasma volume due to blood loss and diuresis
- 1st week postpartum: body fluid mobilised and excreted (decrease in circulating blood
volume due to haemoconcentration and components of blood return to normal)
- Assess for anaemia: decreased haemoglobin levels = iron deficiency (due to excessive bleeding)
oSigns: pallor, tiredness, dizziness, loss of appetite, oedema
- Evaluate need for anti-D gammaglobulin: if mother Rhesus negative but baby not
Renal system
- Immediately following birth: reduced progesterone = able to revert to non-pregnant state
oBladder returns to no-pregnant position
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MIDW1101 MOD 4
oDilation of renal tract resolved
- 2-5 days postpartum: rapid diuresis (sodium and water retention of pregnancy reversed)
due to oestrogen removal and increase in oxytocin
o21 days postpartum: fluid + electrolyte balance restored to non-pregnant
homeostasis
- Should void urine within 6hrs postpartum
- Overstretching of pelvic floor muscles during birth = nerve and ligament damage =
prolapse or urinary or faecal incontinence (decreased through pelvic floor exercises)
Respiratory system
- During pregnancy: oxygen consumption increases 15-25% to meet foetal/placental needs
and demand from increased maternal tissues
oProgesterone increases sensitivity of chemoreceptors to carbon dioxide
(stimulates hyperventilation = decreased partial pressure of arterial CO2 =
respiratory alkalosis)
- Birth of baby: immediate reduction in intra-abdominal pressure (expansion of diaphragm
and full inflation of lungs possible with removal of compression by uterus)
- 1-3 weeks postpartum: respiratory rate returns to normal
Gastrointestinal system
- Progesterone reduces gastrointestinal muscle tone and relaxes abdomen (increases
likelihood of constipation postpartum)
- 2-3 days postpartum: first bowel movements (haemorrhoids may increase time)
oIncreased dietary fire recommended
Thermoregulation
- Stress of labour and dehydration = elevated maternal temperature (can resolve
spontaneously and be non-infectious)
oShould be monitored closely (increased temperature can indicate infection)
Nutrition and weight loss
- Regular meals and fluids promote health and wellbeing
- Breastfeeding requires increase in calories (increased appetite)
- Healthy diet and moderate-intensity physical activity support gradual weight loss
- Return to pre-pregnant weight takes up to 12 months (postpartum weight retention common)
Immediate postnatal period
- 1-2 hours post birth
- Aim: support physiological recovery of mother, transition to motherhood and newborn’s
transition to extrauterine life
Lactogenesis
- Nipple stimulation during suckling initiates neuroendocrine reflex (stimulates secretion
and release of prolactin and oxytocin from pituitary glands)
oProlactin: stimulates milk synthesis and promotes maternal energy storage
oOxytocin: stimulations myometrial contraction and ejection of milk
- During pregnancy: prolactin levels increase, but lactogenesis prevented by progesterone
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Document Summary
Period of time from immediately after birth of baby, placenta and membranes, until reproductive organs returned to non-pregnant state (6-8 weeks) Involves involution and lactation, and psychological, emotional and social changes. Return of uterus to be a pelvic organ. Process of contraction, autolysis and epithelial regeneration and proliferation. Oxytocin (from posterior pituitary gland) induces strong intermittent myometrial contractions o. Immediately after birth of foetus: myometrial spiral fibres compress blood vessels supplying placenta (cause haemostasis and separate placenta from uterine wall) o. Felt as afterpains (reduce pain through frequently voiding, oral analgesia, gentle massage of fundus, applying heat pack or pressure to abdomen, arnica) Autolysis: breakdown of excess myometrial muscle fibres (induced by proteolytic enzymes in cells) o. After birth: uterus about halfway between umbilicus and symphysis pubis, and fundus rises to umbilicus over next 12hrs o o. After 2 weeks: uterus descended into pelvis and fundus can no longer be palpated.
