W8: maternal adaptations to pregnancy Flashcards
hCG
hormone change
secreted from chorion of placenta
stimulates progesterone production from corpus luteum
peaks about 9 weeks of pregnancy
oestrogen and progesterone
hormone change
secreted by corpus luteum for first 3-4 months- then placenta takes over
maintains lining of womb
high levels ensure cervix is tightly closed
return to normal levels after birth
relaxin
hormone change
increases flexibility of public symphysis and ligaments of sacroiliac and sacrococcygeal joints
ease delivery
human placental lactogen
hormone change
prepare mammary glands for lactation and enhanced maternal growth
regulates metabolism as makes more glucose available for use by fetus
corticotropin releasing hormone
hormone changes
produced by placenta during pregnancy
‘clock’ establishing timing of birth- increase throughout pregnancy
increases cortisol secretion- needed for maturation of fetal lungs + surfactant production
increased size of sexual organs
physical changes
uterus
breast double in size
vagina enlarges with more widely open introitus
compression of organs
physical change
bladder is compressed by growing uterus lead to:
- increased frequency and urgency to pee
- stress incontinence
changes in maternal appearance
physical change
oedema
acne
masculine features
weight gain
physical change
25/35 pounds in last 2 trimesters:
weight gain of foetus
increased amniotic fluid
placenta enlargement
xtra fluid in blood and ECF
increased fat deposit and food intake
breast enlargement
changes in GI system
physiological change
additional nutritional demands of foetus:
increased appetite
decreased gastric motility= constipation and delay in poop
changes in maternal circulatory system
physiological change
increased:
blood volume
stroke volume
heart rate
cardiac output
blood flow thru placenta
required to meet addiotnal nutrition and oxygen demands of foetus
can lead to varicose and oedema veins
changes in maternal renal system
physiological change
increased renal tubule reabsorption of nacl and h2o
increased renal blood flow and glomerular filtration rate because of increased blood volume
increased real filtering capacity to allow fast elimination of waste produced by foetus
more peeing because bladder compressed
changes in maternal respiratory system
physiological change
need to meet addiotnal oxygen needs of foetus
increased tidal volume
increased total volume of air inhaled and exhaled per minute
decreased airway resistance in bronchial tree
increased total body oxygen consumption
adjustments of infant to extra uterine life
during preg, foetus totally dependent on mum
oxygen, nutrients
eliminate co2 and waste
protect again shocks and temp change
onset of breathing
birth adaptation outside womb
onset of breathing within <minute due to:
sensory impulses from cooled skin
hypoxia and hypercapnea stimulate the resp centre in medulla
1st inhalation unsullied deep as lungs have no air
1st exhalation is vigourous (crying)
circulatory readjustments at birth
foetal circulation:
lungs, gastrointestinal organs and kidney or not functioning
live is partially functioning
changes in blood supply to these organs occur at birth
foetal circulation of heart and lungs
DURING:
- mix of o2 n no2 enters right atrium
- most does not pass pulmonary circulation
- instead passes thru foramen ovale into left atrium- joins systemic circulation
- some blood enter right ventricle (little reaches lungs)
- most sent thru ductus arteriosus from pul artery into aorta
- enters systemic circulation
ATBIRTH:
- increased systemic vascular resistance due to no placental circ
- decreased pul vascular resistance due to expansion of lungs
- closure of forsaken ovale due to increased left and right heart pressures
- closure of ductus arteriosus due to smooth muscle contraction because of lungs functionining
- doesn’t completely until 3 months after birth
foetal circulation in liver
DURING:
- o2 blood from placenta enters umbilical vein
- ductus venosus- connects umbilical vein to inferior vena cava
- allow blood from placenta to bypass liver
ATBIRTH:
- ductus venosus closes because umbilical venous flow is stop and increased portal venous pressure that forces blood thru liver
- umbilical vein becomes ligamentum teres
functional problems after birth
many organs not developed at birth
controls systems which have not become adjusted to extra uterine life
leads to a range of physiological functional problems that are characteristic in neonates
problems with nutrition after birth
breast milk: fatty acids, lactose, amino acids, mineral, vitamins and water
- growth and development
issues can arise due to maternal dietary deficiency:
- vit D deficiency= reduce absorption of calcium by gut = severe rickets
- vit C deficiency= needed for proper formation of cartilage, bone etc
- iron deficiency= severe anaemia
problems with respiration
normal respiration rate in neonate- 40 breath/min
lower functional residual capacity that adults can lead to excessive cyclical fluctuations in blood gas concentrations if the respiratory rate becomes slow
problems with blood volume
normal volume immediately after birth is 300ml
if infant left attached to umbilical cord or cord stripped to force blood out of infant- additional 75ml of blood enters
additional fluid lost into tissue space
can cause mild pulmonary oedema and resp distress
problem with red blood cells
few new rbc are formed in first few weeks of life
average rbc count falls in initially after birth
returns to normal after 2-3 month
problem with liver
neonatal jaundice:
- after birth bilirubin must be processed by neonates own liver
- liver only excretes very low amounts of bilirubin initially
- plasma conc rise
lack of clotting factor:
- neonatal liver forms insufficient blood factors required for clotting
amount of glucose stored as glycogen in new born baby liver and muscle sustains baby for only few hours
gluconeogenesis function is deficient
blood glucose falls in first day to 40% of normal value
baby is able to use stored fats and protein metabolism until breast milk ready
