Lecture 3 Flashcards
Pregnancy and physiological changes
Conception/Fertilization (5 important steps)
1- Ovulation
2-Fertilisation
3-Cleavage
4-Blastocyst
5-Implantation
Ovulation
development of follicles which end up turning into an egg and through the release of chemicals during the hormonal stages, once a follicle is developed chemicals are released and this tells the fallopian tube that and egg is ready to be collected
Fallopian tube is where fertilisation occurs
Fertilisation
after fertilisation has occured we have what is called a zygote and a zygote is genetically complete
Cleavage
Cleavage through mitosis - dividing of the cell which ends up in a morula 16-cell stage and the morula brings nutrients into the cell
Blastocyst
trophoblast outer (placenta) has a lot of specialised cells that create finger like structures which helps the now blastocyst to implant into the uterus
Embryoblast inner (fetus)
Implantation
Implantation of the blastocyst onto the uterus lining
pregnancy hormonal changes occurs through this time which stops the release of more eggs
EDD
Estimated Date of Delivery typically counted from the first day of last menstrual period: 40 weeks from LMP or 38 weeks after conception
1st trimester
Conception to 12th week
2nd trimester
13th to 28th week
3rd trimester
28th week until birth
Pre-trem (premature)
<37 weeks
Term
37-42 weeks
Post-Term (postmature)
> 42 weeks
How many births occur on the due date
<10%
Perinatal varies from
20-24 weeks and there is a 50% survival chance at 24 weeks
Placenta
An organ that starts forming at implantation of the balstocyst
Placenta carries
Oxygen, nutrients and antibodies from mother to fetus and waste materials including CO2 from fetus to mother
The placenta is fully formed by
18-20 wks but continues to grow throughout pregnancy. At delivery is weighs about 0.5kg
The placenta takes over the hormonal roles of the
Ovary
The placenta is connected to the … by the
Connected to the embryo/ fetus by an umbilical cord
3 components to the umbilical cord
Umbilical vein
Umbilical cord
Umbilical arteries
Teratogens
Any agent that can disturb the development of an embryo or fetus. May cause a birth defect in the child or halt the pregnancy.
The classes of teratogens include
radiation, maternal infections, chemicals and drugs
Hormonal changes during pregnancy
Progesterone and oestrogen rise continually throughout pregnancy, suppressing the hypothalamic axis and thus the menstrual cycles
High circulating levels of oestrogen promote
prolactin production (pituitary gland enlargement by 50%).
what does prolactin production mediate
This mediates a change in the structure of the mammary gland from ductal to lobular-aveolar =milk hormone
Parathyroid hormone change
is increased to enhance calcium uptake in the gut and reabsorption by the kidney
adrenal hormones such as ……. also
adrenal hormones such as cortisol and aldosterone also increase
Human placental lactogen is produced by the
Placenta
HPL decreases
Maternal insulin sensitivity and maternal glucose utilisation which raises maternal blood glucose levels, which helps to ensure adequate fetal nutrition
HPL increases
Gluconeogensis to increase maternal glucose levels so more glucose is available for the fetus
chronic hypoglycemia leads to rise in
HPL induces lipolysis with the release of free fatty acids which become available for the maternal organism as fuel, so that relatively more glucose can be utilised by the fetus. Also, ketones formed from free fatty acids can cross the placenta and be used by the fetus.
Hematological changes - Blood volume increases
40-45% (proportionally with cardiac output)
Plasma volume increases early in pregnancy and faster than
RBC volume, the hematocrit falls until the end of the second trimester, when the increase in the RBC is synchronised with the plasma volume increase - Hematocrit then stabilises
If plasma volume increases during pregnancy
The haemoglobin will be lower (this is called dilution anemia)
Gastrointestinal changes - as pregnancy progresses, pressure from the enlarging uterus
uterus on the rectum and lower portion of the colon commonly causes constipation
GI motility decreases because
elevated progesterone levels relax smooth muscle
Heartburn and belching are common possibly resulting from
delayed gastric emptying and gastroesophageal reflux due to relaxation of the lower esophageal sphincter
hydrochloric acid production ….
decreases thus peptic ulcer disease is uncommon during pregnancy and preexisting ulcers often become less severe
Morning sickness
Nausea & vomiting in pregnancy (NVP)
definition spans from slight dizziness and dry retching to continuous vomiting
Morning sickness commonly occurs between
5 and 18 weeks of pregnancy with between a 50% to 80% of women reporting some degree of nausea with or without vomiting
Severe morning sickness
Hyperemesis gravidarum (HP)
Hyperemesis gravidarum (HP)
Extreme form of NVP accompanied by weight loss, electrolyte imbalance and dehydration requiring hospitalisation
Recent research of HP has found a link between the hormone
Growth Differentiation Factor 15 (GDF15) and NVP
GDF15 plays a crucial role in NVP severity
women who have lower levels of GDF prior to pregnancy will not
be as tolerant to it during pregnancy so may not be able to handle it as well during pregnancy
Pregnancy outcomes when experiencing NVP or NP (4)
Pelvic girdle pain, high blood pressure, proteinuria, preeclampsia, gestational diabetes
Delivery and birth outcomes of NVP or NP (4)
Gestational length, C-section delivery, mortality, growth of infant
Women with NVP or NP more likely to develop pregnancy complications but do
exhibit mostly favourable delivery and birth outcomes
Management of NVP
1- Reduce symptoms via changes in diet/environment and by medication
2- Correct/prevent consequences or complication of NVP
3-Minimise fetal effects pf maternal NVP and their treatment
Management of NVP: diet
Eat what appeals- avoid trigger foods and odours
Eat slowly and small amounts every 1-2 hours: avoid a full and empty stomach
Frequent small CHO meals such as dry toast: evidence that consistent protein intake is key to prevent nausea
Fluids better tolerated if cold, clear, carbonated or sour
Ginger and B6 supplements
NVP: Ginger and Vitamin B6
Ginger improved general NVP symptom, reduced severity of nausea but did not reduce vomiting
Ginger more effective than B6 on reducing nausea but not significantly different
what does of ginger is safely prescribe ?
The total dose is usually approximately 1 g per day, divided into 3-4 per day
What do some cultures do with the placenta
bury the placenta for varoius reasons. Maori traditionally bury the placenta from a newborn child to emphasize the relationship between humans and the earth
In the western world, the placenta is most often
incinerated….. or more recently encapsulated
Placental encapsulation benefits
- Improved lactation
-Prevent postpartum depression
-Relieve pain
-Bonding with your baby
-Increasing iron stored
-Increasing energy
Placental encapsulation concerns
-Safe release of placenta from hospital setting
-Introducing harmful bacteria through processing
placentophagia should be
discouraged as exposes mothers and offspring to infectious risks
