Topic 10 - PART A Flashcards
List ways in which men and women can prepare for a healthy pregnancy
1) maintain good body weight
2) Choose adequate and balanced diet
3) Be physically active
4) Regular medical care
5) Manage chronic conditions
6) Avoid harmful influences
Why is achieving a healthy body weight important prior to pregnancy?
- excess body fat in women disrupts menstrual regularity and ovarian hormone production
- overweight and obese men have low sperm counts and hormonal changes that reduce fertility
Why is it important to avoid harmful influences prior to pregnancy?
- Smoking, alcohol, drugs, and environmental contaminants can cause abnormalities, alter genes and their expression and interfere with fertility
Describe foetal development from conception and how exposure to harmful substances or malnutrition during pregnancy can affect critical periods of development.
- Zygote (<14 days): newly fertilized egg, which begins as a single cell. The germinal period lasts from conception to implantation of the zygote into uterus lining
- Embryo (week 3-9): most organ systems are established; 90% of body structures can be distinguished
- Foetus (week 10- full term): organs that form during embryonic period continue to grow and differentiate
- Critical periods: pre-programmed time periods during development when specific cells, organs, and tissues are formed or functionality is established
As soon as the embryo begins to receive nourishment from the mother through the placenta. . .
it becomes vulnerable to hazards (e.g. diseases from mother), nutritional deficiencies, and drugs / other toxins
When are abnormalities in the feotus most dangerous?
in the first few weeks when cell division is rapidly occurring
The placenta blocks all harmful substances from reaching the foetus. True or False
False
What are the 3 functions of the placenta?
- hormone and enzyme production
- nutrient and gas exchange
- removal of waste products
The placenta governs. . .
the rate of passage of nutrients and other substances in and out of the foetal circulation
What kinds of harmful substances do / do not pass through the placenta?
- alcohol, high doses of vitamins, drugs, and certain bacteria do pass through
- the placenta does act a barrier to the passage of may types of bacteria and viruses, maternal RBC, and large proteins
- the placenta prevents the mixing of maternal and foetal blood until delivery
When does the critical period for neural tube defects (NTDs) occur?
- at 17-30 days gestation
- during normal development, the embryonic neural tube undergoes a process of folding and closing to form an enclosed neural canal
Australian recommendations for folate in / before pregnancy
- folic acid supplements should be taken for at least one month BEFORE and continued for 3 months AFTER conception, in addition to consuming folate from a varied diet
- women who are planning a pregnancy require an additional 400mcg per day of FOLIC ACID in supplement form (400mcg/d from supplement +400mcg/d from food)
- the RDI increases to 600 mcg per day DURING pregnancy from foods (400 mcg/d from folic acid supplement + 600 mcg/d from food). Total is 1000mcg/d in the first trimester
Inadequate folate status is linked to . . .
the development of NTDs
Failure of the neural tube to close results in permanent disability. What are the 2 consequences.
1) Anencephaly (no brain) - occurs when closure fails high up on the neural tube (major part of the brain, skull, and scalp is missing) - usually die at birth or very quickly after
2) Spinda bifida (open spine) - occurs when closure fails lower down the neural tube
- there is a protrusion of nervous tissue with various degrees of damage to nerves
- spinal cord is not fully encased in bone so becomes vulnerable to damage - paralysis / delayed cognitive development
How can folate levels be increased?
by consuming folate-rich foods or ingesting folic acid, a synthetic compound available in dietary supplements and fortified foods
Examples of food with folic acid
- dark green leafy veg
- beans
- peanuts
- sunflower seeds
- whole grains
- liver
Why is iodine important?
essential for synthesis of the thyroid hormones
Functions of thyroid hormones
- play a vital role in the early growth + development of most organs, esp the brain
Problems caused by iodine deficiency
- mild-moderate iodine deficiency may cause cognitive, physical, and behavioural impairments of children, & in extreme cases, stunted growth (cretinism)
- iodine deficiency is an increasing problem in Australia
- studies have shown that median levels of urinary iodine (96mcg/L) are well below the level which defines sufficient intake (150mcg/L)
Iodine recommendation for women
Women who are pregnant, breastfeeding or considering pregnancy should take an iodine supplement of 150 mcg/day
Negative consequences for overweight/obese women (pre-pregnancy weight)
BMI > 25 has been linked to:
- stillbirth
- congenital abnormalities
- preterm birth
- low birth weight
BMI > 30 is also linked to:
- inability to initiate breastfeeding
- postpartum weight retention
- increased rate of caesarean section
A low BMI (pre-pregnancy weight - underweight) is associated with increased risk of:
- preterm birth
- small-for-gestational age babies
- lower birth weight
- infant death
Maternal pre-pregnancy BMI is associated with increasing risk of pre-eclampsia. What are its symptoms?
- increases with increasing BMI
- high blood pressure
- protein in urine
- fluid retention
- restricted blood flow through the vessels to the placenta and other organs
- associated with delivery complications
- can progress to eclampsia
What is the optimal foetal weight?
3.4 kg
Why do pregnant women have weight gain?
- build-up of fat reserves to support foetal growth and later lactation
- several organs increase in size (heart, thyroid, liver, kidneys, and uterus)
- breast tissue gets read for lactation
Why does blood volume increase in pregnant women?
to maintain delivery of nutrients to placenta and foetus
Why are there changes to the GI tract in pregnant women?
- slow gastric emptying and increased GI tract transit time increases nutrient absorption
TRUE OR FALSE.
Pregnancy weight-gain recommendations are the same for all women, regardless of their weight status before pregnancy
FALSE
Optimal weight gain (women) during pregnancy depends on . . .
pre-pregnancy BMI
Inadequate gestational weight gain puts the mother & newborn at increased risk of:
- low birth weight
- small-for-gestational age
- preterm birth
Excessive weight gain puts the mother and infant at increased risk of:
- gestational diabetes
- hypertension and preeclampsia
- large-for-gestational age baby
- difficulties during birth; C-section
- weight-retention after birth
Energy requirements during pregnancy
+ 1400 kJ per day in 2nd trimester
+ 1900 kJ in third trimester
can gain extra energy from cereals or from lean meat, fish, poultry, nuts, legumes etc.
Why is zinc needed in pregnant women?
- for DNA and RNA synthesis for protein & cell development
Why is Vitamin B12 needed in pregnant woman?
- activates the folate enzyme
Why is protein needed in pregnant women?
- growth of foetus, placenta, and maternal tissues
Why is alcohol consumption incompatible with pregnancy?
can cross the placenta and deprive the foetus of nutrients and oxygen
Why is smoking incompatible with pregnancy?
restricts blood supply to the foetus and limits oxygen / nutrient delivery and waste removal
Why should a woman avoid weight-loss dieting during pregnancy?
fasting or low CHO diets that induce ketosis deprive the foetal brain of needed glucose and could impair cognitive development
How can environmental contaminants affect baby during pregnancy?
mercury and lead cross the placenta and can harm the brain and CNS development; also the psychomotor development
How many women drink alcohol before knowing they are pregnant?
47% of Australian women
20% continue drinking after knowing they are pregnant
Drinking alcohol while pregnant can cause. . .
Fetal Alcohol Spectrum Disorder
- poor growth
- brain damage
- birth defects
- delayed development
- social + behavioural problems
- learning problems
What are the 3 main forms of diabetes in pregnancy?
- gestational diabetes (accounts for 8% of all DIP)
- Type 2 diabetes (insulin-resistant diabetes)
- Type 1 diabetes (insulin-dependent diabetes)
What happens in maternal glucose rises (as a result of diabetes)?
- fetal insulin rises
- increased glucose uptake; conversion of glucose to triglycerides
- if baby grows too large = macrosomia
All forms of diabetes share an increased risk of developing. . .
maternal hypertension and pre-eclampsia, foetal death, congenital defects in the offspring and macrosomia
How can newborns develop hypoglycaemia?
- if glucose levels drop after delivery
- might happen if insulin levels are still high, but baby isn’t receiving more glucose bc it isn’t in the mother anymore
- if too low, baby might need an IV of glucose
What is gestational diabetes mellitus?
- a transient state of hyperglycemia first detected in the 2nd or 3rd trimester
- screening is usually b/w 24-28 weeks gestation
Risks of gestational diabetes mellitus to the mother
- hypertension or pre-eclampsia
- later development of type 2 diabetes
- delivery complications (C-section, postpartum haemorrhage)
How is gestational diabetes managed?
- with diet and exercise
- insulin, if necessary
- a moderate amount of carbohydrates with a focus on low GI foods
- moderate exercise
- management of gestational weight gain
Rising blood pressure is . . .
a COMMON feature of pregnancy
Transient hypertension of pregnancy differs from the life-threatening hypertensive conditions:
1) Preeclampsia
- high blood pressure, protein in the urine, fluid retention
- blood flow through the vessels to the placenta and other organs can be restricted
2) Eclampsia
- convulsions and seizures
- life-threatening
The role of dietary factors in the development of pre-eclampsia remains inconclusive; however, research suggests a link with vitamin D deficiency
What is prolactin?
the hormone responsible for milk production
- as long as the infant is nursing, prolactin levels will remain high
What is oxytocin?
the hormone responsible for milk ejection
- causes the muscular tissue to contrast which pushes milk into the collecting ducts - called “let down” reflex
- causes uterus to contract as well
