How does body weight affect fertility?
Percentage body fat is more important than absolute body weight and <22% body fat levels are low
Very low body weight at beginning of pregnancy – increases chance of premature birth, low birth weight, infant morbidity
Obesity is associated with reduced fertility, 30% of couples with low fertility are obese/overweight. Obese women have a higher risk of polycystic ovaries
How does the cardiovascular system change during pregnancy?
- Increased blood volume - Majority is to supply the placental bed.
- Increased red cell mass - This is to enhance the supply of oxygen to the body.
- Increased cardiac output - Due to the increase of heart rate and stroke volume.
How does the respiratory system change during pregnancy?
- Increased tidal volume - The body needs more oxygen causing hyperventilation.
What are the stages of foetal development
- Main Embryonic Period (3-8 weeks)
- Foetal Period (9-38 weeks)
What is the role of the placenta
The placenta is an ENDOCRINE organ. It provides nutrient supply from the mother to the foetus.
What passes into the placenta through simple diffusion?
- Gases – Oxygen, Carbon Dioxide and Carbon Monoxide
- Free fatty acids and LCPUFA
- Steroids
- Electrolytes
- Fat soluble vitamins (A,D,E,K)
What passes into the placenta through facilitated diffusion?
- Glucose (75% of foetal energy requirements)
What passes into the placenta through active transport?
- Amino acids
- Calcium, Iron, Iodine and Phosphate
- Water Soluble vitamins (B and C)
What passes into the placenta through pinocytosis?
- Immunoglobulins (IgG)
- Harmful Substances (drugs, viruses and toxins)
What are the UK recommendations for women who are trying to conceive, and are overweight
Women who are overweight or obese are encouraged to lose weight before trying to have a baby. A healthy diet is recommended to support healthy growth of the foetus, whilst maintaining adequate maternal nutrition. An inadequate energy intake can result in poor foetal development.
How do energy requirements change during pregnancy?
Increase in BMR, resulting in an increase in energy.
This is due to the body producing new tissue in the genital organs and general growth of the foetus.
SACN suggest 200kcal (0.8MJ) per day in third trimester only.
How do protein requirements change during pregnancy?
Increase in protein. This is due to the body producing new tissue in the genital organs and general growth of the foetus.
SACN suggest an extra 6g a day (51g). UK protein intakes are usually high at >70g/day
How do essential fatty acid requirements change during pregnancy?
LCPUFAs (AA, DHA, and EPA) - Helps with the development of new cell membranes and tissues. Essential for neurological and retinal development.
DHA – insufficient amounts can lead to permanent damage to retinal and learning ability.
No more than two portions of oily fish a week - Oily fish can contain contaminants.
Why does Mercury need to be limited during pregnancy?
High levels can damage the foetus
No deep sea fish – shark, marlin, swordfish.
Limit tuna.
What is the main dietary recommendation for pregnant women?
To follow a healthy, balanced diet based on the Balance of Good Health model
This includes consuming plenty of iron- and folate-rich foods and a daily vitamin D supplement.
What is the recommended daily supplement of vitamin D for pregnant women?
10 µg/day
What is the average weight gain recommended for women with a healthy pre-pregnancy weight?
12 kg (range 10–14 kg)
This weight gain is associated with the lowest risk of complications during pregnancy and labour.
What birthweight is associated with optimal maternal and fetal outcomes for a full-term infant?
3.1–3.6 kg
What is LBW and what birthweight qualifies as LBW?
LBW stands for low birthweight and is defined as birthweight <2.5 kg
What is the recommended body mass index (BMI) range for women prior to conception?
20–25
What is the recommended daily intake of folic acid for women who may become pregnant?
200ug/day plus a 400 µg/day supplement prior to and up until the 12th week of pregnancy
Which requirements increase whilst pregnant
Increased requirements for:
Thiamin - + 0.1mg/day for last trimester
Riboflavin - + 0.3 mg/day
Folate - + 100 ug/day (plus 400ug/day supplement for before getting pregnant and first 12 weeks of pregnancy)
Vitamins A - + 100 ug/day
Vitamin C - + 10mg/day for last trimester
Vitamin D - no requirements (just 10ug/day)
Energy - + 200kcal in last trimester
Protein - + 6g a day
What is the estimated energy cost of pregnancy?
Around 321 MJ (77,000 kcal)
What is the extra energy requirement during the third trimester of pregnancy?
200 kcal per day
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Pregnancy46
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Breastmilk33
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Complementary Feeding25
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Nutrition In Pre-School Children40
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Nutrition In School Age Children32
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Nutrition In Adult Population35
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Influence of Religion, Culture and Ethnicity on Nutrition and Food Choices through the Life Cycle38
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Micronutrient Deficiencies44
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Nutrition In Older Adults And Elderly48
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Plant Based Diets35
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Folic Acid18
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Iodine21
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Nutrition Intakes Through The Lifecyle43
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Elderly16
