Lecture 2: Preconception Flashcards
What is preconception?
“the period before (at least 2 years) and between consecutive pregnancies, to improve health related outcomes for women (regardless of their pregnancy status), newborns and children up to 5 years of age”
What is the proximal preconception period?
Period preceding pregnancy (up to 2 years prior to conception)
What is the distal preconception period?
Adolescence or in general a longer time before pregnancy
Why is preconception important?
Because a mothers health at and before conception influences the course and outcome of her pregnancy
What does maternal nutrition at the time of conception influence?
Placental development and function
What is directly tied to maternal preconception nutrition and child’s long-term health?
Fetal genomic imprinting and programming at conception
What is periconception?
“the period preceding, including and immediately following human conception to improve health related outcomes for women, newborns and children up to 5 years of age”
What is the boundary for periconception?
3 months before pregnancy and up to the first trimester
When do most reproductive failures occur?
During periconception
What is the CRITICAL window of life?
First 1000 days of life
What does the first 1000 days of life include?
Pregnancy, and first 2 years of life (not pre-conception)
Why is nutrition in the first 1000 days of life the critical window?
Key to brain development, healthy growth and a strong immune system - one of the most modifiable factors
What percent of the population are malnourished during the first 1000 days of life?
1/3
What does malnourished mean?
Obese, underweight or deficiencies
What do majority of infant deaths occur due to?
Malnutrition
What is happening during periconception?
The eggs and sperm are being developed. Egg = 14 weeks, Sperm =10 weeks
Why should we consider the periconception period longer than 3 months?
Biologically it could be considered 5-6 months
What does malnutrition look like around the world?
1.9 billion adults are overweight (>600 million obese)
462 million adults are underweight
What does the prevalence of malnutrition look like over time?
Increasing overweight and obesity
Undernutrition prevalence is stabilising or decreasing
What BMI indicates obesity?
> 30kg/m2
Most obese men and women tend not to be infertile rather…
Sub fertile
What is sub-fertile?
difficulty conceiving, pro-longed period of misconception
Obese women tend to have higher levels of what?
Estrogen, androgens and leptin than non-obese
How does obesity affect the reproductive processes in women?
Menstrual cycle irregularity (30-47%), ovulatory failure and amenorrhea
Obesity in men is associated with lower levels of what?
Testosterone and increased estrogen and leptin levels
How does obesity affect the reproductive processes in men?
Reduced sperm production and increased erectile dysfunction
What BMI indicates a critical level of body fat?
less than 20kg/m2
What is low levels of body fat during adolescence related to?
delays in the age of onset of menstruation and reduced fertility later in life
What does weight loss exceeding 10-15% decrease?
Estrogen, LH and FSH
What are the consequences of weight loss exceeding 10-15%?
Amenorrhea, anovulatory cycles, short or absent luteal phases
What can periconceptional micronutrient status influence?
Offspring metabolism, organ growth, development and function, leading to an increased risk of chronic disease
What effect does choline have during periconception?
Brain development
What effect does iodine have during periconception?
Neurocognitive
What effect does zinc have during periconception?
Preterm birth, placental function
What effect do omega-3 fatty acids and B12 have during periconception?
Altered lipid metabolism
What effect does iron have during periconception?
- Iron deficiency anemia linked with LBW
- Delayed development
- Preterm birth
- Infections
- Postpartum hemorrhage
What effect does folic acid have during periconception?
- Neural tube defects
- Congenital malformations
- Preeclampsia
- Autism
What did the 2010 Cochrane review confirm?
That folic acid supplementation prevents the first and second time occurence of NTD’s
What are NTD’s that effect the brain?
- Craniorachischisis
- Anencephaly
- Encephalocele
- Iniencephaly
What are NTD’s that effect the spinal cord?
- Spina bifida ***
- Spinal dysraphism
- Meniogelcele
- Myelomenigocele
What is the periconceptional folic acid recommendation?
800mcg (0.8mg) daily at least 4 weeks before and 12 weeks after becoming pregnant - first trimester
What percent of unplanned pregnancies are mistimed and unwanted?
40% mistimed
60% unwanted
What helps bridge the gap for unplanned pregnancies not taking folic acid supplements?
Fortification
Why did NZ withdraw from folic acid fortification?
Some unvalidated evidence that folic acid fortification would increase cancer risk, based on the fact that cancer cells need folic acid to replicate + worries over government control + cost for bakers
What is the current policy?
Fortification of flour used for bread making in NZ
- non-organic wheat flour
- no less than 2mg/kg, no more than 3mg/kg
- includes imported flour
What is the dutch famine?
Took place in german-occupied part of the netherlands, winter of 1944-45 near the end of WWII
Why did the dutch famine occur?
German blockade cut off food and fuel shipments - 4.5 million affected: 22,000 died
Children of pregnant women exposed to famine are more susceptible to what?
Diabetes, obesity, CVD, microalbuminuria and more
What is the Barker hypothesis?
“states that fetal undernutrition in middle to late gestation, which leads to disproportionate fetal growth, programmes later coronary heart disease”
What is considered LBW?
Less than 2.5kg
What disease is LBW associated with?
Coronary artery disease, impaired glucose tolerance, type 2 diabetes
Young mothers are more likely to have babies with lower birth rates. Why?
- Adolescent mother is still growing themselves: there is a competition for nutrients
What is Guatemala?
long-term prospective study to determine the effects of maternal nutrition on offspring physical growth and mental development
What did Guatemala look at?
What happened when energy and protein supplementation were given to mothers
- In those women who complied they had a 50% lower rate of LBW
What Vitamins do NZ recommend for supplementation during pregnancy?
Folic acid and iodine
What are the folic acid recommendations during pregnancy?
1 800ug daily for 4 weeks pre-pregnancy and until end of first 12 weeks
What are the iodine recommendations during pregnancy?
1 150ug iodine-only daily from start of pregnancy to end of breastfeeding
What are other supplements on advice for pregnancy?
- Iron (if indicated)
- B12 (vegan)
- Calcium (subject to diet)
- Vitamin D (subject to enviornment)
