Pregnancy Flashcards
Gestational age
Assessed from the date of conception
Average pregnancy is 38 weeks
Menstrual age
Assessed from onset of last menstrual period
Average pregnancy is 40 weeks
40 weeks conceptualization includes 2 non-pregnant weeks
Embryo-fetal development period
Week 1-2: implantation
Week 3-8: embryonic period
Week 9-38: fetal period
Maternal body composition changes sequence
Maternal plasma volume Maternal nutrient stores Placental weight Uterine blood flow Fetal weight
Maternal anabolic changes
Occur during first half of pregnancy
Ananbolic hormones: Insulin, GH, IGF, anabolic steroids
Blood volume expansion Increased cardiac output Build-up of fat, nutrient, and liver glycogen stores Growth of some maternal organs Increased appetite, food intake Decreased exercise tolerance Increased levels of anabolic hormones
Maternal catabolic changes
Occurs in second half of pregnancy when most fetal growth occurs, catabolic changes make nutrients available to fetus
Catabolic hormones: Adrenaline, cortisol, Glucagon, epinephrine, noreprinephrine
Mobilization of fat and nutrient stores
Increased production and blood levels of glucose, triglycerides, fatty acids
Decreased liver glycogen stores- glycogenolysis
Accelerated fasting metabolism
Increased levels of catabolic hormones
Fluid volume in pregnancy
Increases from ~7 L to 10 L Increased blood volume Increased body tissues Increased extracellular volume Amniotic fluid
Edema (in 60-75% of women)
Hormonal changes in pregnancy
Human chorionic gonadotrophin (hCG)
Progesterone
Estrogen
Human chorionic somatotrophin (hCS)
1st trimester: Placenta secretes hCG, Ovaries secrete estrogen and progesterone
2nd trimester: Placenta secreates hCG, estrogen, progesterone, Ovaries secrete estrogen and progesterone
3rd trimester: Placenta alone secretes hCG, estrogen, and progesterone
Human chorionic gonadotrophin (hCG)
- Stimulates production of estrogen and progesterone
- Stimulates growth of endometrium
- Secreted by placenta
Progesterone
- Maintains the implant
- Stimulates growth of the endometrium and its nutrient secretion
- Stimulates breast development
- Promotes lipid deposition
Estrogen
- Increases lipid formation and storage, protein synthesis, uterine blood flow
- Prompts uterine and breast duct development
- Promotes ligament flexibility
Human Chorionic Somatotrophin (hCS)
- Increases insulin resistance (in order to maintain higher blood glucose levels for fetal use)
- Promotes protein synthesis
- Promotes fat breakdown for maternal energy
Maternal nutrient metabolism
Accelerated fasting metabolism
Insulin resistance, altered blood glucose regulation
Reduced nitrogen excretion and conservation of amino acids
Accumulation of maternal fat stores, enhanced fat mobilization
Altered mineral metabolism
Accelerated fasting metabolism
Increases in:
Glucogenic amino acid utilization
Fat oxidation, lipolysis
Production of ketones
During fasting, allows for:
Maternal use of stored fat
Sparing of glucose and amino acids for fetus
Carbohydrate metabolism
Early pregnancy: High estrogen & progesterone stimulate insulin which increases glucose>glycogen & fat
Late pregnancy: Human chorionic somatotropin (hCS) & prolactin inhibit the conversion of glucose to glycogen & fat
Diabetogenic effect of pregnancy:
Mother goes into transient insulin resistance during pregnancy in order to keep blood sugars higher for the fetus which is the preferred fuel
Protein metabolism
- Aim to ensure nitrogen conservation for fetal growth during the last quarter of pregnancy
- Decreases in nitrogen excretion in later pregnancy
- Conservation of amino acids for tissue synthesis
- Protein is not stored during early gestation for later use
- Increased protein needs must be met by physiological adjustments that enhance dietary protein utilization
Fat metabolism
Fat stores:
- Accumulate in first half of pregnancy
- Enhanced fat mobilization in last half, fat stores broken down (lipolysis)
Blood lipid levels increase
Increased cholesterol is substrate for steroid hormone synthesis
Mineral metabolism
Calcium
-Increased bone turnover & reformation
Sodium
- Accumulation in mother, placenta, & fetus
- Restriction of sodium potentially harmful
Functions of the placenta
Hormone and enzyme production
Nutrient and gas exchange
Removal of waste from fetus
Nutrient Transfer Priorities:
- Maternal needs
- Placental needs
- Fetal needs
Newborn weight
Determined by:
- Energy, nutrient & oxygen availability
- Genetics
- Insulin-like growth factor (IGF-1)
Weight classifications:
- Normal = 5lb 8 oz- 9lb, 4oz
- LBW: Low Birth Weight (< 5 lbs 8 oz)
- VLBW: Very Low Birth Weigh (< 3 lbs 4 oz)
- SGA: small for gestational age (<10th percentile)
- LGA: large for gestational age (>90th percentile)
Weight gain in pregnancy
- Low weight gain during first trimester (~5 lbs)
- Gain of a little less than 1 lb per week for the 2nd and 3rd trimesters
- No weight loss is recommended, even in obese
Fetus is only ~1/3 of weight, the remainder is a combination of:
- breast tissue
- fluid volume
- placenta
- uterus and supporting muscles
- amniotic fluid
- fat stores
Postpartum weight loss
~15lbs lost at delivery
Lactation reset hypothesis
Prenatal energy and nutrient needs
Caloric needs: -1st trimester: little to no increase -2nd trimester: ~340 kcal/day -3rd trimester: ~450 kcal/day Protein needs: -Increase by 25 grams/day (71g/day) Fat needs: -Slightly increased needs for essential fatty acids, DHA and EPA, n-6 Fiber needs: -Increases from 25 to 28 grams/day
Folate
Deficiency leads to:
Impaired DNA synthesis, gene expression, gene regulation
Leads to abnormal cell division and tissue formation
Accumulation of homocysteine (a metabolite) and shortage of methionine may cause placenta rupture, stillbirth, preterm labor, preeclampsia, structural abnormalities
(Methionine gets converted to homocysteine, when levels of homocysteine are too high in the body, will convert back to methionine with the use of B12 and folate. If not enough folate, build-up of homocysteine)
Choline
Component of phospholipids in cell membranes
Precursor of intracellular messengers
Source of methyl groups needed for DNA regulation, brain development
Vitamin A
Involved in cell differentiation
Deficiency is rare, excess is a concern (medications: Accutane, Retin-A)
Teratogenic
Iron
+1000mg additional iron needed during pregnancy (over all of pregnancy, not per day)
300 mg for fetus and placenta
250 mg lost at delivery
450 mg to increase RBC mass
12% of women enter pregnancy with iron deficiency
Increased risk for preterm delivery and LBW
Impaired cognitive development in offspring
Low iron during pregnancy = newborn with low iron stores
Hypertension
Hypertension (HTN) is defined as blood pressure ≥140 mm Hg systolic or ≥90 mm Hg diastolic blood pressure
Affects 6 to 10% of pregnancies
Contributes to stillbirths, fetal & newborn deaths, & other adverse conditions
HTN in pregnancy is related to:
Chronic inflammation
Oxidative stress
Damage to the endothelium of blood vessels
Consequences of endothelial dysfunction:
Impaired blood flow
Increased tendency to clot
Plaque formation
Chronic Hypertension
HTN present before pregnancy or diagnosed <20 weeks
More common in:
African American, obese, >35 years of age, or history of HTN with previous pregnancy
Associated with increased risk of:
preterm delivery, fetal growth retardation, placenta abruption, Cesarean delivery
Gestational Hypertension
Hypertension diagnosed for first time after mid-pregnancy
No proteinuria
Tend to be overweight or obese with excess central body fat
Recommendations for Hypertension
Intervention should aim to achieve adequate & balanced diets for pregnancy
Weight gain is same as for other pregnant women
Continue Na reduction required for blood pressure control without too little that could impair fetal growth
Preeclampsia-Eclampsia
A pregnancy-specific syndrome occurring >20 weeks gestation accompanied by proteinuria
Proteinuria—urinary excretion of ≥0.3 gram protein in 24-hour urine sample (or >30 mg/dL protein or ≥2 on dipstick reading)
Eclampsia—occurrence of seizures not attributed to other causes
Oxidative stress, inflammation, & endothelial dysfunction
Platelet aggregation & blood coagulation due to deficits in prostacyclin relative to thromboxane
Blood vessel spasms & constriction
Increased blood pressure
Insulin resistance
Adverse maternal immune system responses to the placenta
Elevated blood levels of triglycerides, free fatty acids and cholesterol
Recommendations for Preeclampsia-Eclampsia
Adequate calcium intake Adequate vitamin D status Use of multi-vitamin/minerals if needed >5 servings of colorful vegetables and fruits daily Adequate fiber intake (>21 grams/day) Basic foods from MyPlate recommendations Moderate exercise Recommended weight gain
Obesity
Obesity increases risk for:
- Stillbirth
- LGA
- Cesarean section
- Offspring overweight and type II diabetes
Recommendations for Obesity
Meet nutrient needs Consume a variety of basic foods Participate in physical activity Maintain appropriate rates of weight gain Weight loss is not recommended
Gestational Diabetes
Women developing gestational diabetes appear to be predisposed to insulin resistance, and have impaired insulin production
Related to metabolic changes favoring oxidative stress and elevated blood glucose
Elevated glucose from mother – risk of adverse outcomes.
- Spontaneous abortion, stillbirth, neonatal death
- Congenital anomalies
- Glucose uptake & triglyceride formation in fetus
Fetal changes increase likelihood later in life:
- Insulin resistance and/or Type 2 diabetes
- High blood pressure
- Obesity
Recommendations for Gestational Diabetes
First approach is medical nutrition therapy to normalize blood glucose levels with diet & exercise
Blood glucose levels can be brought down with low calorie intake – avoid elevated ketones
Oral medication metformin (glyburide) used to decrease insulin resistance
Regular aerobic exercise
Assess dietary & exercise habits
Develop individualized diet & exercise plan
Monitor weight gain
Interpret blood glucose & urinary ketone results
Ensure follow-up during & after pregnancy
Fetal Alcohol Spectrum Disorders (FASD)
Alcohol-related neurodevelopment disorder (ARND)
- No overt physical features
- Intellectual disabilities
- Problems with behavior, learning, coping, impulse control, attention
Alcohol-related birth defects (ARBD)
-Abnormalities of the heart, kidneys, bones, or hearing
Fetal alcohol syndrome (FAS)
- Most severe form
- Abnormal facial features
- Growth problems
- CNS abnormalities
- Problems with social skills, learning, memory, attention span, communication, vision, hearing
