Nutrition Transfer Across the Placenta

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Questions and Answers

Which mechanism uses energy to transfer nutrients across the placenta?

Facilitated diffusion

Active transport (correct)

Endocytosis (correct)

Passive diffusion

What primarily influences the transfer of nutrients across the placenta?

Size and charge of the molecules (correct)

Blood type compatibility

Fetal age and weight

Maternal hormonal levels

What is a crucial nutrient that the placenta utilizes from maternal circulation?

Glucose (correct)

Iron

Calcium

Protein

How does a decrease in maternal nutrient intake primarily affect the fetus?

It affects fetal growth more than maternal health. (C) Signup and view all the answers

Which of the following cannot easily pass through the placenta?

Insulin (C) Signup and view all the answers

What is a primary function of the placenta concerning nutrient transfer?

To balance nutrient levels between maternal and fetal blood (D) Signup and view all the answers

What type of molecules can pass through the placenta more easily due to size and lipid solubility?

Small molecules and lipids (C) Signup and view all the answers

What is true about the relationship between the fetus and the mother regarding nutrient supply?

Maternal nutrients are prioritized for her own needs before fetal needs. (B) Signup and view all the answers

What happens to maternal fat accumulation in the first half of pregnancy?

Maternal fat accumulation increases. (B) Signup and view all the answers

What is the primary use of increased cholesterol during pregnancy?

Synthesis of steroid hormones by the placenta (D) Signup and view all the answers

What is a potential consequence of low-sodium diets during pregnancy?

Functional and growth impairments in the fetus (C) Signup and view all the answers

What is the function of the placenta in relation to waste products?

It removes waste products from the fetus. (B) Signup and view all the answers

How does maternal cholesterol level respond to cholesterol-lowering diets during pregnancy?

Maternal cholesterol levels significantly decrease. (B) Signup and view all the answers

Which substance is NOT recommended for restriction during pregnancy?

Sodium (C) Signup and view all the answers

What is the shape of the placenta, as derived from its Latin origin?

Round and disk-like (C) Signup and view all the answers

What is a key function of increased fat mobilization in the second half of pregnancy?

To provide energy for fetal growth. (B) Signup and view all the answers

What is the significance of the increased blood volume during the maternal anabolic phase of pregnancy?

It enhances nutrient transfer to the placenta and fetus. (B) Signup and view all the answers

Which hormone is primarily responsible for increasing appetite during pregnancy?

Progesterone (D) Signup and view all the answers

What percentage of fetal growth occurs in the first half of pregnancy?

10% (A) Signup and view all the answers

What is a common result of increased insulin resistance in the late stages of pregnancy?

Increased reliance on fats for energy (B) Signup and view all the answers

During which phase of pregnancy does enhanced lipolysis primarily occur?

Catabolic phase (A) Signup and view all the answers

What condition can prolonged utilization of ketones by the fetus lead to?

Abnormal growth and impaired intellectual development (D) Signup and view all the answers

What is the major risk factor associated with maternal mortality?

Severe bleeding after childbirth (A) Signup and view all the answers

What is the recommended protein intake accumulation during pregnancy?

About 925 grams (A) Signup and view all the answers

What characterizes the 'catabolic phase' of pregnancy?

Mobilization of fat and increased energy production (B) Signup and view all the answers

What is a primary concern associated with very preterm births?

Higher potential for congenital disorders (D) Signup and view all the answers

In terms of body water changes during pregnancy, what is the purpose of increased extracellular fluid?

To enhance nutrient transfer to the fetus and placenta (C) Signup and view all the answers

What role does cholesterol play in pregnancy?

It is essential for fetal growth and development. (C) Signup and view all the answers

How is fetal death defined in the context of pregnancy?

Death of the fetus after 20 weeks of pregnancy (D) Signup and view all the answers

Which of the following best describes the change in maternal metabolism as pregnancy progresses?

Initial anabolic changes followed by catabolic energy sourcing (D) Signup and view all the answers

Study Notes

Nutrition During Pregnancy

General Outcome: Students will become familiar with physiological changes during pregnancy and demonstrate how these changes affect nutritional needs.
Specific Outcomes:
- Describe physiological changes during pregnancy.
- Identify recommended weight gain ranges for underweight, normal weight, overweight, and obese women entering pregnancy.
- Identify relationships between nutritional status during pregnancy and long-term health outcomes in offspring.

Periconceptional: Period before conception (approximately 14 days before the next menstrual period).
Trimester 1: Weeks 0-12
Trimester 2: Weeks 13-28
Trimester 3: Weeks 29-40
Preterm: Born before 37 weeks.
Very preterm: Born before 32 weeks.
Term: 38-42 weeks.
Postterm: More than 42 weeks.
Perinatal: Period from 20 to 24 weeks gestation to 7 to 28 days after birth.

Important Terms & Definitions

Fetal death/Stillbirth: Death of the fetus after 20 weeks of pregnancy.
Perinatal mortality: Death of a fetus between 20 weeks of gestation or death of an infant less than 1 month old.
Neonatal mortality: Deaths from delivery to 28 days.
Post-neonatal mortality: Deaths from 28 days after birth to 1 year.
Infant mortality: Deaths from birth to age 1 year.

Infant Mortality

Indicator: Number of infant deaths under 1 year old per 1,000 live births.
Decreased Mortality: Indicates improvements in environmental factors like safe and nutritious food, better public sanitation & infectious disease control.

Child Mortality Rates

In Malaysia, infant mortality rates have decreased significantly from 41 deaths per 1,000 live births in 1970 to 6.9 in 2017.
Malaysia has seen improvement in health indicators over time.

Causes of Infant Mortality

Conditions originating in the perinatal period such as meningits and pneumonia,
Chronic lower respiratory disease
Congenital malformations/deformations along with chromosomal abnormalities.

Maternal Mortality

Definition: Deaths due to pregnancy or childbirth complications.
Global Trend: Global maternal mortality ratio has decreased by 34% from 2000 to 2020.
Geographic Considerations: Almost 95% of maternal deaths occur in low and lower middle-income countries.
Preventable Deaths: More than 80% of pregnancy-related deaths are preventable.

Causes of Maternal Mortality

Severe bleeding (mostly after childbirth)
Infections (usually after childbirth)
High blood pressure during pregnancy (pre-eclampsia)
Complications from delivery
Unsafe abortions
Malaysia trend Shows a decrease from 141 deaths per 100,000 births in 1970 to 21 in 2019.

Physiology of Pregnancy

Conception: Beginning of pregnancy.
Pregnancy duration: Approximately 38 weeks (266 days) from conception or from first day of last menstrual period (LMP) – approximately 40 weeks(280 days).
Gestational age: Duration of pregnancy measured from conception.
Menstrual age: Pregnancy duration measured form the first day of the last menstrual period (LMP).

Normal Physiology Changes During Pregnancy

Anabolic phase (0-20 weeks): Increased food intake, lipid absorption, and accumulation; increase in hormones.
Catabolic phase (20+ weeks): Mobilization of fats and nutrients stores, increase in blood glucose, triglycerides & fatty acids.

Maternal Anabolic Phase (0-20 weeks)

Blood volume expansion: Increased blood volume and cardiac output, to accommodate increase nutrients.
Fat buildup: Accumulation of fat, nutrients, and liver glycogen stores.
Organ growth: Growth of certain maternal organs.
Increased appetite: Increased hunger as a result of increased need for nutrients.
Decreased exercise tolerance: Body's need to conserve energy

Maternal Catabolic Phase (20+ weeks)

Fat and nutrient mobilisation: Fat and nutrient stores begin to be used.
Increased blood glucose: Blood glucose levels increase
Triglycerides and fatty acids: Levels of triglycerides and fatty acids increase dramatically during pregnancy.
Fasting metabolism: Fast metabolism accelerates to provide energy.
Catabolic hormones: Catabolic hormones also increase

Fetal Growth

Early growth (first half): Approximately 10% of fetal growth during this period
Later growth (second half): Approximately 90% of fetal growth during this period

Body Water Changes

Total body water: Increases from 7 to 10 liters
Extracellular fluid: Increase during pregnancy to enhance transfer of nutrients and wastes.
Edema: Swelling (usually in the legs & feet) due to accumulation of extracellular fluid.

Hormonal Changes

Placenta: Main source of hormones that modify physiological changes in pregnancy.
- Includes hCG, hCS, estrogen, leptin, and progesterone.

Human Chorionic Gonadotropin

Function: Stimulates corpus luteum for estrogen & progesterone production and maintains endometrium.

Human Chorionic Somatotropin

Function: Increases insulin resistance in the mother to maintain glucose for the fetus. Promotes protein synthesis and fat breakdown to supply energy for the mother

Estrogen

Function: Lipid synthesis & uterine/breast development.

Leptin

Function: Regulates maternal appetite & lipid metabolism.

Progesterone

Function: Maintains pregnancy and relaxes uterine muscles.

Carbohydrate Metabolism

Early pregnancy: Insulin production increases, and glucose is predominantly converted to glycogen and fat.
Late pregnancy: hCS & prolactin inhibit glucose conversion to glycogen & fat. Increases reliance on fats for energy. Ensures glucose supply for fetus development.

Accelerated Fasting Metabolism

Fasting: >12 hours
Fat mobilization: Allows pregnant women to utilize stored fats for energy
Glucose & Amino Acid sparing: Spares glucose and amino acids for fetal use.
Ketone bodies: During prolonged fasting, dependence on fetal ketone bodies for energy, causes abnormal growth.

Protein Metabolism

New tissues: Protein is needed for synthesis of new maternal and fetal tissues (about 925 grams during pregnancy).
Intake: Mothers need to meet increased protein demands during pregnancy.
Amino acid conservation: Method to increase protein through reduced nitrogen excretion & protein tissue synthesis.

Fat Metabolism

First half: Accumulation of maternal fat
Second half: Mobilization of maternal fat, dramatically increasing blood lipid levels.
Types of fatty acids: Plasma triglycerides, cholesterol-containing lipoproteins, phospholipids, & fatty acids.
Cholesterol: Used by placenta for steroid hormone synthesis. High concentrations observed do not promote atherosclerosis.

Mineral Metabolism

Calcium: Maternal absorption & mobilization from bones increase, for fetal bone development.
Sodium: Elevated needs, low salt/sodium diets not recommended to prevent impairment.

Placenta

Definition: Derived from "Latin word for cake"- round or disk like structure.
Functions: Hormone & enzyme production, nutrient & gas exchange between mother & fetus; Removal of waste products from fetus; Barrier to harmful substances.
Nutrient transfer: Primarily uses passive/facilitated diffusion across maternal-fetal membranes.
Mechanisms: Passive diffusion, facilitated diffusion, active transport, and endocytosis.

Fetus is Not a Parasite

Fetus cannot take unlimited nutrients.
Nutrient needs are first met by maternal demands, then fetal needs.
Compromised fetal growth & development due to poor maternal nutritional status.

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Description

This quiz explores the intricate mechanisms of nutrient transfer between the maternal circulation and the fetus through the placenta. It covers key nutrients, the impact of maternal diets, and the physiological functions of the placenta in pregnancy. Test your understanding of how maternal health influences fetal development and nutrient availability.