Endocrine System and Metabolism

Subject: Midwifery I (Theory)

Overview

Metabolism is the sum of all chemical events that occur in the body that use absorbed nutrients to create energy via the chemical oxidation of nutrients. The expanding uterus and fetus boost total metabolism. During pregnancy, the three most common estrogens are estrogen, estradiol, and estriol. Estrogen performs a variety of functions during pregnancy, including stimulating the uterus and increasing blood supply to uterine vessels, maintaining breast growth and duct structure, increasing salivary gland activity, and hyperemia of the gums and nasal mucous membrane. Progesterone encourages the development of thick vascular decidua in preparation for the imbedding of the ovum, and it generally maintains healthy decidua throughout the pregnancy.

Metabolism is the sum of all chemical events that occur in the body that use absorbed nutrients to create energy via chemical oxidation.

Changes in Metabolism

  • The developing uterus and fetus require an increase in total metabolism. The average non-pregnant woman's basal metabolic rate is 30 percent higher than that of a pregnant woman.
  • Approximately 1000 gm of protein is stored throughout a normal pregnancy (450 gm in a fetus, 450 gm in a uterus, other are in a breast, plasma protein, and hemoglobin). The conversion of amino acids to urea is inhibited.
    • Carbohydrate metabolism: In non-diabetic women, fasting hypoglycemia and postprandial hyperglycemia contribute to a diabetic type condition, which reverses after delivery.
    • Total body fat increases during pregnancy, and plasma lipid levels rise in the latter half of the pregnancy but fall quickly following delivery.
    • During pregnancy, an average of 3-4 kg of fat is accumulated, predominantly in the abdominal wall, breasts, hips, and thighs.
    • The total iron requirement during pregnancy is estimated to be around 1000mg. This is given in 300mg to the fetus and placenta and 400mg to the expanded red cell volume (Total increase in red cell volume 350 ml and 1ml contains mg of iron).
    • Supplemental iron is beneficial and required during pregnancy and for several weeks after delivery.
    • Because fluid balance is dependent on sodium content, his kidney must compensate for the several factors that favor sodium excretion during pregnancy. Increased GFR, lower plasma protein concentrations, and increased progesterone levels, for example, all result in an increase in sodium excretion.
    • Because of the effect of hormones, the average woman maintains 6 to 8 liters of additional water throughout pregnancy.
    • A total of 4 to 6 L of fluid enters the extracellular spaces. As a result, there is a natural rise in blood volume. (hyperemia) At the end of the day, many pregnant women suffer the usual accumulation of fluid in their legs and ankles. This is known as physiologic edema and is most common in the third trimester.

Changes in the Endocrine system

Placental Hormones

A. Steroid hormone

  • Oestrogen
  • Progesterone

B. Protein hormone

  • Human chorionic gonadotrophin hormone (HCG)
  • Human placental lactogen (HPL)
  • Human chorionic thyrotropin (HCT)
  • Human chorionic corticotropin (HCC)
  • Pregnancy-specific B-1 glycoprotein (PSBG)
  • Pregnancy-associated plasma protein (PAPP)

C. Others

  • Thyroid gland
  • Pituitary gland
  • Adrenal gland
  • Pancreas

Steroid Hormone

1. Estrogen

It is produced by the corpus luteum before the 12th week of pregnancy and by the placenta in combination with a fetus after the 12th week of pregnancy.

During pregnancy, the three traditional estrogens are estrogen, estradiol, and estriol. Estriol accounts for more than 90% of the estrogens released during pregnancy. During pregnancy, estrogen performs the following functions:

  • It stimulates the uterus and promotes blood flow to the uterine arteries.
  • Breast development and duct structure are preserved.
  • External genitalia enlargement
  • Hyperemia of the gums and nasal mucous membrane due to increased salivary gland activity.
  • Estrogen can reduce the release of HCl and pepsin, which can cause digestive distress such as nausea.

2. Progesterone

Progesterone encourages the development of thick vascular decidua, which prepares the ovum for embedding, and it generally maintains healthy decidua throughout the pregnancy. Plain muscles are relaxed by progesterone. If progesterone production is inadequate, the uterus may initiate rhythmic contractions and abortion may occur.

Similarly, the intestinal muscle is loosened; constipation is typical during pregnancy. Relaxation of the plain muscle in the vein walls may result in the formation of varicose veins of the legs, rectum, and vulva. This impact is exacerbated by the pressure of the growing uterus on the pelvic vein, which slows venous return from the legs even further.

Protein Hormone

Human chorionic gonadotrophin (HCG)

This is produced by trophoblast cells from the time the fertilized ovum is embedded. In early pregnancy, the major purpose of HCG is to stimulate the corpus luteum to release progesterone and estrogen. A positive test is caused by this hormone. HCG levels in multiple gestation hydatidiform or choriocarcinoma can be twice as high as in a singleton pregnancy. Between 60 and 70 days of pregnancy, 100 IU/ml in blood and 200 IU/ml in urine. It gradually decreases by 10-20IU/ml between 100-130 days. As a result, maintain consistency throughout the pregnancy.

References

  • Kovacs CS. Calcium metabolism during pregnancy and lactation. NCBI Bookshelf. http://www.ncbi.nlm.nih.gov/books/NBK279173/
  • HealthLine. 2005. 2017 http://www.healthline.com/health/pregnancy/bodily-changes-during
  • BC Open Textbook. https://opentextbc.ca/anatomyandphysiology/chapter/28-4-maternal-changes-during-pregnancy-labor-and-birth/
  • Hadassah Medical Center. http://www.hadassah-med.com/giving-birth/hadassah-birthing-club/throughout-pregnancy/physiological-changes-during-pregnancy
  • Tuitui R. 2002, A textbook of Midwifery A (Antenatal), 3rd edition, Vidyarthi Pustak Bhandari (Publisher and Distributor), Bhotahity, Kathmandu
  • Tuitui R. 2002, A textbook of Midwifery B (Intranatal), 3rd edition, Vidyarthi Pustak Bhandari (Publisher and Distributor), Bhotahity, Kathmandu
Things to remember
  • Metabolism is the sum of all chemical events that occur in the body that use absorbed nutrients to create energy via chemical oxidation.
  • The developing uterus and fetus require an increase in total metabolism.
  • The average non-pregnant woman's basal metabolic rate is 30 percent higher than that of a pregnant woman.
  • Approximately 1000 gm of protein is stored throughout a normal pregnancy (450 gm in a fetus, 450 gm in a uterus, others are in a breast, plasma protein, and hemoglobin).
  • During pregnancy, the three traditional estrogens are estrogen, estradiol, and estriol.
  • Estriol accounts for more than 90% of the estrogens released during pregnancy.
  • Estrogen performs several functions during pregnancy, including stimulating the uterus and increasing blood supply to uterine vessels, maintaining breast growth and duct structure, increasing salivary gland activity, and hyperemia of the gums and nasal mucous membrane.
  • Progesterone encourages the development of thick vascular decidua, which prepares the ovum for embedding, and it generally maintains healthy decidua throughout the pregnancy.
  • Plain muscles are relaxed by progesterone. If progesterone production is low, the uterus may initiate rhythmic contractions and abortion may occur.
Questions and Answers

Changes in Metabolism:

  • The requirements of the developing uterus and the fetus result in an increase in total metabolism. The typical non-pregnant woman's basal metabolic rate is boosted by 30% during pregnancy.
  • A normal pregnancy stores roughly 1000 g of protein (450 gm in fetus, 450 gm in uterus , other are in breast, plasma protein and hemoglobin). There is a suppression of amino acid to urea conversion.
  • Pregnancy causes the body to store an average of 3–4 kg of fat, mostly in the breasts, thighs, hips, and abdominal wall.
  • During pregnancy and for a few weeks after delivery, extra iron is beneficial and required.
  • Due to the influence of hormones, the average pregnant woman retains 6 to 8 liters more water.
  • The extracellular spaces are entered by 4 to 6 L of fluid. Blood volume increases physiologically as a result of this. The typical nighttime fluid buildup in the legs and ankles of many pregnant women is caused by hyperemia. It is known as physiologic edema and occurs most frequently in the third trimester.
  • The metabolism of carbohydrates Fasting hypoglycemia and postprandial hyperglycemia during a typical pregnancy result in a diabetic type.
  • Carbohydrate metabolism: In a non-diabetic woman during a normal pregnancy, fasting hypoglycemia and postprandial hyperglycemia cause a diabetic-like condition, which reverses after delivery.
  • Pregnancy causes an increase in plasma lipids and total body fat, which both decline quickly following delivery.
  • The total amount of iron needed during pregnancy is thought to be around 1000mg. This is distributed as 300 mg in the fetus, 400 mg in the placenta, and
  • A sufficient sodium concentration is necessary for fluid balance, so the kidney must make up for the many factors that encourage sodium excretion during pregnancy. For instance, higher GFR, lower plasma protein concentration, and higher progesterone levels all lead to higher sodium excretion

Changes in the Endocrine system:

  • Placental hormones
  • Steroid hormone
  • Oestrogen
  • Progesterone
  • Protein hormone
  • Human chorionic gonadotrophin hormone(HCG)
  • Human placental lactogen(HPL)
  • Human chorionic thyotrophin(HCT)
  • Human chorionic corticotrophin(HCC)
  • Pregnancy specific B-1 glycoprotein(PSBG)
  • Pregnancy associated plasma protein(PAPP)

Others:

  • Thyroid gland
  • Pituitary gland
  • Adrenal gland
  • Pancreas

Steroid Hormone:
Estrogen:

It is produced by the corpus luteum prior to the 12th week of pregnancy and the placenta along with the fetus after that point. Estriol, estradiol, and estrogen are the three traditional estrogens during pregnancy. Estriol makes up more than 90% of the estrogens secreted during pregnancy. During pregnancy, estrogen serves a variety of functions, including the following:

  • It activates the uterus and boosts blood flow to the uterine arteries.
  • preservation of breast growth and the structure of its ducts.
  • Extensive external genitalia
  • nasal mucous membrane hyperemia and increased salivary gland activity.
  • Estrogen may reduce the secretion of pepsin and HCl, which may be the cause of digestive disturbances like nausea.

Progesterone:

Progesterone encourages the growth of dense, vascular decidua that is prepared for the ovum's imbedding, and it typically keeps the decidua healthy throughout the whole pregnancy. Plain muscles are relaxed by progesterone. A progesterone deficiency may cause the uterus to start contracting rhythmically, which may lead to an abortion.

Constipation is prevalent during pregnancy, and the bowel's plain muscle is also relaxed. Varicose veins in the legs, the rectum, and the vulva may form if the simple muscle in the vein walls relaxes. The uterus' growing size puts strain on the pelvic vein, which worsens this impact by delaying the venous return from the leg.

Protein Hormone:

Human choronic gonadotrophin (HCG)

  • This is created by prophoblast cells that have been present since the fertilized ovum was embedded.
  • Early in pregnancy, the main role of HCG is to encourage the corpus luteum to produce progesterone and estrogen. This hormone is in charge of positive test results.
  • HCG levels can double in multiple gestation hydatidiform or choriocarcinoma cases compared to singleton pregnancies.
  • 100 IU/ml in blood and 200 IU/ml in urine between days 60 and 70 of pregnancy.
  • It gradually decreases by 10–20 IU/ml between 100–130 days. Following that, be consistent the entire pregnancy.

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