Pregnancy Flashcards
Hormonal changes:
Pregnancy is a state of high progesterone levels and brings about profound symptoms, particularly in the first trimester.
The corpus luteum and then the placenta secrete large amounts of progesterone which has multiple functions
- Stabilises the uterine lining for implantation and development.
- Causes uterine quiescence and a degree of immune suppression/alteration in order to allow the mother to accept the immunologically foreign tissue of the fetus.
- Progesterone changes muscle cell dynamics by depressing electrical potential at the cell membrane. Therefore requiring greater levels of stimulation to activate muscles. Effects can be seen across uterus, vascular, gastro-intestinal and respiratory systems.
More symptoms of high progesterone levels:
Mood disturbance and irritability
Tender breasts
Constipation and bloating (reduced gut motility)
Feeling hot
Fainting (due to decreased peripheral resistance
Blood volume and composition in the pregnant woman:
A rapid increase in plasma volume occurs (up to 40%) causing a relative reduction in RBC concentrations
At least 50% of this adaptation occurs by week 8.
There is an increase in leukocytes from fertilization to delivery
Cardiovascular changes:
The heart changes in size and position.
Atria become dilated
ECG’s suggestive of left axis deviation and flattening of T waves suggestive of mild ischaemia seen in 15% or normal women.
Heart rate increase up to 15 beats per minute (due to increase blood volume (35-45%) offset by increase venous capacity due to decreased peripheral resistance and that the feto-placental unit acts like an arterio-venous fistula)
Pitting oedema due to increase fluid, increase intra-abdominal pressure therefore decrease venous return.
Changes to heart sounds (louder)
Respiratory changes:
Increased:
- Tidal volume, rate and alveolar ventilation
- Oxygen consumption by about 20%
- Carbon dioxide content decreases
Gastro-intestinal:
Increased levels of progesterone on the smooth muscle in the gut can cause:
- Reflux
- Constipation
- Bloating
Mouth & pharynx:
- gingivitis
- increased salivation
Oesophagus:
- increased sphincter tone
- Hiatus hernia
Stomach:
- Decreased motility and emptying
- Decreased secretion of HCI
- N&V
Intestines:
- Duodenal villi hypertrophy
- Iron and calcium absorption increases
- Decreased motility increases absorption
Liver & gall bladder
- Alteration of enzymes
- Affected smooth muscle tone of gall bladder (progesterone)
Weight and metabolism changes in pregnancy:
Metabolic rate increases by up to 20%.
Negligible weight gain in the first trimester but average weight gain of 0.5kg a week in the second and third.
Increased requirements for protein, iron and minerals.
Carbohydrate metabolism
Fetuses almost exclusively use carbohydrates as a fuel.
Early pregnancy:
- Increased insulin sensitivity
- Increased uptake of nutrients
- Lower fasting glucose
Late pregnancy:
- Increased insulin resistance (gestational diabetes can occur 24-28 weeks)
- Increased cellular uptake of nutrients
- Increased plasma glucose and amino acids
Protein and fat metabolism:
- Increased use of amino acids result in a decreased serum amino acid level
Fat:
1st and 2nd trimester there is increased fat storage
3rd trimester increased lipolysis to support energy levels
Anatomical changes:
Uterus size increases by 5-6 times and weight increases about 20 times.
The uterus and cervix soften and become bluish in colour at 6-8 weeks
Breasts enlarge
Areolas darken
Chloasma - increased pigmentation on face
Muscular changes:
Increased relaxin:
- Causes pelvic ligaments and the pubic symphysis to relax
- Exaggerated lumbar lordosis
Lactation:
Oestrogens, progesterone and lactogen stimulate the hypothalamus to release prolactin-releasing hormone (PRH) which increased mammary gland size and eventually lactation.
Colostrum (first milk)
- solution rich in vitamin A, protein, minerals and IgA antibodies
- Released in the first 2-3 days after birth
- Is followed by true milk
Advantages of breast milk for infant:
Fats and iron are more readily absorbed
Amino acids are metabolised more efficiently than those of cow’s milk.
Beneficial chemicals:
- IgA + other immunoglobulins
- lysozyme
- Interferon
- Interleukins and prostaglandins
Common complaints during pregnancy:
Most common:
- Muscle contraction headache due to tight neck muscles.
- Hypertension (most common cause of death in pre-eclampsia) subarachnoid haemorrhage
Common complaints (chest pain)
Complicated by changes associated by normal pregnancy:
- dyspnoea, faitgue, orthopnoea, palpitations, syncope, peripheral oedema.
Increased likelihood of DVT
therefore PE’s
