Maternal Adaptation in Pregnancy

Question 1

Process of a ‘normal’ pregnancy.

Answer 1

Question 2

How is pregnancy maintained?

Answer 2

-Corpus Luteum - produces progesterone - acts as temporary endocrine gland of ovaries -> in first few weeks of pregnancy (up to week 10)
-hCG
-Placenta formation – (50-60 days after last menstrual period) -> produces oestrogen & progesterone
–> progesterone (from trophoblast cells) = supports lining of uterus (womb) - providing env for foetus & placenta to grow
-Great changes occur in major systems in pregnancy
-Cardiovascular & haematological systems = particularly affected

Question 3

Changes to uterus during pregnancy?

Answer 3

-Thickening of uterine wall
-Changes from pelvic to abdominal organ
–> inc. weight, size & shape
–> inc. in CTs, size & no. of blood vs supplying uterus (angiogenesis)
-Lower uterine segment forms (from 32-34 weeks gestation)
-Braxton hicks contractions present from 1st trimester
-Muscle fibres inc. length & width
-Uterine ligaments soften & thicken - influence of oestrogen

Question 4

Angiogenesis - uterus vasculature.

Answer 4

-Adaptation of uterine vasculature to rising needs of foetus occurs through both vasodilation & development of new vs
-Angiogenesis = process of neovascularization from pre-existing blood vs in response to hypoxia or substrate demands of tissues
-The hormone relaxin - from corpus luteum & placenta = mediates nitric oxide (NO) release - allows systemic vasodilation & decreasing BP during pregnancy

Question 5

Role of the hormone relaxin (produced by corpus luteum & placenta)?

Answer 5

-CT remodelling & subsequent softening of birth canal, mammary gland growth & differentiation & inhibition of uterine contractile activity
-Mediates nitric oxide (NO) release - allows systemic vasodilation & decreasing BP during pregnancy

Question 6

Changes to cervix during pregnancy?

Answer 6

-Changes from firm structure to elastic tissue - remains ~2.5 cms long
-Purple colour - as oestrogen increases vascularity
-Hormonal control of cervix - changes in oestrogen, progesterone, relaxin & prostaglandins.
-Operculum forms

Question 7

Changes to cardiovascular system in pregnancy?

Answer 7

-Inc. CO by 20-30% in first 10 weeks & by term increased by 40%
-Uterine blood flow takes up 10% of CO at term
-Inc. maternal heart rate by 10-15 bpm
-Plasma vol inc. by 50%
-Dec. BP (systolic & diastolic)
-Risk of compression of Inf Vena Cava (IVC) from 20 weeks gestation
-Inc. blood vol by 45% due to haemodilution ~28 weeks gestation

–> significant as are decreased reserves & potential for large haemorrhage, increase demand on heart

Question 8

Changes to respiratory system in pregnancy?

Answer 8

-Inc. breathing rate & effort (15-17bpm)
-O2 consumption inc. by 20%
-Dec vital capacity - as gravid uterus enlarges & diaphragm is splinted
-Inc. O2 requirements
-Arterial PCO2 reduced
-Laryngeal oedema increased

–> Significant as acidosis more likely, hypoxia will happen quicker & pregnant women are difficult to intubate

Question 9

Changes to endocrine system in pregnancy?

Answer 9

*Pituitary & placental hormones
–> Progesterone & oestrogen
–> Maintain pregnancy (relaxing smooth muscle & dec. uterine activity)
-Deposits fat subcutaneous tissues (abdomen and back)
-Enlargement of uterus, breasts & increases vascularity causing vasodilation
-Relaxation of pelvic ligaments & joints
-Dec secretion of HCl & pepsin = nausea & vomiting
*Oxytocin inc. as foetus matures
–> Stimulates uterine contractions (high progesterone can prevent this until term)

Question 10

What causes nausea & vomiting seen in pregnancy?

Answer 10

Dec secretion of HCl & pepsin

Question 11

Changes to gastrointestinal system in pregnancy?

Answer 11

-Delayed gastric emptying = increases acidity of stomach contents
-Relaxation of cardiac sphincter = increases regurgitation risk
-Nausea & vomiting from 4-8 weeks gestation until 14-16 weeks gestation
-Hyperemesis Gravidarum (rapid dehydration)

Question 12

Changes in urinary system in pregnancy?

Answer 12

-Frequency of Micturition
–> 1st Trimester due to pressure of uterus on bladder

-Late pregnancy = engagement of foetal head
–> Increased risk of UTIs
–> Urinary bladder displacement increasing vulnerability for injury/infection
–> Inc. risk of stress incontinence

Question 13

Changes in musculoskeletal system in pregnancy?

Answer 13

-Hypermobility of joints due to progesterone release
-Symphysis Pubis Dysfunction (SPD)
-Change in centre of gravity
-Backache
-Changed gait

Question 14

Changes in abdomen in pregnancy?

Answer 14

-Gravid Uterus = a pregnant uterus trapped between sacral promontory & pubic symphysis

-3 main landmarks:
-12 weeks uterus palpable above pubic symphysis
->22 weeks - pubic symphysis = above umbilicus
->36 weeks - pubic symphysis = reaches xiphoid process

Question 15

Changes in breast in pregnancy?

Answer 15

-Enlarge due to hormonal changes &increased blood flow
-Areola &nipple darken in colour
-Colostrum may be present during 3rd trimester
-Heightened sensitivity

Question 16

What features are seen throughout pregnancy - emotional & physical?

Answer 16

-Physical changes – skin changes, backache, ligament pain, headaches, stuffy nose

-Emotional changes – mood swings, changed body image, depression, fearfulness, increased sensitivity, indecisiveness, altered libido

Question 17

Changes to skin in pregnancy?

Answer 17

-Linear Nigra – pigmented line
-Chloasma Gravidarum – butterfly mask
-Striae Gravidarum – stretch marks

Question 18

Name some other things that are experienced in pregnancy.

Answer 18

-Mood swings
-Fatigue -> linked to thyroid function (1st trimester replicates hypothyroidism - to accommodate high progesterone)
-Pica -> extreme cravings, can be obscure, link to minerals body is deficient in
-Oedema in hands & feet
-Leg cramps
-Nail & hair changes
-Increased vaginal secretions/discharge
-Weight gain
-Heartburn
-Ptyalism -> overproduction of saliva/reduced saliva swallowing
-Constipation
-Varicosities