Clinical: Normal Pregnancy and Ante-Natal Care Flashcards
3 sources of hormone secretion during pregnancy
- Placenta
- Maternal pituitary
- Maternal adrenal
- Maternal thyroid
- Fetal Adrenal
4 hormones secreted by the placenta
- hCG
- hPL
- Estrogens
- Progesterone
2 main components of the placenta
- Cytotrophoblast
- Syncytiotrophoblast
Function of Hc GnRH in cytotrophoblast
Increase placental steroidogenesis and release of prostaglandins and hCG (similar in structure and action to GnRH)
When and where is hCG produced
Produced by syncytiotrophoblase immediately after implantation (~8 day after ovulation)
Structure of hCG
Similar to LH: consists of (common) alphha and (specific) beta subunit
Where is hCG secreted to?
Maternal and fetal circulation
Describe the hCG levels throughout gestation
Rapid rise in first trimester of pregnancy; maximum at 8-10 weeks of gestation
Important of hCG test (2 reasons)
- Pregnancy test
- Normal rate of rise = indication for fetal well-being
2 conditions that higher than normal [hCG] may indicate
indication for trophoblastic disease (choriocarcinoma or hydatidiform mole) or ectopic pregnancy
Maternal role of hCG
Maintenance of corpus luteum to ensure continued progesterone secretion before placenta takes over
Fetal function of hCG
Increase testosterone production by Leydig cells in fetal testes (as does LH in the adult). Also has TSH activity on fetal thyroid
Alternative name for hPL (human placental lactogen)
Chorionic somatotomammotropin
Where is hPL produced?
syncytiotrophoblast
Describe hPL levels throughout gestation
Rises throughout pregnancy proportional to placental mass (very high synthesis rates: 1-3 g/day)
Where is hPL secreted?
Mainly into maternal circulation
3 maternal effects of hPL
- Increase glucose levels
- Increase lipolysis (to increase free fatty acids) = fuel for fetus
- Decrease insulin action (diabetogenic effect)
4 effects of estrogens
- Increase uterine blood flow and growth
- Increase prostaglandin synthesis
- Increase prolactin secretion
- other effects important for the maternal adaptation to pregnancy
Describe the uterus in pregnancy
50g pre-pregnancy –> 950 g term
Initially hypertrophy, then distension
Describe the changes in the cervix during pregnancy
Softer (ripening)
Describe the changes in the vagina during pregnancy
Mucosa thickens, stretches more easily
5 effects of progesterone that enable implantation of blastocyst
- Induces decidualization
- Decreased uterine contractions
- Decreased prostaglandin formation
- Decreased T-lymphocyte response
- Decrease graft rejection and immune reaction
2 effects of progesterone that protect from hypertension
- Decreased angiotensin II responsiveness
- Smooth muscle relaxation
Causes of varicosities in pregnancy
- Distended veins
- Higher pressure of uterine venous return
- Uterine mechanical pressure
3 locations of varicosities during pregnancy
- Legs
- Hemorrhoids
- Vulvar varicosities
3 effects of pregnancy on the respiratory system
- Deeper breathing –> increased tidal volume
- Increased oxygen conumption (20%)
- Increased ventilation rate (40%)
(Subjective “air-hunger” or overbreathing)
2 reasons why deeper breathing occurs in pregnancy
- Reduced diaphragmatic movement
- Flared ribs
4 effects of pregnancy on the gastro-intestinal system
- Hypertrophic gums
- Nausea and hyper-emesis in early pregnancy
- Acid reflux
- Constipation
2 cause of nausea and hyper-emesis in early pregnancy
- hCG
- E2 mediated
Reason for acid reflux in pregnancy
Relaxed cardiac sphincter
4 effects of pregnancy on the renal system
- Ureteric dilatation
- Increased water excretion
- Increased renal blood flow
- Increased glomerular filtration rate (60%)
2 potential consequences of pregnancy-induced ureteric dilatation
Stasis and urinary infection
2 potential consquences of increase GFR in pregnancy
Occ. proteinuria and glycosuria
4 effects of E2
- Increases uterine size and blood flow
- SOftens connective tissue
- Breast development (PRL)
- Water retention
Describe the regulation of placental ACTH
No negative feedback; inhibition by glucocorticoids
4 effects of increased corticosteroids in pregnancy
- Abdominal striae
- Glycosuria
- Hypertension
- Heavier features
4 effects of pregnancy on the pituitary
- ACTH, TRH, PRL all increase
- Melanocytic activity?
- PRL rises progressively up to wk30
- FSH, LH secretion minimal (PRL effect and E2,P negative feedback)
5 effects of pregnancy on the cardiovascular system
- Increase in blood volume (4L to 5.5L)
- Decrease in iron stores (BM, liver, spleen)
- Increase in CO (SV 20% and HR 15%)
- Decreased peripheral resistance
- Redistribution of blood flow (kidneys, uterus)
2 effects of pregnancy on the hematological system
- Development of hypercoagulable state (estrogen mediated)
- Increased leucocyte count
RIsk of hypercoagulable state in pregnancy
Increased risk of DVT and PE
3 risks of increased leucocyte count in pregnancy
- Increased risk of infection
- Increased severity of infection
- Decreased immunity
Mean weight gain in pregnancy
12 - 15 kg (9kg in final 20 weeks of pregnancy)
3 sources of weight gain from pregnancy itself
- Fetus (3000 to 3500 g)
- Placenta (600 g)
- Liqour (800 g)
5 sources of weight gainfrom mother in pregnancy
- Uterus (1000 g)
- Breasts (500 g)
- Blood (1500 g)
- Fat (3500 g)
- Fluid (2600 g)
Define low-risk pregnancy
Normal women undergoing a normal physiological event
3 criteria for high risk pregnancy
- Pre-existingdisease
- Previous pregnancy complications
- Current pregnancy complications
How often should physician visits be done when pregnant?
Every 3-4 weeks with increasing frequency towards date of delivery
When are initial tests and screening performed?
10 - 12 weeks
When is a detailed anomaly scan performed?
20 weeks
When is screening for gestational diabetes performed?
26 weeks
When should induction of labor be considered?
41 weeks
7 elements of standard antenatal check
- Obstetric assessment
- Smoking history
- BP check
- Measurement in fundal height in cm
- Fetal auscultation from 12 weeks
- Fetal presentation from 30 weeks
- Inspection of legs for edema
4 things to look for in fetal ultrasound
- First trimester screening
- Nuchal translucency/nasal bone
- Anencephaly
- Other major defects
2 fetal anomalies with no chance of being detcted by USG
Cerebral palsy
Autism
4 fetal anomalies with a very high chance of being detected by USG (>90%)
- Spina bifida
- Anencephaly
- Exomphalos/gastroschisis
- Major limb abnormalities
What does the symphyseal fundal height measurement in cm correspond to?
Weeks of gestation
9 initial recommended tests for a pregnant woman
- CBC
- MCHC/MCV (Thal screen. Ferritin and Hb electrophoresis if low)
- Blood group/antibody screen
- HIV
- Hep B (and C)
- Syphilis (ideally prior 16 weeks)
- Rubella antibodies
- Urine microscopy
- Pap (if due)
3 recommended tests at 26 weeks
- Gestational diabetes screening
- Antibody screen on all women
- Rhogam (Anti-Rh D antibodies) if Rh Neg
Recommended test at 36 weeks
Group B Streptococcus screen
When should screening be done for GDM
Between 24-28 weeks
Wen should RVH screening be done?
26 weeks (all women)
WHen should swabs be taken for prevention of early onset GBS
between 35 - 37 weeks
4 reasons intrapartum antibiotics may be recommended to prevent early onset GBS
- <37 weeks
- Ruptures membranes >18 before delivery
- Maternal temperture _>_38 C
- Previous GBS colonisation, bacteruria or infant with GBS
When should prophylactic Anti-D be administered?
28 and 34 weeks gestation (no level I evidence however)
