Chapter 1 - Normal Pregnancy Flashcards
1
Q
Obstetric physical examination
Inspection, palpitation and auscultation
A
Inspection:
- size of distension
- asymmetry
- fetal movements
- cutaneous signs: linea nigra, striae gravidarum, striae albicans
Palpitation:
- symphysis fundal height (measured >20weeks)
- estimate no of fetuses (no of poles)
- fetal lie (longitudinal, oblique or transverse)
- presentation (cephalic, breech or other)
- amniotic fluid vol (tense + impalpable fetal parts, normal or compact abdomen with too easily palpated fetal parts)
Auscultation
- heart heard best at the anterior shoulder
- Doppler US from 12 weeks
- fetal stethoscope from 24 weeks
General exam
- BMI
- BP
- heart and lung auscultation (flow murmurs normal)
- thyroid gland
- breast
- skeletal abnormalities
2
Q
When does the uterus become palpable?
A
12 weeks gestation
3
Q
When does the uterus reach the umbilicus?
A
20 weeks
4
Q
When does the uterus reach the xiphi sternum?
A
36 weeks
5
Q
When is symphysis fundal height most efficacious?
A
In detecting small for gestation (40-60% small for dates fetuses can be detected).
It is less efficacious in detecting large for dates fetuses
6
Q
How do you measure symphysis fundal height?
A
Tape measured from the highest point of the fund us to the upper margin of the symphysis pubis
7
Q
How do you estimate appropriate fetal growth on examination?
A
Symphysis fundal height
- appropriate growth is number of weeks:
+/- 2cm from 20w to 36w
+/- 3cm between 36w-40w
+/- 4cm at 40w
8
Q
When does engagement usually occur?
A
In nulliparous, engagement usually occurs at 37weeks
Afrocarribeans may occur later, even as late as labour
In multiparous it may not occur until labour
Rare causes of non engagement must always be considered and investigated with US.
- placenta previa
- fetal abnormality
9
Q
Describe the assessment of engagement
A
5/5 palpable = head completely above the pelvic brim
2/5 palpable = engaged
- sinciput (forehead) just felt, occiput felt
More easily the head is felt the less engaged it is
Breech can be mistaken for a deeply engaged head
10
Q
Describe fetal positions
A
Insert pic
OA normal
11
Q
Differences between female and male pelvis
A
- female pelvis is broader with more slender bones
- females are oval shaped transversely with the widest part forward rather than heart shaped in men
- females are wider with a larger outlet
12
Q
Pelvic anatomy
Label pic
A
Insert pic
13
Q
Describe the 4 pelvic shapes
A
1) Gynaecoid - classical female pelvis with the inlet transversely oval
2) Anthropoid - long and narrow, oval shaped pelvis due to the assimilation of the sacral body to the 5th lumbar vertebra
3) Android - the inlet is heart-shaped and the cavity is funnel-shaped with a contracted outlet
4) Platypolloid - a wide pelvis flattened at the brim with the sacral promontory pushed forward
14
Q
Name the 5 main bones of the fetal cranium
A
2 parietal
2 frontal
1 occipital
15
Q
Give the name of the suture separating the frontal bones from the parietal?
A
Coronal suture
16
Q
Give the name of the suture separating the two parietal bones
A
Sagittal suture
17
Q
Give the name of the suture separating the occipital bone from the parietal bones
A
Lamboid suture
18
Q
Give the name of the suture separating the frontal bones
A
Frontal suture
19
Q
What is a fontanella?
A
The irregular membranous area at the meeting of two sutures
20
Q
Name the membranous area at the junction of the coronal and Sagittal suture
A
Frontal suture
21
Q
When does the bregma ossify?
A
18months post natal
22
Q
Name the fontanella at the junction of the sagittal and lamboid suture
A
Posterior fontanella or lambda
23
Q
Cause of caput seccedaneum
A
During labour the dilating cervix May press on the fetal scalp preventing venous blood and lymphatic fluid from flowing normally. This may result in a boggy tissue swelling
It usually disappears within 24hours of birth
24
Q
Describe the degrees of moulding
A
Moulding can be assessed vaginally
1+ suture lines meet
2 + bones overlap but can be reduced with gentle pressure
3+ bones overlap and are irreducible with gentle pressure
25
Term given to the lowermost part of the fetus presenting to the pelvis.
Presentation
- in 95% it is the vertex = normal
- anything other than vertex is malpresentation
26
Term given to the most definable peripheral land mark of the presenting part
Denominator
Occiput for vertex
Mentum for face
Sacrum for breech
27
Define station
The relationship of the most prominent leading part of the presenting part to the ischial spines expressed as +/- 1,2,3cm
28
When does the zygote enter the uterus?
Day 3-5
29
When does implantation of the blastocyst occur?
Day 7 and is finished by day 11
30
What does the inner call mass of the blastocyst form?
The embryo, yolk sac and amniotic cavity
31
What does the trophoblast form?
The future placenta, chorion and extraembryonic mesoderm
32
When the blastocyst embeds in the decidua, trophoblastic cells differentiate and the embryo becomes surrounded by two layers:
The inner mononuclear cytotrophoblast
And
The outer mulitnucleated syncytiotrophoblasts
33
In early placenta development__________ Invade endometrial blood vessels forming interotrophoblastic maternal blood filled sinuses_______.
In early placenta development trophoblasts Invade endometrial blood vessels forming interotrophoblastic maternal blood filled sinuses, lacunar spaces
34
In early placenta development,_______ cells advance as early or primitive vili, consisting of cytotrophoblasts surrounded by the syncytium
In early placenta development, trophoblastic cells advance as early or primitive vili, consisting of cytotrophoblasts surrounded by the syncytium
35
When are fetal blood vessels completed by?
Day 21...
Early vili mature into secondary and tertiary vili and the mesodermal core develops to form blood vessels by day 21
36
How many stem vili are there in the placenta?
60, each cotyledon contains 3-4 major stem vili
37
Describe the placenta at term
20cm & 500g
Fetal surface is smooth covered by amnion
Maternal surface is spongy and rough divided by cotyledons supplied by its own spiral artery
38
Name the vessels in the umbilical cord
2 umbilical arteries (carrying deoxygenated blood from the fetus to placenta)
1 umbilical vein (carrying oxygenated blood from the placenta to the fetus)
Blood flow 350ml/min
The cord is 30-90cm
39
Name the systems in the placental circulation
1) Uteroplacental (maternal blood circulating through the intervillous space at 500ml/min)
2) fetoplacental
40
How do spiral arteries adapt to the increasing demand to the placental bed
Spiral arteries become low pressure, high flow vessels
| - they become tortuous, dilated and less elastic by trophoblasic invasion
41
Describe trophoblastic invasion of spiral arteries
trophoblasts invade to enhance blood supply to the placental bed
1) 1st trimester the decidual segments of the spiral arterioles are modified
2) second trimester invasion results in myometrial segment modification
42
Consequence of failure of trophoblastic invasion
pre-eclampsia and intrauterine growth restriction
43
When does venous drainage occur and what is its path?
Only occurs during uterine relaxation
- Blood from the spiral arteries enter the intervillous space and become dispersed through to the chorionic plate and the basal plate, aided by vili movements and uterine contractions
- from the basal plate uterine veins drain the deoxygenated blood
44
How does the venous system maximize blood exchange at the placenta?
Spiral arteries are perpendicular and the the veins parallel to the uterine wall, making large volumes of blood available for exchange at the intervillous space even though the flow is reduced because the veins are blocked and drainage is unable to occur until uterus relaxes
45
Name 5 key features of the placenta
1) To anchor the fetus
2) For gas exchange
3) Endocrine organ - to encourage normal changes in pregnancy
4) Transfer of substances to and from the fetus
5) Barrier against infection
46
Name 5 pathogens that can cross the placenta
1) Hepatitis B
2) Hepatitis C
3) HIV
4) Syphilis
5) CMV
6) Parvovirus
7) Rubella
47
Which antithrombotic is the drug of choice in pregnancy women?
Dalteparin (LMWH) does not pass the placenta
-- Warfarin does as is contraindicated as it is teratogenic
48
What determines the speed and concentration of exchange at the placenta?
1) Concentration gradient
2) Molecule size
3) Lipid solubility (higher = quicker)
4) Ionization
5) Placental surface area
6) Maternofetal blood flow
49
Describe the mechanisms of transfer across the placenta
Simple diffusion e.g. O2, CO2, glucose, water, urea and creatinine
Facilitated diffusion e.g glucose, amino acids and fatty acids
Endocytosis e.g. iron
50
Name 5 main hormones that increase during pregnancy
1) Progesterone
2) Oestrogen (Oestradiol)
3) Human placental lactogen
4) Prolactin
5) ACTH
6) Cortisone
-- Gonadotrophin decreases
51
Describe the role of progesterone during pregnancy
- Synthesized by the corpus luteum until day 35, then by the placenta
- promotes smooth muscle relaxation (gut, ureters, uterus) and raises body temp
- Prevents preterm labor
52
Describe the role of oestrogen during pregnancy
- increases breast and nipple growth + pigmentation
- promotes uterine blood flow, myometrial growth, cervical softening
- increased sensitivity and expression of myometrial oxytocin receptors
- increases water retention and protein synthesis
53
Describe the role of human placental lactogen
(similar to GH)
- modifies maternal metabolism to increase energy supply to the fetus
- increases insulin secretion but decreases insulins peripheral effect (frees maternal fatty acids, sparing glucose to allow it to be diverted to the fetus)
54
Describe the changes that occurs in the pituitary gland during pregnancy
- It enlargens due to anterior lobe changes
- Prolactin increases dur to oestrogen stimulation of the lactotrophes
- Gonadotrophin lowers but ACTH increases
- During labour and suckling the posterior pituitary releases oxytocin
55
Describe the effects of pregnancy on the thyroid gland
- The thyroid increases due to extra demands during pregnancy
- Thus, the thyroid increases its iodide uptake resulting in follicular enlargement
- Thyroid binding globulin is doubled by the end of the first trimester due to high oestrogen levels
- T3 and T4 rise in early pregnancy and then fall to within normal
- TSH may decrease slightly in early pregnancy but tends to remain within normal range
- Very small amounts of T3/4 cross the placenta
56
What can have an effect on the early fetal thyroid function?
- Iodine
- Antithyroid drugs
- Long acting thyroid stimulator
- Antibodies associated with Graves
ALL can cross the placenta and effect the fetal thyroid function which starts at 12 weeks
57
By how much does plasma volume increase during pregnancy?
By 10-15% at 6-12 weeks gestation
By 30-50% at term (+1500mls)
Acute weight gain is due to oedema
58
What is the consequence of increased plasma volume to haemodynamics?
Heamodilution aka physiological anaemia as Hb con, haematocrit and RCC all declining
RC volume increases
Mean corpuscular Hb cons stays the same
59
Describe the changes to WCC during pregancy
Increases due to the increase in neutrophil polymophonuclear leucocytes which peak at 32weeks
- A further massive neutrophilia occurs during labour
- Eosinophils decline during labour
- Lymphocyte counts and T/B cell numbers stay constant but lymphocyte FUNCTION and cell-mediated immunity is depressed = lowered resistance to viral infections.
60
Describe the changes to platelets during pregnancy
Slightly decline in pregnancy
Plt function remains the same
61
Describe the changes that occurs to clotting during pregnancy
Pregnancy is a hypercoagulable state with most clotting factors especially fibrinogen increasing
- ESR can increase 4 fold
62
Describe the cardiovascular changes that occur during pregnancy
1) CO increases by increasing SV by 10% and pulse by 15bom
2) During labour CO increases further by 2l/min
3) Uterus enlargement causes heart and diaphragm displacement upwards
4) The heart enlargens and increases in volume by 80ml due to increased diastolic filling and muscle hypertrophy
63
Describe the changes in BP during pregnancy
1) Peripheral resistance is decreased by 50% due to increased prostaglandin vasodilation
2) BP can decrease (mostly diastolic) by 10-20mmHg mid preg but returns to normal by term
3) Profound hypotension can occur late pregnancy when lying flat/supine due to compression of the inferior vena cava leading to reduced venous return and CO --> supine hypotension syndrome
4) Aortic compresison can cause big differences in brachial and femoral pressures giving a pressure difference of 10-15% from the supine to lateral position
5) Hypotension and vasodilation activates RASS to help regulate
64
Describe the changes to the respiratory system during pregnancy
- Due to the rise in the diaphragm breathing becomes more diaphragmatic than costal
- Tidal volumes increase by 40% due to progesterone
- RR stays the same but they breath more deeply
- SOB is common as maternal pCO2 is set lower to allow the fetus to offload CO2
65
Why does vaginal discharge increase during pregnancy?
Due to cervical ectopy (proliferation of columnar
| epithelium into vaginal portion of the cervix) and cell desquamation
66
Describe the changes in the breast that lead to the formation of colostrum and milk secretion
- From 3–4mths, colostrum (thick, glossy, protein-rich fl uid) is
expressed from the breast.
- Prolactin stimulates the cells of the alveoli to secrete milk:
• effect is blocked during pregnancy by the peripheral action of
oestrogen and progesterone
• shortly after delivery the sudden decrease in these hormones enables
prolactin to act uninhibited on the breast, and lactation begins.
• Suckling further stimulates prolactin and oxytocin release: oxytocin
stimulates contraction of the myoepithelial cells to cause ejection of milk.
67
True or false: Creatinine within normal range may indicate renal impairment
True
Increased CO during pregnancy, increased GRF and renal perfusion --> reduced urea and creatinine
+ increased urinary frequency
68
Cause of increased risk in constipation
- Decrease in gut motility
| - Increased sodium and water absorption
69
Describe 5 skin changes that may occur during pregnancy
1) Linear alba
2) Nipple darkening
3) Chloasma (brown
patches of pigmentation seen especially on the face)
4) Palmar erythema
5) Spider naevi
6) Striae - distrupted collagen, increased cortisol and rapid stretch
70
How can you advise pregnant women on exercise?
* Encourage moderate exercise ( for cardiovascular and muscular fitness)
* Beginning or continuing moderate exercise during pregnancy safe
- Best exercises are low-impact aerobics, swimming, brisk
walking, and jogging.
- Scuba diving may result in fetal birth defects and fetal decompression
disease
71
Is there a delay in return to fertility after stopping contraception?
- None after stopping the pill or coil removal
- The injection can take months for fertility to resume
- Wait 3 months after stopping the pill to conceive
72
"Should I take supplements whilst trying to get pregnant?"
Folic acid is the only vitamin supplement that is recommended for use
before pregnancy and up to 12wks gestation for women who are otherwise eating a healthy balanced diet
73
How much folic acid should I take and why do I need it?
400micrograms/day folic acid has been shown to reduce the
| occurrence of neural tube defects
74
Which women should take increased doses of folic acid?
Women at higher risk (e.g. previous affected child, women with
epilepsy, diabetes, and obesity)
Take a dose of 5mg/day
75
I have diabetes and epilepsy, how much folic acid should i take?
5mg/day
76
"Should I take iron?"
Routine supplementation is not necessary and should be only prescribed when medically indicated
77
"Should i take extra calcium?"
- Only if intake is low
| - Try to increase diet firs
78
what does iodine deficiency cause?
Cretinism
and neonatal hypothyroidism.
Supplementation with iodinized salt or oil
should be considered.
79
what does zinc deficiency cause?
Increased risk of preterm
labour and growth restriction
increased intake from dietary sources,
such as milk and dairy products
80
Why should products with Vitamin A be avoided?
Vit A (e.g. liver pate) may be teratogenic
81
Describe the affects of alcohol on a fetus
Fetal alcohol syndrome
Distinctive facial features, including small eyes, thin upper lip, a short, upturned nose, and a smooth skin surface between the nose and upper lip
Deformities of joints, limbs and fingers
Slow physical growth before and after birth
Vision difficulties or hearing problems
Small head circumference and brain size
Heart defects and problems with kidneys and bones
```
Poor coordination or balance
Intellectual disability, learning disorders and delayed development
Poor memory
Rapidly changing moods
Poor social skills
```
Aim <1 unit per day
82
Describe the risks of smoking in pregnancy
Smoking during pregnancy has an adverse effect on the developing fetus
(e.g. preterm labour, low birth weight)
Stopping smoking at any stage has a beneficial effect
83
Describe the risks of drugs in pregnancy
Drugs cause significant problems including miscarriage, preterm birth, poor fetal development, and intrauterine death.
84
How much weight can a pregnant women expect to gain?
10-15kg
85
How many extra calories should a pregnant woman eat?
350kcals/day
86
Which foods should pregnant women avoid?
Undercooked meats and eggs, pates, soft
cheeses, shellfish and raw fish, and underpasteurized milk should be
avoided as they are potential sources of Listeria (rare) and Salmonella
87
What is involved in a pre-pregnancy check?
Pre-pregnancy general health check
May include:
• A general examination including BP, heart, and lungs.
• Family history of inherited disorders or congenital abnormalities.
• Urine dipstick.
• Blood tests such as thalassaemia and sickle cell disease may be
offered if at risk.
• Rubella (and hepatitis) status should be ascertained and vaccination
given if not immune (women should be advised to avoid pregnancy
for 3mths after immunization).
• HIV screening if at risk.
• Dental examination.
88
Signs of pregnancy
```
N/V
Increased micturition
Tiredness
Breast tenderness/heaviness
Fetal movements felt at 20w (nulip) 18w (mulip)
Cravings or pica
```
O/E
bluish tinge to vagina (blood congestion)
after 12 weeks uterus is palpable and fetal heart may be heard with doppler
89
Which cells secrete hCG
Trophoblastic tissue
Tests can confirm pregnancy after 1 week of missed period
90
How do you date a pregnancy?
Naegele's formula =
LMP + 7 - 3 months
LMP may be inaccurate as: many people forget and ovulation isn't always on day 14
40% will deliver within 5 days of EDD
If IVF, you can date using date of embryo transfer
Dating scan between 8-13weeks is the most accurate way to measure gestational age and EDD
-- Before 8 weeks its too small to be accurate
Crown-rump length can be used between 8-13 weeks (from one fetal pole to the other along the longitudinal axis)
91
How can you assess a fetus you suspect is small or large for dates?
US
1) Biparietal diameter and head circumference
2) Abdominal circumference (most important measure ) - measure when the image of the stomach and portal vein is visualized
3) Femur length - when two blunted ends are shown
92
5 Causes of small for dates
1) Wrong dates
2) Oligohydramnios
3) IUGR
4) Presenting part deep in the pelvis
5) Abnormal lie
93
5 Causes of large for dates
1) Wrong dates
2) Macrosomia
3) Polyhydraminos
4) Multiple pregnancy
5) Fibroids
94
What needs to occur on a pregnant womans first encounter with health care?
Ensure the woman is given information on:
• Folic acid supplementation.
• Lifestyle advice.
• Antenatal screening.
• Booking appointment (ideally before 12weeks, late = 4x increased risk of perinatal mortality/morbidity).
95
What should happen during a booking visit?
```
Booking appointment
(ideally before 12weeks).
```
* Identify high risk women who need additional care.
* Calculate BMI.
* Measure BP.
* Dipstick test urine (protein, glucose, blood, etc.).
* Ultrasound for gestational age and gross structural anomalies.
* Take blood tests for: haemoglobinopathies, rubella, Venereal Disease Research Laboratory test (VDRL), HIV, hepatitis B virus, red cell allo-antibodies and Hb for anaemia
```
Give information on:
• AN classes
• pregnancy care pathway
• nutrition, diet, and vitamin supplementation
• maternity benefits
• how baby develops.
```
96
What should be assessed on every AN visit?
Urine should be dipstick tested and BP
Assess for any new issues
97
In a nuliparous woman, when can she expect her antenatal appointments?
<12w Booking visit
16w - discuss booking bloods + book anomaly scan
18-20w - anomaly scan
25w - BP, urine and SFH
28w - FBC and antibody screen, ?Anti-D injection, BP/urine dip and SFH
31w - BP, urine and SFH
34w - birthing plans, FBC and antibody screen?Anti-D injection
36w - discuss breast feeding, vit K, post natal care and baby blues
38w - BP, urine and SFH
40w - discuss prolonged pregnancy
41w - membrane sweep
42w - induction
98
In a multiparous woman, when can she expect her antenatal appointments?
<12w booking visit
16w - discuss booking bloods + book anomaly scan
18-20w anomaly scan
28w - FBC and antibody screen ?anti-D
34w - birthing plans, FBC and antibody screen, ?anti-D
36w - breastfeeding/ vit K/ baby blues discussion
38w - BP, proteinuria, SFH
40w - discuss prolonged pregnancy
41w - membrane sweep
42w - induce
99
What routine bloods are needed once pregnancy is confirmed?
FBC - anaemia
Blood group + ab screen - rhesus grouping
Rubella screen - 1% -ve --> post partum vaccine
Syphilis screen
Hepatitis screen - 90% of neonates become chronic carriers with risk of post-infective hepatic cirrhosis and hepatocellular carcinoma
- - Active immunisation for those witch sAg +ve mothers.
- - Active + passive immunisation for those with core E ag +ve
HIV screen is an op out screen
-- vertical transmission can be reduced 2/3 by antiretrovirals for the mother, C sec and formular feeding
100
Which ethnicities are at higher risk of thalassaemia?
- Cyprus
- Eastern med
- Middle eastern
- Indian subcontinent
- South east Asia
101
A white woman has persistent anaemia, should she have Hb electrophoresis?
YES
Persistent anaemia, of undiagnosed cause, may be an indication for Hb
electrophoresis in any woman, regardless of racial origin.
102
Give 5 risk factors for gestational diabetes
1) Previous GDM.
2) Family history of diabetes (first-degree relative with diabetes).
3) Previous macrosomic baby.
4) Previous unexplained stillbirth.
5) besity (BMI>30).
6) Glycosuria on more than one occasion.
7) Polyhydramnios.
8) Large for gestational age fetus in current pregnancy
103
A woman at 40 weeks does not wish to be induced, what are the next steps?
- Discuss the risks of prolonged pregnancy
| - Make a plan for increased fetal surveillance with CTG and US assessment of fetal growth and liquor volume
