Pregnancy and Screening Flashcards
1
Q
What nervous system results in uterine ‘cramping’ (menstruation) and uterine contractions (labour)?
A
ANS (via hormes)
2
Q
What nervous system results in pelvic floor muscle contraction (eg. during sneezing)?
A
Somatic motor
3
Q
What nervous system results in feeling pain from the adnexae and uterus?
A
Visceral afferents
4
Q
What nervous system results in feeling pain from the vagina?
A
Visceral afferents (pelvic parts) Somatic sensory (perineum)
5
Q
What nervous system results in feeling pain from the perineum?
A
Somatic sensory
6
Q
What do the visceral afferents supplying the superior aspect of the pelvic organs (touching the peritoneum) run alongside?
A
Sympathetic fibres
7
Q
Where do the visceral afferents supplying the superior aspect of the pelvic organs (touching the peritoneum) enter the spinal cord?
A
T11-L2
8
Q
Where is pain from the superior aspect of the pelvic organs (touching the peritoneum) perceived?
A
Suprapubic
9
Q
What do the visceral afferents supplying the inferior aspect of the pelvic organs (not touching the peritoneum) run alongside?
A
Parasympathetic fibres
10
Q
Where do the visceral afferents supplying the inferior aspect of the pelvic organs (not touching the peritoneum) enter the spinal cord?
A
S2, S3 and S4
11
Q
Where is pain from the inferior aspect of the pelvic organs (not touching the peritoneum) perceived?
A
In the S2, S3 and S4 dermatome - ie. Perineum
12
Q
What nerves supply structures above the levator ani (crossing from pelvis to perineum)?
A
Visceral afferents
PNS
S2, S3 and S4
13
Q
What nerves supply structures below the levator ani (crossing from pelvis to perineum)?
A
Somatic sensory
Pudendal nerve
S2, S3 and S4
14
Q
What organs, in the female, have visceral afferents that enter the spinal cord between T11-L2?
A
Uterine tubes
Uterus
Ovaries
15
Q
What organs, in the female, have visceral afferents that enter the spinal cord between S2-S4?
A
Cervix
Superior vagina
16
Q
What nerve supplies the organs in the female in the perineum:
- Inferior vagina
- Perineal muscles
- Glands
- Skin
A
Pudendal nerve (S2-S4)
17
Q
What does spinal anaesthesia result in in terms of the ANS?
A
Blockade of sympathetic tone to all lower limb arterioles resulting in vasodilation: - Skin looks flushed - Warm lower limbs - Reduced sweating Hypotenstion
18
Q
What does the pudendal nerve have a role in the motor control of?
A
External anal sphincter
External urethral sphincters
19
Q
What will a pudendal nerve block anaesthetise?
A
Majority of the perineum
20
Q
How does the pudendal nerve exit the pelvis?
A
Greater sciatic foramen
21
Q
Where does the pudendal nerve pass in relation to the sacrospinous ligament?
A
Posterior
22
Q
How does the pudendal nerve enter the pelvis again?
A
Lesser sciatic foramen
23
Q
Where is the pudendal canal?
A
Within obturator fascia
24
Q
What does the pudendal canal run alongside?
A
Internal pudendal artery and vein
Nerve to obturator internus
25
Where does the pudendal nerve crosee?
Lateral aspect of the sacrospinous ligament
26
What can be used as a landmark for a pudendal nerve block?
Ischial spine
27
When is a pudendal nerve block used?
During labour:
- Forceps delivery
- Painful vaginal delivery
When repairing tears or an episiotomy
28
What can happen to the pudendal during labour?
Can be stretched
29
What can result from pudendal nerve damage or sphincter damage during labour
Weakened pelvic floor
| Faecal incontinence
30
What is a first degree perineal terar?
Laceration limited to fourchette and perineal skin/vaginal mucose
31
What is a second degree perineal tear?
Extends to perineal muscles and fascia (not anal sphincter)
32
What is a third degree perineal tear?
Anal sphincter torn:
- 3a = <50% of external anal sphincter thickness
- 3b = >50% of external anal sphincter
- 3c = Internal anal sphincter
33
When is the first booking appointment in pregnancy?
12 weeks
34
What is done at the booking appointment in pregnancy
```
FBC
Antibodies and Rhesus
Glucose
Syphilis
Rubella
USS:
- Confirm viability, number of foetuses and gestation
```
35
What tests are done at the 16 week visit?
```
Alpha-fetoprotein
OR
Triple test:
- AFP
- Oestriol
- Beta-hCG
```
36
What test is done at 18 weeks?
Ultrasound
37
When is Anti-D given and when would it be given?
28 weeks
| If mother is Rh negative
38
When is a biophysical score calculated?
If pregnancy lasting longer than 40 weeks AND no induction of labour
39
What examinations are done at follow-up visits?
```
BP and urinalysis
Symphysis-Fundal height
Lie and presentation
Engagement of presenting part
Foetal heart auscultation
```
40
How can the risk of Down's Syndrome be assessed in the first trimester?
Nuchal thickness (NT):
- Measure skin thickness behind foetal neck (USS)
- Measured at 11-13+6 weeks
- Combined with bCG and PAPP-A
41
How can the risk of Down's Syndrome be assessed in the second trimester?
Blood sample at 15-20 weeks
| Assay of hCG and AFP
42
How is the personal risk of a foetus having Down's Syndrome calculated?
Incorporate with maternal age and gestation
43
If there is a high risk (>1:250) of Down's Syndrome, what is done?
Amniocentesis
44
What does a lower AFP level indicate?
Increased risk of Down's Syndrome
45
What does a lower level of hCG indicate?
Reduced risk of Down's Syndrome
46
When is amniocentesis usually carried out?
After 15 weeks
47
What is the miscarriage rate of amniocentesis?
1%
48
When is chorionic villus sampling carried out?
After 12 weeks
49
What is the miscarriage rate of chorionic villus sampling?
2%
50
What can result in a small babe?
Pre-term delivery
Small for gestational age:
- Intra-Uterine Growth Restriction (IUGR)
- Constitutionally small
51
Between what dates is a pre-term delivery?
24 and 36+6
52
What is the prevalence of pre-term delivery?
6-7%
53
What is the survival rate for a baby born at 24 weeks?
20-30%
54
What is the survival rate for a baby born at 27 weeks?
80%
55
What is the survival rate for a baby born at 32 weeks?
>95%
56
What can cause 'over-distension' and result in pre-term birth?
Multiple pregnancy
| Polyhydramnios
57
What intercurrent illness can result in pre-term birth?
Pyelonephritis/UTI
Appendicitis
Pneumonia
58
What else can result in pre-term birth?
Infection
Placental abruption
Cervical incompetence
Idiopathy
59
What is the risk of pre-term labour after 1 previous PTL?
20%
60
What is the risk of pre-term labour after 2 previous PTLs?
40%
61
What is the risk of pre-term labour in a multiple pregnancy?
50%
62
What parity increases the risk of pre-term labour?
=0 or >5
63
What BMI can increase the risk of pre-term labour?
<20
64
Why do 25% of pre-term infants have a planned C-section?
Severe pre-eclampsia
Kidney disease
Poor foetal development
65
What emergency events are responsible for 25% of pre-term infants?
Placental abruption
Infection
Eclampsia
66
What proportion of pre-term infants have an unknown cause?
Idiopathi
67
What proportion of pre-term infants are due to premature rupture of membranes?
20%
68
How is small for gestational age defined?
Birthweight <10th centile for gestation corrected for maternal:
- Height
- Weight
- Foetal sex
- Birth order
69
What vertically transmitted infections can result in IUGR?
Rubella
CMV
Toxoplasmosis
70
What congenital abnormalities can result in IUGR?
Renal agenesis
71
What chromosomal abnormality can result in IUGR?
Down's syndrome
72
What uteroplacental factors, secondary to hypertension (pre-eclampsia), can result in IUGR?
Placental infarcts
Placental abruption
Placental insuffiency
73
What uteroplacental factors, not secondary to hypertension, can result in IUGR?
Uterine malformations
| Multiple gestation
74
What are the two types of IUGR?
```
Symmetrical:
- Small head and abdomen
Asymmetrical:
- Normal head
- Small abdomen
```
75
What risks does IUGR pose during labour?
Hypoxia +/or death
76
What are some post-natal consequences of IUGR?
```
Hypoglycaemia
Effects of asphyxia
Hypothermmia
Polycythaemia
Hyperbilirubinaemia
Abnormal neurodevelopment
```
77
What are the clinical features of poor growth?
Predisposing factors
Fundal height less than expected
Reduced liquor
Reduced foetal movements
78
How can the growth of a baby be assessed?
Head circumference in mm
| Abdominal circumference in mm
79
What are the two traces on cardiotocography?
Upper:
- Foetal heart rate
Lower:
- Uterine contraction pattern
80
In cardiotocography, what does the DR (from the mnemonic DR C BRaVADO) mean?
# Define risk:
- Low or
| - High
81
In cardiotocography, what does the C (from the mnemonic DR C BRaVADO) mean?
Contractions:
| - Comment on frequency
82
In cardiotocography, what does the BRa (from the mnemonic DR C BRaVADO) mean?
Baseline foetal heart Rate:
| - Should be 120-160 bpm
83
In cardiotocography, what does the V (from the mnemonic DR C BRaVADO) mean?
Variability:
- HR should vary by 10-15 bpm
- Persistent reduced (<5 bpm) indicates potential asphyxia (?sedative/analgesic drugs)
84
In cardiotocography, what does the A (from the mnemonic DR C BRaVADO) mean?
Accelerations:
- Increased due to contractions and returning to baseline before end of contraction is normal
- >=15 bpm change for >=15 secs is healthy
85
In cardiotocography, what does the D (from the mnemonic DR C BRaVADO) mean?
Decelerations:
- Early decels. coincide with contractions
- Late decels. have lowest point after contraction
- Variable
86
What kind of decelerations are most associated with asphyxia?
Late
87
In cardiotocography, what does the O (from the mnemonic DR C BRaVADO) mean?
Overall; is it:
- Reassuring
- Non-reassuring
88
What does a biophysical profile consider?
```
Movement
Tone
Foetal breathing movements
Liquor volume
Heart rate
```
89
How is a biophysical profile assessed?
USS
90
What does each component of the biophysical profile score?
0 or 2
91
What scores indicate what in a biophysical profile?
8 - 10 = Satisfactory
4 - 6 = Repeat
0 - 2 = Deliver
92
What are the common causes of a large for dates pregnancy?
Wrong dates
Multiple pregnancy
Diabetes
Polyhydramnios
93
What is polyhydramnios?
Excess amniotic fluid
94
How can polyhydramnios arise?
```
Monochorionic twin pregnancy
Foetal anomaly
Maternal diabetes
Hydrops foetalis:
- Rh isoimmunisation
- Infections (erythrovirus B19)
Idiopathic
```
95
What are the symptoms of polyhydramnios?
Discomfort
Labour
Membrane rupture
Cord prolapse
96
How is polyhydramnios diagnosed?
Clinical
| USS
97
What is the incidence of spontaneous twins?
1:80
98
What is the incidence of spontaneous triplets?
1:10,000
99
What does zygosity refer to?
Number of eggs fertilised
100
What does chorionicty refer to?
Placental membrane pattern
101
What percentage of dizygotic twins are a dichorionic/diamniotic pregnancy?
100%
102
What fraction of monozygotic twins are a dichorionic/diamniotic pregnancy?
~1/3
103
What fraction of monozygotic twins are a monochorionic/diamniotic pregnancy?
~2/3
104
What fraction of monozygotic twins are a monochorionic/monomniotic pregnancy?
~1%
105
What is the USS sign of dichorionic twins?
Twin-peaks sign (lambda sign) at 12 weeks gestation
106
What is the USS sign of monochorionic/diamniotic twins?
T-sign
107
What can help infer zygosity?
Sex of the twins (same sex = monozygotic)
108
How can a multiple pregnancy be diagnosed?
```
12 week USS
Exaggerated pregnancy symptoms (eg. Hyperemesis)
High alpha-fetoprotein
Large for dates uterus
Feeling more than two foetal poles
```
109
What are some complications of multiple pregnancy?
```
Congenital anomalies
Pre-term labour
Growth restriction
Pre-eclampsia
APH
Twin-to-twin transfusion
```
110
How is a multiple pregnancy managed?
More frequent antenatal visits
Detailed anomaly scan at 18 weeks
Regular scans from 28 weeks for growth
Routine iron supplementation
111
How are triplets or more delivered?
C-section
112
How are twins delivered?
If one is cephalic aim for vaginal
~50% risk of C-section
Epidural anaesthesia
113
What is gestational diabetes
Carbohydrate intolerance resulting in hyperglycaemia of variable severity with onset or first recognition during pregnancy
114
What is the incidence of gestational diabetes?
2-18%
115
In what ethnic groups is gestational diabetes more common?
South Asian (India/Pakistan/Bangladesh)
Middle East
Black Caribbean
116
How does gestational diabetes arise?
1. Placental hormones
2. Relative insulin deficiency/resistance
3. Aberrant fuel mixture:
- Glucose
- Amino acids
- Lipids
4. Above compounds go to placenta
5. Hyperinsulinaemia
117
What does foetal metabolic programming in gestational diabetes result in an increased risk of?
Obesity
Insulin resistance
Diabetes
118
What is Freinkels hypothesis?
Abnormal maternal mixture of metabolites gain access to developing foetus modifying phenotypic gene expression in developing cells
119
What does foetal hyperinsulinaemia result in?
```
Reduced arterial oxygen
Increased EPO (polycythaemia)
```
120
What is gestational diabetes screening based on?
Risk factors
Random blood glucose at:
- Booking
- 28 weeks gestation
121
How is gestational diabetes diagnosed?
Glucose tolerance test:
- Fasting >=5.1 mmol/L
- 2 hour glucose >=8.5 mmol/L
122
What are some risk factors for gestational diabetes?
```
FHx of diabetes
Previous big baby
Previous unexplained stillbirth
Recurrent glycosuria
Maternal obesity
Previous gestational diabetes
```
123
What are the complications of pre-existing diabetes in pregnancy?
Congenital abnormalities
Miscarriage
Intrauterine death
124
What are the complications of both pre-existing and gestational diabetes?
```
Pre-eclampsia
Polyhydramnios
Macrosomia
Shoulder dystocia
Neonatal hypoglycaemia
```
125
What are the target levels of blood glucose in pregnancy?
Fasting: 3.5-5.9 mmol/L
| 1 hour post-prandial: <7.8 mmol/L
126
When would hypoglycaemic therapy be considered?
If diet and exercise fail
| Macrosomia on USS
127
What are the advantages of oral hypoglycaemics?
Avoids hypos associated with insulin
Less weight gain
Less 'education' for proper administration
128
How is a large for dates pregnancy managed?
```
Regular monitoring for pre-eclampsia
2-4 weekly foetal abdominal circumference:
- From 28 weeks OR diagnosis
Umbilical doppler if high risk
- Compared to CTG and BPP know
Offer 38 week delivery
```
129
How should a pregnancy in a woman with diabetes and USS diagnosed macrosomia be managed in regards to delivery?
Inform of risks of vaginal delivery
| C-section
130
When is a chorionic villus biopsy carried out?
11.5 weeks
131
How viable is the tissue attained from a chorionic villus biopsy?
Good
132
What is a risk associated with chorionic villus biopsy?
Risk of confined placental mosaicism
133
When is amniocentesis carried out?
16+ weeks
134
How viable is the tissue attained from amniocentesis?
Poor
135
When is foetal blood sampling carried out?
18+ weeks
136
What is the miscarriage rate for foetal blood sampling?
1-2%
137
When can foetal DNA from mother's blood be carried out?
8+ weeks
138
When is a standard karyotype carried out?
During metaphase
139
What genetic analyses are carried out on the whole genome?
Standard karyotype
Array Comparitive Genomic Hybridisation
Quantification of Foetal DNA in maternal serum
Whole genome sequencing
140
What genetic analyses are targeted?
Point mutation testing
Fluorescence in-situ hybridisation
Quantitative Fluorescence PCR
141
What are single nucleotide polymorphisms?
Single base changes
142
What are copy number variations?
Insertions/Deletions of DNA segments
143
What does two equal peaks on QF-PCR mean?
Disomy 1:1 (ratio)
144
What does one tall peak and one smaller peak on QF-PCR mean?
Trisomy 2:1 (ratio)
145
What does three equal peaks on QF-PCR mean?
Trisomy 1:1:1 (ratio)
146
What does one peak on QF-PCR mean?
Uninformative 1:1 or 1:1:1 (ratio)
147
What does the x-axis on QF-PCR indicate?
Length of repeat
148
What does the area under the QF-PCR curve indicate?
Dose/Frequency of this repeat
149
What genetic screening techniques would be used for all of the following scenarios:
- High risk of trisomy on screening
- Foetal abnormality on screening (small size [esp. if symmetricl], increased nuchal thickness, structural malformation)
- Parent has balanced chromosomal rearragement
Array Comparitive Genomic Hybridisation
OR
Chromosome Analysis
150
When is non-invasive prenatal testing used?
Sex determination
| Trisomy testing
151
When is non-invasive prenatal testing occasionally used?
Chromosome deletions
| Single gene
152
What is a chromosomal change where all genetic material is present?
Balanced chromosome rearrangement
153
What is an unbalance chromosome rearrangement?
Extra/Missing chromosomal material:
| - Usually 1 or 3 copies of the same genome
154
Why is sex chromosome aneuploidy better tolerated?
X-inactivation
155
What is a Robertsonian Translocation?
Two acrocentric chromosomes stuck end to end
156
Given a father has a normal genotype, explicitly two copies of chromosome 14 and two copies of chromosome 21 and the mother has a Robertsonian Translocation R(14;21), what are the possible outcomes of offspring?
```
Normal
Balanced translocation R(14;21)
Trisomy 14 (miscarriage)
Monosomy 14 (miscarriage)
Trisomy 21 (Down's Syndrome)
Monosomy 21
```
157
What would the aCGH be in a balance translocation?
Normal
158
What chromosome rearrangements are possible?
```
Translocations:
- Robertsonian or Reciprocal
- Balanced
- Unbalanced
Inversions
Deletions/Duplications
Aneuploidy
```
159
What is the structure, from superficial to deep, of the ectocervix?
```
Exfoliating cells
Superficial cells
Intermediate cells
Parabasal cells
Basal cells
Basement membrane
```
160
What causes physiological changes of the position of the transformation zone?
Menarche
Pregnancy
Menopause
161
What are Nabothian follicles/cysts?
Cervical surface mucous filled cyst
162
How can cervicitis present?
Often asymptomatic
Can present as infertility:
- Due to silent fallopian tube damage
163
What can cause cervicitis?
```
Follicular:
- Subepithelial reactive lymphoid follices
Non-specific
Chlamydia
HSV
```
164
What is a cervical polyp and how can it present?
Localised inflammatory outgrowht
| Can bleed if ulcerated
165
What is the initial stage of neoplasia of the cervix?
Cervical Intraepithelial Neoplasia
166
What types of cervical cancer are there?
Squamous carcinoma
| Adenocarcinoma
167
When is the squamocolumnar junction most vunerable?
Age at first intercourse (if early)
Long term use of oral contraceptives
Non-use of barrier contraception
168
How much does smoking increase the risk of CIN/Cervical cancer?
3x
169
What is condyloma acuminatum?
Epidermal HPV manifestation (genitals):
- Thickened papillomatous squamous epithelium
- With cytoplasmic vacuolation (Koilocytosis)
170
What is CIN and what can cause it?
Cervical Intraepithelial Neoplasia:
- Infected epithelium remains flat
- May show koilocytosis
- HPV 16 and 18
171
How can CIN be detected?
Cervical smears
172
What cancer does HPV increase the risk of? How?
Invasive squamous carcinoma
| Virus integrated into host DNA
173
How long from HPV does it take for high-grade CIN to develop?
6 months - 3 years
174
How long does high-grade CIN take to develop into invasive cancer?
5 - 20 years
175
In CIN, what cells occupy more of the epithelium and why?
Immature basal cells:
| - Delay in maturation/differentiation
176
What nuclear abnormalities are seen in CIN?
Hyperchromasia
Increased nucleocytoplasmic ratio
Pleomorphism
177
Where is excess mitotic activity seen in CIN and what can be seen?
Above basal layer
| Abnormal mitotic forms
178
What does koilocytosis on histology indicate?
HPV infection
179
What is a koilocyte?
A squamous epithelial cell that has undergone structural changes:
- Nuclear enlargement
- Irregularity of nuclear membrane
- Hyperchromasia
- Perinuclear halo
180
What is CIN Grade I?
Basal 1/3 of epithelium occupied by abnormal cells
Increased mitotic figures
Surface cells quite mature:
- Nuclei slightly abnormal
181
What is CIN Grade II?
Abnormal cells extend to middle 1/3
Mitoses in middle 1/3
Abnormal mitotic figures
182
What is CIN Grade III?
Abnormal cells occupy full epithelial thickness
Mitoses:
- Often abnormal
- In upper 1/3
183
What is Stage 1A1 of Invasive Cervical Squamous Carcinoma?
Depth up to 3mm
| Width up to 7mm
184
What is Stage 1A2 of Invasive Cervical Squamous Carcinoma?
Depth up to 5mm
| Width up to 7mm (and low risk of LN metastases)
185
What is Stage 1B of Invasive Cervical Squamous Carcinoma?
Confined to cervix:
- Clinically visible
- B1 is <4cm
- B2 is >4cm
186
What is Stage 2 of Invasive Cervical Squamous Carcinoma?
Spread to adjacent organs:
- Vagina
- Uterus
187
What is Stage 3 of Invasive Cervical Squamous Carcinoma?
Involvement of pelvic wall
188
What is Stage 4 of Invasive Cervical Squamous Carcinoma?
Distant metastases
OR
Involvement of rectum or bladder
189
How can an invasive cervical carcinoma present?
```
Abnormal bleeding:
- PCB
- PMB
- Brownish or blood stained vaginal discharge
- Contact bleeding (Friable epithelium)
Pelvic pain
Haematuria/UTI
Ureteric obstruction/Renal failure
```
190
What kind of spread of invasive cervical cancer is early and where does it spread?
Lymphatic:
| - Pelvic and para-aortic nodes
191
What kind of spread of invasive cervical cancer is late and where does it spread?
Haematogenous:
- Liver
- Lungs
- Bone
192
How is invasive cervical squamous carcinoma?
Well differentiated
Moderately differentiated
Poorly differentiated
Undifferentiated/Anaplastic
193
Where do Cervical Glandular Intraepithelial Neoplasia arise from?
Endocervical epithelium
194
What is a Cervical Glandular Intraepithelial Neoplasia?
Pre-invasive stage of endocervical adenocarcinoma
195
In who is endocervical adenocarcinomas more common?
Young women
196
Which has a worse prognosis, cervical squamous carcinoma or endocervical adenocarcinoma?
Endocervical adenocarcinoma
197
What are the risk factors for endocervical adenocarcinoma?
Higher socioeconomic class
Later onset of sexual activity
Smoking
HPV (particularly HPV 18)
198
What are some other HPV-driven dieases?
Vulvar Intraepithelial Neoplasia
Vaginal Intraepithelial Neoplasia
Anal Intraepithelial Neoplasia
199
What are the two types of vulvar intraepithelial neoplasia?
Squamous VIN
| Non-squamous
200
What is Extramammary Paget's Disease?
Non-squamous vulvar intraepithelial neoplasia
201
What are the features of vulvar intraepithelial neoplasia in young women?
Often multifocal, recurrent or persistent
| Treatment problems
202
What are the features of vulvar intraepithelial neoplasia in older women?
Increased risk of progression to invasive squamous carcinoma
203
How does vulvar invasive squamous carcinoma usually present?
Elderly woman
| Ulcer or exophytic mass
204
What grade are most vulvar invasive squamous carcinomas?
Well differentiated
205
What type of vulvar invasive squamous carcinomas are extremely well differentiated?
Verrucous
206
Where do vulvar invasive squamous carcinoma spread?
Inguinal nodes
207
How is vulvar invasive squamous carcinoma treated?
Surgical:
- Radical vulvectomy
- Inguinal lymphadenopathy
208
What is the prognosis of node-negative vulvar invasive squamous carcinoma?
90% five-year survival
209
What is the prognosis of node-positive vulvar invasive squamous carcinoma?
<60% five-year survival
210
What is vulvar Paget's disease?
Crusting rash
Tumour cells in epidermis containing mucin
Tumours arises from sweat gland in skin
211
What do the inner cells of the blastocyts develop into?
Embryo
212
What do the outer cells of the blastocyte do?
Burrow into uterine wall
| Form placenta
213
What happens when the blastocyst adheres to the endometrial lining?
Cords of trophoblastic cells (surface) begin to penetrate endometrium
Tunnel deeper - Carves a hole for blastocyst
214
As the blastocyst burrows deeper, what happens to the cell boundaries?
Boundaries between cells in advancing trophoblastic tissue disintegrate
215
At what stage is the blastocyst completely buried in the uterine lining?
By day 12
216
What tissues is the placenta derived from?
Trophoblast
| Decidual
217
What specifically do the trophoblast cells form?
Chorion
218
What do the trophoblast cells differentiate into?
Multinucleate cells:
| - Syncytiotrophoblasts
219
Once the trophoblast cells have differentiated, what do they do?
Invade decidua
| Break down capillaries to form cavities filled with maternal blood
220
What are placental villi formed from?
Developing embryo sending capillaries into syncytiotrophoblasts
221
What do placental villi contain?
Foetal capillaries separated from maternal blood by a thin tissue layer
222
At what stage of pregnancy are the placenta and foetal heart functional?
5th week
223
Where does the embryo initially receive nutrition?
Via trophoblastic invasion of decidua
224
What does hCG signal?
Corpus luteum to keep secreting progesterone
225
What does progesterone do in pregnancy?
Stimulates decidua to concentrate:
- Glycogen
- Proteins
- Lipids
226
Placental villi increase contact area between uterus and placenta. What does this allow?
More nutrients and waste can be exchanged
227
What does the circulation in the intervillous space act as?
An AV shunt
228
How does oxygen saturated blood reach the foetus?
Umbilical vein
229
How does oxygen saturated blood return to the mother?
Uterine veins
230
How is foetal oxygen supply facilitated?
Foetal Hb:
- Increased carrying ability of oxygen
Higher [Hb] in foetal blood (50% more in foetuses)
Bohr effect:
- Foetal Hb can carry more oxygen in low pCO2 than high pCO2
231
When does the diffusion of water into the placental increase until?
Week 35 of pregnancy
232
What electrolytes follow water into the placenta?
Iron
| Calcium
233
How does glucose pass into the placenta?
Simplified transport
234
When is a high glucose needed during pregnancy?
3rd trimester
235
How do fatty acids enter the placenta?
Free diffusion
236
When is human chorionic somatomammotropin (human placental lactogen) produced from?
Week 5 of pregnancy
237
What effects does human chorionic somatomammotropin have?
```
GH-like effects:
- Protein tissue formation
Reduces insulin sensitivity in mother:
- Increases glucose for foetus
Involved in breast development
```
238
What effects does progesterone have?
Development of decidual cells
Reduces uterine contractility
Preparation for lactation
239
What effects does oestradiol have?
Enlargement of uterus
Breast development
Ligament relaxation
240
What does oestriol indicate?
Foetal vitality
241
What effect does corticotropin-releasing hormone released from the placental have in the mother?
```
ACTH release:
- Aldosterone and cortisol release
Aldosterone results in hypertension
Cortisol results in:
- Oedema
- Insulin resistance
- Gestational diabetes
```
242
What effect do hCG and HC thyrotropin released from the placental have in the mother?
Hyperthyroidism
243
What effect does increased calcium demands from the placental have in the mother?
Hyperparathyroidism
244
What happens to cardiac output during pregnancy? By how much does it change?
Increases by 30-50%
245
When do the cardiac output changes begin and peak?
Begin at 6 weeks
| Peak at ~24 weeks
246
What does the cardiac output change during pregnancy?
Placental circulation
Increased metabolism
Thermoregulation
Renal circulation
247
What happens to cardiac output during the last 8 weeks of pregnancy? What is it sensitive to?
```
Decreases
Body position (uterus compresses IVC)
```
248
How does cardiac output change during labour?
Increases by 30%
249
How is heart rate affected in pregnancy and why?
Increases to ~90 to increase CO
250
What happens to BP during the 2nd trimester and why?
Drops:
- Uteroplacental circulation expands
- Reduced peripheral resistance
251
In a twin pregnancy, what physiological changes are enhanced?
CO increases more
| BP drops more
252
What happens to plasma volume in pregnancy?
Increased proportionally with CO (50%)
253
How is erythropoesis affected in pregnancy?
Increases by 25%
254
What happens to Hb in pregnancy and what effect does this have?
Decreases due to dilution:
| - Reduces blood viscosity
255
What happens to iron requirements in pregnancy?
Increases significantly:
- 6-7mg/day in 2nd half of pregnancy
- Supplements needed
256
Why does lung function change during pregnancy?
Increased progesterone AND
| Enlarging uterus interfering with lung function
257
What does progesterone do to lung function?
Signals brain to reduce pCO2:
| - Increases CO2 sensitivity in resp. centres
258
How does oxygen consumption change in pregnancy?
Increases:
- To meet foetal and placental metabolism
20% above normal
259
How does the respiratory system reduce CO2 in pregnancy?
Increased respiratory rate
Increased tidal and minute volumes (50%):
- Reduced functional residual capacity
Reduced pCO2
260
What does change in the context of the respiratory system in pregnancy?
Vital capacity
| pO2
261
How do GFR and renal plasma flow change in pregnancy?
Increase:
- Up to 30-50%
- Peaks at 16-24 weeks
262
Why is there increased renal reabsorption of ions and water during pregnancy?
Placental steroids
| Aldosterone
263
Does urine production increase or decrease in pregnancy?
Slight increase
264
How does posture affect renal function in pregnancy?
When upright function decreases
When supine function increases
When lateral during sleep it increases a lot
265
What is pre-eclampsia?
Pregnancy induced hypertension and proteinuria:
- Increased BP since 20th week
- Kidney function drops (results in sodium and water retention -> Oedema mainly of hands and face_
- Renal blood flow and GFR decrease
266
Who is pre-eclampsia more common in?
```
Pre-existing hypertension
Diabetes
Autoimmune diseases
Renal disease
FHx of pre-eclampsia
Obesity
Multiple birth
```
267
What is the most significant risk factor for pre-eclampsia?
Previous Hx of pre-eclampsia
268
How is eclampsia treated?
Vasodilators
| C-section
269
How can eclampsia present
Vascular spasms
Extreme hypertension
Chronic seizures
Coma
270
What is the average weight gain in pregnancy?
24lbs:
- Foetus (7lbs)
- Extraembryonic fluid/tissues (4lbs)
- Uterus (2lbs)
- Breats (2lbs)
- Body fluid (6lbs)
- Fat accumulation (3lbs)
271
How many extra calories should be ingested during pregnancy and why?
250-300:
- 85% for foetal metabolism
- 15% for maternal fat
272
How much extra protein should a woman consume during pregnancy?
30g/day
273
What is the foetal glucose need at the end of pregnancy?
5mg/kg/min
| Mother is 2.5mg/kg/min
274
In terms of metabolism, what is the first phase during pregnancy?
1st to 20th week:
- Mothers anabolic phase
- Quite small nutritional demands
275
In terms of metabolism, what is the second phase during pregnancy?
21st to 40th week (esp. last trimester):
- High foetal demands
- Accelerated starvation of mother
276
What occurs during the mother's anabolic phase?
```
Normal/Increased insulin sensitivity
Reduced plasma glucose
Lipogenesis and increased glycogen stores
Breast and uterus grow
Weight gain
```
277
What occurs during the catabolic phase?
```
Maternal insulin resistance due to:
- HCS
- Cortisol
- GH
Increased transport of nutrients through placenta
Lipolysis
```
278
What iron supplements are needed in pregnancy?
300mg ferrous sulphate
279
Why are B vitamins needed in pregnancy?
Erythropoiesis
280
What is the effect of Vitamin K before parturition?
Prevents intracranial bleeding during labour
281
What happens to the uterus towards the end of pregnancy? Why?
Becomes more excitable
Oestrogen:Progesterone ratio changes:
- Progesterone inhibits contractility
- Oestrogen increases contractility
282
What effect does oxytocin have at the end of pregnancy?
Increases contraction and uterine excitability
283
What foetal hormones are released at parturition?
Oxytocin
Adrenal gland hormones
Prostaglandins
284
What do foetal prostaglandins control?
Labour timing
285
What does mechanical stretch of uterine muscles result in?
Increased uterine contractility
286
What does cervical stretching result in?
Increased uterine contractility
287
What kind of contractions increase towards the end of pregnancy?
Braxton Hicks contractions
288
What do strong uterine contractions and pain result in?
Neurogenic spinal reflexes:
| - Intense abdominal contractions
289
At the end of pregnancy, what effect does oestrogen released from the ovaries result in?
Induces oxytocin receptors on uterus
290
When the foetus/placenta/uterus are stimulated by oxytocin, what happens?
Contractions
| Placental makes prostaglandins
291
What effects do prostaglandins have at the onset of labour?
```
More prostaglandin release
More vigorous contractions
More oxytocin release from:
- Foetus
- Mother's posterior pituitary
```
292
What happens when the foetus drops lower into the uterus?
Cervical stretch
293
What does cervical stretch in labour stimulate?
Oxytocin release
Uterine contractions:
- Which stretch cervix more
294
What is the first stage of pregnancy and how long does it last?
Cervical dilatation
| 8-24 hours
295
What is the second stage of pregnancy and how long does it last?
Passage through birth canal
| Up to 30 minutes
296
What is the third stage of pregnancy?
Expulsion of placenta
297
What effect does oestrogen have on the breasts?
Growth of ductile system
298
What effects does progesterone have on the breasts?
Development of lobule-alveolar system
299
How do oestrogen and progesterone affect milk production?
Inhibit milk production
300
What happens to oestrogen and progesterone levels at birth?
Sudden drop
301
From when in pregnancy does prolactin rise?
Week 5 to birth
302
When after birth does prolactin induce high milk production?
1-7 days after
303
What does prolactin stimulate immediately after birth?
Colostrum:
- Low volume
- No fat
304
What hormone stimulates the 'milk let-down' reflex?
Oxytocin
305
What happens when a child cries in regards to lactation?
Higher brain centres instructs:
- Hypothalamus to stimulate oxytocin neurones which causes oxytocin release from posterior pituitary
- DA neurones to be inhibited, reducing DA levels and resulting in more PRL release from anterior pituitary
306
What does increased oxytocin levels do during lactation?
Smooth muscle contraction:
| - Ejection of milk
307
How else is milk ejection stimulated (apart from hormonally)?
Baby suckling
| Nipple mechanoreceptors
308
What is the milk let-down reflex?
1. Receptors in nipple stimulated
2. Impulses propagated to spinal cord
3. Stimulation of hypothalamic nuclei
4. Oxytocin released
4. Milk ejected
