Early Pregnancy Flashcards
1
Q
What is the most common site of metastatic spread (90% of cases) of gestational choriocarcinoma?
A
Lungs
2
Q
What is the USS appearance of gestational choriocarcinoma?
A
- Heterogenous mass within an enlarged uterus
- Invasion of the myometrium
- Cystic spaces associated with haemorrhage
- No fetal parts
3
Q
What proportion of complete molar pregnancies result in choriocarcinoma?
A
2%
4
Q
How common is gestational choriocarcinoma (GTN)?
A
1 in 50,000 pregnancies
5
Q
How common is GTD (hydatidiform mole, invasive mole, choriocarcinoma, PSTT) overall?
A
1 in 714 live births
6
Q
What is the chemotherapy rate in GTN?
A
Chemotherapy rate of 0.5–1.0% for GTN after partial molar pregnancy and 13–16% after complete molar pregnancy
7
Q
How is treatment option decided upon for GTN?
A
FIGO 2000 scoring system
Score of 6 or less = IM MTX
Score of 7 or more = IV multi-agent chemo
Treatment continued until hCG normalised, and then for 6 consecutive weeks after
8
Q
In GTN, a FIGO 2000 score of >/= 13 suggest?
A
Higher risk of early death (within 4 weeks), often due to bleeding into organs, or late death due to multihyphenate drug-resistant disease
9
Q
How long is an embryo an embryo?
A
10 weeks
10
Q
When is a pregnancy considered a fetus?
A
> 10 weeks
11
Q
What is the rate of growth of an embryo?
A
1mm per day from 1-2mm (i.e. when first detectable on USS, between 5-6 weeks)
12
Q
Cleavage at days 1-3 (morula stage) results in what type of twin pregnancy?
A
Dichorionic, diamniotic
13
Q
Cleavage at days 4-8 (blastocyst stage) results in what type of twin pregnancy?
A
Monochorionic, diamniotic
14
Q
Cleavage at days 8-13 (implantation stage) results in what type of twin pregnancy?
A
Monochorionic, monoamniotic
15
Q
What proportion of pregnancies are monochorionic, monoamniotic?
A
1%
16
Q
What are the more unique risks of monochorionic, monoamniotic twin pregnancies?
A
Cord entanglement and pregnancy loss <24 weeks
17
Q
Dichorionic, diamniotic twins result from cleavage at what stage?
A
Days 1-3 (Morula)
18
Q
Monochorionic, diamniotic twins result from cleavage at what stage?
A
Days 4-8 (Blastocyst)
19
Q
Monochorionic, monoamniotic twins result from cleavage at what stage?
A
Days 8-13 (Implantation)
20
Q
When is the gestational sac visible on USS?
A
4.5 weeks
21
Q
When is the fetal pole visible on USS?
A
From 6 weeks - when 1-2mm
22
Q
When is cardiac activity normally visible on USS?
A
6 weeks
If the CRL is 7mm or MORE and cardiac activity is not visible, this is diagnostic of pregnancy loss (after a 2nd opinion - if no 2nd opinion available, will also need a F/U in 7 days).
23
Q
If these is no cardiac activity and CRL is LESS than 7mm, what should be done?
A
PUV - scan again in 7 days, before diagnosis made
24
Q
What should you do if you measure a CRL, with no cardiac activity by means of a TRANSABDOMINAL scan?
A
Repeat scan in 14 days (rather than 7 days as with a TVUS)
25
At what size embryo is cardiac activity usually present?
2mm+
26
When should the fetal pole be visible on TVUS, relative to the size of the MSD
Should be visible once the MSD has reached 15-20mm
If the MSD >25mm, with no fetal pole, this is diagnostic of pregnancy loss
27
On TVUS, if the MSD is <25mm, and there is not fetal pole, what should happen?
PUV
Scan again in 7 days to confirm Dx
28
On TVUS, if the MSD is >25mm, and there is not fetal pole, what should happen?
Seek a 2nd opinion to confirm Dx, or if no 2nd opinion available, again, wait 7 days and re-scan to confirm Dx
29
If the MSD is measured by TA scan, and there is not fetal pole, what should happen?
Repeat scan in 14 days
30
From what does the primary yolk sac develop?
The hypoblast, derived from the inner cell mass (inner cell mass differentiates into the hypoblast and epiblast)
31
When does the primary yolk sac develop?
Weeks 1-2
32
When does the secondary yolk sac develop?
After week 2, it is the first structure visible within the gestational sac on TVUS, normally visible at week 5
33
When does the yolk sac disappear?
After the first trimester
34
What is the incidence of ectopic pregnancy?
11 in 1000 (1 in 90)
35
What is 'sliding sign' on TVUS?
An adnexal mass, moving separate to the ovary
36
What is 'tubal ring' or 'bagel sign'?
An adnexal mass, moving separately to the ovary with an empty gestational sac
37
When there is an empty uterus and positive pregnancy test and a 48hr bhCG shows a 63%+ increase, what should be done?
TVUS between 7-14 days later
Consider an earlier scan for women with a serum hCG level greater than or equal to 1,500 IU/litre.
38
When there is an empty uterus and positive pregnancy test and a 48hr bhCG shows a decrease in serum hCG levels greater than 50%, what should be done?
Urine pregnancy test 14 days after the second serum hCG test - if negative no further action required
39
If a woman has a threatened miscarriage (bleeding, but FH), and has had a previous miscarriage, what should be done?
Offer vaginal micronised progesterone 400 mg twice daily until 16 weeks gestation
40
For what time period should expectant management be used?
7-14 days, except if there is concerns in relation to bleeding (later trimester, coagulopathy etc.); infection or prev. traumatic experience
41
When can expectant management of ectopic pregnancy be offered?
Clinically stable and pain free
AND
Tubal ectopic pregnancy <35mm, no FH
AND
Serum hCG levels of 1,000 IU/L or less
AND
Able to attend F/U
42
When can expectant management of ectopic pregnancy be considered?
Clinically stable and pain free
AND
Tubal ectopic <35mm, no FH
AND
Serum hCG levels 1,000 IU/L-1,500 IU/L
AND
Able to return for F/U
43
What monitoring is put in place for expectant management of ectopic pregnancy?
Repeat hCG levels on days 2, 4 and 7 after the original test:
- If hCG levels drop by 15% or more from the previous value then repeat weekly until a negative result (less than 20 IU/L) is obtained
- If hCG levels do not fall by 15%, stay the same or rise from the previous value, review
44
When can medical management be offered in ectopic pregnancy?
No significant pain
AND
Unruptured, adnexal mass <35 mm, no FH
AND
Serum hCG <1,500 IU/litre
AND
Do not have an IUP
AND
Able to attend F/U
45
When should surgical management be offered for ectopic pregnancy?
1. Significant pain
2. Adnexal mass >/= 35 mm
3. Live ectopic
4. Serum hCG level >/= 5,000 IU/litre
5. Unable to attend for F/U
46
With what progesterone level, can a PUL be discharged with a F/U PT in 14 days?
<2 (as probably FPUL)
47
What types of tests are urinary pregnancy tests?
A type of sandwich enzyme-linked immunosorbent assay (ELISA) and utilises monoclonal antibodies to detect HCG present within urine
48
What are the different zones of a urine pregnancy test?
Reaction zone; Test zone; Control zone
49
What happens in the reaction zone of the urine pregnancy test?
Monoclonal antibodies specific to HCG bind to any HCG present within the urine and these HCG-antibody complexes are carried along the strip. Any unbound antibodies will also be carried along the strip
50
What happens in the test zone of a urine pregnancy test?
There are more anti-HCG antibodies which are fixed to this area of the strip. They will bind to the HCG component of the HCG-antibody complexes and a chemical reaction between them results in a colour change
51
What happens in the control zone of a urine pregnancy test?
Antibodies located in the control zone will bind to the antibody component of the HCG-antibody complex
If there is no HCG present, the antibodies at the control zone will still bind to the antibodies that have traveled up from the reaction zone and a colour change will occur --> this confirms that the test has worked.
52
What is the medical name for chromosomal abnormality?
Aneuploidy
53
What is the most common cause of first trimester miscarriage?
Aneuploidy
54
What proportion of first miscarriages are caused by aneuploidy?
50%
55
What are the different types of aneuploidy?
Trisomy (most commonly 16)
Polyploidy
Monosomy
56
What chromosome trisomy most commonly accounts for first trimester miscarriage?
Chromosome 16
57
What proportion of first trimester miscarriages caused by aneuploidy, are a trisomy?
50%
58
What is the most common mechanism of trisomy?
Meiotic non-disjunction = failure of chromosome separation during cell division (anaphase)
Strongly associated with increasing maternal age
59
Trisomy 16 occurs in what proportion of pregnancies overall?
1.5%
Incompatible with life
Majority of these pregnancies will end between 8 and 15 weeks
60
What proportion of pregnancies will miscarry in those aged 40-44?
51%
61
What frequency does a pelvic ultrasound use?
3.5 – 7.0 megahertz (MHz), usually >5MHz
62
What frequency does a TA transducer use?
3.5 – 5.0 MHz
63
Where the CRL exceeds 84mm in a never previously dates pregnancy, ,what measurements should be used for dating?
HC +/- FL
64
From 14 weeks, what measurements should be used for dating?
HC +/- FL
65
On machines that don't have the automatic measurement, how can HC be estimated?
Measurement of the biparietal diameter (BPD) and the occipitofrontal diameter (OFD)
The apply the formula - HC = 1.62 x (BPD+OFD)cubed
66
What anatomical landmarks should be present for a BPD or HC measurement to be made?
1. Transverse view of the fetal head at the level of the
thalami
2. Ideal angle of insonation is 90◦ to the midline echoes,
3. Symmetrical appearance of both hemispheres
4. Midline echo (falx cerebri) interrupted anteriorly only
by the cavum septi pellucidi
5. Cerebellum not visible.
67
A placental edge, what distance from the internal os on TVUS warrants F/U in the 3rd trimester?
68
When may higher doses of anti-D be require in instances of fetomaternal haemorrhage?
>5mls
69
How does the fetal rhombencephalon (hindbrain) first appear on TVUS?
First appears as cystic, hypoechoic structure in the posterior aspect of the fetal head, from 7 weeks gestation
It will develop into the pons, medulla, cerebellum and fourth ventricle
70
What are features on USS are suggestive of a normally sited pregnancy?
1. Eccentrically placed within the endometrium
2. Well circumscribed/round shape
3. Evidence of a trophoblastic reaction (double layer border, high peripheral flow)
71
What type of drug is methotrexate?
A potent inhibitor of the enzyme dihydrofolate reductase (DHFR)
DHFR is a key component of the tetrahydrofolate pathway, which is required for synthesis of amino and nucleic acids
72
How does a complete molar pregnancy occur?
Duplication of a single spermatozoa inside an empty ovum (75-80%) or dispermic fertilisation of an empty ovum (20-25%)
73
What is the karyotype of a complete molar pregnancy?
46XX or 46XY (less commonly)
74
How does a partial molar pregnancy come about?
Partial molar pregnancies occur, in almost all cases, following dispermic fertilisation of an ovum - most are triploid in origin, with two sets of paternal haploid chromosomes and one set of maternal haploid chromosomes
75
How does a molar pregnancy present clinically (commonly)?
Vaginal bleeding (60% of presentations), large for dates uterus
76
How can a molar pregnancy present less commonly?
1. Hyperemesis
2. Hyperthyroidism
3. Early-onset pre-eclampsia
4. Abdominal distension due to theca lutein cysts
77
What could persistent bleeding 8 weeks after a pregnancy event suggest?
GTN - always do a urine hCG to exclude
78
How should a molar pregnancy be managed?
Complete - surgical evacuation of the uterus
Partial - surgical if possible (i.e. the fetal parts are small enough)
79
Why is surgical management of a molar pregnancy preferred over a medical management?
Higher rate of incomplete removal with medical methods, and so chemotherapy rates 16-fold higher with medical methods
80
Why should oxytocic drugs be avoided in molar pregnancies?
Potential to embolise and disseminate trophoblastic tissue through the venous system leading to adult respiratory distress syndrome, similar in presentation to amniotic fluid embolism
81
What is more likely to result in a gestational choriocarcinoma - complete molar or partial molar pregnancy?
Complete molar pregnancy
82
What are the ultrasound appearances of a complete molar pregnancy?
5-7 weeks: polypoid mass
>8 weeks: cystic appearances of villous tissue, no gestation sac/fetus
>13 weeks: ‘bunch of grapes’ appearance
83
How does a complete molar pregnancy present on ultrasound at 5-7 weeks?
Polypoid mass
84
How does a complete molar pregnancy present on ultrasound at 8 weeks?
Cystic appearances of villous tissue, no gestation sac/fetus
85
How does a complete molar pregnancy present on ultrasound at >13 weeks?
‘Bunch of grapes’ appearance
86
What should take place where it is unclear if the pregnancy is a complete mole with a coexisting normal twin or a possible singleton partial molar pregnancy?
Fetal karyotype
87
What is the F/U for a complete molar pregnancy?
hCG returned to normal within 56 days - F/U for 6/12 from uterine removal
hCG not returned to normal within 56 days - F/U for 6/12 from date of hCG normalisation
88
What is the F/U for a partial molar pregnancy?
Concluded once the hCG has returned to normal on two samples, at least 4 weeks apart
89
When can women whom have had a GTD (molar pregnancy/GTN) conceive again?
Recommended not to do so until F/U complete
Women who undergo chemotherapy are advised not to conceive for 1 year after completion of treatment, as a precautionary measure
90
What proportion of women achieve a further pregnancy after treatment for GTN?
80%
91
What is the risk of a further molar pregnancy?
1% (and more associated with complete rather than partial)
92
What are the pathological features of a complete molar pregnancy?
1. Absence of fetal tissue
2. Extensive hydropic change to the villi
3. Excess trophoblast proliferation
93
Whilst hCG levels are decreasing in GTD, what UKMEC rating are the coils?
UKMEC 3
94
Whilst hCG levels are persistently elevated, or there is malignant disease in GTD, what UKMEC rating are the coils?
UKMEC 4
95
What are the pathological features of a partial molar pregnancy?
1. Presence of fetal tissue
2. Focal hydropic change to the villi
3. Some excess trophoblast proliferation
96
What type of cyst is associated with molar pregnancies?
Theca lutein cysts - almost always bilateral
97
What is the ultrasound appearance of the corpus luteum?
A thick walled cystic structure with peripheral vascularity (the ring of fire)
98
What maintains the corpus luteum intially?
hCG produced by the syncytiotrophoblast layer
99
What is the function of the corpus luteum?
HCG released by the syncytiotrophoblast activates enzymes within the corpus luteum to convert cholesterol into pregnenolone followed by progesterone
Progesterone is released in large quantities which activates secretory changes in the endometrium via paracrine signalling.
100
What are the USS appearance of monochorionic pregnancy?
Single placental mass
T-sign present (absent Lambda sign)
101
What is the USS appearance of dichorionic pregnancy?
Two placental masses
Lamda sign present (absent T-sign)
102
What is T-sign?
A single placental mass is seen with a thin inter-twin membrane that inserts into the placenta in a perpindicular plane
103
What is Lamda sign?
Two placental masses are seen
The inter-twin membrane is thick where it inserts into the placenta forming a curved, wedge-like protrusion
104
What can occur to the endometrium in the event of ectopic pregnancy?
Patients with an ectopic pregnancy may shed the decidua (an endometrial cast) during an episode of vaginal bleeding.
The endometrial cast can be mistaken for early pregnancy tissue giving the false impression of miscarriage.
105
At what hCG level should a gestation sac be seen on TVUS?
1000-1500 IU/l
106
At what hCG level should a gestation sac be seen on TA USS?
6000 IU/l
107
In what circumstances may the gestation sac not be visible, despite being expected to be able to do so base don the hCG?
Circumstances where imaging is more challenging - e.g. obesity or fibroids
108
At what hCG can low sensitivity urine pregnancy test detect?
1000-1500 IU/l
109
At what hCG can a high sensitivity urine pregnancy test detect?
25 IU/l, however there are some branded pregnancy tests that claim detection as low as 10 IU/l
110
What is the age-related risk of miscarriage between the ages 30-34?
15%
111
What is the age-related risk of miscarriage between the ages 35-39?
25%
112
What is the age-related risk of miscarriage between the ages 40-44?
51%
113
What is the structural abnormality in a small proportion of Turner syndrome patients?
Isochromosome X
114
How long after the LH surge does ovulation occur?
36 hours
115
What is the embryological origin of the chorionic villi of the gestational sac?
Extraembryonic mesoderm
116
What size does a mature follicle reach just before ovulation?
20mm
117
What is the sensitisation rates following the introduction of antenatal and postnatal anti-D?
0·17-0·28%
118
What is the reduction in mortality rate from Haemolytic Disease of the Newborn (HDN) following the introduction of antenatal and postnatal anti-D?
46/100 000 births to 1·6/100 000 births
119
In pregnancies <12/40, when is anti-D indicated?
Ectopic pregnancy
Molar pregnancy
STOP
Cases of uterine bleeding where this is repeated, heavy or associated with abdominal pain
120
After a sensitizing event, when is a test for FMH indicated?
>20/40
