1st TRIMESTER
PREGNANCY FAILURE
Shortened to emphasize
medical student curriculum
requirements
Carlos M. Fernandez, M.D
Department of Obstetrics and Gynecology
Advocate Illinois Masonic and Medical Center
ULTRASOUND DIAGNOSIS OF
INTRAUTERINE PREGNANCY
Diagnosis of IUP
1.
2.
3.
4.
“Double decidual sign” at 4½ to 5 wks
Gestational sac + yolk sac at 5 wks
(a definitive sign of IUP)
GS + yolk sac + embryo at 5½ to 6 wks
CRL >5 mm – fetal cardiac activity present
Seeber BE and Barnhart KT. Obstet Gynecol 2006;107:339-413
Tips for Students
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IUP=intrauterine pregnancy
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Could include a live intrauterine pregnancy, a threatened
abortion, an inevitable abortion, an incomplete abortion, or a
missed abortion
Does not include ectopic pregnancy, completed miscarriage,
or a molar pregnancy
Gestational age
The age of the pregnancy in weeks since the last
menstrual period
 About 2 weeks longer than the embryonic age
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Tips for Students
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Try to memorize the gestational ages at which the
markers of an intrauterine pregnancy appear….
But more importantly, you should understand what is
required to confirm an intrauterine pregnancy
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This is how we rule out ectopic pregnancies and molar
pregnancies
If there is any possibility of an intrauterine pregnancy, you
cannot give methotrexate or cytotecyou could cause an
elective abortion
The first sign of an intrauterine pregnancy
GESTATIONAL SAC
DOUBLE DECIDUAL SIGN
First sign of IUP: double
decidual sign
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Earliest finding is the
“double decidual sign”
(arrows)
seen around 4½-5 wks
gestation
initially eccentric in
location
It excludes
pseudogestational sac
(free fluid or blood within
endometrium)
Gestational Sac (confirmed by
double decidual sign)
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Grows 1 mm per day
Usually seen by 4 ½ to 5 weeks of gestation
Discriminatory ß-hCG with TVUS (the level of ß-hCG
above which you should be able to see a gestational sac
on transvaginal ultrasound):
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Usually quoted 1000 - 2000 ß-hCG IU/L
At AIMMC, we use 1500 IU/L
Gestational Sac
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Discriminatory ß-hCG with transvaginal
ultrasound :
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1000 - 2000 ß-hCG IU/L
Discriminatory ß-hCG with trans-abdominal
ultrasound:
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≥ 6500 ß-hCG IU/L
Bhatt & Dogra, Radiol Clin N Am 45 (2007) 549-560
The gestational sac diameter is
used to calculate gestational age
Long axis
Short axis
Second sign of intrauterine pregnancy
YOLK SAC
Second sign of IUP: Yolk Sac
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First structure visualized within
the gestational sac
Round , bright ring
A definitive sign of IUP
Involutes after 11 weeks
Can be seen half a week before
normal embryo is seen
When enlarged (“hydropic”), solid
or duplicated, it is a very poor
prognosis sign
Third sign of intrauterine pregnancy
FETAL POLE
Third sign of IUP: GS + yolk sac
+ embryo
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GS + yolk sac + fetal
pole at 5½ to 6 wks
The fetal pole (arrow) is
better seen on the
zoomed in image
GS grows 1mm/day
Embryo grows
1mm/day
Fourth sign of intrauterine pregnancy
CARDIAC ACTIVTIY
Fourth sign of IUP: GS + YS +
embryo + cardiac activity
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Double decidual sign +yolk
sac+ fetal pole +cardiac
activity
Cardiac activity confirms a
live intrauterine pregnancy
(rules out a miscarriage)
Cardiac activity is usually
detected at 5 ½ to 6 weeks
from last menstrual period
CRL ≥5 mm – fetal cardiac
activity present
BHCG AND PROGESTERONE
IN EARLY PREGNANCY
Serum concentrations of ß-hCG in 443 normal pregnancies
ß-hCG is first detected in maternal serum
6 to 9 days after conception. The levels rise
in a logarithmic fashion, peaking 8 to 10
weeks after the last menstrual period,
followed by a decline to a nadir at 18
weeks, with subsequent levels remaining
constant until delivery
Second International Standard ß-hCG
Braunstein G D, et al. Am J Obstet Gynecol 1976; 126:678-81.
Serial ß-hCG
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The doubling time for a normal IUP is 2
days
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ß-hCG peaks at ~10 weeks gestation
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It can get as high as 100,000 IU/L
Doubling of ß-hCG is less reliable after 10
weeks gestation. At this time, pregnancy is
better evaluated with U/S
15% of normal IUPs can demonstrate an
abnormal rise of ß-hCG
Kadar N, et al. Obstet Gynecol 1981;52:162-6
ß-hCG up to 10000 mIU/ml
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The minimal rise in ß-hCG for a viable
pregnancy is 53% in 48 hours
The minimal decline of a spontaneous
abortion is 21-35% in 48 hours
A rise or fall in serial ß-hCG values that is
slower than this is suggestive of an ectopic
pregnancy
Seeber BE and Barnhart KT. Obstet Gynecol 2006;107:339-413
Hypothetical illustration of the rise, or fall, of
serial hCG values in women with an EP
53%
21-35%
Seeber BE and Barnhart KT. Obstet Gynecol 2006;107:339-413
SPONTANEOUS ABORTION:
BACKGROUND, ETIOLOGY
Spontaneous abortion or miscarriage
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Spontaneous abortion is a fetal loss before 20
weeks gestation
80% of miscarriages occur in the first
trimester (first twelve weeks)
 Biochemical pregnancy:
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A woman has a positive pregnancy test, but does not miss a
period (her period might come a few days late)
The pregnancy has miscarried very early (~3wks gestation)
Ferri: Ferri's Clinical Advisor 2012, 1st ed.
Background
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Miscarriage is the most common serious pregnancy
complication affecting approximately 30% of
biochemical pregnancies and 11–20% of clinically
recognized pregnancies
The diagnosis of miscarriage is made most commonly
by trans-vaginal ultrasound (TVS) assessment
After a diagnosis of miscarriage, half of women
undergo significant psychological effects
Cecilia Bottomley, Tom Bourne. Diagnosing miscarriage. Best Practice & Research
Clinical Obstetrics & Gynecology 2009; 23:463-77
Etiology
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Approximately 50–60% of first-trimester
spontaneous abortions have karyotype
abnormalities
Igor N Lebedev, Nadezhda V Ostroverkhova, Tatyana V Nikitina, Natalia N Sukhanova
and Sergey A Nazarenko. Features of chromosomal abnormalities in spontaneous
abortion cell culture failures detected by interphase FISH analysis. European Journal of
Human Genetics 2004; 12:513–20
Etiologies
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The most frequent type of chromosomal
abnormalities detected are:
Autosomal trisomies ─ 52 %
2. Monosomy X ─ 19 %
3. Polyploidies ─ 22 %
4. Other ─ 7 %
1.
Hsu, LYF. Prenatal diagnosis of chromosomal abnormalities through amniocentesis. In:
Genetic Disorders and the Fetus, 4th ed, Milunsky, A (Ed), The Johns Hopkins University
Press, Baltimore 1998. p.179
CLASSIFICATION OF
MISCARRIAGE
Clinical classification of spontaneous abortion
Laifer-Narin SL. Ultrasound for Obstetrics Emergencies. Ultrasound Clin . 2011; 6: 177-193
Type
Definition
Threatened abortion Vaginal bleeding during the first 20 weeks of pregnancy and no
evidence of cervical dilation. <50% of threatened abortions will
progress to loss of pregnancy.
Missed abortion
Intrauterine demise of the embryo without either vaginal bleeding
or expulsion of the products of conception. Includes both an
embryo with no heart tones (>7mm) or an empty gestational sac
(>20mm).
Incomplete abortion Vaginal bleeding with dilation of the cervix and partial expulsion of
products of conception.
Complete abortion
Vaginal bleeding with expulsion of all of the products of
conception.
Inevitable abortion
Abortion in progress with cervical dilation but the products of
conception have not been expelled.
Differential Diagnosis of
Threatened Abortion
1. Undetermined or physiologic (implantation
2.
3.
4.
5.
6.
related)
Ectopic pregnancy
Sub-chorionic bleed, found in ~20% of
threatened Ab
Gestational trophoblastic disease (molar
pregnancy)
Impending spontaneous miscarriage
Cervix, vaginal or uterine pathology
This section is too in-depth for most medical students; read it for
background, but you don’t necessarily have to memorize!
ULTRASOUND DIAGNOSIS OF
MISCARRIAGE
Different organizations use different cutoffs to diagnose miscarriage…
COMPARISON OF
INTERNATIONAL CRITERIA
How to define miscarriage using ultrasound-comparing and contrasting national guidelines
Royal College of Obstetricians and Gynaecologists.
The Management of Early Pregnancy Loss. GreenTop Guideline No. 25. October 2006
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Miscarriage:
 Mean sac diameter greater than 20 mm and no
embryonic contents, or
 Embryo crown-rump length > 6 mm with no heart
beat, or
 If sac remains empty after at least one week or still
no cardiac activity 1 week after initial ultrasound
How to define miscarriage using ultrasound-comparing and contrasting national guidelines
The Institute of Obstetricians and
Gynaecologists
Royal College of Physicians of Ireland
Transvaginal
Ultrasound
Embryo > 7 mm
No cardiac activity
Miscarriage
Gestational sac > 20 mm
No embryo or yolk sac
Miscarriage
What is the evidence to support the cut-offs used to
diagnose miscarriage?
UOG 2011 November, Jeve Y et al.
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Systematic review of ultrasound diagnosis of miscarriage
Problems: studies are 15–20 years old, small study numbers,
and various cut-off values used (4–6mm for CRL, 13–25mm
for MSD), making pooling of data impossible
Best (most specific) criteria appeared to be MSD > 25mm
with a missing embryo or MSD > 20mm with a missing
yolk sac
These criteria had a 95% CI of 0.96–1.00, therefore up to 4
out of 100 diagnoses of early fetal demise may be wrong.
A single incorrect diagnosis of miscarriage is one too many
Abdallah Y, et al. Limitations of current definitions of miscarriage using mean
gestational sac diameter and crown–rump length measurements: a multicenter
observational study. Ultrasound Obstet Gynecol 2011; 38: 497–502
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Prospective multicenter study
1060 patients of IPUV
Conclusions
In order to minimize the risk of a false-positive diagnosis of
miscarriage the following cut-off could be introduced
 Empty gestational sac or sac with a yolk sac but no
embryo seen with MSD >25 mm
 Embryo with an absent heartbeat and CRL > 7 mm
Summary
Summary
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Significant interobserver variability may be associated
with a misdiagnosis of miscarriage
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This could result in interventions (D&C, misoprostol use)
that could harm a viable pregnancy
Current national guidelines should be reviewed to avoid
inadvertent termination of wanted pregnancy
Large prospective studies with agreed reference
standards are urgently required