Embryonic Demise

80

Transcript of Embryonic Demise

Page 1: Embryonic Demise
Page 2: Embryonic Demise

The embryonic phase of development is complete by the end of the 10th G.wk

embryonic phaseembryonic phase

Page 3: Embryonic Demise

Although a variety of terms are used to describe early pregnancy failure, in the presence of clear-cut sonographic evidence that a nonliving embryo is present, the term embryonic demise should apply

Although a variety of terms are used to describe early pregnancy failure, in the presence of clear-cut sonographic evidence that a nonliving embryo is present, the term embryonic demise should apply

Page 4: Embryonic Demise

Early pregnancy loss

Only about 1/2 of zygotes persist as a clinical (symptomatic or noticeable) pregnancy.

Page 5: Embryonic Demise

Anatomic Points

True gestational sacs implant into the endometrial lining, and are seen

eccentric to the endometrial canal. Fluid collections within the canal are not true gestational sacs.

Page 6: Embryonic Demise

The Gestational sac and yolk sac are seen beginning at 4.5-5 weeks, before a recognizable embryo is seen

Anatomic Points

Page 7: Embryonic Demise

As the gestation enlarges into the endometrial cavity, only the early placenta need be in tight contact with the decidua. Small amounts of bleeding into the cavity are commonly seen, and may surround much of the gestational sac, but if the decidua basalis remains intact, the gestation can and usually does continue to develop normally.

Anatomic Points

Page 8: Embryonic Demise

Some causes of first trimester demise are well understood; however, in most instances, the etiology is unknown (Moore, 1998 )

causes

Page 9: Embryonic Demise

Chromosome abnormalities are the leading known cause of pregnancy loss. An estimated 6-7% of zygotes have chromosome aberrations (Moore, 1998),

and more than 95% of chromosomally abnormal concepti die in utero

causes

Page 10: Embryonic Demise

cytogenic abnormalities in 20% in women who undergo in vitro fertilization

(Bateman, 1992) and in 70% of women with spontaneous abortion

(Ohno, 1991). many chromosome aberrations increase with

advancing maternal age (Hook, 1981). This is particularly true for Down syndrome (trisomy 21) but is also evident with other less common trisomies

causes

Page 11: Embryonic Demise

environmental causes

immunologic factors, drugs, infectious agents, alcohol, smoking, environmental chemicals, radiation

Page 12: Embryonic Demise

environmental causes Exposure before 5 weeks gestational age

(GA), has an all-or-none result such that the embryo will either die or be unaffected (Moore, 1998).

(5-10 wk) usually affects organ development and results in either demise or severe congenital abnormalities.

Page 13: Embryonic Demise

Luteal phase defect Once implantation has occurred, another

cause of early pregnancy failure relates to an inability of the corpus luteum to adequately support the conceptus (Blumenfeld, 1992).

This condition, which tends to occur with maternal obesity and/or advancing maternal age, can be treated successfully during the embryonic phase of development by administrating human choriogonadotropin (hCG).and /or progestrone.

Page 14: Embryonic Demise

Uterine causes

A developmental uterine anomaly such as a

uterine septum or acquired uterine

anomalies such as submucosal, large, or

degenerating leiomyomas also can increase

the incidence of embryonic demise

Page 15: Embryonic Demise

Clinical Details

Page 16: Embryonic Demise

first trimester

50% fail

mild vaginal bleeding and/or

cramping

50%continue

25%25%

Page 17: Embryonic Demise

Clinical Details Clinical Details

Some women with embryonic demise will be asymptomatic, and in these patients the diagnosis may be suggested based on subnormal uterine growth,

Page 18: Embryonic Demise

Clinical DetailsClinical Details

The earliest visible gestational sac is seen at 4.5 weeks as an echogenic ring, with a tiny central hypoechoic area.

Gestational. Age (days)= 30 + Mean Sac Diam.(mm.)

Page 19: Embryonic Demise

To confidently diagnose an IUP, most sonographers rely on the double decidual sac (DDS) finding, which is not universally present until the MSD is 10 mm (40 days GA) (Nyberg, 1983).

Clinical DetailsClinical Details

Page 20: Embryonic Demise

This very small sac (arrow) is positioned within the

anterior endometrium. Note the linear central cavity echo

positioned just deep to the sac. This relationship

characterizes a normal-appearing intradecidual sac sign.

Page 21: Embryonic Demise

when using a transabdominal approach, cardiac activity should be visible by 8 weeks GA., 9 mm should be considered the discriminatory embryonic length for detecting cardiac motion

with a transvaginal approach. can detect cardiac activity approximately 2 weeks earlier or by 6 weeks GA. 5mm be considered the discriminatory embryonic length for detecting cardiac motion

Clinical Details

Page 22: Embryonic Demise

the discriminatory value

TAUS:8WK,

9mm,CR

25MSD

TVUS:6WK

5mm,CR 18MS18MSD

CardiacactivityCardiacactivity

Cardiacactivity

Cardiacactivity

Page 23: Embryonic Demise

A limitation of the transvaginal approach is if a

large pelvic mass is present. Most often, large

or strategically placed calcified uterine fibroids

cause this problem. Under these

circumstances, an abdominal approach

should be used in an effort to image the

uterus and its contents.

Clinical Details

Page 24: Embryonic Demise

Using a vaginal approach, the yolk sac should be observed by 5.5 weeks GA.

yolk sac

Clinical Details

Page 25: Embryonic Demise

Yolk sac should be seen when sac is 10mm. MSD by

vaginal probe, or 20 mm. MSD by abdominal probe.

Clinical Details

Page 26: Embryonic Demise

NORMAL YOLK SAC

TAUS

(MSD) is 20 mm

7 weeks

TVUS

MSD is10 mm

5.5 weeks

Yolk sac must be visible

Page 27: Embryonic Demise

Yolk sac

3mm

A normal appearing yolk sac (arrow) is seen on this transvaginal scan done at 5.5 weeks gestational age.

Page 28: Embryonic Demise

An abnormally large yolk sac is present (arrow) within this gestational sac. Diameter measured 10 mm. Follow-up imaging confirmed a failed pregnancy.

Page 29: Embryonic Demise

If a small saclike structure is imaged but it does not contain a yolk sac, it is often not possible to determine if the intrauterine finding is the result of an early IUP or a pseudosac associated with an ectopic pregnancy.

In these instances, careful evaluation of the adnexa may be helpful to detect an ectopic pregnancy. Occasionally, serial ultrasound and/or hCG determinations may be required to determine the etiology for the intrauterine sac

If no yolk sac

Page 30: Embryonic Demise

Visualizing a dead embryo

Page 31: Embryonic Demise

Visualizing a dead embryo using a transabdominal approach, 9 mm

should be considered the discriminatory embryonic length for detecting cardiac motion. Used in this manner,

( the discriminatory level denotes the numeric value when a certain finding should always be present. )

Page 32: Embryonic Demise

Visualizing a dead embryo when a transvaginal approach was used,

5 mm be considered the discriminatory embryonic length for detecting cardiac motion.

Page 33: Embryonic Demise

the discriminatory value

TAUS:8WK,

9mm,CR

25MSD

TVUS:6WK

5mm,CR 18MS18MSD

Cardiacactivity

Cardiacactivity

Page 34: Embryonic Demise

Visualizing a dead embryo an embryo exceeds the discriminatory length and

cardiac activity is absent, a nonviable gestation should be diagnosed.,

this observation should be made by two independent observers, and interpretive caution must be exercised in any questionable case. Documentation should be available by M mode imaging and/or by obtaining a videotape or video clip.

Page 35: Embryonic Demise

TVUS

TAUS

CRL>5MM

FETAL DEMISE

NO CARDIAC MOTION

CRL>9MMNO CARDIAC MOTION

Page 36: Embryonic Demise

Visualizing a dead embryo

If the length of the embryo is less than the discriminatory value, the patient should be managed expectantly,

a repeat ultrasound examination should be performed when the expected embryonic CRL exceeds the discriminatory value. Alternatively, or additionally, the level of serum hCG may be useful for determining whether a normal IUP is present.

Page 37: Embryonic Demise

Visualizing a living embryo

Although seemingly a paradox, it is well known that detecting cardiac activity when using a vaginal transducer does not guarantee as favorable an outcome as detecting cardiac activity when using an abdominal transducer

the vaginal approach detects cardiac activity earlier when the incidence of pregnancy loss is relatively higher.

Page 38: Embryonic Demise

Predicting a poor outcome

Page 39: Embryonic Demise

Predicting a poor outcome

a number of other important observations have been made, which, when observed with a living embryo, are predictive of a poor outcome (Falco 1996).

Page 40: Embryonic Demise

Predicting a poor outcomemean embryonic heart

rate (MEHR)mean gestational sac

size (MSS)

Abnormal yolk sac/amnion

Subchorionic hemorrhage

Abnormal sac criteria Doppler findings

Page 41: Embryonic Demise

At 5-6 weeks GA, the mean embryonic

heart rate is 101 beats per minute (bpm).

This rate increases to 143 bpm by 8-9 weeks GA

Predicting a poor outcome

(MEHR)

Page 42: Embryonic Demise

it is not unusual for an initially detected embryonic heart rate to be somewhat slower than the fetal heart rate recorded later in pregnancy. An unusually slow heart rate is cause for concern. In one study, all embryos from 5+ to 8+ weeks GA in which the heart rate was less than 85 bpm resulted in spontaneous miscarriage (Benson, 1994

Predicting a poor outcome

(MEHR)

Page 43: Embryonic Demise

At 5.5 weeks gestational age, the embryonic heart rate was 92 beats per minute. Follow-up scan revealed embryonic demise

Page 44: Embryonic Demise

Small sac size: From 5.5-9 weeks GA, the mean gestational sac size (MSS) is normally at least 5 mm greater than the CRL

Predicting a poor outcome

(MSS)

Page 45: Embryonic Demise

When this difference is less than 5 mm, the subsequent spontaneous abortion rate exceeds 90% (Bromley, 1991)

(MSS)

Predicting a poor outcome

Page 46: Embryonic Demise

This embryo was 8 weeks gestational age. Lack of fluid surrounding the embryo results in a disproportionately small sac. A follow-up scan 1 week later revealed demise

(MSS)

Page 47: Embryonic Demise

Subchorionic hemorrhage: As many as 18% of women with vaginal bleeding during the first half of pregnancy have sonographic evidence for a Subchorionic hemorrhage as the etiology for their bleeding (Pederson, 1990).

Subchorionic hemorrhage

Predicting a poor outcome

Page 48: Embryonic Demise

Early pregnancy bleeding

Subchorionic hemorrhage

18%

Page 49: Embryonic Demise

Several authorities have suggested that the size of the blood clot can be used to predict the outcome (Abu-Yousef 1987); this has not been universally accepted (Dickey, 1992).

Predicting a poor outcome

Subchorionic hemorrhage

Page 50: Embryonic Demise

A large Subchorionic hemorrhage is present superior to the gestational sac (white arrow). Follow-up scan revealed embryonic demise

Page 51: Embryonic Demise

Hemorrhage volume (Estimated from formula Length (cm) X Height (cm) X Depth (cm) X 0.52 = Volume ml), less then 75-200 ml. is often associated with continued development

Predicting a poor outcome

Subchorionic hemorrhage

Page 52: Embryonic Demise

Abnormal yolk sac/amnion

Page 53: Embryonic Demise

NORMAL YOLK SAC

TAUS

(MSD) is 20 mm

GA of 7 weeks

TVUS

MSD is 8 mm

GA of 5.5 weeks

Yolk sac must be visible

Page 54: Embryonic Demise

Abnormal yolk sac/amnion

The amnion develops somewhat earlier than the yolk sac, but because this membrane is so thin, it is more difficult to visualize than the yolk sac. Normally, the amnion is visible on transabdominal scans late in the embryonic period. If the amnion is easily seen, it is probably too thick and most likely is abnormal

Page 55: Embryonic Demise

Abnormal yolk sac/amnion

Other features consistent with pregnancy failure include a visible amnion without a simultaneously visible yolk sac, embryo, or cardiac activity. An enlarged amniotic sac is another sonographic sign that predicts a failed pregnancy or embryonic death (Horrow, 1992).

Page 56: Embryonic Demise

An abnormally large yolk sac is present (arrow) within this gestational sac. Diameter measured 10 mm. Follow-up imaging confirmed a failed pregnancy.

Page 57: Embryonic Demise

Doppler findings conflicting reports exist with regard to the

usefulness of first trimester Doppler for predicting pregnancy outcome. Some reports suggest if the resistive index is measured at the Subchorionic level and exceeds .55, a high likelihood of spontaneous abortion exists (Jaffe, 1995); however, others claim that Doppler analysis of these vessels are not predictive of outcome (Frates 1996).

Page 58: Embryonic Demise

Abnormal sac criteria

Page 59: Embryonic Demise

Abnormal sac criteria

An early normal intrauterine gestational sac often can be identified transabdominally by 31 days GA and can consistently be identified by 35 days GA. To confidently diagnose an IUP, most sonographers rely on the double decidual sac (DDS) finding, which is not universally present until the MSD is 10 mm (40 days GA) (Nyberg, 1983).

Page 60: Embryonic Demise

Abnormal sac criteria

By transabdominal approach, size criteria that unequivocally suggest an abnormal sac include

failure to detect a DDS when the MSD is equal to or greater than 10 mm,

failure to detect a yolk sac when the MSD is equal to or greater than 20 mm,

failure to detect an embryo when the MSD is equal to or greater than 25 mm (Nyberg, 1986).

Page 61: Embryonic Demise

Abnormal sac criteria

Using vaginal ultrasound, a normal intrauterine gestational sac can be detected reliably at 4-5 weeks GA, at which time the MSD approaches 5 mm. Using vaginal transducers, criteria that suggest an abnormal sac include

failure to detect a yolk sac when the MSD is 8 mm or greater, and

failure to detect cardiac activity when the MSD exceeds 16 mm (Levi, 1988)

Page 62: Embryonic Demise

Visualizing an "empty" gestational sac

The earliest appearance for a normal sac is a small fluid collection surrounded by high-amplitude echoes embedded in the decidualized endometrium. This appearance has been termed the “intradecidual sac sign” (IDSS)).

Page 63: Embryonic Demise

Visualizing an "empty" gestational sac

An "empty " gestational sac is the result of 1 of 3 entities:

1) a normal early IUP, 2) an abnormal IUP, or 3) a pseudogestational sac in a patient

with an ectopic pregnancy.

Page 64: Embryonic Demise

Using a vaginal approach, the mean diameter of this sac exceeded 20 mm. Neither a yolk sac nor embryo was visible. These findings are consistent with a "blighted ovum

Page 65: Embryonic Demise
Page 66: Embryonic Demise

DDS

MSD is

10 mm

TAUS

yolk sac

TAUS

MSD 20mm

embryo

TAUS

MSD 25mm

transabdominally

Page 67: Embryonic Demise

Note the irregular shape to this sac. In addition, the choriodecidual reaction is somewhat thin. Not surprisingly, this pregnancy failed.

Page 68: Embryonic Demise

Growth rate In normal gestation, mean sac growth is 1.13

mm/day; in comparison, mean sac growth in an abnormal intrauterine gestation is 0.70 mm/day (Nyberg, 1987).

Based on these observations, abnormal sac growth can be diagnosed confidently if the gestational sac fails to grow by at least 0.6 mm/day.

Page 69: Embryonic Demise

Choriodecidual appearance

This refers to the sonographic appearance of the echoes that surround an early intrauterine gestational sac. An abnormal appearance includes a distorted sac shape;

a thin (<2 mm), weakly echogenic, irregular choriodecidual reaction;

absence of the double decidual sac sign when the MSD exceeds 10 mm

Page 70: Embryonic Demise

The Living Embryo and threatened abortion

Page 71: Embryonic Demise

The Living Embryo and threatened abortion

The presence of an embryonic heartbeat is highly reassuring. When visualized by Low Resolution Abdominal sonography, more than 90% of pregnancies continue

Visualization by high resolution vaginal sonography is associated with a 70% continuance rate.

Page 72: Embryonic Demise

< 6 week.,

33% are lost With bleeding

16% are lost if no bleeding present

The Living Embryo and threatened abortion

Page 73: Embryonic Demise

7-9 week

10% are lost With bleeding

5 % are lost if no bleeding present

The Living Embryo and threatened abortion

Page 74: Embryonic Demise

9-11 week

4 % are lost With bleeding

2% are lost if no bleeding present

The Living Embryo and threatened abortion

Page 75: Embryonic Demise

The prognosis for the living embryo improves as

gestation proceeds

conclusion

Page 76: Embryonic Demise

Visualizing a central cavity complex

When the central cavity complex is abnormally thickened (and often irregularly echogenic), the differential diagnosis includes:

intrauterine blood, retained products following an spontaneous abortion,

decidual changes secondary to an early but not yet visible intrauterine pregnancy,

or a decidual reaction from an ectopic pregnancy.

Page 77: Embryonic Demise

Degree of Confidence If certain findings are not observed at the

appropriate time, if the ultrasound findings are equivocal, if the examination is technically difficult, or if the sonographer is inexperienced, caution is warranted.

The embryo always should be given the benefit of the doubt, and a follow-up ultrasound examination should be performed to obviate any risk of terminating a normal intrauterine pregnancy.

Page 78: Embryonic Demise

False Positives/Negatives

Prior to visualizing the yolk sac, it is often not possible to be certain if a small intrauterine saclike structure is due to an early intrauterine pregnancy (normal or abnormal), or a pseudosac associated with an ectopic pregnancy. This is because it may not be possible to clearly identify the DSS. Under these circumstances, a follow-up examination should be performed if clinically feasible.

Page 79: Embryonic Demise

Occasionally, a subchorionic hemorrhage may resemble a second intrauterine sac. However, since most of these women are bleeding, with careful scanning, the correct diagnosis usually can be made. Whenever uncertainty exists, perform a short interval follow-up examination at 5-7 days

False Positives/Negatives

Page 80: Embryonic Demise