early pregnancy

Complications of Early Pregnancy

Definition

• Early pregnancy is described as first 12 weeks from beginning of the last normal menstrual period to the end of the first three months.

Things to look for in Early Pregnancy Ultrasound

• Gestational Sac

• Yolk sac

• Embryo

Early Pregnancy Scans

TVS TAS

Gestational Sac 4 ½ wk 5 wk

Yolk Sac 5 6-7

Fetal Heart 5 ½ 6 ½

1.Gestational Sac

Definition

• An-echoic space surrounded by hyper-echoic rim of trophoblastic tissue. Only the an-echoic space is measured.

2.Gestational Sac

Important features to look for• Double decidual sac

• Continuous hyper-echoic rim of at least 2mm in thickness

• Spherical or ovoid shaped without marked angulations.

• Growth of more than 1.2 mm/ day

3. Gestational SacCharacteristics of Abnormal Sac

• Distorted Contour

• Thin decidual rim ( < 2mm) echoic rim

• Weakly hyper-echoic rim

• Low GS position

• Note: when in doubt , advice Follow Up scan

Double Decidual Sac

• Useful and seen in majority of normal pregnancies

• Hyper-echoic rim without DDS more likely in– Abnormal IUP– Pseudo-gestational sac of fluid

Double Decidual Sac sign

• This consist of two concentric echogenic rings, surrounding at least a part of gestational sac.

• It differentiates it from pseudo-gestational sac which is seen in ectopic pregnancy, in which only a single echogenic layer of decidua surrounds an intra-endometrial fluid collection.

Double Decidual Sac

Embryo • Trans-vaginally

– Often seen when MGSD of approx 12 mm ( 6.2 weeks)

– Almost always seen with MGSD of 16 mm – Still no embryo at 25 mm – consider pregnancy abnormal

• Trans-abdominally

– MGSD at least 27 mm or 8.1 weeks

Complications of Early Pregnancy

• Bleeding in first trimester: Possible explanations:

– Intrauterine Pregnancy 50%– Missed abortion 25-30%– Blighted ovum 20-25%– Incomplete abortion – Inevitable abortion– Complete spontaneous abortion– Ectopic Pregnancy – Hydatidiform Mole

Intrauterine Pregnancycharacteristics

• Gestational Sac – Gestational sac – yolk/sac embryo– foetal heart

– Gestational sac is round or oval with smooth contour and generally located in the fundus or middle uterus

Intrauterine Pregnancy

Transvaginal ultrasound image showing intrauterine gestation at 59 days LMP. Calliper's clearly mark a crown to rump length (CRL) of 17 mm. Yolk sac can also be seen.

Missed Abortion

• Fetus without heart or limb motion which still remains with in the gestational sac

• Standing Joint Committee (Royal Colleges of Radiologist,

Obstetrician and Gynaecologist) on Obstetric Ultrasound has indicated that on TVS, if an embryo greater than 6 mm in length has no evidence of cardiac pulsation than this is highly suggestive of missed abortion

Missed Abortion

These ultrasound images show an intrauterine gestation sac with an abnormally large yolk sac (7mm size). This pregnancy is of 10 weeks gestational age (going by the date of last menstrual period). However the poorly developed embryo measures 6 mm. in size (6 weeks 2 days) and shows no cardiac activity. These ultrasound findings suggest embryonic demise. (Note: By current criteria, an embryo of more than 5 mm. in size showing no cardiac activity on transvaginal sonography, is considered to be non-viable/ case of embryonic demise).

Blighted ovum

• An embryonic pregnancy in which gestational sac is present but empty

• Standing Joint Committee (Royal Colleges of Radiologist, Obstetrician and Gynaecologist) has indicated that on TVS a sac diameter of greater than 20 mm with no yolk sac or embryo is highly suggestive of blighted ovum.

Blighted Ovum

This picture shows bulky (enlarged) gravid uterus showing a gestation sac of 13mm. (5 weeks, 1 day). The images show absence of the embryo. These ultrasound images suggest an embryonic gestation (usually known as missed abortion or blighted ovum). It is advisable to repeat the sonography (after 1 week to 10 days ), in such cases to rule out delayed development of the embryo.

Incomplete Abortion

• Only part of products of conception remains with in the uterus, the remainder having been expelled.

• Findings will vary in these cases. Sometimes, it is obvious that there is nothing left inside the uterus, as evidenced by a thin, complete endometrial stripe. In other cases, there will be obvious pregnancy tissue. In the remaining cases, some material will still be present inside the uterus, but it won't be clear (on ultrasound) whether this is blood, blood clot, or retained products of conception.

Incomplete Abortion

This image shows an endovaginal longitudinal view of a low-lying gestational sac within the uterus representing an incomplete miscarriage.

Inevitable Abortion

• Gestation sac and the fetus has been detached from the implantation site and lie in the lower uterine segment or vaginal canal. Once cervix becomes dilated abortion is inevitable.

Inevitable Abortion

Abortion in Progress. Trans abdominal image shows a gestational sac containing a dead embryo presenting at an open cervical os. Expulsion of the pregnancy is inevitable. The balloon of a Foley catheter is evident in the bladder.

Inevitable Abortion

Complete Spontaneous abortion

• All the products of conception has been expelled.

Complete Spontaneous abortion

The absence of the gestational sac and the presence of intrauterine debris are typical of a complete abortion.

Complete Spontaneous abortion

Ectopic Pregnancy

• Implantation of fertilized ovum outside the endometrial lining of the uterus

• This may occur within the peritoneal cavity, fallopian tubes, ovaries, cervix or within a scar of prior uterine surgery.  95% of all ectopic pregnancies occur within the fallopian tubes. 

• The most definitive sonographic sign of ectopic pregnancy is the visualization of an extrauterine gestational sac containing a yolk sac, embryo or fetal heart beat. This occurs in approximately 14% of ectopic pregnancies. 

Ectopic Pregnancy

Ectopic Pregnancy

Hydatidiform mole

• When the pregnancy test is positive and ultrasound detects multiple, hypoechoic and hyperechoic spaces filling and distending the endometrium canal (without a well defined embryo), H Mole is likely.

Hydatidiform mole

Hydatidiform mole

Thanks