Miscarriage- Diagnosis

Bleeding or pain in early pregnancy can be stressful for the patient.

As clinicians, we need to diagnose the condition and to be able to plan further management.

This section deals with diagnosis of miscarriage.

A further section dealing with ‘Ectopic pregnancy’ and ‘Pregnancy of Unknown Location’ will be added later.

In talking to a patient, try using the term miscarriage rather than ‘abortion’( which implies that the woman herself did something to end the pregnancy)

The health of an early pregnancy cannot be guaranteed with one ultrasound.

The patient will usually present with bleeding or pain in early pregnancy. Be mindful that these may be symptoms of miscarriage or ectopic pregnancy. If the patient is stable , and not bleeding heavily, an ultrasound should be ordered ( along with Full blood count, Blood group, Type and screen) .

The history should include – Last menstrual period, history of present pregnancy, Obstetric history and other relevant history.

When you look at the ultrasound result- If a fetal heart beat has been recorded ( and the pregnancy is intrauterine) – Reassure the patient and discharge her to continue routine care unless any new problems arise.

(Because menstrual cycle can vary, DO NOT USE Gestational age from the LMP to say whether cardiac activity should be present).

What to do if fetal heart rate has not been detected –

Till the cardiac activity is seen, the intrauterine pregnancy is labelled as ‘Pregnancy of unknown viability’.

Check whether the ultrasound was transvaginal or transabdominal.

On transvaginal ultrasound-

1. If fetal heart rate has not been detected- Check the CRL (Crown rump length) –

– If CRL is 7 mm or more, and no fetal heart has been detected- counsel her that it is difficult to make a diagnosis on a single ultrasound . Repeat a second ultrasound ( Transvaginal) scan after 7 days or more. If no cardiac activity detected in the second scan also- diagnose miscarriage.

If the CRL is more than 7 mm, , and no fetal heart has been detected- a second opinion can be taken from another colleague.

2. If CRL is less than 7 mm , and no fetal heart beat has been detected on transvaginal ultrasound- Repeat a transvaginal scan after 7 days or more. Counsel the patient that a further ultrasound scans may be needed.

3. If a CRL has not been recorded ( No fetal pole on ultrasound) – Check the ‘Mean gestational sac diameter’(MSD) .

– If MSD is less than 25 mm– repeat the ultrasound in 2 weeks.

– If MSD is more than 25 mm – Repeat the ultrasound in 1 week. Or seek second opinion.

For transabdominal ultrasound–

1. If fetal heart rate has not been detected- Check the CRL (Crown rump length) –

– If CRL is 7 mm or more, and no fetal heart has been detected- still, counsel her that it is difficult to make a diagnosis on a single ultrasound . Repeat a second ultrasound scan after 14 days or more. If no cardiac activity detected in the second scan also- diagonse miscarriage.

If the CRL is more than 7 mm, , and no fetal heart has been detected-

a second opinion can be taken from another colleague( to be sure that cardiac activity is not present) .

2. If CRL is less than 7 mm , and no fetal heart beat has been detected on TRANSABDOMINAL ultrasound- Repeat a scan after 14 DAYS or more. Counsel the patient that further ultrasound scans may be needed.

3. If No fetal pole has been detected on transabdominal ultrasound- Record the Mean sac diameter and Perform a second ultrasound scan a minimum of 14 days from the last scan.

Another approach followed by the US Society for Radiologists in Ultrasound ( 2012) is as follows-

It proposes that miscarriage can be diagnosed on a FOLLOW UP ultrasound( Not initial ultrasound ) as follows-

1. CRL More than 7 mm with no cardiac activity ( On FOLLOW UP ultrasound)

2. MSD More than 25 mm with no heart beat ( On FOLLOW UP ultrasound)

3. If Gestational sac with yolk sac has been seen on scan 1à repeat scan after at least 11 days à if no cardiac activity—diagnose miscarriage.

4. If gestational sac( but no yolk sac) has been seen on scan 1 à repeat scan at least after 2 weeks à if no cardiac activity seenà diagnose miscarriage.

5. In case of any doubtà repeat ultrasound should be done, and opinion of a colleague should be sought. ( Seeking second opinion only reflects how safe a doctor is and how much he or she values the safety of a patient) .

I usually inform my patients that ‘Bleeding or pain in early pregnancy are common, and do not always mean that there is a problem. However, they may indicate that there is problem with the pregnancy. We will need to examine you and run some tests( blood and ultrasound) . Many times, the health of pregnancy cannot be diagnosed with one ultrasound, and that she may need more than one ultrasound. Also , transvaginal ultrasound can look more closely at the womb and the baby, and is therefore more accurate at detecting the location of pregnancy, and the health of the baby. Transvaginal ultrasound has no bad effects on the health of the pregnancy.’

In a private practice, it is difficult to tell the patient that further scans will be needed. In the comments below, tell us what you tell your patients presenting with problems in early pregnancy.

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