A tutorial on concepts related to when the uterine size shows a discrepancy with gestational dates

1. DISCREPANCY IN
UTERINE SIZE
An understanding of the issues involved when a
uterus doesn’t correspond to its gestational age

2. Associate Professor Dr
Hanifullah Khan

3. Objectives
 To understand the  To understand the  The important points to
definitions involved implications of this situation consider

4. Discrepancy – what is
it?
When the uterine size does not
correspond to the expected gestation
May be larger or smaller
Objective measurement - > 2 cm
variation with symphysiofundal
height (SFH)

5. Implications of this situation
Implications of this situation
Is the fetus
Is the fetus
Has there
Has there Is there an
Is there an Is there a
Is there a at risk?
at risk?
been a
been a underlying
underlying problem
problem •If so, when
•If so, when
mistake in
mistake in problem
problem
causing this with the
do we
do we
calculating
calculating causing this with the
discrepancy? mother?
discrepancy? mother?
deliver it?
deliver it?
gestation?
gestation?

6. Points to consider
 The patient has been found to
have a gestation which does
not correspond to calculations.
 This may be a feature of an
underlying problem
 The problem may be related to
the mother, fetus or placenta
 It is our job to determine the
underlying cause of this
problem

7. In all cases, always begin by
Dates confirming the dates
Be absolutely positive
The mother remembers the exact LMP (1st
day)
The periods have been regular
The onset of pregnancy symptoms &
quickening correspond to the dates
That an early pregnancy ultrasound (if
done), confirmed the dates
Subsequent antenatal check ups have
noted previous corresponding growth of

8. Remember, an early pregnancy
ultrasound scan is the definitive
decider of dates

9. IUGR
 Intrauterine growth restriction or Fetal growth restriction
 Leads to uterus < dates
 A manifestation of underlying problem
 Maternal, fetal or placental
 Most commonly caused by placental insufficiency (unknown
cause), hypertensive disease, maternal disease, fetal anomaly
 Most non-fetal causes lead to asymmetrical FGR (the so-called
head-sparing effect)
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10. Fetal Growth Restriction
Leads to long term problems

11. The left ear

12. Big baby
• If fetal macrosomia is the
cause in an uterus > dates,
it is most often a
consequence of
gestational diabetes
• GDM can also lead to
polyhydramnios on its
own
• It is mandatory to look
hard for GDM in such
cases

13. Macrosomia
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14. Fetal anomalies
 Any discrepancy in uterine size must lead to an extensive
search for fetal anomalies
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15. Multiples
 Any large uterus may
be caused by a
multiple pregnancy
 There may be more
than one
 See for yourself
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16. The diagnosis of SGA
 A constitutionally small fetus is a diagnosis of exclusion
 This is the last diagnosis in your list of differentials
 Always rule out disease before you can say its normal
 These fetuses display linear growth despite being small
 Usually, the mother is also small (this is logical)
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17. Summary

18. Discrepancy in uterine size
 This denotes a uterine size not corresponding to gestational
age
 It may be a sign of an underlying problem
 This problem could be of maternal, fetal or placental origin
 One common cause is wrong dates
 Rule out disease before diagnosing a constitutionally small
fetus
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19. THE END
 Thank You Very Much