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. Is there an
Is there a
underlying
problem with
problem causing
the mother?
this discrepancy?
Is the fetus at
Has there been a
risk?
mistake in
calculating • If so, when do we
deliver it?
gestation? Implications
of this
situation
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)
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
14. Fetal anomalies
Any discrepancy in uterine size must lead to an extensive
search for fetal anomalies
15. Multiples
Any large uterus may be caused by more than one passenger
in it
See for yourself
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)
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