00:01
Now we'll discuss fetal
growth restriction.
00:04
Fetal growth restriction is defined
as the estimated fetal weight of less than
the 10th percentile, or an abdominal circumference
less than the 10th percentile.
00:14
Now there are several causes
and we are going to divide these
into maternal,
fetal and placental.
00:20
So starting with maternal,
these factors can be anything,
from pre-pregnancy
medical conditions.
00:25
Such as chronic
hypertension, diabetes.
00:29
Substance abuse such as cocaine,
tobacco, amphetamines, alcohol.
00:34
Pregnancy related conditions
such as preeclampsia.
00:37
Multifetal gestation
or infections.
00:41
And mostly infections we're
speaking of the TORCHeS.
00:43
And that's discussed
in another lecture.
00:45
It's important to note however
that malaria is a number one
cause of infectious reasons
for fetal growth restriction
worldwide.
00:54
Now moving on to fetal reasons
for fetal grow restriction.
00:58
Usually those are divided into
chromosomal abnormalities
and anatomical abnormalities.
01:04
For chromosomal abnormalities,
the Trisomy 21, 13 and 18
are the most common.
01:10
And those we usually screen for
with our aneuploidy screening
in the 1st trimester
or 2nd trimester.
01:17
Anatomical abnormalities
are things such as cardiac
and renal.
01:21
We screen for those on an
anatomy ultrasound between 18
and 22 weeks of gestation.
01:28
Now placental issues.
01:30
Now there are various reasons
why the placenta can cause
growth restriction.
01:33
From the things we've
already discussed.
01:36
These are anything that will
affect the blood vessels going
to the placenta.
01:40
That can lead to fetal
growth restriction.
01:44
So how do we screen for
fetal growth restriction.
01:46
Well, for every patient after
24 weeks when they come in for
their prenatal visit,
we measure the fundal height.
01:52
So with a measuring tape, we
measure from the pubic symphysis
to the top of the uterus.
01:57
We expect that measurement to
plus or minus 3 centimeters
of the gestational age.
02:02
So for example, if a patient
is 30 weeks pregnant they can
measure as small as 27
centimeters
or as large as 33 centimeters.
02:11
And that's considered normal.
02:13
If a patient is measuring
less than 3 centimeters of
the gestational age,
an ultrasound is warranted to
determine if the fetus is
indeed growth restricted.
02:21
So when we do that ultrasound,
we're looking at the head
circumference and biparietal
diameter,
the abdominal circumference
as well as the femur length.
02:33
If those together add up to less
than the 10th percentile,
then the fetus indeed has fetal
growth restriction.
02:41
How do we manage fetal
growth restriction?
Well, most importantly we want
to increase surveillance
of that fetus.
02:47
We want to measure fetal growth
by ultrasound every 3
to 4 weeks.
02:51
We would like to see interval
growth during that time.
02:54
If we stop seeing interval
growth, that is concerning
and we would actually start
looking for our time
to deliver that fetus.
03:01
We also want to look at
the amniotic fluid volume.
03:04
We expect to see a maximum
vertical pocket of at least
2 centimeters.
03:09
If we see less than that,
then that fetus is suffering
from oligohydramnios.
03:13
The umbilical artery Doppler.
03:17
So this is also an important
management tool that we use with
fetal growth restriction to see
if our baby is at increased risk
for intrauterine fetal demise.
03:26
What we're looking for is to
see that we have flow during
systolic and diastolic.
03:31
We start seeing some issues with
growth when we have absent in
diastolic flow and worse
if we have reversal flow.
03:39
If we start seeing that on
our Doppler's that indicates
it's time for delivery.
03:44
And then a non-stress test
or biophysical profile.
03:46
This is another way to assess
the status of our fetus.
03:50
And these are discussed in
a little bit more detail
in other lecture set.