Fetal Growth Restriction

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.