12. Intrauterine-Growth Restriction (IUGR)
Intrauterine-growth restriction (IUGR)
indicates a fetus is small for its gestational age. Weight is below the
tenth percentile (in the lowest 10%) for the baby’s gestational age.
This means 9 out of 10 babies of normal growth are larger.
When gestational age is
appropriate—meaning dates are correct and the pregnancy is as far along
as expected—and weight falls below the tenth percentile, it’s a cause
for concern. Growth-restricted fetuses have a higher rate of problems
than infants in the normal-weight range.
Diagnosing IUGR can be difficult. Your
doctor measures you at each visit to see how your uterus and baby are
growing. A problem is usually found by measuring the uterus over a
period of time and finding no change. If you measured 10¾ inches (27cm)
at 27 weeks gestation and at 31 weeks you measure only 11 inches (28cm), your doctor might become concerned about IUGR and may order tests.
Diagnosing this problem is one important
reason to keep all your prenatal appointments. You may not like being
measured and weighed at every appointment, but it helps your doctor see
if your pregnancy is growing and baby is getting bigger.
IUGR can be diagnosed or confirmed by
ultrasound. Ultrasound may also be used to assure baby is healthy and
no malformations exist that must be taken care of at birth.
When IUGR is diagnosed, avoid doing
anything that could make it worse. Bed rest is another treatment.
An infant with IUGR is at risk of dying
before delivery. Avoiding this may involve delivering the baby before
it is full term. Infants with IUGR may not tolerate labor; a Cesarean
delivery is more likely because of fetal stress. The baby may be safer
outside the uterus than inside of it.
Becky said she weighed 9 pounds at
birth, and all her brothers and sisters were also big. She was worried
her baby would be so big she’d need a Cesarean delivery. I reassured
her that her pregnancy growth had been normal and told her it was
difficult to estimate the size of the baby. She laughed and relaxed a
little when I told her if 100 healthcare providers tried to guess the
weight of her baby, the guesses would range from 6 to 8 pounds. When
she delivered the baby, it weighed 8 pounds, and Becky did fine.
Causes of IUGR
What causes IUGR? Many conditions can
increase the chance of intrauterine-growth restriction or a small
fetus. Research shows a woman who has delivered a growth-restricted
infant may be more likely to do so again in sub sequent pregnancies.
Lifestyle choices can cause IUGR. Smoking
can inhibit a baby’s growth. The more cigarettes smoked, the smaller
the baby. Alcohol and drug use can also restrict growth. Anything that
causes baby to receive less nutrition can be a factor.
How Often Birth Defects Actually Occur
Birth defects aren’t as common as you might think. Below is a chart showing how often they occur in North America.
| Cleft lip/cleft palate |
1 in 730 births |
| Clubfoot |
1 in 1000 births |
| Congenital heart defects |
1 in 125 births |
| Dislocated hips |
1 in 400 births |
| Down syndrome |
1 in 900 births |
| Neural-tube defects |
1 in 1600 births |
| Pyloric stenosis |
1 in 250 births |
| Sickle-cell disease |
1 in 400 births of Black/African-American babies |
A woman who doesn’t gain enough weight
may have a growth-restricted baby. Research indicates when you eat
fewer than 1500 calories a day for an extended time, IUGR may result,
so practice good nutrition and eat a healthful diet during pregnancy.
Don’t restrict normal pregnancy weight gain.
Pre-eclampsia and high blood pressure
(hypertension) can have a marked effect on fetal growth.
Cytomegalovirus, rubella, kidney disease and other infections may also
restrict fetal growth. Maternal anemia may be a cause.
Women who live at high altitudes are more
likely to have babies who weigh less. Carrying more than one baby may
also be causes of a smaller-than-normal baby.
Other reasons for a small baby, unrelated
to IUGR, include the fact that a woman who is small might have a small
baby. In addition, an overdue pregnancy can lead to an undernourished,
smaller baby. A malformed or abnormal fetus may also be smaller,
especially when chromosomal abnormalities are present.
Ways to Deal with IUGR
The greatest risk associated with IUGR
is stillbirth (the baby dies before delivery). Delivery of the baby
before full term may be required to avoid this serious problem. The
following advice may help you avoid giving birth to a low-birthweight
baby.
•Gain enough weight during pregnancy. This may mean changing your body image and your eating habits.
•Quit smoking before pregnancy, and avoid second-hand and third-hand smoke.
•Get prenatal care as soon as you find out you’re pregnant. Keep all your prenatal appointments.
•Follow your healthcare provider’s suggestions and instructions during your pregnancy.
•If
you’re considering fertility treatment, understand the risks as well as
the benefits of ART and multiple births (multiple births often deliver
early or prematurely).
•Ask your healthcare provider about screening for lower-genital-tract infections early in pregnancy.
•Wait at least 18 months between delivery of one baby and conception of the next.
