Macrosomia and Intrauterine Growth Restriction(IUGR)

DR Manal Behery Zagazig

University, 2013

Macrosomia

Definition: A fetal weight of more

than 4.5 kg at term or fetal birth weight > 90 percentile for the

gestational age..

Causes Genetic or constitutional: obese women tend to give birth to macrosomic babies. Diabetes and prediabetes. Post-date (postmaturity). Multiparity: The first baby is about 100 gm smaller than the next. Hydrops foetalis.

Macrosomia and diabetes¼ th of insulin dependent mothers have Macrosomic infants

Excess growth happens in 3rd trimester.

GDM mothers have same incidence of Macrosomic infants as other diabetics

Risk factorsExcessive maternal weight gain during pregnancy.

Advanced maternal age.

Male fetus than female.

Previous macrosomic infant.

DiagnosisClinical palpation: can give a rough idea. Ultrasonography: can calculate the fetal weight

Hazards

Prolonged pregnancy

Cephalopelvic disproportion Obstructed labour. Shoulder dystocia. Meconium aspiration syndrome. Nerve and bone injuries.

Management

Proper antenatal care: to prevent macrosomia and diagnose it before labour commences.

Cesarean section: is the safest for both mother and fetus.

IUGR

Definition !IUGR is defined as a fetus that has an

estimated weight that is less than the 10th percentile for it’s gestational age

At term, the cutoff birth weight for IUGR is 2,500 g (5 lb, 8 oz)

Growth percentiles for fetal weight versus gestational age

Correlation of birth weight percentile to perinatal morbdity and mortalility

Is small for gestational age (SGA) the same as IUGR?

• IUGR is used synonymously with small for gestational age (SGA) but implies a pathologic condition.

EFW at or below 10th percentile is used to identify fetuses at risk

However a certain number of fetuses at or below the 10th percentile just may be constitutionally small and not growth restricted

About one third of all infants weighing less than 2500 grams at birth have IUGR

IUGR VS SGAIUGR: fetus with birth weight <10th percentile for gestational age due to pathologic process.

SGA: fetus with birth weight <10th percentile for gestational age in the absence of pathologic process

1. Symmetrical growth restriction

20 % of IUGR Infants

proportional decrease in all organs

HC/AC ratio is normal

Occurs in early pregnancy : Cellular hyperplasia

Increase risk for long term neurodevelopmental dysfunction

Due to Intrinsic factor Chromosomal abnormalities Congenital anomalies Intrauterine infection

2.Asymmetrical growth restriction

80% of IUGR Infants

Increase HC/AC ratio : decrease in abdominal size

Brain sparing effects

Occurs in late pregnancy : cellular hypertrophy

Risk for perinatal hypoxia, neonatal hypoglycemia Good prognosis Due to extrinsic factors : Uteroplacental insufficiency

Maternal vascular disease: hypertension Multiple gestations Placental disease

3. Combined type

Asymmetrical symmetrical Symmetrical asymmetrical

More morbidities and mortalities More long term effects

Ponderal IndexUltrasound criteria for diagnosis of fetal malnutrition;Gestation age independent;Way of characterizing the relationship of height to mass for an individual.

PI = 1000 x

Typical values are 20 to 25.PI is normal in symmetric IUGR.PI is low in asymmetric IUGR.

Mass (kgs) Height (cms)

Etiology- Overlapping

,,

Fetal

Placental

Maternal

Fetal causes

Infection CMV, Rubella, Toxoplasma gondii – severe IUGR Syphilis, Tuberculosis, Malaria, listeriosis Herpes simplex, chicken pox

Chromosomal abnormality Trisomy 18,13 –severe IUGR Trisomy 21 Turner syndrome (45,XO), Klinefelter syndrome (47,XXY)

Congenital anomalies Congenital Heart diseases Anencephaly

Case # 1A baby is delivered at 36 WGA via repeat C- section BW- 2 kg HC- < 10th %tile Lt- < 10th %tile

CMV

Case #2- What if?

Toxoplasmosis

Rubella

Case #3- What if?

Trisomy 18 Turner syndrome

Maternal causes

• Maternal malnutrition • Poor maternal weight gain• Severe anemia• Chronic hypoxemia• Cardiovascular disease• Drugs and teratogens• Multiple pregnancy• Antiphospholipid antibodies syndrome

Case #4Infant is delivered at 38 weeks to mom who presents with headaches and epigastric pain BW: 2.1 kg HC: 50th%tile Lt: 30th%tile

Pre-eclampsia/ HELLP

Case # 5- What if?Mom with no prenatal care delivers undiagnosed twins at EGA 34 weeks

Discordant twins

Case # 6- What if?An infant is delivered at 42 weeks via c- section due to NRHTs after induction

Post dates

- decreased subcutaneous fat- skin desquamation- wizened facies - large AF(diminished membranous bone formation)- meconium staining

Placental causes

• Placental infarction• Placental abruption• Chorioangioma• Placenta previa , circumvallate placenta• Marginal or velamentous insertion of umbilical cord

Cause

Fetal causes (intrinsic factors)

Symmetrical IUGR

Maternal causes Plcental causes

(extrinsic factors)

Asymmetrical IUGR

IUGRSymmetric IUGR Asmmetric IUGR

Small symmetrically. Head is larger than abdomen.

Ponderal index is normal. Ponderal index is low.

Normal head-abdomen ratio. High head-abdomen ratio.

Genetic, infections. Placental vascular insufficiency.

Complicated neonatal course. Benign neonatal course if complications are treated adequately.

Diagnosis• Clinical assessment

• Ultrasonic measurement

• Doppler velocity

History for risk factor

– Teen age– High altitude– Socioeconomic factor– Smoking , Alcohol , Drugs– Previous IUGR pregnancy history– previous IUGR in family

Signs:

Seldom elicited before 28 weeks of gestation:Failure of fetus and uterus to grow at the normal rate over

a 4 week period;Uterine fundal height should be at least 2cm less than

expected for the length of gestation;Poor maternal weight gain;Diminished fetal movements.

Physical examination

Uterine fundal height Uterine fundus Pubic symphysis Simple, Safe, Inexpensive for screening

Between 18 and 30 weeks, the uterine fundal height in centimeters coincides with

weeks of gestation. If the measurement is more than 2 to 3 cm from the

expected height or < 1oth percentile from normal curve, inappropriate fetal growth may be suspected

Errors in Fundal Height Estimation:

Inter-observer variations Obese patients Transverse lie Multiple gestation Polyhydramnios / Oligohydramnios Uterine fibroids

Ultrasonic measurement

Initial U/S at 16 to 20 weeks to establish gestational age and identify anomalies and repeated at 32 to 34 weeks to evaluate fetal growth

Ultrasonography BiometryThe measurements most commonly used to measure and follow fetal growth are:

Biparietal Diameter

Femur Length

Head Circumference

Abdominal Circumference

Ratio :- Head circumference to the abdominal circumference (HC/AC).

Amniotic Fluid IndexMild IUGR – Normal amniotic fluidSevere IUGR – Oligohydramnios (AFI is ≤ 5)

Incidence 40%On ultrasonography - a pocket of fluid < 1cm is diagnosed as oligohydramnios.

The amniotic fluid index is obtained by summing the largest cord-free vertical pocket in each of the four quadrants of an equally divided uterus.

Abnormal umbilical artery Doppler velocimetry

A. Normal velocimetry pattern with an S/D ratio of <30.

B. The diastolic velocity approaching zero reflects increased placental vascular resistance.

C. During diastole, arterial flow is reversed (negative S/D ratio), which is an ominous sign that may precede fetal demise

– characterized by absent or reversed end-diastolic flow

– associated with fetal growth restriction

An IUGR infant is at risk for

Hypothermia?

Hypoglycemia?

Or

Hypocalcemia?

decreased subcutaneous fat, increased surface- volume ratio, decreased heat production

decreased glycogen stores/ glycogenolysis/ gluconeogenesis

increased metabolic ratedeficient catecholamine release

Associated with perinatal stress, asphyxia, prematurity

Management Prepregnancy: to prevent it by identifying risk factors and treat as necessary (e.g. improve nutrition intake, stop smoking or alcohol, ASA in APA syndrome, and Heparin in thrombophilias)

Antepartum: identify risk factors that can be changed. Fetal surveillance by ultrasound (BPP) and fetal heart monitoring (Non-Stress Test). To decide on timing and mode of delivery.

Growth restriction near term

Prompt delivery

Recommend delivery at 34 weeks or beyond if there is clinically significant oligohydramnios

Growth restriction remote from term

No specific treatment If diagnosed in prior to 34 weeks, and amnionic

fluid volume and fetal surveillance are normal “Observation is recommended

± screening for toxoplasmosis,herpes,rubella,CMV and others”

Specific treatment(causes of IUGR) and supportive care

If severe IUGR or bad obstetric conditions Terminate pregnancy should be

considered

IUGR- OutcomeNeurodevelopment

etiology and adverse event dependent lower intelligence, learning/ behavioral

disorders, neurologic handicaps symmetric, chromosomal disorders,

congenital infections--- poorer outcome school performance influenced by social

class

Case study

CaseSW a16 years old G1 P0+0 presented early for

prenatal care

PMH: NonePSH: NoneAllergies: NoneMedications: Prenatal vitaminsSocial Hx: + Tobacco 1ppd x > 5 years, No illicit drug use

• B average in high school and good support system• Lives in Denver, HIGH ALTITUDE • Poor nutrition

She followed up regularly and had an uncomplicated 1st trimester…..

• At 18 weeks fundal height measured 17 cm• At 22 weeks fundal height measured 20 cm• At 24 weeks fundal height measured 21 cmAt this point I am worried about IUGR with this

sluggish growth.

Although we do not use fundal height to diagnose IUGR, it can be a clue to a developing problem.

• A fundal height that lags by more than 3 cm or is increasing in disparity with the gestational age may signal IUGR.

• A lag of 4 cm or more certainly suggests growth restriction.

• The size of the uterus should be assessed at each prenatal visit.

So now we have increasing concern over her poor fundal height. What other risk factors for IUGR does AMY have?

A) TeenB) Poor nutritionC) Poor abdominal girth

growthD) High altitudeE) SmokerF)All of the above

ANSWER F

Maternal weight Gain

Decreased maternal weight gain is a relatively insensitive sign of IUGR baby…

Risk Factors of IUGRWith all these risk factors, poor weight

gain, and an inadequate fundal height…

What would you do to further evaluate for potential IUGR?

1)Consult OB now2) Get an ultrasound 3) Do an NST4) Continue to watch one more weekANSWER 2

The result of 32 wks USComments:a single intrauterine pregnancy. No obvious fetal anatomic abnormalities were seen. Not all malformations of the above mentioned organ systems can be detected by ultrasound. There is an overall growth lag of two weeks, with the head and abdomen lagging three weeks. Amniotic fluid is lower limits of normal measuring 8.5 cm . S/D ratio is slightly elevated. She declined amniocentesis.

Recommend follow up growth in three weeks. This appointment was scheduled today

History of Present Illness• That was her ultrasound at 24 weeks. You repeat it

at 27 weeks: 3 week growth lag and AFI 8.5

• Repeat US at 30 weeks: normal growth since last US – 15 day lag; AFI 10.5

• Repeat US at 32 weeks: EFW 9% AFI 5.9

Is this IUGR? What do you do now?

She has an overall 3 week lag and an EGW 12% at 32 weeks. Is this IUGR?

A) Yes ,any growth lag is IUGR B)Yes any EFW<l15% is IUGR C)No ,too early to diagnose IUGRD) No, IUGR is EGW overall lag 4 weeks

ANSWER C

IUGR is usually not detectable before 32-34 weeks (maximal fetal growth). But it must be suspected earlier

Signs rarely occur before 28 weeks of gestation

What is Intrauterine Growth Restriction (IUGR)?

A fetus with IUGR often has an estimated fetal weight associated with which of the following?

A) Abdominal circumference is below 5th percentile

B) Abdominal circumference is below the 2.5th percentile

C) Less than the 5th percentile for its gestational age

D) Less than the 10th percentile for its gestational age

ANSWER D

What is one of the pathologic Maternal/Placental causes for IUGR?

A.Gestational DiabetesB.HypertensionC.ObesityD.Hyperemesis Gravidarum

ANSWER B

Which of the following is not a pathologic FETAL cause for IUGR?

D)CMV infectionC)Congenital heart disease

B)Cleft lip/palateA)Trisomy 21

ANSWER B

Does SW have symmetrical or asymmetrical IUGR?

A)Asymmetrical

B) Symmetrica

lAnswer B

Comments of the ultrasound at 32 weeks. It reads:

A complete detailed scan of a single intrauterine pregnancy was performed. Noobvious fetal anatomic abnormalities were seen. Not all malformations of theabove mentioned organ systems can be detected by ultrasound. There is an overallgrowth lag of two weeks, with the head and abdomen lagging three weeks. Amnioticfluid is lower limits of normal measuring 5.9 cm . S/D ratio is slightlyelevated.

How else can IUGR be diagnosed in addition to a <10% weight for

gestational age?

A) USB) Inadequate Maternal Weight gainC) Non-reassuring NSTD) Fundal Height

ANSWER A

So SW has had a 32 wk US with EFW 10% and AFI 6.9. What is your next step?

A)Repeat US in

8 weeks

B)No further US needed

C)Repeat US in

4 weeks

D)Transfer to OB

ANS C

Yes! Correct Answer: Repeat US in 3-4 weeks

Repeat US at 35 weeks:Comments:

A repeat ultrasound of this single intrauterine pregnancy was performed. EFW is in the less than 10th percentile in growth.

Amniotic fluid is within normal limits for this gestation. Umbilical artery dopplers performed and S/D ratio isnormal.

Recommendations include: 1. follow up ultrasound in 1 week for AFI and dopplers2. follow-up ultrasound in 2 weeks for growth 3. NST testing twice weekly.

SW is in your office to review the results. You explain the results and schedule her for an ultrasound next week and the week after. Any other advice for her?

Click for advice1. Rest as much as possible- she does not work and is out of school.2. Perform daily kick counts.

3. She will need weekly visits with biweekly NSTs.

She asks you: “Why so many ultrasounds?” What do you tell her?

You tell her:“Ultrasound measurement of the fetus is the gold standard for assessing fetal growth.”

AND“We need to follow the amount of fluid around the

baby as well. If it is too low, we will need to deliver your baby early.”

Click here.

Click here next

When should we (Family Practice) Transfer care to the Obstetricians? A)Whenever you are unsure or

uncomfortable with the situation B)Definite need for C-Section C)Worsening fetal status D)Severe/worsening Maternal Disease E)Unsure of IUGR etiology F)All of the above

Answer F

Which of the following may we see after the birth of a baby with IUGR?

A) Decreased oxygen levels B) Meconium aspiration C) HypoglycemiaD) Difficulty maintaining normal body temper

atureE) PolycythemiaF) StillbirthG) All of the Above

ANSWER G

Case Close• SW remained on the family practice service

because she remained stable and her biweekly BPP and NST were reassuring.

• In the 36th week, she was found to have oligohydramnios by US AFI = 3.2 along with IUGR EFW < 10%

• Pt was at this time transferred to OB for care. • She was already known to them because we

consulted them at the first signs of IUGR.• Amniocentesis was done to ensure fetal lung

maturity and she was induced soon there after. • Patient vaginally delivered a baby with Down’s

Syndrome • No other complications at birth

Thank you