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what is the fundal height measurement?
- with external palpation of the uterus and measurement of the distance from the symphysis pubis to the uterine fundas by the referring physician
fundal hight measurement if not highly accurate and may not always be a reflection of excessive fetal growth because is can be affected by multiple factors including? (5)
- technique of clinician
- maternal weight
- fetal position
- increase in amniotic fluid
- size of the placenta
fetal weight estimation incorpotates several fetal parameter including? (4)
- biparietal diameter
- HC
- AC
- femur length
what is large for gestational age? (LGA)
- Estimated fetal weight is greater than the 90th percentile for GA
what is macrosomia?
determined when the estimated fetal weight is greater than or equal to 4500g
macrosomia is defined as?
- an abnormally large size of the body
- refers to entire fetus, neonate, or newborn
macrosomia in respect to delivery?
any fetus that is too large for the maternal pelvis through which it must pass is macrosomic
The most straightforward approach to the sonographic
determination of macrosomia is ?
to use estimated fetal weight
Risk factors of macrosomia?
- gestational diabetes (40% of cases)
- enlargement of placenta
how is placental thickness obtained?
- at a right angle to its long axis that measures >3cm before 20 weeks GA or
- > 5cm before 40 weeks GA is considered abnormal
risk of macrosomia- perinatal complications? (8)
Shoulder dystocia soft tissue trauma humeral and clavicular fractures brachial plexus injury facial palsies meconium aspiration prolonged labor asphyxial injuries
shoulder dystocia occurs when?
the arm of the fetus prevents or complicates delivery and may result in serious traumatic injury
Evidence strongly suggests an increased risk of prenatal complications for pregnancies with fetuses weighing greater than?
4500 gms
The sonographic fetal AC measurement has been determined to be helpful in identification of?
potential macrosomic infants
Hydrops fetalis is also associated with macrosomia and may manifest sonographically with one or more of the following? (7)
Increased placental thickness Increased thickness of scalp Body wall greater than 5 mm Hepatosplenomegaly Pleural and pericardial effusions Ascites Structural fetal anomalies
what is a single pocket assesment?
performed with identification of the largest vertical pocket of amniotic fluid and measurement of the anteroposterior depth
Polyhydramnios is indicated when the pocket exceeds?
8 cm
Oligohydramnios is indicated when the pocket is less than?
2cm
what does AFI method involve?
method involves dividing the maternal uterus into four quadrants and adding the anterior-to-posterior measurements of the amniotic fluid in each of the quadrants
The AFI total is normally?
10 to 13 ± 5 cm
The normal range for the AFI is usually
5-20 cm
A 21-year-old woman is seen for an obstetric examination with an indication of large for gestational age at 28 weeks by first-trimester sonography. The sonogram shows a fetus measuring 28 weeks. The AFI is 25 cm. What is the most likely diagnosis?
Polyhydramnios
A 29-year-old woman presents for obstetric sonography at 35 weeks’ gestation. She has a history of gestational diabetes in two prior pregnancies. Sonograms at 11 weeks and 23 weeks have confirmed gestational age and have been otherwise unremarkable. The current examination reveals an average sonographic age of 38 weeks, 4 days. The placenta appears generous in size, measuring 6.2 cm. What is the most likely diagnosis?
Microsomia
A 22-year-old woman is seen for an obstetric sonogram at 16 weeks’ gestation by LMP for increased uterine size and absent heart tones. The sonogram shows a large heterogeneous mass within the uterus. No identifiable fetus or amniotic fluid can be detected. What is the most likely diagnosis?
Hydatidiform mole
25-year-old woman is referred for sonographic dating, with unknown LMP, no prior studies, and a fundal height measuring approximately 35 weeks. The average of four fetal parameters measured calculate to 32 weeks. AFI measures 17 cm. What is the most likely diagnosis?
The fetus is most likely normal, with mild polyhydramnios
The functions of amniotic fluid are?
Preventing fetal injury, regulating temperature, providing mobility for practicing breathing, swallowing exercises, fighting infection, discouraging contractions, and maintaining cervical length and consistency
Oligohydramnios?
- significant decrease in the normal volume of amniotic fluid
- patients may notice a decrease fetal activity
Amniotic fluid volume (AFV) results from?
a balance between what enters and exists from the amniotic cavity
a decrease in AFV is directly correlated with?
perinatal mortality and many serious morbidities
Renal agenesis?
- congenital absence of one or both kidneys from the complete lack of formation
- incidence rate of renal agenesis is 1 in 3000 births in 1 in 250 still births
- more common in males
Bilateral absence of the kidneys is more common in?
twins than singletons
Autosomal recessive polycystic kidney disease (ARPKD) si caused by?
mutations in the PKHD1 gene and is characterized by nonobstructive dilations of the collecting ducts in the kidneys and hepatic fibrosis
Hydronephrosis
Dilation of the renal collecting system
hydronephrosis mild, moderate, severe
Mild hydronephrosis: dilation of the renal pelvis
Moderate hydronephrosis: dilation of the renal pelvis and calyces
Severe hydronephrosis: gross dilation of the collecting system with a decrease in the renal cortical tissue
mild pyelectasis has been associated with?
down syndrome
Oligohydramnios occurs when?
the obstruction is severe, bilateral, or associated with a serious contralateral anomaly
The most common congenital obstructive genitourinary anomalies?
Ureteropelvic junction (UPJ) obstruction Ureterovesical junction (UVJ) obstruction Posterior urethral valves (PUV)
Posterior urethral valves - PUV?
The most common cause of bladder outlet obstruction resulting from the development of abnormal valves in the posterior urethra
PUV is accompanied by?
- enlarged bladder
- bilateral hydronephrosis
- hydroureters
PUV occurs in?
occurs only in male fetuses and may be accompanied by prune-belly syndrome
female version of PUV?
has similar findings occurs with urethral atresia
treatment when PUV is identified early in pregnancy?
- Patients may be offered prenatal vesicoamniotic shunting to decompress the bladder and kidneys
- Provides a pathway for fluid from the fetus into the amniotic cavity
- If successful, this shunt also aids in fetal lung development and reduces fetal growth restriction anomalies
Intrauterine growth restriction-IUGR refers to?
a fetus that has not reached growth potential because of genetic or environmental factors
SGA is generally defined as?
a birth weight or fetal weight less than the 10th percentile at any given gestational age
why must you distinguish SGA from IUGR?
IUGR is associated with stillbirth, neonatal death, and perinatal morbidity
2 subdivisions of IUGR?
- symmetric
- asymmetric
symmetric IUGR?
20-30%
- both the fetal head and the abdomen are proportionately decreased
symmetric IUGR is associated with?
with intrinsic insults, such as: chromosomal alterations or fetal infections (toxoplasmosis, cytomegalovirus)
asymmetric IUGR?
(70-80%)
- a greater decrease in abdominal size is seen
Associated with extrinsic insults such as placental insufficiency
asymmetric IUGR placental factors?
Tumors and placental or umbilical cord accidents or abnormalities (velamentous or marginal cord insertion)
Maternal causes of IUGR?
Maternal diseases that compromise oxygen availability or cause endothelial vascular damage are associated with fetal growth restriction:
Hypertension Renal disease Insulin-dependent diabetes mellitus Systemic lupus erythematosus Sickle cell anemia Severe lung disease Cyanotic heart disease
Pre-eclampsia is characterized by?
by the new onset of hypertension and proteinuria after 20 weeks of gestation
pre-eclampsia risk factors?
History of preeclampsia first pregnancy family history multiple gestation obesity preexisting hypertension renal disease collagen vascular disease advanced age prolonged interval between pregnancies change of partners between pregnancies
Preeclampsia may cause?
fetal growth failure, especially when the onset is early
The finding of IUGR in the context of preeclampsia?
makes that condition severe and is considered an indication for delivery
Evaluation and management of fetuses suspected to have IUGR is based on?
serial sonographic examinations
examination of symmetric IUGR?
Measurements of the fetal head, abdomen, and femur that all are below the expected values for a given gestational age
examination of asymmetric IUGR?
The abdominal circumference is smaller than expected, but fetal head and femur measurements are appropriate for gestational age
Doppler findings with IUGR?
- An increase in the ratio of systolic to diastolic flow in the umbilical artery
- An increase in the pulsatility index and resistive index are indicative of increasing placental resistance and poor fetal outcome
- Diastolic flow may eventually disappear or may reverse in direction toward the fetus
