chapter 30,iugr.pptx

Chapter 30 Tina Welch,MA,RDMS,RVT,RCS,RT, ( R )  Fetal Growth Assessment  Sonographic measurements determines Intrauterine Growth Restriction (IUGR) also called SGA small for gestational age.  IUGR  a fetus at or below the 10th percentile in weight for a given ges...

Chapter 30 Tina Welch,MA,RDMS,RVT,RCS,RT, ( R )  Fetal Growth Assessment  Sonographic measurements determines Intrauterine Growth Restriction (IUGR) also called SGA small for gestational age.  IUGR  a fetus at or below the 10th percentile in weight for a given gestational age.  Earliest sonographic dating – Most accurate Gestation dating should not be changed on subsequent examinations based on measurements  MSD-used when no embryo visible – 4-5 weeks gestation Endovaginal Accuracy of MSD ± 1 week CRL-most accurate – Used 6-11 weeks – Accuracy of CRL ± 5-7 days  BPD- used 11-40 weeks – Measure outer to inner cranial boder – Accurate predicts 11-20 weeks – Accuracy ± 1 week when obtained prior to 20 weeks – 5.0 mm per week early 2nd tri – 3.6 mm per week end of 2nd tri – 2.3 mm per week mid 3rd tri – 1.5 per week late 3rd tri  If skull is round or narrow BPD is inaccurate. – Use CI measurement Measure bpd Measure occipital to frontal Obtain ratio x 100 Bpd/ofd x 100 Normal CI 70-85%  Quiz time Less than 70%= Greater than 85%-  Symmetric IUGR is a fetus that is small all over.  This does not have head sparing.  Symmetric IUGR  result of severe insult in the first trimester,  low genetic growth potential  intrauterine infection,  severe maternal malnutrition  fetal alcohol syndrome  chromosomal anomaly  congenital anomaly  Symmetric IUGR is the worse  brain is not spared causing mental deficits.   IUGR can be caused by placental insuffiency  Approximately 75% of time  This type is asymmetric  Abdomen small for gestational age  Causes of placental insuffiency  Maternal behavior  smoking  alcoholism  poor nutrition  drug use  Chronic maternal medical condition can cause IUGR  Chronic hypertension  Diabetes type 1  Anemia  Heart conditions  Chronic lung disease  thrombophilia  Placental abnormalities associated with IUGR  Abruption infarcts  Previa  Neoplasm  Vascular anastomoses  Twin to twin transfusion syndrom  Post mature pregnancy  Other causes for IUGR – High altitude – Low o2 levels – Irradiation – Maternal age 35  IUGR has been found in fetuses with no maternal factors for increased risk.  All fetuses should be evaluated for IUGR.  BPD is not ideal for diagnosing IUGR :  due to head sparing  altered head shape due to lack of amniotic fluid  Fetal abdominal circumference is altered due to the decrease of liver size reducing the AC and the reduction of fetal adipose tissue.  This is the best way to determine IUGR.  The HC to AC ratio is only useful in determining asymmetric IUGR.  Ratio is not helpful in symmetric IUGR.  Fetal weight when determined by several parameters is useful since it can show an overall reduction in fetal body mass  Placental Grade  The placenta is graded 0 to 3.  Determines placental maturity  The placenta may be useful in determining IUGR.  A placenta that is a grade 3 before 36 weeks or with a thickness of less than 1.5 cm are signs.  Only 10% – 15% of term placentas are grade 3  Placental thickness should not be greater than 5 cm.  Maternal portion placenta – Basal plate or decidua basalis – Fetal surface Chorionic plate – Umbilical cord should insert centrally  Placental responsible for – fetal metabolism – Nutrition – Excretion of waste – Protection – Storage Placenta produces HCG Estrogen progesterone  Localize placental in relation to internal cervical os – Low lying 1-2 cm from os – Do not diagnosis low lying placental until after 32 weeks migration  BPP High risk factors require extra exams – Fetal macrosomia due to macrosomia – Maternal renal disease,hypertension and IUGR Assess fetal distress due to asphyxia – Hypoxia – Acidosis – IUGR  BPP  Biophysical Profile (BPP)  determine fetal well being or distress  BPP parameters  Fetus has 30 minutes to demonstrate  Cardiac non-stress test (NST) –we don’t perform  Fetal breathing movements (FBM)30-60 seconds  Gross fetal body movements (FM)3 body movements  Fetal tone (FT) 1 episode flexion or extension  Amniotic fluid volume (AFV) 1 pocket measures 2 cm in vertical diameter  Score of 2 for demonstration of each criteria for possible 8 points.  Non-stress test adds 2 more points totalling possible 10.  Zero is given if criteria not demonstrated  A normal or reactive test is given 2 points and occurs when the fetal heart rate increases by 15 BPM or more twice in the study, accelerations last a least 15 seconds, and gross fetal movements are noted over 20 minutes without late decelerations. NST is done using Doppler to record fetal heart rate and its reactivity to uterine contractions.  Fetal breathing movements – This is positive when the fetal chest is seen moving inward and the abdominal wall is moving outward. It may also be documented by the movement of the kidneys (like ours move during respiration).  At least one episode lasting 30 seconds during a 30 minute study gives 2 points.  These patterns vary with the sleep-wake cycle.  Fetus with a score of 0/10 or 2/10 is at high risk for mortality and permanent morbidity.  Doppler Ultrasound  Qualitative Doppler Assessment (approximate flow resistance) can be done with:  systolic to diastolic ratio (S/D ratio) S/D  resistance index (RI)( S-D)/S  pulsatility index (PI)(S-D)/Mean   With IUGR, vascular resistance increases in the aorta and umbilical artery.  A Doppler wave form should be obtained in the umbilical artery.  The peak (systole) of one wave and the trough (diastole) should be measured. Some authors say that a S/D ratio of 3 or above after 30 weeks is at high risk.  Abnormal characterisitics  High resistance  Diastolic flow decreased  Absent diastolic flow after 18-20 weeks  Reversed end-diastolic flow >>>>>>>>>Early delivery Normal Umbilical artery waveform Abnormal  Large for gestational age  A birth weight of 4000 g (8lbs 13 oz) or greater or above the 90th percentile for the EGA. EFW above 45oo grams  High risk for maternal and fetal injury  Shoulder dystocia  Fractures  Facial and brachial plexus palsies  Risk Factors  Gestational diabetes  Type 1 or type 2 diabetes  Multiparty  Advanced maternal age  Excessive maternal weight gain  Obesity  Post term delivery  History of LGA fetus  If you ever have to convert grams to pounds, just move the decimal 3 places left and multiply by 2.2. Example 2000g would be 2.0 x 2.2 or 4.4 pounds. 3500 would be 3.5 x 2.2 or 7.7 lbs.  Accurate diagnosis of macrosomia is invaluable to the physician delivering the fetus. A BPD above the 97th percentile is indicative of macrosomia. When abdominal circumference increases more than 1.2 cm/ week between weeks 32 and 39 it indicates possible macrosomia.  Fetal weight estimates are useful, but not perfect due to the different parameters used.  FL/AC ratio is questionable.  Chest circumference is useful when used with the BPD. Chest circumference is taken at the level of the upper abdomen just below the area of cardiac visualization. When the BPD is subtracted from the chest circ. if the result is 1.4 cm or greater, this is a good indicator.