ASSESSMENT OF Fetal Well-beingLectures 3

Assessment of fetal well-beingThe major expected outcome is the detection of potential fetal compromiseUsed before intrauterine asphyxia of the fetus and health care provider can take measures to prevent or minimize adverse perinatal outcomesFirst- and second-trimester antepartal assessment is directed primarily at the diagnosis of fetal anomalies. The goal of third-trimester testing is to determine whether the intrauterine environment continues to be supportive to the fetus.

Daily Fetal Movement Counts

Daily Fetal Movement Counts Kick CountsAssessment of fetal activity by the motherNon-invasive, inexpensive, simple to understand, and does not interfere with routine at homeonce a day, roughly at the same time every day in a comfortable sitting or lying positionwhen baby is usually active (after meals, after activity, and in the evening). Since healthy babies have sleep cycles, baby may not kick, or kick less than usual, or have less than 10 kicks in 2 hours. If so, wake up the baby by drinking fluid or by walking for 5 minutes. Repeat the kick count.

Daily Fetal Movement Counts Kick CountsNo less than3 movements in 30 minutes Most healthy babies should take less than 2 hours for 10 kicks. not moved 10 times in 2 hours or the baby has sustained significant changes. Fetal alarm signal if no movement in 12 hoursThe evaluation may include: Ultrasound - taking pictures from sound waves to evaluate the growth of the baby, amniotic fluid quantity, placenta, blood flow pattern etc. Non stress test (NST) -Baby's heart rate monitoring in response to its own movements Biophysical profile (BPP) -using an ultrasound exam with a non stress test (NST) to evaluate baby's heart rate, breathing, body movement, muscle tone, and amniotic fluid quantity Contraction stress test (CST) -Baby's heart rate monitoring in response to uterine contractions

OBSTETRICULTRASOUND

*Ultrasound in obstetrics can provide good information about the fetus and its environment

With ultrasound, can be determined an early intervention or conservative management in pregnancy Latest developments in ultrasound examination is a transvaginal ultrasound discovery - the observation of "FLOW DOPLLER" and the most sophisticated ultrasound 3 D and 4D which has a high ability to determine fetal condition

UltrasonographyIndications for useFetal heart rate activityGestational ageFetal growthFetal anatomyFetal genetic disorders and physical anomaliesPlacental position and functionvisual assistance to other invasive testsFetal well-being

UltrasonographyAbdominal After 1 trimester Full bladerVaginal1 trimesterEarly diagnostic of uterine pregnancy Empty blader Obese woman

UltrasonographyAn important and safe technique in antepartum fetal surveillance Levels of ultrasonography:Standard examinationUsed for specific indications, i.e., fetal viability, fetal presentation, gestational age, locate the placenta, fetal anatomy and malformationSpecialized or targeted examinationSuspicion of an abnormal fetus (abnormal finding on clinical examination, poly- or oligohydramnionios, elevated AFP)

Ultrasonography: Indication for use 1 trimesterNumber, size, location of gestational sacFetal cardiac and body movementUterine abnormalities (bicornuate uterus, uterine fibroid, IUD) or adnexal massesDuration of pregnancy (crown-rump length)Visualization during chorionic villus sampling

*Ultrasonography: Indication for use ( 2nd and 3rd trimester )Fetal viability, number and presentation, Establishment of fetal age and growth by fetal biometry including:BPD ~ biparietal diameterFL ~ femur lengthAC ~ Abdominal circumferenceBiophysical profileEvaluation of fetal anatomic structures: Cerebral lateral ventriclesSpine Four chamber view of the heartStomach-bowel, abdominal wall at the area of the umbilical cord insertionBladder and kidneyLimbs and umbilical cordAmount of amniotic fluid Placental localization and maturityEvaluation of the uterine, and adnexae for abnormalities and massesCervical lengthVisual assistance to invasive tests

Fetal heart activity6-7 weeks by echo scaner10-12 weeks by DooplerFetal viability Fetal cardiac activityFetal movementBreathing movement

Gestational ageGestational sac dimensions (about 8 weeks)Crown-rump length (7-12 weeks)Biparietal diameter (after 12 weeks)Femur length (after 12 weeks)

BPD, FL and AC the most important parameters for determination of gestational age Determination of gestational age should be performed prior to 26 weeks gestational age 3rd trimester determination of gestational age does not acurately reflect gestational age

Fetal growthBPD ~ biparietal diameter FL ~ femur lengthAC ~ Abdominal circumference

Discrepancy resulting from inaccurate dates True intrauterine growth restriction (IUGR)Symmetric - the fetus being small in all parameters, reflects a chronic or long-standing insult and may be caused by low genetic growth potential, intrauterine infection, undernutrition, heavy smoking, or chromosomal aberration. Asymmetric - head and body growth varying, suggests an acute or late-occurring deprivation, such as placental insufficiency resulting from hypertension, renal disease, or cardiovascular disease.

Macrosomia - weighing more than 4000 g, associated with maternal glucose intolerance, carries an increased risk of intrauterine fetal death, and at increased risk for trauma during birth.

*

Ultrasonography: gestational agea In decreasing orderb Only if cephalic index ( BPD divided by occipital-frontal diameter ) is normal ( 76-84%) ; otherwise , the fetal head may be dolichocephalic or brachycephalic

**1st trimester fetus CRL

**28 mm CRL in 10 weeks twin pregnancy

**Biparietal Diametera cross section through the fetal head at the level of the thalamus. The skull is represented by the thick white lines which surround the brain. This view is used to measure the biparietal diameter (line) and the circumference of the head (dots).

**Fetal Femur

**Pregnant uterus - longitudinal

**Fetal : intracranial structure and extremity

Fetal anatomyHead (ventricles, blood vessels)NeckSpineHeartStomachSmall bowelLiverKidneyBlader Limb

**Fetal CardiacStructure

**Fetal Liver andLung interface

**Fetal Liver3rd Trimester

**Fetal Spine

**Spine3 D

*Neural tube defectsNTDs result from failure of tube closure by the 6th weeks gestational age (embryonic age 26 28 days )Various NTDs anomalies :AnencephalyEncephaloceleSpina Bifida

*Gross malformation may be detected in 1st trimester sonogram 1: Anencephalus (absence of a major portion of the brain, skull, and scalp)

Acrania (partial or complete absence of the cranium).

**

**Spina BifidaConsist of a hiatus, usually in the lumbosacral vertebrae, through which a meningeal sac may protruded meningocele90% of cases, the sac contains neural elements meningomyeloceleThe fetal spine should be examined by sonography with: sagittal, tranverse and coronal views

**SpinaBifida

**NEURAL TUBE DEFECTS

**NEURAL TUBE DEFECTS

*Fetal anatomyGross malformation may be detected in 1st trimester sonogram 2: Hydrancephaly (the cerebral hemispheres are absent and replaced by sacs filled with cerebrospinal fluid

Cystic Hygroma (is a congenital multiloculated lymphatic lesion that can arise anywhere, but is classically found in the left posterior triangle of the neck.

**Abdominal Wall DefectsThe two most common are :OmphaloceleGastroschisis

Can be ascertained early in pregnancy by maternal serum alphafetoprotein screening programs

*Gross malformation may be detected in 1st trimester sonogram 3: Omphalocele (abdominal wall defect in which the intestines, liver, and occasionally other organs remain outside of the abdomen in a sac)

Gastroschisis (paraomphalocele congenital abdominal wall defect in which the intestines and sometimes other organs develop outside the fetal abdomen through an opening in the abdominal wall)

OMPHALOCELE

**GASTROSCHISIS

**Duodenal atresiaDiagnosed prenatally by the demonstration of the double bubble sign ( distension of the stomach and first part of the duodenum ) Must be differentiated from other cystic structures in the upper abdomenDiagnosis generally is not possible before 24 weeks30% of cases has been associated with trisomy 21

*Gross malformation may be detected in 1st trimester sonogram 4: Fused twins (Siamese twins) are identical twins whose bodies are joined in utero

*Fetal genetic Disorders Nuchal TranslucencyThe maximum thickness of the subcutaneus translucent area between the skin and the soft tissues overlying the posterior aspect of the cervical spine in sagital scane plane. (10-14 weeks)A thickness > 3 mm ( sagital plane):90% trisomy 18 and 1380% trisomy 215% normal

Placenta position and functionLocationRelationship between cervical osMaturation

*Uterus and Adnexa Cervical incompetence :Tunneling of the internal ( dilatation )Cervical length < 3 cmBulging membranes ( with or without prolaps of the cord or fetal parts )30 weeks of gestational age: length of cervix more than 3 cmAdnexal mass :Physiological: Diameter corpus luteum at pregnancy about 2 cmUterine fibroid

*Sonographic assesment of the amniotic fluidNormal : at 2nd and 3rd trimester vertical pocket about 2 cmAFI ( amniotic fluid index ): sum of the depth of the largest pocket of fluid in the four quadrants of abdomen AFI < 5 cm : strongly asociated with oligohidramnions postmaturity

**Amniotic FluidIndex

Interpretation of the AFl

10.1 to 24.0 cm Normal5.1 to 10.0 cm BorderlineLess than or equal 5.0 cm Abnormal (Oligohydramnios)Greater than 24.0 cm Abnormal (Polyhydramnios) Oligohydramnios is associated with congenital abnomalies (ex. renal agenesis) growth restriction fetal distress

Polyhydramnios is associated with neural tube defects obstruction of the fetal gastrointestinal tract, multiple fetuses and fetal hydrops

*DOPPLER VELOCIMETRYThe primary use of Doppler echo shifts in obstetrics have been to detect and measured blood flow Basis of Doppler Velocimetry : The sound of moving blood cells within vasculature generates an effective Doppler Shift There are 2 methods of estimating circulatory hemodynamics :Direct measurement of the volume of blood flowIndirect estimation of flow velocity using wave form analysis

DOPPLER VELOCIMETRYThe shifted frequencies can be displayed as a plot of velocity versus time, and the shape of these waveform can be analyzed to give information about blood flow and resistance in a given circulationVelocity waveforms from umbilical and uterine arteries, reported as systolic/diastolic (S/D) ratio achieve

*Most fetuses will achieve an S/D ratios of 3 or less by 30 weeksPersistent elevation of S/D ratios after 30 weeks is associated with IUGR resulting from uteroplacental insuficiencyIn postterm pregnancies an elevated S/D ratio indicates a poorly perfused placentaAbnormal result are seen with chromosome abnomalities in the fetusDOPPLER VELOCIMETRY

**Fetal Umbilical Cord Doppler

DOPPLER VELOCIMETRY

**Fetal Breathing Movement

**Fetal Umbilical arteryand Bladder

Biophysical profile (BPP)Real-time ultrasound permits detailed assessment of the physical and physiologic characteristics of the developing fetus and cataloging of normal and abnormal biophysical responses to stimuli. The biophysical profile (BPP) is a noninvasive dynamic assessment of a fetus and its environment by ultrasonography and external fetal monitoring. BPP scoring is a method of fetal risk surveillance based on the assessment of both acute and chronic markers of nonreassuring fetal status. The BPP includes:fetal breathing movements, fetal movements, fetal tone, fetal heart rate patterns by means of a nonstress test, AFV; The fetal response to central hypoxia is alteration in movement, muscle tone, breathing, and heart rate patterns. The presence of normal fetal biophysical activities indicates that the central nervous system (CNS) is functional and the fetus therefore is not hypoxemic

Biophysical profile (BPP)

Biophysical profile (BPP)The BPP is an accurate indicator of impending fetal death. Fetal acidosis can be diagnosed early with a nonreactive nonstress test and absent fetal breathing movements. An abnormal BPP score and oligohydramnios are indications that labor should be induced.Fetal infection in women whose membranes rupture prematurely (at less than 37 weeks of gestation) can be diagnosed early by changes in biophysical activity that precede the clinical signs of infection and indicate the necessity for immediate birth. When the BPP score is normal and the risk of fetal death low, intervention is indicated only for obstetric or maternal factors.

Magnetic resonance imaging

Magnetic resonance imaging (MRI)Noninvasive radiologic techniqueLike CT provides pictures of soft tissueUnlike CT is not use ionizing radiation

Magnetic resonance imaging (MRI)Fetal structurePlacenta (position, density, and presence of gestational trophoblastic disease) Quantity of amniotic fluidMaternal structures (uterus, cervix, adnexa, and pelvis)Biochemical status of tissues and organsSoft tissue, metabolic, or functional anomalies

BIOCHEMICAL ASSESSMENT

BIOCHEMICAL ASSESSMENTInvolves biological examination and chemical determinationProcedures used to obtain needed speciment AmniocentesisPercutaneous umbilical blood samplingChorionic villus samplingMaternal sampling

BIOCHEMICAL ASSESSMENT. Amniocentesis

AmniocentesisFirst introduced by Serr and Fuchs and Riis in the 1950s for fetal sex determinationOnly at the late 70th a static ultrasound was used to locate the placenta and amniotic fluid pocketOnly In 1983, Jeanty reported a technique of amniocentesis under ultrasound vision

Amniocentesis is perform to obtain amniotic fluid, which contains fetal cells. Under direct ultrasonographic visualization, a needle is inserted transabdominally into the uterus, amniotic fluid is withdraw into a syringe, and the various assessment are performed

Amniocentesis: IndicationsGenetic disorderswomen more than 35 years old, with a previous child with a chromosomal abnormality, or with a family history of chromosomal anomalies. Inherited errors of metabolism (such as Tay-Sachs disease, hemophilia, and thalassemia) and other disorders for which marker genes are known may also be detected.Cells are cultured for karyotyping of chromosomes. Karyotyping also permits determination of fetal sex, which is important if a sexlmked disorder is suspected.Alpha-fetoprotein (AFP) levels are assessed as a followup for elevated levels in maternal serum. High AFP levels in amniotic fluid help confirm the diagnosis of a neural tube defect such as spina bifida or anencephaly or an abdominal wall defect such as omphalocele. AFP levels may also be elevated in a normal multifetal pregnancy and with intestinal atresia, presumably caused by lack of fetal swallowing.

Assessment of pulmonary maturity L/S > 2:1Diagnosis of fetal hemolytic disesasebilirubin level < 0.015

AmniocentesisAfter 10-14 weeks gestationEarly earlier than 15 weeks Late second trimester after 15 weeksOnly the amniotic (inner) sac should be aspiratedApproximately 1 cc for gestational agelaboratory failure op to 20%

ComplicationsLeakage of amniotic fluid (better prognosis than spontaneous leakage)AmnionitisVaginal bleeding Needle puncture of the fetusLong term complications:Respiratory distress??Isoimmunization??

AmniocentesisMaternal complicationsHemorrhageFetomaternal hemorrhage with possible maternal Rh isoimmunizationInfectionLaborAbruptio placentaeDamage to intestines or bladderAmniotic fluid embolismFetal complicationsDeathHemorrhageInfection (amnionitis)Direct injury from the needleMiscarriage or preterm laborLeakage of amniotic fluid

Amniocentesis and HIV positive women Increased rate of vertical transmissionChemoprophylaxis previous to amniocentesis appears to be beneficial in preventing vertical transmission

Multiple GestationThree methods:Indigo carmine injection to the first sacA single needle puncture sampling technique (Jeanty 1990)Simultaneous visualization of two needles on each side of the separating membrane (Bahado-Singh 1992) Abortion risk probably higherDetailed description of fetus position and placental location

BIOCHEMICAL ASSESSMENT

Percutaneous umbilical blood sampling (CORDOCENTESIS)

CORDOCENTESISInvolves the insertion of the needle directly into fetal umbilical vessel under ultrasound guidance and the removing 1-4 ml of blood

CORDOCENTESISIndications for usePrenatal diagnosis of inherited blood disordersKaryotyping of malformed fetusesDetection of fetal infectionDetermination of the acid-base status of fetuses with IUGRAssessment and treatment of isoimmunization and trombocytopenia in the fetus

CORDOCENTESIS. ComplicationsBlood leaking from puncture siteCord lacerationThromboembolismPreterm labourPremature rupture of membranesInfections

BIOCHEMICAL ASSESSMENT

Chorionic villus sampling

Chorionic villus sampling (CVS)

Earlier diagnosis and rapid results Performed between 10 and 12 weeks of gestationRemoval of small tissue specimen from fetal portion of placentaChorionic villi originate in zygote and reflects genetic makeup of fetus

Chorionic villus samplingWas developed in the 80thpercutaneous transabdominaltransvaginal transcervical

Chorionic villus sampling (CVS)Complications:vaginal spotting or bleeding immediately afterward,MiscarriageRupture of membranes, chorioamnionitis.Because of the possibility of fetomaternal hemorrhage, women who are Rh negative should receive immune globulin (RhoGAM) to avoid isoimmunization.

Chemical determination

SERUM MARKERSerum markermaternal serum alphafetoprotein MS-AFPmaternal unconjugated estriolmaternal serum beta-human chorionic gonadotropin (hCG)Others Pregnancy associated plasma protein - A (PAPP-A) Inhibin A

SERUM MARKERPositive test indicates increased riskNegative test indicates no increased risk but not mean normal fetusMultiple fetuses cannot be assessed

AFPAFP is produced by the fetal liver, and increasing levels are detectable in the serum of pregnant women from 14 to 34 weeks.Approximately 80% to 85% of all open NTDs and open abdominal wall defects Screening is recommended for all pregnant women.If findings are abnormal, follow-up procedures include genetic counseling for families with a history of NTD, repeat AFP, ultrasound examination, and possibly amniocentesis.

Triple screening (16-18 weeks)Maternal serum alpha-fetoprotein (MS-AFP)Human chorionic gonadotropin (hCG)Unconjugated estriol (UE3)

Quadruple Screen (15-22 weeks most accurate 16-18 weeks)AFP hCGUE3Inhibin

Quadruple ScreenDown SyndromePAPP-A is lowInhibin A is elevated

Electronic fetal monitoring

Indications for Electronic Fetal Monitoring Assessment Using NST and CSTMaternal diabetes mellitus Chronic hypertensionHypertensive disorders in pregnancyIUGRSickle cell diseaseMaternal cyanotic heart diseasePostmaturityHistory of previous stillbirthDecreased fetal movementIsoimmunizationMeconium-stained amniotic fluid at third-trimester amniocentesisHyperthyroidismCollagen diseaseOlder pregnant womanChronic renal disease

Contraindications for Electronic Fetal Monitoring AssessmentNSTNo but results may not be conclusive if gestation is 26 weeks or less.CST :rupture of membranes, previous classic incision for cesarean birth, preterm labor, placenta previa,placenta abruptio

multifetal pregnancy, previous preterm labor,hydramnios, more than 36 weeks of gestation, incompetent cervix

Fetal Responses to Hypoxia or Asphyxia

Hypoxia or asphyxia elicits a number of responses in the fetus. There is a redistribution of blood flow to certain vital organs. This series of responses (redistribution of blood flow favoring vital organs, decrease in total oxygen consumption, and switch to anaerobic glycolysis) is a temporary mechanism that enables the fetus to survive up to 30 minutes of limited oxygen supply without decompensation of vital organs.However, during more severe asphyxia or sustained hypoxemia, these compensatory responses are no longer maintained, and a decrease in the cardiac output, arterial blood pressure, and blood flow to the brain and heart occurs, with characteristic FHR patterns reflecting these changes.

Fetal heart rate terminologyBaseline rate-110-160Bradycardia&TachicardiaVariability-Longterm & Short termAccelerationDeceleration-Early-Late-Varible

NSTis the most widely applied technique for antepartum evaluation of the fetus.Basis: the normal fetus will produce characteristic heart rate patterns in response to fetal movement. can be performed easily in an outpatient setting because it is noninvasive. relatively inexpensive and has no known contraindications. Disadvantages center around the high rate of false-positive results for nonreactivity as a result of fetal sleep cycles, medications, and fetal immaturity. The test is also slightly less sensitive in detecting fetal compromise than are the CST and BPP.

NST InterpretationTwo or more accelerations of 15 beats per minute lasting for 15 seconds over a 20-minute periodNormal baseline rateLong-term variability amplitude of 10 or more beats per minute

If the test does not meet the criteria after 40 minutes, it is considered nonreactive, in which case further assessments are needed with a CST or BPP. twice weekly (after 28 weeks of gestation) with patients who are diabetic or at risk for fetal death.

NSTReactive 2 or more accelerations of FHR of 15 beats/min lasting 15 sec, associated with each fetal movement in 20-min periodAllow to continueNonreactiveAny tracing with either no FHR accelerations or accelerations

CSTUterine contractions decrease uterine blood flow and placental perfusion. If this decrease is sufficient to produce hypoxia in the fetus, a deceleration in FHR will result, beginning at the peak of the contraction and persisting after its conclusion (late deceleration).Nipple-Stimulated 10 min massage 2 min massage 5 min breakOxitocin-Stimulated10 U in 1000 ml fluid IV

CSTNEGATIVENo late decelerations, with minimum of three uterine contractions lasting 40 to 60 sec within 10-min period Reassurance that the fetus is likely to survive labor should it occur within 1 wk; more frequent testing may be indicated by clinical situationPOSITIVEPersistent and consistent late decelerations occurring with more than half of contractionsManagement lies between use of other tools of fetal assessment such as BPP and termination of pregnancy; a positive test result indicates that fetus is at increased risk for perinatal morbidity and mortality; physician may perform expeditious vaginal birth after successful induction or may proceed directly to cesarean birth; decision to intervene is determined by fetal monitoring and presence of FHR reactivitySUSPICIOUSLate decelerations occurring in less than half of uterine contractions once adequate contraction pattern establishedNST and CST should be repeated within 24 hr; if interpretable data cannot be achieved, other methods of fetal assessment must be used*HYPERSTIMULATIONLate decelerations occurring with excessive uterine activity (contractions more often than every 2 min or lasting longer than 90 sec) or persistent increase in uterine tone UNSATISFACTORYInadequate uterine contraction pattern or tracing too poor

CST

!

**********************************************