1. OBSTETRICAL ULTRASOUNDBy
Dr/ Dina Metwaly

2. Obstetrical Ultrasound
Indications:
Unsure last menstrual period
Vaginal bleeding during pregnancy
Uterine size not equal to expected for dates
Use of ovulation-inducing drugs confirm early pregnancy
Obstetric complications in a prior pregnancy: ectopic, preterm delivery
Screen for fetal anomaly: abnormal serum screens, certain drug exposure in early pregnancy, maternal diabetes. Rhisoimmunization
Postdate fetus
Twins (monochorionic)
Intrauterine growth restriction (IUGR)

3. FIRST TRIMESTER ULTRASOUND

4. ROLE OF ULTRASOUND
Ultrasound is a valuable diagnostic tool in assessing the following indications:
Unsure of Dates
Vaginal Bleeding
Pelvic Pain
Exclude an ectopic pregnancy
Maternal past history ( Threatened Miscarriage )
Nuchal Translucency (11-14 weeks : CRL 45-84mm)
EQUIPMENT SELECTION AND TECHNIQUE
Use a curvilinear probe (3.5-6MHZ) with low power to reduce risk of biological effects. use of doppler should be avoided in the 1st trimester.
Transvaginal probe approx 5-9 MHz

5. SCANNING TECHNIQUE PATIENT PREPARATION
Confirm presence of intrauterine gestation, and number
Look for bright trophoblastic reaction around sac.
Assess maternal ovaries, adnexae and Pouch Of Douglas (P.O.D)
Cervix = assess if closed and measure length between internal and external os
If multiple pregnancy, confirm number of foetuses, number of sacs, and number of placentas present to determine chorionicity. ie Monochorionic/Monoamnionic(MCMA),Monochorionic/Diamni onic(MCDA),Dichorionic/Diamnionic(DCDA)
Confirm heart beat(s) & rate with M-Mode only (Use of Colour or Doppler traces is not recommended in the 1st trimester)
Measure CRL to calculate gestational age and Estimated Date of Delivery(EDD). If too early to see the foetal pole measure the average sac diameter.

6. Items must be examined in 1st. Trimester (less than 12 weeks)
Gestational sac location / size / shape
Yolk sac & Amnion
Crown rumple length (CRL) & Embryo
Fetal cardiac activity (heart beat)
Amnionitic fluid
Fetal morphology>11 weeks)
Cranium
Heart
Stomach/Bladder/Cord insertion/presence of limbs, hands and feet

7. GESTATIONAL SAC
The gestational sac(GS) is the earliest sonographic finding in pregnancy.
The GS is an echogenic ring surrounding an anechoic centre.
An ectopic pregnancy will appear the same but it will not be within the endometrial cavity.
The GS is not identifiable until approximately 4 & 1/2 weeks with a transvaginal scan.
The GS grow at least 0.6 mm daily.
Gestational sac: seen at 4 weeks, fluid filled with echogenic border

8. YOLK SAC &Amnion The yolk sac appears during the 5th week.
It is the second structure to appear after the GS.
It should be round with an anechoic centre.
It should not be calcified or >5mm from the inner to inner diameter.
Yolk sacs larger than 6 mm are usually indicative of an abnormal pregnancy.
Failure to identify (with transvaginal ultrasound) a yolk sac when the gestational sac has grown to 12 mm is also usually indicative of a failed pregnancy.

9. a transvaginal approach the gestational sac can be seen during week 4-5.
Mean Sac Diameter measurement is used to determine gestational age before a Crown Rump length can be clearly measured.The average sac diameter is determined by measuring the length,width and height then dividing by 3 .
5 week gestation. Yolk Sac Only seen.The yolk sac will be visible before a clearly definable embryonic pole. 

10. CROWN RUMP LENGTH (CRL) & Embryo
CRL(Crown Rump Length):
Longest length excluding limbs and yolk sac
Made between 7 to 13 weeks
Fetal CRL in centimeters plus equals gestational age in weeks

11. HEART BEAT
An intrauterine gestational sac should be visualized by transvaginal ultrasound with β-hCG values between 1000 and 2000 IU and abdominal exam IU
Visible heart activity: 43 days (6.1w)
Normal heart rate at 6 weeks: bpm
At 9 weeks: bpm.

12. The very early embryonic heart measured using M-Mode
The Crown Rump Length (CRL) measurement in a 6 week gestation.

13. Nuchal translucency:
Translucent space between the back of the neck and the overlying skin
The scan is obtained with the fetus in sagittal section and a neutral position .
The fetal image is enlarged to fill 75% of the screen, and the maximum thickness is measured, from leading edge to leading edge. (inner to inner measurement)
> 6 mm considered abnormal

14. Obstetrical Ultrasound
Ultrasound findings in a pregnancy destined to abort include:
A poorly-defined, irregular gestational sac
A large yolk sac (6 mm or greater in size)
Low site of sac location in the uterus
Empty gestational sac at 8 weeks' gestational age (the blighted ovum).

15. 2nd trimester ULTRASOUND 18-20 WEEKS - (MORPHOLOGY SCAN)

16. 2nd TRIMESTER ULTRASOUND PROTOCOL
ROLE OF ULTRASOUND
In the 2nd trimester, ultrasound is essential for assessing the
Current viability
Structural integrity of the foetus
Placental position and condition
This scan must not be done before 18weeks. 19weeks is optimal. 
EQUIPMENT SELECTION AND TECHNIQUE
Warm gel, clean towels
Use a curvilinear probe (3.5-6MHZ) with low power to reduce RISK of bio effects. 

17. SCANNING TECHNIQUE PATIENT PREPARATION
Ensure the patient presents with a full bladder. This will aid in the cervical measurement and placental position and measurement in relation to the cervix.
Start from the cervix then placenta then baby head, heart, abdomen, limbs and spine as a rough guide
Have your worksheet with you and mark off as you go so you will not forget anything.

18. WHAT TO CHECK WHEN BABY IS SUPINE WHEN BABY IS DECUBITUS
Profile ,nasal bone, nose/lips, mandible, palate, orbits.
Head, BPD, HC
Heart
Humerus, rad/ulna, hands, fingers
Diaphragm, liver, GB, bowel
AC measurement, stomach, umbilical vein,
Heart,4chamber & heart beat
Chest cavity
Spine coronal, trans
Cord insertion,2 umblical arteries
FL, femora, tib/fib, feet
WHEN BABY IS LYING PRONE
Bladder, gender
Spine
Kidneys
Diaphragm
Head, choroids

19. Cervical length Transvaginal probe Full bladder
Cervical Length: internal os to external os

20. Biparietal Diameter and Head Circumference (BPD AND HC):
The plane for measurement of head circumference (HC) and bi-parietal diameter (BPD)must include:
Cavum septum pellucidum
Thalamus
Choroid plexus in the atrium of the lateral ventricles.
Measure outer table of the proximal skull to the inner table of the distal
HC:
Measure the longest AP length

21. Abdominal circumference
Determined on transverse view atthe level of the junction of the umbilical vein, portal sinus,and fetal stomach NO KIDNEYS in the view
Assessing fetal weight/IUGR/macrosomia

22. Femur Length (FL):
Aligning the transducer with the lower end of the fetal spine and rotating toward the ventral aspect of the fetus
Measurement origin to distal end of shaft and shows two blunted ends
Do not include femoral head or distal epiphysis
It increases from about 1.5 cm at 14 weeks to about 7.8 cm at term.
Humerus
Measured similarly

23. Amnionitic Fluid
AFI: measure four quadrants of largest verticle pocket
normal, 6-8 cm.
borderline,<5 cm
less than 5 Oligohydramnios
Polyhydramnios is defined as an amniotic fluid volume in excess of mL. A single pocket of fluid that is 8 cm or larger

24. Grade 0
Placenta:
Determining its upper and lower edges r/o placenta previa
With increasing gestational age, the placenta increases in echogenicity because of increased fibrosis and calcium content.
This feature of placental maturation has led to a grading of placentas from immature (grade 0) to mature (grade 3).
Placentolmegaly
Diabetes, fetal hydrops
Small placenta:
Severe IUGR (symmetrical/asymmetrical)
Grade 1
Grade 3

25. Obstetrical Ultrasound
Fetal anatomy:
Head
Atrium of lateral ventricles
Choroid plexus assessment
Cerebellum
Cisterna magna
Nuchal fold

26. Obstetrical Ultrasound
The atrium of lateral ventricles should be less than 10mm in diameter (best measured at the occipital horn).
The choroid plexii should be homogenous.

27. Obstetrical Ultrasound
The cerebellar diameter should approximately equal the weeks of gestation.
(Ex: 19weeks=19mm)
Cisterna magna: < 10mm
Nuchal fold: (outer edge of occipital bone to skin surface )
<6mm (between 17-20weeks).

28. Face:
Profile
Nasal bone
Nose
Lips

29. Obstetrical Ultrasound
Thorax
Lung volumes
Diaphphram

30. Obstetrical Ultrasound
Abdomen/Stomach
(presence, size, and situs)
Liver

31. Cord Insertion:
Ensure the abdominal wall around the cord insertion is intact
No bowel has herniated into the cord.
3-vessel

32. Kidneys/Bladder
Kidneys: Confirm the presence and position of both kidneys.
Look for the anechoic renal pelvis.
The renal pelvis TS diameter should be less than 5mm.

33. Obstetrical Ultrasound
Spine:
Coronal or Sagital of entire spine:
cervical
Thoracic
Lumbar
Sacral
Transverse assessment of entire spine

34. Upper Extremities Normal
Abnormal
Fist clenched
Phocomelia

35. Obstetrical Ultrasound
Lower Extremities:

36. 3rd trimester ultrasound>26 WEEKS

37. 3rd Trimester Ultrasound - Protocol
Role of Ultrasound
Ultrasound is a valuable diagnostic tool in assessing the following indications:
Follow up of previously identified, or suspected, abnormality.
Suspected or known low placental position
Bleeding, fluid loss or pain
Altered maternal health (eg hypertension or proteinuria)
Decreased foetal movements
Small for dates (SFD)or Small for Gestational Age (SGA) or Large for dates (LFD) or Large for Gestational Age (LGA)
Patient Preparation The patient does not need to drink a lot of water at this stage.

38. Scanning Technique
Cervix - assess if closed and measure length between internal and external os
Assess placental location and distance from internal os.
Check for retroplacental haemorrhages, placental masses etc
Maternal adnexae (if indicated, also maternal kidneys)
Confirm heart beat & rate
Foetal lie: ( eg cephalic, spine to maternal left) If breech, describe the 'type' of breech.
Frank
Complete
Footling
Head:
Shape
Symmetry/falx
Cerebellum
Cavum septum pellucidum
Ventricles

40. Chest:
Heart~ rate (check for arrhythmia) position & orientation (4 chambers, outflow tracts)
Diaphragm
Lungs (homogenous & echogenic relative to liver)
Abdo     
stomach
kidneys
bladder
anterior abdo wall & cord insertion
Limbs:
12 long bones
Position of hands/feet
Movement & tone
Spine: Symmetry from C spine to the sacral taper and an intact posterior skin edge

41. BIOPHYSICAL PROFILE ASSESSMENT (For utero-placental vascular insufficiency)
Look for foetal movements such as leg, hand flexing and diaphragmatic movements.
Assess foetal tone and posture.
Biophysical Score is a combination of the following assessments giving them a mark out of 8 in total.
Foetal breathing 2/2
Foetal limb/body movements 2/2
Foetal posture 2/2
AFI 2/2
If the score is below 7 then this is a concern which will need close follow up. The assessment must span a minimum of a 30minute period before a negative report is suggested.

42. Obstetrical Ultrasound
Three-Dimensional Ultrasound3D
Display multiple longitudinal, transverse, and coronal images.
Images may improve the accuracy of anomaly detection of the fetal face, ears, and distal extremities

43. Obstetrical Ultrasound
Abnormal 3D Images
Cleft lip Cyclopia

44. Obstetrical Ultrasound
4D Ultrasounds that adds the element of time to the 3D process.
Offers live images
Fetal changes like movement, kicking, reach with hands and facial expressions can be seen

45. Obstetrical Ultrasound