Ultrasound has become an essential tool in obstetrics, allowing visualization of the fetus and assessment of growth and well-being. Doppler ultrasound can evaluate blood flow in fetal and maternal vessels. While ultrasound is generally safe, concerns have been raised about potential neurological effects with prolonged or frequent use. Estimation of fetal weight and biophysical profiling helps monitor high-risk pregnancies. Overall, ultrasound has dramatically improved prenatal care and outcomes over the past decades.

1. Ultrasound in
obstetrics
Igbodike Emeka Philip, Specialist
registrar OBGYN , cert MAS
With Dr Idowu BS, Consultant
OBGYn

2. Outline
• Introduction
• history/evolution/Physics/Routes
• Indications
• Doppler/Effects
• Controversies
• Local experience
• Conclusion

3. Introduction
• Over 25 years now !
• Dramatic changes observed
• Improved resolution now allows far better imaging of the
fetus.
• Pulsed wave, colour and power Doppler, assessment of the
fetal circulation is possible
• We can now Screen, Diagnose , Treat & Monitor
• Today we talk about point of care ultrasound!
• Heading towards the concept of an ‘ultrasound stethoscope!!

4. Before Donald !
• Thomas Young 1801 described “phase shifting” in relation to light
waves ….. used in ultrasound phased array systems to control
interference patterns [production of 3D images].
• Christian Doppler in 1842 described “Doppler effect” in relation to
the motion of stars … the basis for blood flow studies in pelvic
vessels and the fetus.
• Pierre Curie in 1880 - the piezo electric effect - mechanical
distortion of ceramic crystals would produce an electric charge; the
reverse of this effect --- transducers to generate ultrasonic waves.

5. Evolution
1953 Inge Edler and Carl Hertz in Lund University
adapted a metal flaw detector to obtain M-mode
recordings from the adult heart.
Wild & John Read --- 2D images in 1952 but his
efforts were directed towards tissue characterization
[breast Tumours ]
Ian Donald 1958!

6. Historical background –
Glasgow Experience
• Origin is clear & Momentous
• Ian Donald , Mac Vicar J and
Brown TG in THE LANCET ,1,
1188-94, London , 1958
• Investigation of Abdominal
Masses by Pulsed Ultrasound
• “Misnomer” entirely devoted to
ultrasound studies in clinical
obstetrics and gynaecology and
contained the first ultrasound
images of the fetus and also
gynaecological masses.

7. The physics of ultrasound
• Medical ultrasonography was developed from principles of
sonar pioneered in World War I
• Ultrasound is defined as a frequency above that which
humans can hear, or more than 20,000 Hz (20 kHz).
Therapeutic ultrasound, designed to create heat
• using mechanical sound waves, is typically lower in
frequency than diagnostic Ultrasound
• Lower-frequency ultrasound has better penetration, but at
lower resolution.
• Higher-frequency ultrasound provides better images, but it
does not visualize deep structures well

8. Principles
• A typical transabdominal or cardiac probe has a frequency
in the range of 2 to 5 MHz
• Some dermatologic ultrasound probes have frequencies as
high as 100 MHz
• Ultrasonography uses a “crystal” — a quartz or composite
piezoelectric material — that generates a sound wave when
an electric current is applied.
• When the sound wave returns, the material in turn
generates a current.
• The crystal thus both transmits and receives the sound

9. Principle
• A single crystal to create a one dimensional image
known as A-mode.
• The B-mode (also called two-dimensional or gray-
scale ultrasonography), is created by an array of
crystals (often 128 or more) across the face of the
transducer.
• Each crystal produces a scan line that is used to create
an image or frame, which is refreshed many times
per second to produce a moving image on the screen.
• There are three-dimensional, four-dimensional,
Doppler, and tissue Doppler modes.

10. Principles
• Ultrasound penetrates well through fluid and solid
organs (e.g., liver, spleen, and uterus)
• It does not penetrate well through bone or air,
limiting its usefulness in the skull, chest, and areas of
the abdomen where bowel gas obscures the image.
• Fluid (e.g, blood, urine, bile, and ascites), which is
completely anechoic, appears black on ultrasound
images

11. The ultrasound machine

12. KNOBOLOGY
• Be aware of the variations in Machine.
• One veritable tool in new machines is Cine loop.

13. The probes

14. The probe physics

15. Principles

16. Principles

17. Principles

18. Doppler physics

19. Effects
•Ultrasonography has been used in obstetrics for
decades, with no epidemiologic evidence of
harmful effects at normal diagnostic levels.
•Ultrasonography is a user-dependent
technology!
•There is a need to ensure competence, define
the benefits of appropriate use, and limit
unnecessary imaging and its consequences.

20. The principle of ALARA
•As Low As Reasonably Achievable- is a safety
principle designed to minimize radiation doses
and releases of radioactive materials
•It is predicated on legal dose limits for
regulatory compliance
•Required for all radiation safety programs
•Ultrasound obeys this principle

21. Effects
•Sweden 2001 – increased incidence of left-
handedness and speech delays in boys following
a subtle effect of neurological damage
•Larger sample of 8865 children disputed the
later
•Yale study – 2006 found a small significant
correlation between prolonged and frequent use
and abnormal neurological migration in mice

22. Classification
•According to ACOG
•Standard USS
•Limited USS
•Specialized USS
•Can also be
•Basic
•Comprehensive

23. Routes of obstetrics USS
•TVS - Transvaginal route/ENDOvaginal
[higher frequency( 5-7.5mHz)
•Transabdominal route after 12 weeks
gestation
•Trans perineal /Translabial

24. Routes

25. Indications for Obstetrics ultrasound
• The ultrasound in this branch of medicine and surgery
concerned with childbirth and midwifery will be
divided into trimesters
• Roles can be to either diagnose, screen or treat or as
an adjunct in other investigations.
• Indication can be maternal of foetal
• An early ultrasound is one done within the first 24
weeks of gestation.

26. Diagnostic Indication
• Confirm pregnancy
• Localisation of
pregnancy
• Dating scan BEST
8week to 11 weeks +
6days
• GTD
• Number of fetuses
• Chorionicity – 11-
14weeks
• Anatomy scan – 18-
22wks/24wks
SCREENING
• Nuchal
Translucency
• CVS 16-18wk
• Amniocentesis
TREAT
• Adjunct to
embryo transfer

27. Doppler Interrogation
ARTERIES
• Uterine
• Umbilical artery
• Middle cerebral
• Aorta
VEINS
• Umbilical
• Ductus venosus
• IVC

28. Maternal/maternofetal/placental
• Placenta localization
• Placenta abruption
• Fibroid existing with
pregnancy
• Uterine anomalies
• Cervical
length/diameter

29. First trimester
•Adjunct to pre-gestational screening / diagnosis
•Anaembroyic gestation/Missed abortion
•GTD/Abortion
•Ectopic gestation
•Unsure dates
•Pelvic masses
•Multiple gestation
•Adjunct to Invasive diagnostic procedure

30. Second trimester
•Uterine artery flow velocity waveforms-
predictive for pre-eclampsia
•Cervical length
•Estimation of gestational age
•Determination of number of fetuses
•Evaluation of cause of vaginal bleeding

31. Second trimester
•Fetal well being
•Localization of placenta …. Follow up
•Foetal Anatomy scan
•Fetal gender

32. Third trimester --- peculiarities of the tropics
• Fetal growth assessment
• Lie
• Fetal Presentation
• Fetal biophysical profile
• Localization of initially low lying placenta
• Amniotic fluid index
• Fetal weight estimation

33. First Trimester
• Dating ultrasound
• Very important
• GSD, Yolk sac diameter, CRL
• Mean sac diameter? NO*
• Crown Rump Length
• Head circumference/Biparietal
diameter/Abdominal circumference/
femur length
• AC– the junction of the umbilical vein
and the left portal vein [hockey stick
like echolucent area]

34. MSD

35. Yolk sac diameter

36. CRL wrong?

37. Nuchal translucency

38. Multiple gestation
False Twin

41. BPD
• Outer to inner table measurement
of the proximal fetal skull
• Taken at the level of the following
• Falx cerebrei
• Thalami
• Cavum septum pellucidium
• Oval shape at this level
• Best when in occipito-transverse
position

42. Important to note
•When composite biometry is not consistent in
all of the parameters (i.e. BPD, AC,HC,FL)
•Trans-cerebellar diameter can be used to
accurately date a pregnancy
•The diameter in millimeters corresponds to
weeks of gestation up to 24 weeks.

43. Femur length
•Mostly in second and third trimesters
•Parameters correlates well both in Caucasians
and Africans

44. WHAT’S THE BEST PARAMETER?
• •depends on timing and purpose of measurement
• •CRL: best parameter for early pregnancy dating
• •BPD: has closest correlation with GA in 2nd trimester
• •HC: effective alternative in case of variation in fetal head
• •AC: most useful parameter for evaluating fetal growth
• •FL: best parameter for evaluating skeletal dysplasia
• •use of multiple parameters improves accuracy.

45. Anatomy scan
•5% of newborn has congenital malformation
•Detection of one of such anomalies, the goal of
ANC screening
OBJECTIVES OF ANC SCREENING PROGRAM
•Provide adequate information to make informed
choice
•Identify serious fetal anomaly

46. USS “Soft Markers” of Chromosomal
Abnormalities:
These are :
Nuchal translucency
Hyperechogenic bowel
Cardiac echogenic foci
Short femur or humerus
2-vessel umbilical cord
Choroid plexus cyst
Renal pelvi-calyceal dilatation

47. Soft markers – less common
Sandal Gap
• Short ear length
• Ventricular dilatation
• 5th digit mid phalanx hypoplasia
• Increased iliac length
• Short frontal lobe

48. Papers
•Smith –Bindman et al , JAMA 2001 – found
•sensitivities for individual markers in isolation of
only 1-16% whereas,
• the sensitivity of multiple markers in
association with structural anomalies was 69%.

49. Placenta localization
• Better defined as pregnancy progresses
• Low lying --- seen early second trimester
• Repeat scan at 34-36 weeks
• USS assessment of previa has been enhanced with the
use of trans-perineal/trans-labial and TVS
• Improved spatial and contrast resolutions compared
with transabdominal
• Less interposed soft tissues and diminished acoustic
attenuations

50. Placenta abruption
•Sensitivity of diagnosis at 50%
•Lack of gold standard
•Sonographic appearances of retroplacental
hemorrhages varies:
•0-48hours – hyperechoic
•3-7days – isoechoic
•1-2weeks - hypoechoic

51. Growth scan
• For detected cases of growth disorder. IUGR and MAcrosomia
• Twin gestation
• Obesity
• Unreliable LMP and No early scan
• Diabetic with no early uss.

52. DOPPLER
INTEROGATION

58. Middle cerebral artery doppler

60. Ductus venosus doppler

61. Ultrasound and intrauterine growth restriction
• Biometry
• AC
• HC/AC ratio
• Estimated fetal weight
• Doppler
• Umbilical artery
• End diastolic volume
• MCA?

62. Fetal Biophysical profile
Parameter Score 2 Score 0
Qualitative
amniotic fluid
volume
>1 pool of fluid in 2
perpendicular plane at least
1cmx1cm
Either no measurable
pool or a pool <1x1cm
Gross body
movement
> 3 body/limb movt in 30 mins <3 body/limb movt in 30
mins
Fetal breathing
movt
>1episode lasting 30s in 30mins Absent or episode <30s in
30mins
Fetal tone >1 episode of body/limb
extension ffed by return to
flexion or open-close cycle of
hand
Absent or slow extension-
flexion of body or limbs
Reactive fetal heart
rate
> 2 FHR acceleration with fetal
movt in 30 mins
<2acceleration or 1+
deceleration in 30mins.
62

63. Score Clinical
significance
Risk of PNM
within 1wk
Intervention strategy
 8 Normal 0.7/1000 No intervention
6 Equivocal Variable •Assess for delivery if 37w
•Repeat test in 24h if
immature
4 Abnormal 89/1000 •Assess for delivery if 32w
•Repeat test in 24h if < 32w
 2 Very
abnormal
125/1000 If persistent on extended
testing assess for delivery
except in extreme
prematurity.

64. Fetal weight estimation
• Equipped with the information about the weight of the fetus,
the obstetrician during labour is able to take informed
decisions, thereby decreasing Risk of PNM and Morbidity.

65. Formulae for EFW
• Most of the fetal weight estimation models have been derived from data on
Western populations.
• Ethnicity and secular factors have been known to affect birth weight. Thus, it
has been advocated that birth weight models derived from one ethnic
population and applied in another locality without the validation of clinical
applicability, might result in wrong estimations.

66. EFW
• Methods of Fetal Weight Estimation
• Ultrasonography
• Clinical measurement (SFH)
• Maternal assessment/ self-estimation
• Ultrasound estimation of fetal weight has been found to be more accurate
than the other methods which have been criticized as less accurate due to inter
observer variations and subjectivity.

67. The formulae in use
• Hadlockin United States of America (USA)
• Campbell and Wilkin
• Shepardin Great Britain
• Merzin Germany.
• In Nigeria, the Nzeh1 and Nzeh2 formulae have been
produced.

68. Formulae
• Shepard(1983) Log10BW=1.7492+0.0166(BPD+) + 0.0046(AC)-0.00002646
(AC x BPD)
• Campbell (1975) LnBW=4.564+0.0282 (AC)-0.0000331(AC)2
• HadlockI (1985) Log10BW=1.326 -0.0000326 (AC x FL) x 0.00107(HC) +
0.00438 (AC) + 0.0158(FL)
• Hadlock2 (1985) Log10BW=1.304+0.005251(AC) + 0.01938 (FL) 0.00004(AC x
FL)
• Hadlock3 (1985) Log10BW=1.335-0.000034(AC x FL)+0.00316x
(BPD)+0.0045(AC)+0.01623 (FL)

69. Formulae
• Warsof1 (1986) LnBW=4.6914+0.00151(FL)2-0.0000119
(FL)3
• Warsof2 (1986) LnBW=2.792+0.108 (FL)+0.000036 (AC)2-
0.00027 (FL x AC)
• Combs (1993)
BW=(0.00023718x(AC)2x(FL)2)+0.00003312(HC)3
• Ott(1986) Log10BW=0.004355(HC)+0.005394 (AC)-
0.00008582 (HC x AC)+1.2594 (FL/AC)-2.0661

70. Nigeria population based.
• Nzeh1 (1992) Log10BW=0.470 + 0.488
Log10BPD+0.554 Log10FL+1.377 Log10AC
• Nzeh2 (1992) Log10BW=0.326+0.00451(SDI)+0.383
Log10BPD+0.614 Log10FL+1.485 Log10AC
• Deter (1985) EFW=10 1.335-0.0034 AC x FL+0.0316
BPD+0.0457AC+0.1623 FL

71. Why 15% error marging ?
• Factors affecting EFW using the formaulae
• The nature of the patient population
• The number and types of fetal biometric parameters being
measured
• Technical factors that affect the resolution of ultrasound
images
• The weight range being studied
• Scan delivery interval (SDI)

72. Challenges of ultrasonography in sub-Saharan Africa
•Machine
•Work force/staffing
•Training
•Dating /presentation
•Follow up visit
•Poor record
•Poverty
•Filling system

73. controversies
•Should it be routine?
• For all pregnancies?
• Not widely available
• Time consuming
• Expensive
Supported by Reproductive Health Library [RHL]
commentary by Belizan and Cafferata
September 2011.

74. Controversies
• Should result be discussed with patient?
• By sonologist or send to referral physician?
• What of self referral?
• Easier when result is normal?
Should the fetal sex be determined or disclosed?
TVS in placenta previa, why not also a ‘gentle’ digital
exam?

75. STUDIES

76. RADIUS Study
•Did not support routine scan
•Routine Screening ultrasound did not improve
perinatal outcome
•Routine Screening ultrasound were not of
significant clinical benefit
•Therefore it is important to individualize scan
indications

77. Routine 3rd trimester scan

78. FBPP
• At present, there is insufficient evidence from randomised trials to support the
use of BPP as a test of fetal wellbeing in high-risk pregnancies

79. Doppler
• The use of Doppler ultrasound of the umbilical artery in high-risk pregnancy
was associated with fewer perinatal deaths (risk ratio (RR) 0.71, 95% confidence
interval (CI) 0.52 to 0.
• 98, 16 studies, 10,225 babies

80. Umbilical doppler in Normal pregnancy
• No benefit

81. Uss as adjunct
• combine ultrasound markers with serum markers, especially PAPP-A and free
ßhCG, and maternal age weresi gnificantly better than those involving only
ultrasound markers (with or without maternal age)
• nasal bone is highly reliable.

82. ROUTINE THIRD TRIMESTER SCAN

83. Normogram

84. c

85. FBPP vs Doppler

86. LOCAL EXPERIENCE

87. OBSTETRIC ULTRASOUND IN OAUTHC ILE
IFE 2005-20016
Total
Number
Average per year
Indications
Commonest indication
Commonest gestational age at first ultrasound

88. Knowledge and Attitude of Pregnant women regarding
Obstetric Ultrasonography : A Pilot Study at OAUTHC Ile-
Ife May 2017
• Total number studied 21
• Data collection by purpose designed questioner
• Average age 23-37 years
• Modal tribe Yoruba 15 of 21[68.2%]
• Highest level of education – Tertiary 13 [61.9%]
• Married 20 [95.2%]
• Gravidity – primigravidity 6[28%]
• GA at registration 8-23weeks

89. Data analysis
Gestational age Frequency of ultrasound
8-12weeks
12weeks +1day -26weeks
26weeks +1 day -37weeks
>37weeks

90. Analysis
Question right Wrong/
no
Not
sure
Did not
answer
What is an ultrasound? 11 6 1 2
How early can ultrasound be
done in pregnancy?
8 13
The earlier dating USS is done
the better?
16 1 4

91. How many times should USS
be done in pregnancy Answers
Not at all 0
Once or more if necessary 9
As many as possible 12

92. Question yes no Not
sure
5. Is ultrasound important? 21 0 0
8. Early USS can help in dating pregnancy? 20 0 1
10. USS can tell if a baby is twin or not 20 1
11.USS can detect babies that have
developed problems in the womb already?
18 3
12. USS harmful following about 5
exposures?
2 8 11

93. Question yes no Not
sure
13. Not doing USS at all can lead to the
mother having C/S because of wrong date
12 3 6
14. will ensure I do USS in this pregnancy
because I and my baby will benefit
21 0 0
15. Accuracy of USS depend largely on who
is performing it
17 1 3
16. Do you have your husbands support as
regards doing USS during pregnancy?
16 4 1
17. Is USS expensive? 7 11 3
18. Do you think the money should be
reduced?
13 5 3

94. Frequency of Ultrasound
performed in previous
pregnancies
frequency
1
2
3
4
5
>5

95. comments

96. recommendation

97. conclusion

98. references
1. Donald I, j. MacVicar, TG Brown. Investigation of abdominal masses by
pulsed ultrasound. Lancet, 1, 1188-94,London,1958.