health article
home / all about health / health article

Obstetric Ultrasound

Posted: 09-Sep-2013
Obstetric Ultrasound 

Obstetric ultrasound is a test that assists obstetricians in diagnosing and screening pregnant women for any abnormalities in the fetus, as well as anomalies in the mother’s pelvic organs including the uterus and the ovary. It is a safe procedure as it uses sound waves as opposed to radiation.

Types of Ultrasound

2D ultrasound 
- Creates an image without depth to observe fetal size and any abnormalities of organs, as well as observe the pelvic organs of the mother.

3D ultrasound  
- Creates a virtual still image with depth to be used in conjunction with 2D ultrasound to enhance the effectiveness of diagnosis in case there are abnormalities found in the fetus.
4D ultrasound  
- Creates a 3D moving image with depth of the fetus’s postures. The objectives of using 4D ultrasound are the same as those of 3D.

Remark: The screening test during pregnancy is principally performed by 2D ultrasound. 3D and 4D ultrasounds are used only when the doctor deems them appropriate. 

Gestational Age and Indications
Ultrasound can be performed in every gestational age in accordance with the doctor’s opinion. Appropriate gestational ages for ultrasound are as follows: 

5-11 Weeks
To confirm a intrauterine pregnancy and diagnosis for a multiple pregnancy
To determine the gestational age by measuring the size of the fetus
To diagnose excessive bleeding beneath the placenta membrane
To diagnose an abnormal pregnancy including ectopic pregnancy, blighted ovum, and molar pregnancy
To diagnose myoma uteri and ovarian cyst or tumor  

11-13 Weeks and 6 Days
To measure the size of the fetus and determine the gestational age
To measure fluid accumulation beneath the skin of fetal neck (nuchal translucency). The result of the measurement is used in conjunction with the mother’s blood test for down syndrome screening*
To identify the early stages of many disabilities in the fetus
To evaluate the mother’s pelvic organs such as the uterus and the ovary 

*Remark: If the fetus has unusual thickness of nuchal translucency, it is possibly related to down syndrome or other chromosomal abnormalities. In addition, this is possibly related to fetal abnormalities including heart diseases, abnormal limbs, genetic disorders, etc. 
18-23 Weeks  
This is a crucial age and takes the longest to perform ultrasound at 30 minutes-1 hour 
To screen and diagnose structure-related abnormalities such as of the skull, cerebral tissue, spinal cord, arms, legs, heart, etc.
To observe fetal growth, the position of the placenta and estimate  the amount of amniotic fluid
To observe the length of the cervix in order to determine the possibility of a premature birth

28 weeks until the immediate stage before the delivery*
-  To observe development and determine the weight of the fetus 
-  To diagnose fetal growth restrictions 
-  To check the position of the placenta, fetal posture and the amount of amniotic fluid
-  To observe the length of the cervix in order to determine the possibility of premature labor
-  To check the health of the fetus by observing its breathing, movement and evaluating amniotic fluid

- If the mother has no risk factors, it is recommended that an ultrasound is performed during the 30-32 weeks.
- If the mother is at potential risk, having a multiple pregnancy, or complications, it is recommended that the health of the fetus should be evaluated as often as per the doctor’s suggestion.

The Effectiveness and Limits of Ultrasound 
Ultrasound tests need water to create an image and depend on the sound waves penetrating through the tissues. Therefore, the effectiveness of ultrasound depends on the amount of amniotic fluid present, the thickness of the mother’s abdomen, obesity, surgical wounds at the abdomen, and the fetus not being ready for the test. 

Samitivej, We Care
OB/GYN and Maternal Fetal Medicine Specialist 
Samitivej Sukhumvit Hospital
For further information, please contact:
Samitivej Sukhumvit Hospital
2st Floor, Building 2
Tel: 66 (0) 2711-8555-6
Call Center: 66 (0) 2711-8181 

(Update 09/09/2013)

Samitivej Sukhumvit Hospital
133 Sukhumvit 49, Klongtan Nua, Vadhana, Bangkok 10110
Telephone: +66 (0) 2711-8181
Fax: +66 (0) 2391-1290
Open in GoogleMaps
 all about health
promotion & package  
Copyright © 2011 Samitivej PCL. All rights reserved. terms of use | sitemap