Having a 7 Week Ultrasound Scan
Congratulations on starting your journey to being a mum. We are here to support you every step of the way, one of those ways is to explain to you what you will be experiencing during your scan and what it may mean.
A 7 week ultrasound for pregnancy, otherwise known as a First Trimester ultrasound or a Dating/Viability scan, is a very common scan that may be requested by your doctor for many reasons.
Those reasons may be:
- Confirming your pregnancy and checking that everything is looking okay
- Assess the gestational age of your baby – that is how far along your pregnancy is, also check that the size of the embryo is the right size for that stage and this helps to confirm the due date
- The cause and source of any blood loss you may be experiencing
- Confirming the presence of a heart beat in your baby
- A general check of your uterus, fallopian tubes and ovaries
- Ensuring that there is no ectopic pregnancy and rule out twins
When is a dating scan necessary?
A dating scan is generally done if you are:
- Uncertain about the date of your last normal menstrual period
- For women who have irregular menstrual cycles
- For women who have recently had a miscarriage and have conceived again quickly
- For women who have recently stopped using oral contraceptives or alternative forms of hormonal contraception
- For women who are breastfeeding and although they may not have resumed menstruating, have conceived again
- In any other situation, or for any other reason why confirming viability and the gestational age of the embryo is considered important
What size will my baby be at the time of doing a 7 week ultrasound for pregnancy?
The average length of the embryo at 7 weeks ranges between 5mm-12mm. The average weight is less than 1 gram. Be aware though that every pregnancy is unique and individual factors influence the size of the embryo at this early stage.
How will my 7 week ultrasound be done?
You may have your scan done – via the abdomen – transabdominally
You will need a full bladder to “lift” the uterus up and out of the pelvis so the embryo can be seen more clearly. A full bladder assists easier passage of ultrasound waves into the pelvis as well. Later on as the pregnancy progresses, a full bladder is not necessary as the enlarging uterus grows.
Or via the vagina – transvaginally
The sonographer might decide to use this method to achieve the most accurate visualisation.
The transducer is placed in the vagina and the sound waves are transmitted via the cervix and directly into the uterus. With this form of scan, it is not necessary for you to have a full bladder.
You may have your scan done - via the abdomen – transabdominally
You will need a full bladder in order to “lift” the uterus up and out of the pelvis so the embryo can be seen more clearly. Later on as the pregnancy progresses, a full bladder is not necessary as the enlarging uterus grows.
Or via the vagina – transvaginally
The sonographer might decide to use this method to achieve the most accurate visualisation. The transducer is placed in the vagina and the sound waves are transmitted via the cervix and directly into the uterus. With this form of scan it is not as necessary for you to have a full bladder.
What is the sex of my baby?
It is too early to identify if you are having a boy or girl at this stage. Only the larger body parts such as the head can be seen at 7 weeks.
Can I see my baby’s heartbeat yet?
Yes, this should be visible, especially if you are having a transvaginal ultrasound. The average number of beats per minute (BPM) is between 90-110 BPM at 6-7 weeks of gestation. But by the time the baby has developed to full term, this rate ranges between 120 -160 BPM.
Will my seven week ultrasound be clear and accurate?
These can be clear and accurate, depending on the skill of the sonographer and quality of the equipment. At Specialist Ultrasound for Women we have the newest, most state of the art equipment, operated by the highest skilled sonographers. In case the ultrasound findings are inconclusive a follow up scan will be organised.