Congratulations on your pregnancy! You become a mom right from the time you see those pink lines in your home pregnancy kit. Visits to the doctor and regular scans become normal thereafter – all for the benefit of both the mother and the growing fetus.
In this blog, you will get to know everything about first trimester scan for your growing baby.
What is first trimester of pregnancy and what types of scans are performed?
A pregnancy lasts for about 280 days or 40 weeks. These weeks are grouped into three trimesters. The first trimester of pregnancy is the time in between conception and week 12 of pregnancy.
Usually, doctors will ask you to go for two types of scans when you are in your first trimester – a dating and viability scan and an early morphology scan (NT scan). While the former is done between six and nine weeks, the latter is done between eleven and thirteen weeks.
Importance of first trimester scan for first time pregnancy
If you are a first time mom, you will have many inhibitions about first trimester scanning (why and how it is done). Please understand that you are not alone and your doctor is always there to answer your queries.
The first trimester scan is of utmost importance as it helps your doctor to understand a lot about your growing baby – if the little one is in the right position inside the uterus, if he is growing well or not, hear his heartbeat, calculate your due date etc.
How many scans are done in the first trimester?
Generally, two scans are done during the first trimester – a dating and viability scan, between six and nine weeks and an early morphology scan (NT scan) between eleven and thirteen weeks.
Can you hear your baby’s heartbeat at 6 weeks?
Your baby’s heart begins to beat from around 6 weeks of pregnancy. However, sometimes it may be earlier and sometimes later as well. It is normal to be unable to detect a heartbeat until closer to 7 or 8 weeks.
Can you hear your baby’s heartbeat at 7 weeks?
Your doctor can find your baby’s heartbeat in the 7th week as well. Sometimes the baby’s heartbeat will not be clearly audible until seven or eight weeks.
List of scans during first trimester pregnancy
The list of scans to be done during pregnancy usually varies from person to person. A low-risk pregnancy may have four or five scans during the entire pregnancy.
Here is a list of the routine scans:
- Dating and viability scan between 6 and 9 weeks.A dating scan is performed to establish the gestational age of the pregnancy, besides understanding the heartbeat and detecting any unusual features of the uterus like the presence of fibroids if any.
- Nuchal translucency (NT) scan sometimes called the early morphology scan between 11 and 13 weeks.This test is done to measure the baby’s head and thickness of the neck to determine whether the growing baby will be born with a genetic disorder known as Down syndrome.
- Anomaly scan between 18 and 20 weeks.The scan looks at the baby’s bones, heart, brain, spinal cord, face, kidneys, and abdomen.
- Growth scan or fetal well-being scan between 28 and 32 weeks.This scan, as the name suggests determine the growth and health of the fetus.
- Doppler scan between 36 and 40 weeks.A Doppler scan shows the rate of the blood flow and blood pressure in placenta, umbilical cord, brain and heart of the baby.
However, please be informed that you may need more scans if:
- You are 35+.
- You are carrying twins or more.
- There is a difference in your baby’s expected size based on your due date, and her actual size as measured in a scan.
- Any complication with the pregnancy like aging placenta, low or high levels of amniotic fluid, an irregularity in blood circulation in the umbilical cord, a sudden fall etc.
- You have high blood pressure, gestational diabetes, and aliver problem which may cause any complications.
Fetal development at first trimester scan
Right from the time you conceive your baby till the time of delivery, your growing baby goes through several stages of development (from a fertilized egg to a garlic bulb size baby) in the womb before he or she is born.The early scan can reveal some fantastic things about fetal development in the womb.
First Trimester – Week 5
– The ultrasound expert generally observes a small sac that looks like a black hole because it is filled with amniotic fluid. This is the gestation sac. The expert can identify the location of the sac to determine whether it is in your uterus or not. This is to make sure that there is no sign of an ectopic pregnancy.
She may ask you to come back for another scan in one or two weeks.
First Trimester – Week 6
– The yolk sac is attached to the embryo and contains nutrients to feed the fetus while it is developing. At this time, the head to bottom length of the embryo is measured to calculate your due date.
First Trimester – Week 7
– A tiny embryo with a heartbeat can be heard.
First Trimester – Week 8
– The developing embryo (measuring up to 1cm-2cm) should be easier to see on the scan by now. It will grow rapidly in the coming weeks.
First Trimester – Week 10
– Your growing baby now measures 3cm and you can see and hear her heartbeat.
In the next few weeks,the doctor may advise you for an early morphology scan (NT scan). This scan estimates the risk of Down’s syndrome and other abnormalities.
What will the doctor examine at the first trimester ultrasound scan?
It is advisable to plan a visit to the doctor/gynaecologist when you first learn that you are pregnant. The doctor will then take note of your entire health history and perform a full physical and pelvic exam. Usually at this time, your doctor may perform an ultrasound scan to confirm the pregnancy. The ultrasound scan is one of the routine tests conducted during pregnancy which determines the normal development of your baby and detects any fetal abnormalities as well. This is also done to calculate the due date and determine the heartbeat of the baby.It is delightful to see the little blob with a heartbeat that will soon become your baby!
Interestingly, the ultrasound scan also helps your doctor to understand how many babies you are carrying and if there are twins, the scan will help to identify whether they are identical or not.
Once you sail smoothly through the first trimester, it is time for you to enter the second trimester with your baby.