The Purpose of Early Pregnancy Scan: Viability and Due Date

I think it was during my first pregnancy when I found myself at the clinic much earlier than expected. There was no plan for an early pregnancy scan. But it was one of those situations where I had gone to the clinic for a separate medical issue and suddenly found myself having to attend an early scan—before even reaching the seven-week mark. What made it overwhelming was the combination of physical discomfort from the other condition and the emotional rollercoaster of early pregnancy.

As I lay down for the scan, my heart raced. I had no idea what to expect. Was it too early to see anything? Would I even hear a heartbeat? I wanted to connect with the little life growing inside me, but all I knew at that point was this: the purpose of the early scan wasn’t about seeing the baby but about gaining clarity—confirmation that the pregnancy was viable and determining exactly how far along I was.

Early pregnancy scans, typically performed between 6 and 8 weeks of gestation, are crucial for monitoring the initial stages of pregnancy. However, for me, that early scan was more than just a medical check—it marked the beginning of truly connecting with my pregnancy and realising that every step forward was significant. Whether you're newly pregnant, managing a medical condition, or experiencing symptoms that need attention, an early scan can provide valuable reassurance.

What is an Early Pregnancy Scan?

An early pregnancy scan is an ultrasound performed in the first few weeks of pregnancy. It is sometimes referred to as a prenatal scan or a dating scan. This is typically a transvaginal procedure, where a probe is inserted into the vagina, as it provides more precise and detailed images of the early stages of the baby's development in the uterus. Less commonly, some may have an abdominal scan done before eight weeks.

The procedure itself is usually quick and often painless. In a vaginal scan, a small probe is gently inserted into the vagina to capture clear images of the uterus and baby.

While most pregnancies typically have a first scan around 8-12 weeks, an early scan may be recommended in certain situations, such as:

• You are unsure of the date of your last menstrual period, making it difficult to estimate the gestational age.
• You’ve experienced bleeding, pain, or other concerning symptoms.
• You’ve had previous pregnancy complications or multiple pregnancies, such as twins.
• You’ve undergone fertility treatments, including IVF, and the progress of the pregnancy needs to be monitored.
• There is a medical history that could impact maternal health, requiring confirmation of the presence of a gestational sac and yolk sac (in early pregnancy) to ensure the pregnancy is progressing normally.

Confirming Pregnancy Viability

The primary function of an early pregnancy scan is to establish and determine if the pregnancy is viable.

The first appearance of the fetus’ heart is around the sixth week and that usually marks the healthy growth of the fetus. This ultrasound scan helps parents-to-be understand that the pregnancy is progressing and alleviates any doubts.

The sole purpose of the viability scan is to confirm that the baby is growing as it should and to check for routine implantation within the uterus. This is significant because it eliminates the risk of an ectopic pregnancy, where fertilisation happens outside the uterus.

In my case, it was also reassuring, helping ease my concerns about potential health issues that might arise during the pregnancy.

Accurate Dating of the Pregnancy

Pregnancy dating is another essential part of early pregnancy scans. These scans are performed to look at the size of the embryo, perform a gestational assessment, and determine if there is more than one pregnancy.

Since all embryos develop uniformly during the early weeks of pregnancy, your doctor can estimate the date of conception with an ultrasound scan and see what stage of development the embryo has reached.

If the gestational age is questionable, then determining an accurate due date is important for providing appropriate prenatal care throughout the pregnancy. The true purpose of pregnancy dating is for you to have a clear and informed perspective of your pregnancy. It also allows your gynaecologist to monitor the baby's development effectively and adjust possible therapeutic interventions, if necessary, during pregnancy.

When to Schedule an Early Pregnancy Scan

The scan typically takes place between 6 to 8 weeks of pregnancy. Gestational age is calculated from the first day of your last menstrual period (LMP) and works best for those with a regular 28-day cycle.

If your cycles are irregular, it is okay to let your doctor know beforehand. I was one of those people, who did not have a vague idea of when my last period was. If you are like me, another way to approach the situation is to go in for the scan about three weeks after the confirmation of your pregnancy or your positive pregnancy test. 

Depending on the situation, it may be done externally (abdominal scan) or internally (transvaginal scan) for clear images, especially during the first trimester.

What Will You See In Your Scan?

• At 6 Weeks: The embryo should be visible, along with the fetal heartbeat, if the dates are correct.
• At 7 Weeks: The fetal heart rate should be present.
• At 8 Weeks: The fetal form will be clear with the head and limbs.

If your scan was performed too early, you may need to schedule a follow-up scan in about 10 to 14 days to ensure your pregnancy is progressing well. Early dating helps you to organise your scans and manage your ongoing prenatal care effectively.

Transvaginal and Transabdominal Ultrasound Techniques

Here’s a table comparing Transvaginal and Transabdominal Ultrasound:

The early pregnancy scan represents several important structures and provides essential information about the health of reproductive organs. You will be able to see the developing fetus at various stages of growth (depending on when the scan is performed) as well the fetal heartbeat. These moments are truly magical, so make sure to savour them!

Gestational Sac and Yolk Sac

• Gestational Sac: This is the first recognisable structure, which looks like a fluid-filled pouch in the uterus. It encircles the growing embryo and is typically apparent by the fourth or fifth week of pregnancy.
• Yolk Sac: Within the gestational sac is a tiny, round structure called the yolk sac. It provides nutrients to the developing embryo before the functioning of vascular circulation, which can be seen around weeks 5-6 of gestation.

Fetal Pole and Heartbeat

• Fetal Pole: The fetal pole is the thickening of the embryo that will develop into a fetus. It is prominently visible during the first trimester, usually at 6-7 weeks.
• Heartbeat: One of the best things that an early scan can provide is the fetal heartbeat—you should be able to see your baby's heart beating from the sixth week of pregnancy. A healthy heart beat, even for a fetus, indicates a healthy pregnancy

The early pregnancy scan is a significant procedure and an essential part of pregnancy assessment to ensure the health of the baby and the mother. In addition to providing reassurance, the scan also gives vital information regarding the condition of your pregnancy. You can find out the health and progress of your pregnancy, and early detection of any complications and ectopic pregnancies.

The findings are absolutely crucial to developing a prenatal care plan that will eventually determine the course of your pregnancy and the medical care available to you.

Normal Early Pregnancy Development

Weeks 6 to 8 of pregnancy feature many key developments. During this phase, the baby grows rapidly, reaching about 1.5 to 2.5 centimetres in length.

Major organs begin to form, such as the heart and brain at around 6 weeks, and by week 8, the heart is already beating. This heartbeat is typically one of the first signs checked in a viability scan.

Between 6 and 8 weeks, the baby also begins developing limbs, facial features, and internal organs, with early limb formation marking the foundation of arms and legs.

Signs of Early Pregnancy Complications

To begin with, it is crucial to monitor the earliest signs of any complex symptoms during early pregnancy to ensure the health of both mother and child. If you experience any of these warning symptoms, seek prompt advice from your doctor. While it is okay to be scared, most of these concerns can be addressed. So, remember, early intervention allows for necessary treatment and support during this critical time.

• Severe abdominal pain or cramping
• Vaginal bleeding or pain and burning during urination
• Severe nausea with dizziness and vomiting
• Fever or signs of infection
• Severe back pain

An early pregnancy scan typically provides essential information about the baby’s health and development. Based on the findings, here are the potential next steps:

In most cases, a healthy pregnancy is characterized by a visible fetal heartbeat, appropriate growth for the gestational age, and no significant issues.

However, if no fetal heartbeat is detected despite other preliminary vital signs, the specialist may recommend a follow-up scan in 1-2 weeks. This second scan will confirm whether the baby is developing normally or if issues like miscarriage need to be addressed.

If left untreated, an ectopic pregnancy can lead to internal bleeding, infection, and further complications for the mother. Early scans assess pregnancy within the uterus to screen for risks like ectopic pregnancy, allowing for the prevention of complications at an early stage.

Early pregnancy scans were incredibly reassuring for me. Seeing that tiny flicker of a heartbeat for the first time was an emotional moment that made everything feel so real. It wasn’t just about confirming the pregnancy or finding out the gestational age—it was about knowing my baby was okay and feeling that first connection. Each scan helped me feel closer to my baby, giving me peace of mind and the confidence that both of us were on the right track. Those early glimpses truly marked the beginning of our journey together.