Congratulations on your pregnancy! Most women don’t know that they are pregnant at this stage, so you are one of the lucky few who do!
How many weeks pregnant isn’t measured from the date of conception, but rather the date of your last period (menstrual cycle). So, if you conceived your baby 2 weeks ago, and your last period was 4 weeks ago, you are 4 weeks pregnant and you are officially in the first trimester of pregnancy.
You at 4 Weeks Pregnant
At four weeks pregnant, the first pregnancy symptom you typically notice is that you have a missed period. The pregnancy is then usually confirmed with positive pregnancy tests.
At four weeks pregnant, you should already be taking 400 micrograms of folic acid daily, until you are 12 weeks pregnant. You should start taking folic acid before you are pregnant.
This is to reduce the risk of any issues or birth defects developing during the early stages of pregnancy.
It is also recommended that pregnant women take vitamin D tablets daily.
Early Pregnancy Symptoms – 4 Weeks Pregnant
During early pregnancy, your progesterone levels- or pregnancy hormone levels- increase. The rise in progesterone slows down your body’s digestive system, causing bloating and constipation.
Morning sickness is one of the most troublesome early pregnancy symptoms to deal with. The rise in progesterone causes nausea, as well as hypersensitivity to certain smells/odours (e.g. coffee or perfume) which can trigger vomiting. Thankfully, this symptom usually fades by the second trimester.
Spotting can occur at week 4 due to implantation. A bit of light bleeding is completely normal. If, however, you are bleeding heavily, or are bleeding bright red blood, you should consult your doctor as soon as possible.
Cramping can be a worrying symptom for some mums-to-be- but it’s actually a sign that your baby has properly implanted into your uterine lining. However, if you experience any very painful or uncomfortable cramps, you should contact your doctor.
Mood swings occur due to your rapidly changing pregnancy hormone levels. After the first 12 weeks of pregnancy, your hormone levels should even out a bit and this symptom should subside.
It’s no wonder that you might be feeling this particular symptom! Your body has new life forming within it-and it’s a process that will definitely sap some of your energy. This is one of the most common pregnancy symptoms.
This symptom is also due to the increased bloodflow in your body. The breast tenderness usually eases off by the second trimester.
Baby at 4 Weeks Pregnant
At 4 weeks pregnant, the embryo is developing within the lining of the womb. Your baby (embryo) is currently the size of a poppy seed. Even though your baby is currently tiny, a lot is going on! The fertilised egg has embedded itself into the side of the womb and the outer cells reach out to form links with the mother’s blood supply. The inner cells form into 3 layers:
Inner layer: This will eventually become the lungs, stomach, gut and bladder.
Middle Layer: This layer will become the heart and circulatory system, muscles and bones.
Outer Layer: This layer will become your baby’s brain and nervous system, as well as the eye lenses, tooth enamel and skin and nails.
The embryo is attached to a small “yolk sac” which provides the nutrients to your developing baby. Later in the pregnancy, the placenta will form and transfer nutrients to the baby.
Why would I need an Ultrasound at 4 Weeks Pregnant?
Ultrasounds can be used during the early stage of pregnancy to estimate the age of the gestational sac, which, in turn, helps the sonographers estimate how many weeks pregnant you are.
If you are at risk of ectopic pregnancy or miscarriage (you have experienced either of these during past pregnancies) or if you used in vitro to get pregnant, your doctor may want to do an early ultrasound.
What can I expect during a 4-week ultrasound scan?
At 4 weeks pregnant, you are still in the very early pregnancy stages- in the first half of the first trimester.
Since you are still in the early stages of pregnancy, the ultrasound scan will be performed via the vagina, rather than via your tummy. This is called a transvaginal ultrasound.
During a transvaginal ultrasound, a well-lubricated wand is inserted into the vaginal canal. This type of ultrasound provides a clearer view ultrasound image of the uterus- which is important since your baby is currently so small!
Additionally, transvaginal ultrasounds can be used to check for ectopic pregnancy and possible miscarriage. They can also be used to check the cervix for any changes that could lead to miscarriage or premature delivery and examine the placenta for any abnormalities (later on in your pregnancy).
What will I see during a 4 week ultrasound?
At the 4 week ultrasound, your baby is still very very small, measuring just 0.04inches long. It is completely normal if you can’t see your baby on the scan! The only things that you will most likely see are yolk sac and gestational sac.
The embryo will show up on the screen as a tiny dot that is white in colour.
It is around the embryo that you will be able to see the yolk sac, which provides nourishment and blood to the embryo during early pregnancy. This is because the umbilical cord and placenta still need to develop (it will form at around 7 weeks pregnant).
Around the yolk sac is a black area- this is the gestational sac. You can see the gestational sac as early as 4.5 weeks into your pregnancy via an ultrasound scan.
For information about ultrasound scans at other weeks, you can visit:
- 5 Week Ultrasound Scan
- 6 Week Ultrasound Scan
- 7 Week Ultrasound
- 8 Weeks Ultrasound Scan
- 9 Week Ultrasound Scan
- 10 Week Ultrasound Scan
- 12 Week Ultrasound Scan
- 13 Week Ultrasound Scan
- 14 Week Ultrasound Scan
- 15 Week Ultrasound Scan
My name is Louise and I am the Digital Marketing and Administrative Assistant at MyBump2Baby. I have been writing in the parenting niche for over 2 years specialising in fertility, pregnancy, baby and baby name support articles.