While finding out about a pregnancy is often an exciting time for a woman filled with tears of joy, the first ultrasound scan can bring a bag full of mixed emotions. While the majority of pregnancies are low risk, meaning there are no known abnormalities, due to advances in technology the majority of birth defects are picked up well before the baby enters the world.
Only 3-5% of babies will be born with a birth defect.
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What is a Birth Defect?
A birth defect, sometimes referred to as a congenital anomaly or abnormality is any abnormality that occurs prior to the birth of the baby. While some birth defects are detected during pregnancy, others are not noticed until birth or early on in the child’s life. Birth defects are classed as major or minor and are generally structural or functional.
While some birth defects that are physical can be treated with surgery, unfortunately other defects have life long affects on the child. With extreme birth defects, survival is not possible.
What Causes a Birth Defect?
During the first three months of being pregnant is when your baby is developing rapidly and unfortunately in some cases a birth defect develops. While some birth defects baffle scientists of how they occur, others occur by genetics and a mother’s lifestyle factors.
Genetics:
Genetics is the most common cause of a birth defect but unfortunately many families do not release they are carrying a deadly gene until they become parents. Many men and women these days under go genetic testing for common defects prior to trying to conceive.
Maternal Age:
A mothers age when falling pregnant can have some affect on whether or not the baby will have a birth defect. Older woman are often advised to undergo more testing during early pregnancy to rule out any birth defects.
Inadequate Nutrition:
Many woman are advised to take folate prior to trying to conceive and up until the first trimester of their pregnancy. Adequate folate reduces the risk of a baby having spinal defects.
Drugs and Alcohol:
Consuming drugs and alcohol while pregnant will increase the likelihood of your child having a birth defect. There are many helplines for those wishing to quit drugs and alcohol and expectant mothers can also seek help from their local GP.
Environmental Exposure:
If you are exposed to certain pesticides and chemicals during your pregnancy your baby may be at a higher risk of having a birth defect.
Blood Compatibility:
If the mother’s blood and the babies blood type are reactive, the mother’s body may try and reject the fetus. Incompatible blood types are often discussed with the GP who will gather information about the mother’s and father’s blood types.
If you fall into one of the categories where you are at a higher risk of conceiving a child with a birth defect, your doctor should order additional tests. The tests will rule out birth defects and give the mother peace of mind to carry on with a healthy pregnancy.
Why are Ultrasounds Conducted During Pregnancy?
While many woman can’t wait to see their baby up on the big screen, those woman who have had pregnancy complications in the past may be more skeptical. Ultrasounds are conducted for a number of reasons, with the first and foremost reason being to establish a due date. Other reasons an ultrasound is conducted include:
- To Confirm a Viable Pregnancy (After HCG Blood Results Come Back)
- To Confirm the Number of Babies (Singleton, Twins, Triplets)
- To Rule Out the Possibility of an Ectopic Pregnancy
- To See Where the Placenta is Sitting
- To Establish if the Baby Has any Chromosomal Abnormalities
- To Confirm the Amount of Amniotic Fluid Surrounding the Baby
- To Check the Position of Baby (Nearing Due Date Scan)
While the 12 week scan is common among many countries, the other scans you will be advised to have differ from country to country. You can expect to have one ultrasound per trimester of your pregnancy with more regular scans if an abnormality is picked up.
Types of Ultrasounds During Pregnancy
There are two main types of ultrasounds, one more invasive than the other. The two types of scans are referred to as trans-abdominal and vaginal.
A trans-abdominal scan requires the mother to drink large quantities of water prior to arriving at the ultrasound clinic so that the bladder that sits in front of the uterus moves slightly out of the way giving the ultrasound technician a better look at the baby. Gel is applied to your abdomen for a trans-abdominal scan and at times more pressure will need to be placed to get a better visual of the baby depending on how he/she is situated.
The other type of ultrasound is slightly less common and is often used in early pregnancy or when the baby cannot be visualized by a trans-abdominal scan. A vaginal ultrasound requires a thin instrument to be inserted into the vagina, often highly lubricated to get better visuals of the uterus and baby. A vaginal ultrasound should never be painful, but some woman find them uncomfortable at times. The woman should try to maintain relaxed during the procedure so that the technician can get the best look possible at the uterus and baby.
| Gestational Age (Since LMP) | Sightings at Ultrasound |
| Prior to 5 Weeks | The uterus lining may have thickened although not much else can be visualized at this point. |
| 5 to 6 Weeks | A small gestational sac can usually be seen within the uterus. The yolk sac may also be able to be seen within the gestational sac. |
| 6 to 7 Weeks | The babies heart beat should be able to be detected at this stage. The ultrasound technician may also measure the fetus to give a rough expected due date. |
| 8 to 11 Weeks | Your baby can be seen without the need for a vaginal ultrasound. |
| 10 to 11 Weeks | A baby with a body, head, arms and legs can be seen and many other features may also be recognized. Your baby may in fact be moving around in the sac. |
What are the Most Common Birth Defects?
The most common birth defects detected during a routine ultrasound include although are not limited to:
- Club Foot
- Cleft Lip/Pallet
- Kidney Defects
- Spina Bifida
- Down Syndrome
- Haemophilia
Only 0.5 percent of babies will have one less or one more chromosome. Missing or added chromosomes result in Downs Syndrome.
How is a Birth Defect Diagnosed?
A birth defect is diagnosed by a trained medical personal either via blood tests or an ultrasound. Below are a number of tests that may be conducted if you are at a higher risk of having a baby with a birth defect:
First Trimester Screening:
This is a maternal serum screening. It looks at the babies limbs and features to attempt to rule out chromosomal abnormalities such as trisomies 13, 18 and 21.
Non-Invasive Prenatal Testing (NIPT):
This is a blood test that many woman get during the first trimester that works alongside the first trimester screening to rule out chromosomal abnormalities. A second trimester blood test may also be conducted if doctors are still concerned.
Ultrasounds:
Ultrasounds are recommended at many points during pregnancy although an early scan around the 12 week mark allows technicians to rule out any physical abnormalities. If an abnormality is noticed, doctors will order more tests.
Amniocentesis:
This involves a needle being inserted into the uterus to gain some amniotic fluid for testing. This is only recommended if doctors are concerned.
What Happens if a Birth Defect is Detected?
For many mothers this is never a question that they want to ask. While some minor birth defects can be corrected by providing the mother with medication, or intervening through key hole, other birth defects cannot be treated. Detecting a birth defect early allows the mother to make a choice of whether she will or will not keep the baby. While in some countries and states abortion is illegal, in others abortion is recommended if the baby will suffer immensely after birth.
A mother never wants to have to make this decision. While the decision is hard, it should always be up to the parents of the child with informed information from doctors and trained personal. The mother will need support during this time from both family and medical staff. While some woman choose to continue a pregnancy after finding out their baby has a chromosomal issue or birth defect, other woman choose to terminate the pregnancy. Neither decision is the right decision, and it is ultimately up to the mother at the end of the day.
FAQs – Pregnancy Ultrasound
Q. I had an Ultrasound Conducted Between 5-6 Weeks Pregnant. There was no Visible Heart Beat. What Does this Mean?
A. At 5 to 6 weeks pregnant there may be or may not be a heart beat. Sometimes it is simply to early for the flickering of a heart beat to be visible, and in other cases you may be only 4-5 weeks where a heart beat is very rarely detected. By 8 weeks, a heart beat can be detected on a ultrasound.