Ultrasounds in Pregnancy
When you found out you were pregnant you couldn’t wait to have your first ultrasound and to find out the sex of your baby. To see that little blip is confirmation of motherhood, it reaffirms the future ahead. Not all ultrasounds are created equal though so it’s important to understand how and why ultrasounds are performed and at what stages.
Most women will have the first ultrasound, done vaginally, at or around seven weeks after the last period. Seven or eight weeks after the missed period is the most reliable time to do the early ultrasound of pregnancy. This helps to confirm the pregnancy and sure up the due date. We confirm the due date by ultrasound once a fetus AND heartbeat are seen. “How far along” is based on fetal size, the crown rump length. Sometimes an ultrasound is done before the heartbeat is visible. A fetus measuring 5 or 6 weeks may not have a visible heartbeat. A 7 week fetus MUST have a visible heartbeat. If no heartbeat is visible then you will be seen for a follow to confirm that your pregnancy is progressing accordingly. Occasionally a first ultrasound can confirm a poor or problematic pregnancy or miscarriage.
The twelve week ultrasound typically occurs between 10 and 13 weeks of gestation. The purpose of this ultrasound is to more accurately date your pregnancy, particularly if you have not had a previous ultrasound, as well as to check your baby’s heartbeat and confirm the number of babies you are carrying. During this ultrasound you may elect to have a first trimester combined screening which will check for any abnormalities. These tests consist of nuchal translucency or nuchal fold measurement via ultrasound and a blood test to check levels of human chorionic gonadotrophin (hCG) and the plasma protein-A (PAPP-A). Any abnormalities in these results could be an indicator of Down syndrome. It is not likely at this point that you will be able to determine the gender of your baby.
The date has finally arrived! If your baby cooperates during this ultrasound, we can often determine the gender. The twenty week ultrasound takes place between 18 and 20 weeks pregnant and the real purpose of this ultrasound is to confirm that the baby is growing well. Your sonographer will look for all the fingers, toes and internal organs. This ultrasound can not necessarily find Down Syndrome, but it can find many other serious and rare birth defects, including spina bifida. Your sonographer will also be checking to make sure that your uterus is behaving appropriately during the pregnancy as well and that the placenta is where it’s supposed to be. This will help eliminate any surprises when it comes time to deliver. This scan usually takes 20 – 30 minutes and is primarily used to check the following areas of your baby:
- The head: Checking the shape and structure will rule out any severe brain problems which would be visible at this stage.
- The face: Checked for cleft lips or cleft palates which are sometimes difficult to see via an ultrasound.
- The spine: To make sure that all the bones are in alignment and that the skin covers the spine at the back.
- The abdominal wall: To confirm that the internal organs are in place.
- The heart: The top two chambers (atria) and the bottom two chambers (ventricles) are measured and the valves are checked to make sure they open and close with each heartbeat.
- The stomach: To confirm that the baby’s stomach is working properly. Baby swallows amniotic fluid and flushes it through it’s body while in the womb.
- The kidneys: Confirm that there are two kidneys, and that urine flows freely into his bladder.
- The arms, legs, hands and feet: To confirm that everything is growing and developing accordingly.
Once you become pregnant there will be a series of tests conducted throughout the course of your pregnancy to insure that everything is progressing appropriately. Here is a brief overview of what you can expect. Read more…