We are pleased to provide 1st trimester limited obstetrical ultrasounds at the Sacramento Life Center in the Sacramento clinic. The 1st trimester is the time between 1st day of the last menstrual period until the end of the 12th week of pregnancy. Ultrasounds are performed by either a Registered Diagnostic Medical Sonographer or a Registered Nurse who has had special training in performing 1st trimester ultrasounds.
Prior to your ultrasound appointment, you will be instructed to drink lots of water. This is because ultrasounds work on a principle of sound waves, and sound waves travel better through water. Because your bladder is in the front of your abdomen and the uterus is behind the bladder, we’ll get clearer pictures if your bladder is full of water. When you arrive in the clinic, you will be asked to complete a consent form for the ultrasound. Once the ultrasound technician calls you to the ultrasound exam room, she will ask you questions about your health and pregnancy.
There are six things we attempt to accomplish during the ultrasound, and all of these will be discussed with you during the course of the ultrasound:
- Establish that the pregnancy is inside the uterus. Most pregnancies are inside the uterus; however, a pregnancy can implant outside the uterus (in the fallopian tube, ovary, or abdomen), and this is called an ectopic pregnancy. An ectopic pregnancy can become a life-threatening situation for the mother and baby, so we want to know early if an ectopic pregnancy has occurred. If evidence of an ectopic is found, we will consult with our obstetrician and most likely send you immediately to the emergency room
- Count how many fetuses are present. If there is more than one fetus, we will measure them all.
- Measure the fetus. The type of measurement is determined by how far along is the pregnancy. A minimum of three measurements are taken, then averaged. In the first 12 weeks of pregnancy, the measurement is from the top of the fetus’ head (crown) to the bottom of the buttocks (rump)—called the crown-rump length. Later in pregnancy after the 1st trimester (12 weeks), measurements may be of the diameter of the fetus’ skull, the circumference (round measurement) of the skull, the fetus’ femur (upper leg bone), and/or the chest circumference (round measurement). The measurements are in centimeters, and there are 2.54 cm in one inch.
- Determine how far along the pregnancy is in weeks and days based on the measurements. Our ultrasound machine calculates this based on the measurements.
- Calculate the due date (abbreviated EDD which stands for estimated date of delivery) based on the measurements. Our ultrasound machine also calculates this based on the measurements.
- Measure the fetus’ heart beat. Generally in the first trimester, a fetal heart rate of 120-180 beats per minute is considered normal. We will not hear the heart beating but will see it either quivering or beating. The ultrasound technician will point it out to you.
There are also other things we attempt to accomplish during your ultrasound appointment.
- Take pictures. We will provide the expectant mother with keepsake ultrasound pictures of the fetus.
- Provide education. After the ultrasound the ultrasound technician or nurse will spend a few minutes going over many issues you need to be aware of to keep you and your baby healthy during pregnancy. This information will be given to you in a neat written package, so you can take it home with you to read over in detail and consult as needed. We also have educational videos available in the clinic for you to watch as you desire.
Here are a few pictures to give you an idea of what to expect based on how far along you are when the ultrasound is performed.
Fetus at 7 weeks 0 days with yolk sac (circle)
The yolk sac is what nourishes the fetus early in pregnancy and becomes the placenta later
Fetus at 8 weeks 3 days
Fetus at 10 weeks 0 days, showing arms
Fetus at 12 weeks 0 days