You’ll never forget the first time you see your baby on that glowing black-and-white ultrasound screen. It’s exciting and scary, and it’s a relief to find out exactly what’s happening inside your body. We asked the experts all you need to know about that six-week ultrasound or first ultrasound appointment.
Your doctor will usually wait until at least six weeks to perform the first ultrasound. However, if your periods are irregular or you’ve had a history of complications, such as an ectopic pregnancy, a miscarriage, pain, or bleeding, your doctor might send you for an earlier scan, says Susan Kinnear, manager of diagnostic imaging at Hamilton Health Sciences Centre and director at large for Sonography Canada. Generally, if your period is regular and you know the “guesstimated” date of conception, you won’t have your first ultrasound until you are closer to the end of the first trimester, at 11 to 14 weeks. (Remember, pregnancy is calculated from the first day of your last menstrual period.)
If your first ultrasound is earlier than seven weeks, the baby is often so small that it’s hard to see with a traditional abdominal ultrasound. Instead, you will have a transvaginal ultrasound, where they insert a tampon-length transducer (ultrasound wand) into the vagina to see the fetus. “Vaginal ultrasound is the best way to do the first-trimester ultrasound,” says Doug Wilson, a professor of obstetrics and gynecology at the University of Calgary in Alberta. At around seven to eight weeks, the sonographer can confirm the gestational age (your due date), plus or minus three days. Your doctor will continue to use this date as a marker throughout your pregnancy, says Kinnear.
What are they looking for during the first ultrasound?
The sonographer is looking for a few main things in this first scan.
To determine your baby’s gestational age, the sonographer will measure the crown-rump length, which generally indicates the baby’s date of arrival.
At six weeks, sonographers may be able to see a heartbeat on the monitor (more on this below).
The technician is looking at whether the embryo implants in the uterus. If it implants outside of the uterus, this indicates an ectopic pregnancy, which happens when a fertilized egg implants in the fallopian tube or somewhere besides the uterus. Where the embryo implants is also important as it can be higher or lower in the uterus. (“Higher is better,” says Kinnear.)
The technician is looking for multiple embryos or sacks to tell if you’re having twins (or more!).
At this early stage, the sonographer will be looking for a yolk sac, which is attached to the baby like a balloon to provide nourishment, explains Kinnear. Sonographers look at the size and shape of the yolk sac (it’s an indicator of the baby’s health), which eventually goes away at around 12 weeks.
It’s very common for women to have a corpus luteum cyst during the first three months, which forms on the follicle where the egg is released, so they will note any signs of a cyst during this scan.
The sonographer may or may not be able to detect a heartbeat, depending on how far along you are, says Wilson. The earliest you can see a heartbeat is at five weeks and two days gestation, says Kinnear. Even then, sonographers often only see a heartbeat in 20 percent of early dating scans. While it may be nerve-racking, your doctor will likely send you for a repeat scan in one to two weeks to re-evaluate, says Kinnear. (If your doctor breaks out a Doppler to use on your tummy, you might also be able to hear the heartbeat but probably not until at least 10 weeks.)
Don’t freak out if the technician doesn’t say much. Depending on the province and medical clinic, they may or may not be able to give you details about your baby, such as heartbeat and size. Most clinics will fax the results to your doctor for a follow-up appointment. If there’s a concern, they may get you to speak to someone right after your ultrasound appointment.
At six weeks pregnant, your fetus is the size of a single sweet pea (or a quarter of an inch), so you won’t be able to see much, though it’s starting to have some cranial development and limb marks. On-screen, it will probably just look like a glowing little blob (but, hey, that’s your beautiful little blob!).
Whether it’s six weeks or later, you’ll need to prepare for your first ultrasound appointment. Drink a glass of water 45 minutes before your ultrasound appointment in case you have an abdominal ultrasound, recommends Kinnear. A full bladder provides an ultrasonic window to better see what’s inside the uterus. “A lot of people overfill their bladders,” she explains. “They come in and say ‘Oh, I drank 10 glasses of water,’” she says. “It will show the baby better, but you can actually be too full.” Not only will you have to pee before the scan is over but it’s also not necessary. Besides, if you’re really early on in your pregnancy, you will probably end up getting a transvaginal scan anyway, which doesn’t require a full bladder or any preparation.
Taking a photo home after your first ultrasound (whether it’s at six weeks or later) depends on the hospital or clinic where you have your scan. Many places use digital machines these days and don’t print out sonograms (ultrasound photos) anymore, says Wilson. However, you may be able to take a shot of the screen with your phone, if the technician allows, or order a CD of your photos.
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