Ultrasound: Sonogram

Answers to common questions related to an ultrasound exam

If an ultrasound is done at 6 to 7 weeks and a heartbeat is not detected, does that mean there is a problem?
No it does not mean there is a problem. The heartbeat may not be detected for reasons that include: tipped uterus, larger abdomen, or inaccurate dating with last menstrual period. Heartbeats are best detected with transvaginal ultrasounds early in pregnancy. Concern typically develops if there is no fetal heart activity in an embryo with a crown-rump length greater than 5mm. During a six week ultrasound exam, your healthcare provider will begin to be concerned if there is no gestational sac.

How accurate are ultrasounds in calculating gestational age?
Your healthcare provider will use hormone levels in your blood, the date of your last menstrual period and results from the ultrasound to generate an estimated gestational age. However, variations in each woman's cycle and each pregnancy may hinder the accuracy of generating an accurate gestational age. Physician's use an ultrasound to get an estimated delivery date to base the timing of your prenatal care, and normally will not change the original estimated gestational age.

Why do some healthcare providers schedule ultrasounds differently?
Scheduling an ultrasound every seven weeks is an average for most physicians. If there are any questions regarding gestational age, possible complications or health risks, then more ultrasounds may be scheduled.

Some healthcare providers may only schedule two sonograms, one between 6 to 10 weeks and the second around 20 weeks, because most of the information needed for effective prenatal care may be retrieved during these exams.

How accurate are ultrasounds in determining the conception date to determine paternity?
Your healthcare provider will use hormone levels in your blood, the date of your last menstrual period and results from an ultrasound to generate an expected date of conception. However, the many differences in each woman's cycle may hinder the accuracy of generating an accurate date of conception. The viability of sperm varies as well, which means that intercourse three to five days prior to ovulation may result in conception. Ultrasound dating of conception is not reliable for determining paternity unless the encounters in question are at least two weeks apart.

When can an ultrasound determine the sex of the baby?
The gender of the baby can begin to be determined between 18 to 20 weeks. Accuracy is improved when the observation is made of male genitals because they are more distinct. However, even when these have been observed, the birth can reveal something different!

Are ultrasounds a necessary part of prenatal care?
Ultrasound procedures are part of routine prenatal care and provide your healthcare provider with valuable insights for giving you the highest level of care. As noted above, ultrasounds enable your healthcare provider to confirm normal development as well as diagnose potential problems. Because there are no risks to you or the developing baby, there are no reasons not to use ultrasound technologies.

Reprinted with permission from American Pregnancy Association