Ultrasound is a test that is painless, in which the physician transmits sound waves of high frequency in your uterus by using a plastic transducer. The signals are returned by the sound waves, which are interpreted into exclusive images of your growing baby. During a standard ultrasound, a doctor gets a lot of essential information with regard to the developing baby in the uterus. They can track and monitor the growth of the baby and also detect any congenital abnormalities. Whether you are having a single baby or multiples can also be determined by an ultrasound. The position of the placenta can also be seen, which is crucial to determine the time of delivery. And lastly, the sex of the baby can also be determined by an ultrasound.
How Early Can an Ultrasound Detect a Baby?
Ultrasound machines vary in technology. The time when a heartbeat is visible on an ultrasound depends on the size of the mother, the location of the fetus, the position of uterus and the accuracy of the date when conception happened. Though there are so many variables, still the baby is mostly visible on ultrasound at around 6 weeks’ gestation. It is almost impossible to detect the heartbeat of a baby during early pregnancy and is a challenge for majority of the physicians, since it cannot be determined conclusively whether the fetus is alive or not. In such a case, you may be asked to repeat the scan later. During repeated scan, your physician will look at the differences and changes in the size of the pregnancy sac along with development of the fetus and heartbeat.
In some cases, several scans may be required before your physician is able to detect the state of your baby or his/her development. For some females, this uncertainty is very hard to deal with.
What Exactly Can You See on Ultrasound?
Baby’s Location
When an ultrasound is performed at 6 weeks gestation, the baby’s location can be easily determined, therefore, ascertaining that the baby is present in the correct location. An ectopic pregnancy can also be determined depending upon the blood flow patterns that are visible on ultrasound.
Heartbeat of the Baby
In majority of the cases, heartbeat of the baby will be detected during a 6 week ultrasound. The heartbeat rate at this time normally is around 90 to 110 beats per minute. Detection of heartbeat at this time automatically implies that pregnancy will continue till the end and miscarriage will not happen; however, it cannot be guaranteed. If heartbeat is not detected during this ultrasound, then you will be asked to return for a repeat ultrasound at 7 weeks or later.
Fetal Pole
This is the basic shape of the embryo that is normally visible at 6 week ultrasound. It is shaped like a bean and the physician can determine its inclination including the head and rump ends of the baby. Fetus pole is essential in measuring the size and length of the embryo.
Chorionic Sac and Yolk Sac
Chorionic sac, also referred to as the gestation sac, is the fluid sac that covers the fetus all through the period of pregnancy. The yolk sac is present inside the chorionic sac and its function is to provide essential nourishment to the embryo. The yolk sac degenerates after the development of the placenta. Both the chorionic sac and the yolk sac should be visible at this time.
What If No Baby Is Seen?
We have discussed "how early can an ultrasound detect a baby" and "what can you see on an ultrasound", but some of you may ask what if no baby is seen on an ultrasound, here is the answer:
If no heartbeat is detected in an ultrasound done during 6-8 weeks of gestation, does it indicate a problem? No, it does not indicate a problem. There could be multiple reasons for not detecting a heartbeat, including large abdomen, inaccurate date of the last period or tipped uterus. No fetal heartbeat at this stage can make you concerned. However, the physician will not only rely on the heartbeat but they will most probably be concerned with the gestational sac. The size of the fetus is also measured, which helps in finding out age of the baby. Your due date may be off if the baby’s size is smaller than normal. Normally, the due date is estimated on the basis of the date of your last menstrual period. Additionally, an ultrasound done before 6 weeks of gestation may not provide desired results. Repeat ultrasounds may be needed if the baby’s size is smaller. Most importantly, if the heartbeat of the baby is not detected after 6 weeks, then likely you may be having an ectopic pregnancy or a miscarriage. However, you need to discuss this with your physician, because there are other tests that could be performed before reaching to a conclusion.
More Questions About Ultrasound You Might Want Answers
What Is the Accuracy of the Ultrasound in Calculating the Gestational Age?
The due date is calculated by using the date of your last menstrual period, results of an ultrasound and hormone levels. How accurate is the estimation of the due date is affected by the date of your last menstrual period and usually they are mostly close to the date that you will deliver.
At What Time of Pregnancy Can an Ultrasound Find the Gender of the Fetus?
An ultrasound done between 18 and 20 weeks of gestation can be used to determine location of placenta, any complications, multiple pregnancies and gender of the fetus.
Are Ultrasounds a Necessity as Part of Prenatal Care?
Ultrasound is a necessity only when there is some medical problem. Ultrasounds are done to determine whether the baby is normal and also determine any possible complications.
What Are the Side Effects and Risk of Ultrasound to the Baby and the Mother?
When done properly, an ultrasound does not have any side effects. However, it is recommended that it should be done only if medically indicated.
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