Gestational sac: Detection, Vacuum and Transvaginal Ultrasound

One of the first signs of pregnancy that appears on ultrasound is the gestational sac.

The sac encloses the developing baby and contains the amniotic fluid. It is found in the uterus, and on ultrasound, it appears as a white border around a clear center.

The gestational sac is formed around five to seven weeks after the last menstrual period in natural cycles. It is usually visible using a transvaginal ultrasound between three and five weeks of gestational age.

Transvaginal ultrasound has a higher sensitivity and produces more explicit images than transabdominal ultrasound. The gestational sac is usually seen when your HCG (human chorionic gonadotropin) levels are between 1500 and 2000.

If a gestational sac is seen on your ultrasound, is this a guarantee of a normal pregnancy?

Visualizing a gestational sac is undoubtedly a positive sign of pregnancy, but it does not guarantee that your pregnancy will be healthy and will continue typically.

For example, after the sac becomes visible, the following positive sign of pregnancy is a yolk sac that develops within it. The yolk sac provides nutrition to the developing embryo until the placenta takes over and, therefore, is an essential indicator of the health of the pregnancy.

In some cases, a gestational sac will be detected in the ultrasound, but later, a yolk sac will not be found. The yolk sac is usually visible on a transvaginal ultrasound between weeks 5 1/2 and 6 of gestation.


Possible reasons that may limit the detection of the gestational sac

If you do not see a gestational sac in your ultrasound, what does that mean? There are several possible reasons for the lack of a gestational sac. It could be that:

Your dates are late: This is a common reason and may mean that you need a repeat ultrasound later. It may be helpful to compare this finding with HCG levels, which would probably be less than 1500 if you are not as advanced as you thought you were during pregnancy.

You have aborted: You could have a very early miscarriage (chemical pregnancy) or that you are aborting. The decrease in HCG levels is also a sign of spontaneous abortion.

You have an ectopic pregnancy: If your HCG levels are between 1500 and 2000, but you do not see a gestational sac, it could mean that you have an ectopic pregnancy.

An ectopic pregnancy can be a medical emergency, and if this is a possibility, your doctor will want to do more tests and talk about treatment options.

What does an empty gestational sac mean?

Usually, an embryo is seen inside the gestational sac at six weeks.

One of the most common types of miscarriage, an anembryonic pregnancy, an empty sack, or an affected ovum, occurs when a gestational sac does not contain an embryo.

In other words, an embryo could not develop. This type of pregnancy loss occurs early in the first trimester and often before a woman realizes she is pregnant.

It can result from an abnormal cell division, poor quality sperm, or a poor quality egg.

In most cases, chromosomal abnormalities will cause the woman’s body to undergo a natural abortion without intervention. However, there are some cases in which a woman can choose a dilatation and curettage (D & L) to complete the miscarriage.

This procedure may be appropriate for women who want a pathologist to find a cause for the miscarriage. Those who believe it will help them cope better with the loss or the physical or medical concerns raised by their doctor.

If your doctor discovers an empty gestational sac on an ultrasound, you can confirm that your pregnancy is not viable; in other words, pregnancy will not result in the birth of a baby since it is not progressing normally.

But sometimes (depending on the size of the gestational sac), it may be too early to determine that the sac is really “empty.” In this case, your doctor will ask you to return for a repeat ultrasound.

This can be a moment full of anxiety, but it is meant to guarantee a 100 percent accurate diagnosis (whether the pregnancy is viable or not viable).

In search of good progress

Early transvaginal ultrasounds are a relatively easy way to follow a pregnancy from the beginning. Together with the HCG levels, you and your doctor have an idea of ​​how your pregnancy progresses.

With an early ultrasound, the gestational sac is the first structure doctors look for. It can be a positive sign when present (between 3 and 5 weeks of gestation).

Sometimes, a gestational sac is seen but empty, without evidence of an embryo at six weeks.

On the other hand, sometimes, you do not see a gestational sac. The most common reason for this is inaccurate dates, and it is simply too early.

But if a gestational sac is not seen at follow-up, or if HCG levels indicate that one should be seen, you may have a miscarriage or an ectopic pregnancy.

Pregnancy can be a happy time and full of anxiety when things do not go as you would like.

Lean on your friends and family. It can be a big emotional blow if you think you are having a miscarriage, have a withered egg, or have an ectopic pregnancy.

This is especially true since many couples have not yet shared their pregnancy with family and friends so they may feel very lonely. There are stages of affliction associated with spontaneous abortions, even when they occur early.

The often well-meaning but damaging comments like “you can always have another.” It is essential to honor your feelings and grieve in the best way for you.