Ultrasounds are a cause of relief, as they tell you how well your baby is doing. But you are concerned the moment you miss twins on the ultrasound pictures. How is that even possible? You wonder.
The thing is, it is relatively common that a twin pregnancy is undetected in the initial ultrasounds. Research shows that almost 36% of twin pregnancies end up in vanishing twin syndrome. It is up to your doctor to determine if you are having twins or not at the very first ultrasound. But how does that happen?
Why Twins Go Hidden In Ultrasound?
There is not one definite reason for a hidden twin ultrasound. Multiple scenarios contribute to this condition. Oftentimes it is up to your healthcare provider to look for hints as best as he can. But even then, nothing guarantees that the ultrasound will be 100% accurate.
Keeping that in mind, you can consider any of the following reasons why one baby can be seen in the ultrasound and not the other.
Error On Your Doctor’s Part
Human error is one of the most common reasons behind a hidden twin. Technology has developed, but the interpreters of the ultrasounds are still humans; therefore, you can never eliminate the chances of human error.
So ignoring a twin due to small fetus size or any other cause may happen because your health care provider cannot interpret the sonogram properly.
Small Fetus And Early Stages
Your doctor starts with your ultrasound at the onset of the pregnancy. At such an initial time, the fetus is tiny. Even if you are having twins, they will go totally undetected. This makes the initial ultrasounds less precise compared to the ones taken later when the pregnancy has matured.
This is why the later ultrasounds appear really surprising. You can always determine if you are having a twin or not after 6 to 7 weeks of pregnancy, as that will definitely show on the transvaginal ultrasound or the anatomy scan.
One Amniotic Sac
It is extremely common for twins to share the same amniotic sac. This condition is called monoamniotic. They both won’t necessarily develop in their separate sacs, but that happens too.
So if the babies share the same amniotic sac, one can be hidden behind the other during the ultrasound making one twin go undetected.
Of course, the twin can not hide till birth. Regular ultrasounds will indeed expose him. But till then, it will be a mystery and may come as a surprise later on!
Insufficient Prenatal Care
One should never ignore prenatal care. Regular ultrasounds throughout the nine months of pregnancy are the only way to ensure and monitor the health of the fetus and the mother. Moreover, if, in any case, you ignore regular checkups, it will definitely allow your baby to go undetected till birth.
In the absence of ultrasound technology, twin birth was more common. Therefore, if you want to avoid any such situation, keep your ultrasound pictures up to date.
Similar to sharing an amniotic sac, the twin baby can remain hidden from view for apparently no reason. Your baby may be mischievous to take hiding in any nooks and crannies he can find inside your uterus. So it is very easy to miss it in the ultrasound.
So these are some of the common causes, but it should be noted that other minor causes, like health problems, incompetent doctors, or faulty technological systems, can also give similar results.
How Soon Can Twins Show Up On Ultrasound?
As mentioned earlier, it is hard to detect a twin at the very early stages of pregnancy. But regardless of that, new mommies will definitely find out about the hidden twin during their first trimester. It cannot remain hidden forever in the ultrasound.
If you need a timeline, it will appear on your ultrasound between the 12th and 16th week of pregnancy, and the pregnancy will also appear somewhat different than a single pregnancy. After the twelfth week, the hidden twin is easy to detect due to the fetus development that has occurred during the first three months and can no longer hide behind his sibling.
You can get detailed pictures and reports of your babies at the 20-week anatomy scan that is conducted halfway through the pregnancy. It not only determines the baby’s health by showing the skeleton, heart, and brain but also reveals the sex.
At this point, nothing can hide your baby from you. You can even try drinking something sweet right before the scan, and your baby’s reactions will be recorded. So there is no way a hidden twin can conceal himself anymore. It is bound to show.
4 Signs You Are Having Twins
Having to deal with two babies instead of one can be a little overwhelming, especially when the second one is a total surprise to you. But my dear mama-to-be, you need not worry as we have all the telltale signs for you to look out for if you’re having twins.
Increased Morning Sickness
Start with the most typical symptom of pregnancy which is nausea and morning sickness. While one baby can give you nausea, you can never imagine hidden twins. It is just worse. The reason for this lies in the concept that two babies are more work than one.
Nausea, when you are having twins, is not only limited to morning sickness but takes over your entire day. This extreme condition is known as hyperemesis gravidarum and is characterized by an entire day of feeling nauseous unless you keep eating. But how is that possible when you feel an aversion to food?
Frankly, it is hard. But you will be able to eat some foods, so you must stock up on them so that you don’t lose any nutrition and the babies’ health is not affected.
Similarly, fatigue is experienced by almost all women in early pregnancy but depending upon how many babies you are having, you will definitely experience more fatigue when having twins.
While carrying twins, you will notice you are drained of energy. This is not just during the first trimester but continues throughout the pregnancy as your body is under a lot of pressure to provide for two babies. There is only so much pressure your body can take. During such a time, it becomes important to consult your doctor for some energy-boosting supplements.
Energy boosters can help you cope with the double pregnancy. If, after doing everything you can, you still feel fatigued, you must have a detailed sonogram.
Rapid Weight Gain
Weight gain is normal during pregnancy. However, if you are carrying two babies instead of one, naturally, you are going to have a bigger baby bump and experience sharp weight gain in a shorter time. The uterus does stretch to accommodate the twin, but still, the weight gain and bump are more pronounced.
Your gynecologist will definitely investigate your pregnancy if she has the slightest doubt about a multiple pregnancy. She will determine the fundal height and the high levels of amniotic fluid inside your uterus to discover if you are having twins.
Higher Pregnancy Hormones
The hormone in the blood that indicates pregnancy is known as Human Chorionic Gonadotropin, or HCG, or the pregnancy hormone. It is present in the blood during pregnancy to prepare the body for fetal development.
If you are having twins, your HCG count will be higher than normal to accommodate the needs of two developing fetuses. The presence of HCG hormones in excess can make you develop excessive pregnancy symptoms too. For example, you can develop an extreme case of diarrhea, morning sickness, or even nose bleeds due to excessive blood being produced in your body.
Other than these symptoms, you can expect swelling on the face, feet, and hands. You can have extreme mood swings due to hormonal changes as well.
When Can You Be 99.99% Sure?
There are two ways you can be absolutely sure that you are having twins. First, when you visit your doctor, hear the heartbeat. If there is one heartbeat, you definitely have one baby. If you are hearing two heartbeats, you are having twins. The doctor will know at this point if you are having twins.
The other way is the much talked about anatomy scan. It reveals everything from the baby’s health to gender, to any abnormalities, to the number of babies you are having. So once the anatomy scan is done in the 20th week of pregnancy, you can be absolutely sure that you are having twins.
Can A Hidden Twin Be Detected In Ultrasound Imaging?
That is the only way to detect a twin pregnancy; however, even that is only successful if the pregnancy has matured over a specific time period. You cannot expect one blood test to expose hidden twins. You need an ultrasound tech for that. You may be able to see your hidden twin when you are six weeks pregnant. It is rare that by this time the baby will remain hidden.
Even if this happens, you can always see your baby in the anatomy scan. Just make sure you do not have an ectopic pregnancy.
Ectopic pregnancy can shadow your twin until later. It is a life-threatening condition where your fetus starts developing inside your fallopian tubes instead of the uterus. Since it has the danger of bursting the fallopian tubes and harming you, ectopic pregnancy results mainly in miscarriage.
So when the baby is growing in the fallopian tubes, it will naturally be overshadowed till it has grown to a certain point. This complicates the pregnancy as the baby in the fallopian tube cannot survive and can put the other baby in danger too. Timely detection of an ectopic pregnancy is crucial for proper treatment.
What Do We Know So Far?
Pregnancies are highly unpredictable. You can never be fully prepared for it, but you can always know how many babies you are having through regular checkups and the 20-week anatomy scan. So you shouldn’t be bothered if your hidden twin refuses to show up during your initial stages of pregnancy.
Early ultrasounds seldom do justice to accuracy, but you can see signs if you are having a twin, like increased fatigue, nausea, or increased levels of pregnancy hormones. But until you have the final scan, you can never be sure. So keep calm and wait for your pregnancy to mature.