It’s hard enough planning for one baby without worrying about whether there will be more. Even if you’re told multiple times that you’re only having one, you might still be convinced you’re having double. Tales of twins discovered late in pregnancy may cause you to wonder, how often are twins missed on ultrasounds, really?
The thought of overlooking an entire baby on an ultrasound is worrisome. You want to be as prepared as possible for however many babies you have before they arrive. But before you go buying a second crib, take a moment to read what experts have to say about the likelihood — or unlikelihood — of twins discovered late in pregnancy.
How Reliable Are Ultrasounds?
An ultrasound is the best way to get information about your pregnancy. It allows you and your doctors to see clearly inside the womb from multiple angles. As ultrasound technology has increased, the more reliable the imaging has become. And today, it’s pretty dang reliable.
With very rare exceptions, your doctor should be able to detect twins via ultrasound by week ten at the latest. The later in the pregnancy the ultrasound is taken, the more obvious the twins will become. This is why sometimes you’ll find twins discovered late in pregnancy — although “late” is relative and usually refers to a few weeks. While the delay may be inconvenient if you’re hoping to get an early jump on baby prepping, you can rest assured that, if you have ultrasounds throughout your pregnancy, it’s highly unlikely you’re going to end up with twins discovered late in pregnancy.
Exceptions with Twins Discovered Late in Pregnancy?
While modern ultrasounds are overwhelmingly reliable, images from early-on in the pregnancy may not be able to rule out the possibility of twins conclusively. In ultrasounds taken in the first two months of pregnancy, one baby may conceal a secret sibling. This occurs when one twin is positioned directly in front of the other, blocking the second twin from view. This positioning happens most often with twins sharing the same amniotic sac, as they are forced closer together. However, even this is exceedingly rare.
So how often are twins missed on an ultrasound? Although the likelihood is there, doctors will eventually notice the second baby. Even if they’re unable to detect the twin in the ultrasound, they will likely hear a second heartbeat or see other symptoms in the mother, such as extra-high hormone levels or quick pregnancy progression.
So, unless other factors make you more likely to have twins, you typically have nothing to worry about. The later in your pregnancy you are, the harder it becomes for a twin to hide from you and your doctor — or from its sibling.
Should You Be on the Lookout for Hidden Twins?
If you’re wondering about the possibility of having twins, and you’re still waiting on a later ultrasound result to confirm the number of babies you’ll be welcoming into your home, there are a few factors you might consider.
Some of the most significant factors that impact the likelihood of having twins are age and use of fertility treatment. Women over 35 are more likely to have twins because they are more likely to release multiple eggs during one cycle. If you’re older — sorry, ladies — you might want to be on the lookout for twins during your ultrasounds.
Fertility treatment can increase the likelihood of having twins. This is especially true if you are using fertility drugs, as they can also cause you to release multiple eggs during one cycle. If you’re wondering how your fertility treatment may affect your chances of having twins, consult your doctor sooner rather than later.
Other factors including heredity, history of twins and stature can all make you more or less likely to have twins. Evaluating your likelihood using these factors may help put your mind at ease if you’re worried about twins discovered late in pregnancy. However, this line of thinking shouldn’t be a substitute for a professional, thorough ultrasound.
Will You Be Bringing Home a Second Baby Unexpectedly?
The short answer is: no, probably not. Twins are very rarely missed on ultrasounds — even when they are overlooked early on, they tend to become easily identifiable after a few months. If you’re going to be having twins, you’ll know about it before you deliver. Don’t let the surprise twist-endings of movies make you believe otherwise.
If you do happen to be one of the few legendary people who discover secret twins during your pregnancy, take comfort in that you’ll still have plenty of time to prepare the nursery. Just be sure to give the little ones enough space when they finally arrive — it can’t be easy sharing space in the same belly for nine months! 😉