Are twin pregnancies actually higher risk?
Yes — carrying twins raises the likelihood of several specific complications compared with carrying one baby, and that is the reason a twin pregnancy is followed more closely from early on rather than being treated as a bigger version of a singleton pregnancy. The main concerns are preterm birth, preeclampsia, gestational diabetes, anaemia, and uneven growth between the two babies. Exactly how closely you are monitored also depends on whether your twins share one placenta or have one each, which your care team will have determined at your dating scan.
None of this means something will go wrong. Most twin pregnancies reach a safe delivery, and the extra appointments exist specifically to catch problems while they are still small and manageable rather than because something is already wrong. It is worth holding both of those facts at once — the risks are real and worth understanding, and the majority of twin pregnancies do not run into the more serious ones.
Why does preterm birth come up so much with twins?
Twins are considerably more likely than a single baby to arrive before 37 weeks, and preterm birth is the single biggest reason a twin pregnancy is managed differently from the start. It is common for twins to be born some weeks earlier than the 40-week point that is typical for one baby, and this is one of the main things your care team is watching for as the pregnancy goes on.
This is also why the conversation about when and how birth will happen tends to start much earlier with twins than with a single baby. Your provider may talk with you, sometime in the third trimester, about a planned delivery date rather than waiting for labour to start on its own, particularly if there are other concerns alongside the twin pregnancy itself. If you notice regular tightening, cramping, or a change in vaginal discharge well before your due date, that is worth calling about the same day rather than waiting to mention at your next scheduled visit.
What other complications are more common with twins?
Preeclampsia, gestational diabetes, and anaemia all occur more often in twin pregnancies than in singleton ones, which is part of why your blood pressure, urine, and blood tests are checked so regularly. Preeclampsia involves high blood pressure and can affect other organs, and it is watched for at every antenatal visit because it can develop without you feeling unwell at first. Gestational diabetes is checked with a screening test, usually at some point in the second trimester, and anaemia is picked up through routine bloodwork.
Growth is watched closely too, because one twin growing notably more slowly than the other is a meaningful signal whatever your placental situation is. If you notice a sudden, marked change in how your bump looks or feels, or a clear reduction in one or both babies' movements, contact your provider the same day rather than waiting. A change in movement is one of the clearer signals in a twin pregnancy and is never something to sit on.
How does the monitoring schedule change with twins?
You will be scanned more often than someone carrying one baby, and how much more often depends on your specific pregnancy. Twins who each have their own placenta are typically scanned around every four weeks from about 20 weeks, while twins sharing a single placenta are usually scanned roughly every two weeks from around 16 weeks, continuing right through to delivery. That difference is set out in more detail in our article on identical versus fraternal twins and why chorionicity — the number of placentas — matters so much clinically.
Alongside growth scans, you can expect more frequent blood pressure and urine checks, more bloodwork, and earlier, more detailed conversations about the plan for birth. It adds up to a great deal more time in clinic than a singleton pregnancy involves, and it is worth planning around that early — work, travel, and how far you live from the hospital where you are seen all become relevant in a way they might not otherwise.
What is twin-to-twin transfusion syndrome, and does it apply to me?
Twin-to-twin transfusion syndrome, or TTTS, is a condition where blood flows unevenly between twins who share a single placenta, so it can only happen in monochorionic twin pregnancies — never when each twin has their own placenta. It happens because the blood vessels within a shared placenta can connect unevenly, sending more blood to one twin than the other. This is one of the main reasons monochorionic twins are scanned so much more frequently than dichorionic twins, since the condition can develop quickly and is far more treatable when caught early.
If you are carrying dichorionic twins — each with a separate placenta — this particular condition does not apply to your pregnancy at all, which is worth knowing if you come across it while reading. If you are monochorionic, your care team will explain what is being looked for at each scan and what the plan would be if signs of it appeared. It is entirely reasonable to ask directly which category you are in if nobody has told you.
What symptoms mean I should call my provider the same day?
Certain symptoms warrant a same-day call in any twin pregnancy, and it is worth having this list somewhere you can find it easily. These include: regular tightening or contractions before 37 weeks, a sudden gush or ongoing trickle of fluid, vaginal bleeding of any amount, a severe or persistent headache, sudden swelling in your face or hands, or vision changes such as flashing lights or blurring. Any of these can be a sign of preterm labour or preeclampsia, and neither is something to wait out.
A clear reduction in movement from either twin, or a sudden marked increase in the size of your bump, are also reasons to call promptly rather than waiting for your next appointment. None of this means the worst outcome is likely — many of these symptoms turn out to have straightforward explanations. But a twin pregnancy is not the setting to apply the general advice of waiting to see if something settles down on its own.
What does all this extra monitoring look like day to day?
In practice, it means a fuller calendar than most first-time parents expect — regular scans, regular bloods, and check-ins that continue right up to delivery. Weight-gain guidance is different for twins too; national guidance from bodies including the Institute of Medicine and the CDC sets out separate ranges for twin pregnancies rather than applying singleton targets, so it is worth asking your provider what range applies to you specifically rather than assuming.
Most general pregnancy advice you encounter online quietly assumes one baby, so it is worth checking anything you read against what your own care team tells you rather than applying it directly. It can also help to connect with other people carrying twins earlier than you might otherwise think to — organisations that specialise in multiples exist partly because the practical, day-to-day questions are often answered better by people who have lived through it than by clinical guidance alone.