A twin pregnancy requires closer monitoring, higher nutritional intake, and earlier delivery planning than a singleton pregnancy. The risk of complications like preterm labor, anemia, and high blood pressure is significantly higher, which means more frequent checkups, specific dietary adjustments, and awareness of warning signs that need immediate attention. Here’s what matters most at each stage.
More Frequent Prenatal Visits
Twin pregnancies follow a more intensive checkup schedule than singleton pregnancies, and the exact frequency depends on whether your twins share a placenta. If your twins each have their own placenta (the most common type, called dichorionic), you’ll typically visit every four weeks until 28 weeks, then every two weeks until 36 weeks, and weekly after that until delivery.
If your twins share a placenta (monochorionic), the schedule tightens earlier. Visits shift to every two weeks starting at 16 weeks rather than 28. This earlier monitoring exists because shared-placenta twins face a risk of uneven blood flow between the two babies, a condition called twin-to-twin transfusion syndrome (TTTS). Ultrasound every two weeks starting at 16 weeks is the best strategy for catching this early, when treatment is most effective. The signs doctors look for include major differences in fluid levels around each baby and differences in bladder size.
Ultrasound monitoring for growth also follows a tighter schedule. Twins with separate placentas get growth scans every four weeks starting around 24 weeks. Shared-placenta twins get fluid checks every two weeks and growth assessments every four weeks, with more frequent scans if anything looks off.
Weight Gain and Calorie Targets
You need substantially more calories to support two growing babies. Current recommendations suggest increasing your intake by about 700 calories per day during the second and third trimesters compared to the first trimester. Some guidelines go higher: the Canadian Higgins Nutrition Intervention Program recommends an additional 1,000 calories per day after 20 weeks compared to a non-pregnant baseline.
The weight gain targets vary by your pre-pregnancy body mass index. For women starting at a normal weight, the recommended total gain is 37 to 54 pounds. For overweight women, the range is 31 to 50 pounds. For obese women, it’s 25 to 42 pounds. These ranges come from the Institute of Medicine and are endorsed by the American College of Obstetricians and Gynecologists. Falling within your range is associated with better outcomes for both babies, including healthier birth weights and lower risk of preterm delivery.
Key Nutrients to Prioritize
Iron demand is nearly double in a twin pregnancy, and anemia rates are four times higher than in singleton pregnancies. A daily intake of 30 mg of elemental iron from the 12th week of gestation is the standard recommendation. Your provider will monitor your iron levels throughout pregnancy, and some women need additional supplementation if levels drop despite this baseline dose.
Folic acid intake should total 1,000 micrograms per day from food and supplements combined. This is higher than the 400 to 600 micrograms typically recommended for a single baby. Calcium needs also increase, with guidelines suggesting 2,000 to 2,500 mg per day, roughly double the standard adult recommendation. Dairy products, fortified foods, and supplements can all contribute to hitting this target.
Preeclampsia Prevention
Carrying twins is itself a high-risk factor for preeclampsia, a dangerous condition involving high blood pressure that can harm both you and your babies. Because of this elevated risk, the American College of Obstetricians and Gynecologists recommends that all women with twin pregnancies take a daily low-dose aspirin to reduce the likelihood of developing preeclampsia. The optimal window to start is between 12 and 16 weeks of gestation, and it’s continued daily until delivery.
Your provider should discuss this with you at an early visit. If they don’t bring it up, it’s worth asking. Beyond aspirin, staying within your recommended weight gain range and keeping up with your visit schedule helps catch early signs of preeclampsia, like rising blood pressure or protein in your urine, before they become dangerous.
Exercise and Activity
Routine bed rest was once standard advice for twin pregnancies, but research has consistently shown it does not improve outcomes for mothers or babies. Activity restriction without a specific medical reason is no longer supported by evidence.
That said, exercise guidelines do shift after 28 weeks. Up to that point, most women with uncomplicated twin pregnancies can stay physically active at moderate intensity. After 28 weeks, current guidelines recommend checking with your provider about what level of activity remains appropriate, as the physical demands of carrying twins increase rapidly in the third trimester. Walking, swimming, and prenatal yoga are generally well tolerated. High-impact or high-intensity exercise is worth avoiding, and any activity that causes contractions, pain, or bleeding should stop immediately.
Recognizing Preterm Labor
About half of twin pregnancies deliver before 37 weeks, making preterm labor the single biggest concern. Knowing the warning signs gives you the best chance of getting to a hospital in time for interventions that can help your babies. The symptoms to watch for include:
- Contractions every 10 minutes or more frequently
- Low, dull backache that doesn’t improve with position changes
- Menstrual-like cramping in the lower abdomen, sometimes with diarrhea
- Increased pelvic pressure or a feeling of heaviness in the vagina
- Change in vaginal discharge, especially a sudden increase or fluid leaking
- Vaginal bleeding
- Reduced movement from one or both babies
Some of these overlap with normal late-pregnancy discomfort, which makes them easy to dismiss. The key difference is persistence. Normal Braxton Hicks contractions are irregular and stop when you rest or change positions. Preterm labor contractions keep coming at regular intervals and don’t let up.
Travel Restrictions
The window for safe air travel closes earlier with twins. While most airlines allow singleton pregnancies to fly until around 36 or 37 weeks, the cutoff for twin pregnancies is typically around 32 weeks. The NHS notes that the natural chance of going into labor rises significantly after 32 weeks with twins, and most airlines set their restrictions accordingly. If you plan to travel, do it during the second trimester when risks are lowest and you’re likely feeling your best. Check your airline’s specific policy before booking, as requirements vary and some request a doctor’s letter even before the cutoff.
Delivery Timing and Planning
Twin pregnancies are generally not allowed to continue as long as singletons. Research published in the American Journal of Obstetrics and Gynecology found that inducing labor at 37 weeks for shared-placenta twins resulted in fewer complications compared to waiting longer. For twins with separate placentas, delivery is typically planned between 37 and 38 weeks, though the exact timing depends on how both babies are doing.
Your care team will discuss whether a vaginal delivery or cesarean section is appropriate based on the babies’ positions. If the first baby is head-down, vaginal delivery is often possible. If either baby is in a difficult position or if complications arise, a cesarean is the safer route. Having this conversation well before your due date, ideally by 32 to 34 weeks, helps you feel prepared rather than caught off guard.