Is exercise during twin pregnancy safe during pregnancy?

What does the evidence say about exercise during twin pregnancy during pregnancy?

1. A survey of 652 women who had a twin pregnancy found that only 25% did any physical exercise during the pregnancy and 7% felt discriminated against by other people's opinions about exercising while carrying twins, yet the physically active women in this group did not deliver preterm more often than the inactive ones. 1
2. The same researchers describe no specific physical activity guidelines for multiple pregnancy, since existing exercise recommendations were built from singleton-pregnancy research; one national guideline classifies a twin pregnancy beyond 28 weeks as a relative contraindication to structured exercise, and the study's authors concluded that twin pregnancy is often discouraged from activity that showed no harm in their own data. 1
3. A national survey of 276 women who had delivered twins found about 75% received some provider advice on physical activity, but 42% were specifically told to restrict activity and another 13% were prescribed bed rest; walking was the single activity recommended most often, named for 51.9% of the women who received any advice, while only 13% were told moderate-intensity activity was fine. 2
4. In that same survey, women whose provider raised physical activity first reported different activity levels over pregnancy than women who brought the subject up themselves, and 70% of respondents said they were satisfied with the physical-activity and nutrition information they did receive. 2
5. A systematic review of exercise guidelines from 12 professional societies for healthy pregnancy found multiple gestation listed as a reason to stop or modify exercise among the groups that published contraindications, even though the review's own general recommendation of about 150 minutes a week of moderate-intensity activity was built for singleton pregnancy and not extended to twins. 3
6. Twin pregnancies carry higher rates of gestational diabetes, hypertensive disorders of pregnancy, and anemia than singleton pregnancies, and preterm birth is described as the greatest fetal risk of carrying twins, which is part of why activity guidance for twin pregnancy tends to be individualized rather than drawn from a standard checklist. 4
7. The Society for Maternal-Fetal Medicine recommends against routine hospitalization and activity restriction to reduce preterm birth in multiple gestations. Its review identifies harms from prolonged restriction and distinguishes routine bed rest from an individualized response to a specific complication. 5

What twin-pregnancy patients were actually told about activity