Conditions That Make Exercise Dangerous During Pregnancy If you have any of the conditions below, do not exercise. Check with your health care provider.
Heart disease
Lung disease
Incompetent cervix: The cervix is the narrow, outer end of the uterus. If it is weak, it cannot hold the fetus in the uterus.
Preterm labor (before 37 completed weeks of pregnancy)
Multiple pregnancy (twins, triplets or more) at risk for preterm labor
Frequent bleeding from the vagina during months 4-9 of pregnancy
Placenta previa: The placenta connects the baby's blood supply to the mother's blood. Attached to the mother's uterus, it is an unborn baby's lifeline. Placenta previa is a low-lying placenta that covers part or all of the cervix. This can block the baby's exit from the uterus.
Source: American College of Obstetricians and Gynecologists. Exercise during pregnancy and the postpartum period. Obstetrics & Gynecology, volume 99, number 1, January 2002, pages 171-173.