BY SANDRA GUY

While it’s not unusual to see vigorous exercisers lift heavy weights well into their pregnancies, stretching remains a robust secret weapon to staying strong.

Yoga stretches in particular promise to heighten body awareness and mindfulness — a nice positive during pregnancy and preparing for birth and the aftermath.

It’s time to consider the ancient exercise, given that September is National Yoga Awareness Month.

A study by Pamela J. Reis found that women who practiced yoga in a six-week program in late pregnancy were stronger, more optimistic and had better well-being than those who didn’t do so.

The Mayo Clinic website says prenatal yoga also can help prepare for labor because it includes not only stretching but focused breathing and can increase muscle strength, flexibility and endurance.

Experts caution that it’s best to practice prenatal, hatha or restorative yoga — and to avoid hot yoga. They also advise talking with your doctor before starting a yoga practice, strive for at least 30 minutes of moderate physical activity on at least five days a week, but preferably all seven days, and practice yoga in a well-ventilated room, according to the Mayo Clinic.

The key is to stay hydrated and don’t push yourself. For example, it’s wise to steer clear of twisting poses and deep forward or backward bends, the Mayo Clinic website advises.

And watch for warning signs, such as contractions, bleeding, or sensing decreased fetal movement, in which case it’s wise to stop and contact your doctor.