A study published in Obstetrics and Gynecology explored the practical and real-time maternal and fetal responses to a moderate intensity yoga session in the third trimester of pregnancy. A typical 1-hour, moderate intensity prenatal yoga session was evaluated in this prospective observational study in low-risk, pregnant women. Exclusion criteria included hypertension, IUGR, preterm labor, or contraindications to exercise. Wireless fetal monitors helped monitor fetal beat-to-beat variability, accelerations, and decelerations as well as maternal heart rate and uterine activity. Fetal and maternal heart rates were constantly recorded over the yoga session. The pre- and post NST tracings were assessed for loss of fetal heart rate variability and decelerations.In all, 20 participants were enrolled, of which, 19 completed the session (average age 32 years). Mean gestational age was 35 weeks, 6 days. Fetal heart rates fluctuated over the course of the yoga session; however, no significant fetal heart rate decelerations or changes were noted in beat-to-beat variability that would indicate detrimental fetal effects. The average fetal heart rate was 135.3 bpm (SD±12.2), irrespective of activity level. Maternal heart rate also demonstrated fluctuations from a mean resting heart rate of 88.7 bpm (SD±9.7), increasing to an average heart rate of 104.8 bpm (SD±18.6) during the session, reaching a maximum of 154.9 bpm (SD±12.8), and subsequently decreasing to 88.7 bpm (SD±11.2) during meditation.Researchers concluded that yoga can be recommended for low-risk women during pregnancy since there seemed to be no adverse fetal heart rate effects during a realistic, continuous yoga session.