Pregnancy transforms respiratory physiology: progesterone increases respiratory drive (you breathe 40% more air per minute by the third trimester), the growing uterus pushes the diaphragm upward, and increased blood volume demands more oxygen. These changes can make normal breathing feel insufficient, triggering anxiety and breathlessness that have nothing to do with fitness or health. Understanding these changes — and adapting breathing techniques to them — reduces discomfort and prepares you for labor.
First trimester: coherence breathing (inhale 5, exhale 5) addresses nausea and anxiety. The vagal stimulation from slow breathing reduces nausea intensity (the vagus nerve directly innervates the stomach). Second trimester: lateral rib breathing — place hands on the sides of the ribcage and breathe into the hands, expanding the ribs laterally. This compensates for the upward displacement of the diaphragm. Third trimester: three-part breath (belly, ribs, chest) maintains respiratory capacity despite physical compression.
All trimesters: extended exhale breathing (inhale 4, exhale 6) before bed addresses the insomnia common in pregnancy. The technique is safe throughout pregnancy — there are no breathing exercises that are contraindicated during normal pregnancy. The positions may change (avoid supine breathing after 20 weeks; use side-lying or semi-reclined instead), but the techniques remain the same. Begin labor breathing practice in the third trimester so the patterns are automatic when needed.