You are already taking the right steps in preparing your body for pregnancy just by stepping on the mat. When trying to conceive I recommend a gentle flow practice with a focus on restorative poses. 

You do not need to avoid any particular poses but do skip hot, vigorous, or dehydrating exercise.  Focus on poses like Reclined Cobbler’s Pose (Supta Baddhakonasana)  or Uptavistakonasana (wide angle pose)  because these two poses open and soften the belly and pelvis.

You can also include inversions like Shoulderstand (Sarvangasana), Plow and Supported Plow (Halasana)  which gently compress the thyroid, an endocrine gland that helps regulate hormones in the body. The two hormones produced by the thyroid gland are called - t3 (triiodothyronine) and t4 (thyroxine).  This delicate balance of hormones not only effects fertility, but also effects menstruation.  
 
Stress can also play a factor in fertility.  Yoga has been proven to reduce the production of stress hormones which can hamper conception.  I see great things happen to those who stay committed to their practice. Good Luck.

-Question from Anette in Denmark and Patricia in Brazil.

Deb Flashenberg, is Director of The Prenatal Yoga Center in New York City and a certified Doula and Lamaze instructor