Yan Feiqing knew that Zhang Tie possessed too many secrets. As a smart woman, although she could take away her husband's purse, even extrude his physical strength, she could never get all of his secrets.
Zhang Tie said he had telepathy with the oncoming baby; whereas, Yan Feiqing could clearly sense that her pregnancy was completely under Zhang Tie's control. Although she didn't know whether Zhang Tie had used a secret method or not, for practical purposes, she could imagine it when she referred to the bygones of the other women's pregnancy.
Zhang Tie didn't say it; therefore, Yan Feiqing didn't ask about it.
When in Xuanyuan Hill, Zhang Tie didn't make Yan Feiqing pregnant because he might think that the overall situation and environment were not suitable to her pregnancy, which, otherwise, would be affected by many aspects. Therefore, he procrastinated it until now.