Niddah 38: Predicting Childbirth

For the sake of understanding states of niddah and ziva, the rabbis want to be able to understand the timing of conception, pregnancy, labour and post-labour.  We still want to be able to understand women's bodies.  The rabbis teach that a woman can conceive and go into labour on the two hundred and seventy-first, second or third day following conception (because conception itself might be slightly delayed).  This means that a normal pregnancy is a full nine months.  The rabbis also consider a pregnancy of seven months to be normal, for Channa went into labour after "two seasons".  

We learn that the pious men of old would have intercourse with their wives only from Wednesdays until Sundays to avoid the desecration of childbirth on a Shabbat.  However, Shabbat desecration is permitted after a mother gives birth.  A desecration of Shabbat to help a sick person may be hutra, entirely permitted, or dechuya, pushed aside.  The Chasidim HaRishonim considered desecrations of Shabbat in order to help the sick were dechuya, and so efforts were made to avoid any of this work on Shabbat.

The rabbis also speak at length about the number of days that a woman might be a zava, the number of days that she might see - or not see - blood while pregnant, and similar questions involving counting days.  It would seem that all of us hope to predict the unpredictable when we feel particularly out of control.  Childbirth is certainly one of those times.