Astanga Hrudaya
तेन तौ म्लानमुदितौ तत्र जातो न जीवति। शिशुरोजोनवस्थानान्नारी संशयिता भवेत्॥६३॥
because of this, they become fatigued or connected respectively; and life born during this month, does not survive, and life of the woman is also doubtful, because of the instability of Ojas in the child.
english translation