Phaladeepika
आद्ये चतुष्के जननीकृताघै- र्मध्ये च पित्रार्जितपापसङ्घैः । बालस्तदन्त्यासु चतुःशरत्सु स्वकीयदोषैः समुपैति नाशम् ॥ ४॥
If the child dies in the first four years, it is because of the mother's sins. If in the middle four years, it is owing to the accumulated sins of the father. If it comes by its death in the last four years, it must be due to its own sins (in a previous birth)
english translation
Adye catuSke jananIkRtAghai- rmadhye ca pitrArjitapApasaGghaiH । bAlastadantyAsu catuHzaratsu svakIyadoSaiH samupaiti nAzam ॥ 4॥
hk transliteration by Sanscript