One verse

Srimad Bhagavatam 6.18.54

6.18.54

सांवत्सरं पुंसवनं व्रतमेतदविप्लुतम् । धारयिष्यसि चेत्तुभ्यं शक्रहा भविता सुत: ॥ ५४ ॥

samvatsaram pumsavanam vratam etad aviplutam dharayisyasi cet tubhyam sakra-ha bhavita sutah

samvatsaram
for one year
pumsavanam
called pumsavana
vratam
vow
etat
this
aviplutam
without violation
dharayisyasi
you will perform
cet
if
tubhyam
for you
sakra-ha
the killer of Indra
bhavita
will be
sutah
a son.

Kasyapa Muni continued: If you perform this ceremony called pumsavana, adhering to the vow with faith for at least one year, you will give birth to a son destined to kill Indra. But if there is any discrepancy in the discharge of this vow, the son will be a friend to Indra.