अन्वयः

सपत्नया by her cowife, गर्भजिघांसया with a motive to destroy the embryo, तस्यै to her, गरः poison, दत्तः given, तेन for that reason, गरेण सहैव with poison, जातः born, सः he, सगरः Sagara, अभवत् became.

M N Dutt

And since intending to destroy her foetus she that was co-wife with her had administered poison to her, Sagara* was born together with the poison. *Gara-poison. Sagara means, with poison, i.e. here, one born with poison.

Summary

With a motive to destroy the embryo her cowife had poisoned her. That child was born with gara or poison for which he was called Sagara.

पदच्छेदः

सपत्न्या	सपत्नी (३.१)
तु	तु (अव्ययः)
गरस्	गर (१.१)
तस्यै	तद् (४.१)
दत्तो	दत्त (√दा + क्त, १.१)
गर्भजिघांसया	गर्भ–जिघांसा (३.१)
गरेण	गर (३.१)
सह	सह (अव्ययः)
तेनैव	तद् (३.१)–एव (अव्ययः)
जातः	जात (√जन् + क्त, १.१)
स	तद् (१.१)
सगरो	सगर (१.१)
ऽभवत्	अभवत् (√भू लङ् प्र.पु. एक.)

छन्दः

अनुष्टुप् [८]

छन्दोविश्लेषणम्

१	२	३	४	५	६	७	८
स	प	त्न्या	तु	ग	र	स्त	स्यै
द	त्तो	ग	र्भ	जि	घां	स	या
ग	रे	ण	स	ह	ते	नै	व
जा	तः	स	स	ग	रो	ऽभ	वत्