Having heard that the eighth pregnancy of Devaki could not bring forth a female child, Kamsa may certainly consider this point and suspect that Krsna is the son of Devaki and Vasudeva - SB 10.8.8-9

Expressions researched:
"having heard that the eighth pregnancy of Devakī could not bring forth a female child" |"may certainly consider all these points and suspect that Kṛṣṇa is the son of Devakī and Vasudeva"

Srimad-Bhagavatam

SB Canto 10.1 to 10.13

Kaṁsa is both a great diplomat and a very sinful man. Therefore, having heard from Yogamāyā, the daughter of Devakī, that the child who will kill him has already been born somewhere else, having heard that the eighth pregnancy of Devakī could not bring forth a female child, and having understood your friendship with Vasudeva, Kaṁsa, upon hearing that the purificatory process has been performed by me, the priest of the Yadu dynasty, may certainly consider all these points and suspect that Kṛṣṇa is the son of Devakī and Vasudeva. Then he might take steps to kill Kṛṣṇa. That would be a catastrophe.

SB 10.8.8-9, Translation and Purport

Kaṁsa is both a great diplomat and a very sinful man. Therefore, having heard from Yogamāyā, the daughter of Devakī, that the child who will kill him has already been born somewhere else, having heard that the eighth pregnancy of Devakī could not bring forth a female child, and having understood your friendship with Vasudeva, Kaṁsa, upon hearing that the purificatory process has been performed by me, the priest of the Yadu dynasty, may certainly consider all these points and suspect that Kṛṣṇa is the son of Devakī and Vasudeva. Then he might take steps to kill Kṛṣṇa. That would be a catastrophe.

Kaṁsa knew very well that Yogamāyā was, after all, the maidservant of Kṛṣṇa and Viṣṇu and that although Yogamāyā had appeared as the daughter of Devakī, she might have been forbidden to disclose this fact. Actually this was what had happened. Garga Muni argued very soberly that his taking part in performing the reformatory process for Kṛṣṇa would give rise to many doubts, so that Kaṁsa might take very severe steps to kill the child. Kaṁsa had already sent many demons to attempt to kill this child, but none of them had survived. If Garga Muni were to perform the purificatory process, Kaṁsa's suspicions would be fully confirmed, and he would take very severe steps. Garga Muni gave this warning to Nanda Mahārāja.