Brief Answer:
No it is not advisable.

Detailed Answer:
Hi, I think using lubricants or saliva can affect the sperms motility. Lubricants can be toxic to sperms also. So, these are safe to use as such but when you are trying to get pregnant, these are not advisable. Regarding saliva as vaginal lubricant, it also decreases sperm motility to a great extent. So, this is also not recommended. Hope I have answered your question.
Regards

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Brief Answer:
Yes.

Detailed Answer:
Hi, I think it would be far better to have a natural vaginal secretion rather than using commercial lubricants and saliva. Many studies have proven that these decrease sperm motility.

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Brief Answer:
Both are progesterone.

Detailed Answer:
Hi, actually chemically susten and duphaston both are progesterone only. Both are very much similar to natural progesterone and free from androgenic side effects. The difference is that susten is recommended for vaginal use, while duphaston is effective orally. Also duphaston has been found to have some immunomodulating effect which increases the chance of implantation, which is an extra effect than susten. However, both of them are equally effective as progesterone support. Hope I have answered your question.

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