In the book of "Marriage to Parenthood – by Abbas Merali", it states regarding the conception of a child, under the section of what are the Makruh Times.
It says, it is not recommended during the first hours of the night, with a fill stomach and one is tired.
What exact time does this mean? That a few hours after Isha is not recommended and then later hours of night, is okay.
But one is usually more tired towards the end of the night.

For example, Maghrib is 6.30 pm. I have dinner at 8 pm.
So if I wait till my stomach is not full anymore (meaning dinner has digested), that means atleast 2 to 3 hours after dinner. So between 10 pm and 11 pm. But one is usually more tired at that time, as compared to earlier hours.
Kindly explain. As this note also states that conception when one is tired, has a negative effect on the child.

First hour of the night is after the total disappearance of the sun