BeNissan (not the car)
I looked this up as I was thinking about having been born in Nissan myself. It's not a great time for a birthday given all the Pesach bustle that falls out then, overshadowing mere birthday recognition. (BTW for observation on birthdays -- not mine -- see http://divreichaim.blogspot.com/2008/04/in-defense-of-birthdays.html)
But I am certain my mother would have been very relieved that I was a girl so that she did not have the prospect of an erev Pesach bris. (Worst case bris scenario I've heard of was on that fel out within the 3 day Yom tov of Pesach, requiring one to host quite a number of guest for the sedarim and many meals in order for them to also be present at the bris -- someone in Passaic had that situation.
To come to the point, though, I thought of the fact that Yitzchak was said to have been born on or just before Pesach. Yitzchak is clearly linked to saving his offspring in the debate he has with the Almighty in Shabbos 89b. In that case, it sounds like a situation after the redemption from Egypt. Perhaps it is from the spiritual power imbued in the month of Nissan that both the original redemption and the future one spring, and this power is also manifest in the traits of Yitzchak. That is something to consider.
But another question came to my mind from the previous page of the Gemara in Rosh Hashana. There is the debate on lengths of gestations. It also goes on to say that Sarah -- like Chana -- nifkeda on Rosh Hashana. Then Yitzchak would have been born in Nissan -- which would allow just 6 or 6 1/2 months for the gestation, assuming the pikadon signifies conception, as I would assume, for Sarah's return to a state of fertile youth already occurred months earlier -- Pesach time -- when the angels appeared to give Avraham the news. But if that was a leap year with 2 Adars -- which would have allowed for a 7 or 71/2 month gestation period.