How long are Sang'gre pregnancies?
Without a canon source, I could only speculate as to how long it takes.
Assuming that there are no time lapses,
- Raquim is informed of Mine-a's pregnancy at either dawn or sunset (I'll pick dawn)
- Raquim visits Mine-a in daylight, fights war with Hathoria by afternoon
- At night, Arvak is slain, Amihan is born
- Mira and Lira
- Pirena and Amihan meet with the dads of their babies in dreams
- By morning, Amihan tells her sisters of her pregnancy
- Night - Amihan meets Ybarro in Adjantao
- Later that night - Mine-a dies, Amihan gives birth. Same with Pirena.
Based on the continuous action - especially from Lira's conception to birth - the shortest period is probably 24 hours.