Dragonheart by Todd Mccaffrey
Fiona didn't mean to Impress the dragon at the Hatching. She didn't want to leave her father, Lord Holder Bemin all alone - she was the only one of his children to survive the plague. But she knew her duty and Talenth was the most wonderful being a person could ever have love her. Then a dreadful illness started killing the dragons just as they were about to fight Thread. To have some dragons in reserve some of the younger ones, including Fiona and Talenth, jumped back in time, they returned three days later but three years older and stronger.Meanwhile Lorana, at the cost of her queen dragon, found a cure and the dragons were saved. Saved, only to fight outnumbered against Thread. Where the Weyrs could usually expect to have three thousand dragons all together, less than a thousand dragons survived to fight Thread. The Weyrleaders tried everything they could - timing it, enlisting the watch-whers, training more groundcrew but it was a losing battle. Lorana realized they were in desperate trouble, she knew that time was needed - and if it can't be had in the past, then perhaps in the future? But Lorana is pregnant, if she jumps into the future she may find help but she will almost certainly kill her child. Can she do that? And can anyone jump into the future? Or will she disappear forever, taking Minith with her? And who would miss her if she did? Ambivalently, Lorana takes her leap forward into time.