A pregnant Arkansas woman has gotten pregnant, again.
During a routine prenatal checkup, doctors discovered Julie Grovenburg was carrying two embryos, and they're not twins. It seems the two babies were conceived two and a half weeks apart from each other.
Doctors noticed a second tiny sack during the ultrasound and heard a second heartbeat. They say that the two babies aren't twins because their developmental stages are both at different rates.
Both babies also have separate expected due dates. The first one is expected in December of 2009 while the second is due in January of 2010.
This phenomenon is quite rare, as there have only been 10 related cases reported.