It sounds like she may have had a "miscarriage," for lack of a better term. It was most likely a baby that was not fully developed. If she seems okay now, then it is even more likely that is the case. If it were some kind of medical problem, she would probably still be very sick. It's hard to say why she aborted the baby, if that is what it is. Could be nutritional problems, too hot or too cold, stress, etc. I have 8 emerald swifts and have had many babies without any problems. The thing most people do wrong with these lizards is keep them too hot. They come from high elevation forests and do not like it too hot all the time. They need it to cool off a lot at night time and to have a cooler place in their tank to go during the day if it gets really hot in their enclosure.