In general, the diagnosis for a panda’s pregnancy are:
1. external observation method: this is the observation of the panda’s appetite which decreases when she’s pregnant, she starts to act cautiously, she starts to be afraid of being in a crowded environment, and she starts to sleep more.
2. ultrasonic diagnosis method: making use of physical characteristics of the ultrasonic wave, that is, the reflections of different tissue structures of the uterus during the propagation process, in order to detect the presence of the embryo, the fetal movement, the fetal heartbeat, the fetal pulse, etc.
To diagnose the pregnancy. To take this approach, the panda must be domesticated (This is because the required anesthesia will cause certain damages to the panda).
Female pandas have a gestation period ranging from 74 to 324 days. The first signs of pregnancy appear probably 3 months after conception.
During this period, the panda’s embryo (fertilized egg) “wandered” in the mother’s womb for many days, and has been unable to “be implanted”, that is, it has not attached to the uterine wall to obtain the maternal nutrition.
Until the month before delivery, the embryo adhered to the wall of the uterus and the “progesterone” peaked. As the “implanting” happened too late, many organs have not fully grown, and it is very difficult to perform ultrasound for panda babies.
Through the study of the images obtained from the ultrasound, experts found that 15 to 20 days before the adult female pandas give birth, the fetus can be detected by ultrasound.
Next, we will look into pseudo-pregnancies – through diagnosis by the abovementioned method, we found that if a panda has abnormal signs such as a decreased appetite, and the progesterone hormone in the urine sample is detected, and it has maintained at a high level for a period of time, but the panda is not pregnant, we can call it a pseudo-pregnancy.
There have been many reports on the pseudo pregnancy of pandas domestically and abroad, and it is difficult to find out whether the panda is really pregnant at the early stage.
Humans have been studying the diagnosis of panda pregnancy since the 1980s, and have used the methods of pregnancy diagnosis related to other animals and humans, such as checking progesterone levels during pregnancy, CG substances, etc., However, after many years, related researches are still progressing slowly, and the technology related to the diagnosis of panda pregnancy has not been thoroughly developed.
Examination of progesterone and CG substances during pregnancy are one of the most important methods for the diagnosis of panda pregnancy. But once there are pseudo-pregnancies, not only do they have the same reactions and behaviors as the pandas going through a real pregnancy, but also their hormones are exactly the same (its concentration becomes very high).
Such a method hence fails to make an accurate diagnosis. In addition, due to the long implantation time of the embryo, sometimes up to 4 months, the gestation time is also within 74~324 days (the longest and shortest time recorded), and the ultrasound examination must be performed 15 to 20 days before the adult female panda gives birth in order to successfully detect the fetus.
Moreover, since pandas are rare animals, ultrasound examinations have to be done with extra care, they can’t be moved around too much like other animals. Other latest diagnostic technologies have yet become widely used, all the above factors explain the difficulty in the diagnosis of pregnancy of pandas.