It's such a strange concept that you might never have thought it could ever be done. In humans, there is no break from a pregnancy: excited by the news or devastated, the pregnancy chugs for about nine months and along comes a baby. If you have a particularly stressful series of projects at work, you will not be able to stop and resume development when the stress is over and life becomes more balanced.
But that's the exact breeding strategy of kangaroos. Kangaroos are fertile breeders and female kangaroos are more or less permanently pregnant for the duration of their fertile years. However, given the limited amount of energy and resources available to care for their offspring, a permanent pregnancy could prove problematic. As such, they use a clever adaptation known as "embryonic diapause" to ensure maximum success of their progeny.
The female kangaroo, after becoming pregnant, can "pause" the process and put the embryo into a state of rest. It remains viable, but does not implant and does not develop further. Once environmental stressors such as drought and famine are over or the previous Joey leaves the bag, the embryo ceases to rest and ends the implantation process to resume the pregnancy.
Although kangaroos may be the most notable example of this phenomenon, maternity adjustments (such as short gestation periods in which the boy lives in the mother's pocket to stop the growth and ability to add different varieties of milk for different ages in her bag There are about 1
Image of Fir0002 / Flagstaffotos (licensed under GFDL v1.2).