If there is no problem with pregnancy of your sister, there is no justification to administer Pubergen. Pubergen is the brand name of a medicine called Human Chorionic Gonadotrophin. It is to be given only to patients of infertility or habitual abortion (i.e. cases of miscarriages in the past) or documented, proven cases of corpus luteum insufficiency to help a person concieve (i.e. before pregnancy).
In other words, once a person has conceived there is no need to give Pubergen. Its use during pregnancy is prohibited in the United States. This medicine is categorised as Category X i.e. Animal or human studies have shown fetal abnormalities or toxicity, and the risk outweighs the benefits.