a difference affecting the entire one side of the body. individuals who do not have bws can also have hemihypertrophy. isolated hemihypertrophy is associated with a higher risk for cancer. the types of cancer and age of the cancers are similar to children with bws. as a result, children with hemihypertrophy should follow the general cancer screening protocol for bws. hemihypertrophy can also cause various orthopedic problems, so children with significant limb hemihyperplasia should be evaluated and followed by an orthopedic surgeon. hemihyperplasia affecting the face can sometimes cause significant cosmetic concerns that may be addressed by a cranial facial team. prognosis in general, the prognosis is very good. children with bws usually do very well and grow up to become the heights expected based on their parents' heights. while they are at increased risk of childhood cancer, most of them do not develop the disease, and the vast majority of the children who do can be treated successfully. children with bws for the most part had no significant delays when compared to their siblings. however, some of them do have speech problems that could be related to macroglossia or hearing loss. advances in treating neonatal complications and premature infants in the last twenty years have significantly improved the true infant mortality rate associated with bws. in a review of pregnancies that resulted in 304 children with bws, no neonatal deaths were reported. this is compared to a previously reported mortality rate of 20%. the data from the former study was derived from a bws registry, a database that may be slightly biased towards involving living children; however, death was not an exclusion criterion to join the registry. this suggests that while infants with bws are likely to have a higher than normal infant mortality risk, it may not be as high as 20%. assisted reproductive technology assisted reproductive technology (art) is a general term referring to methods used to achieve pregnancy by artificial or partially artificial means. according to the cdc, in general, art procedures involve surgically removing eggs from a woman's ovaries, combining them with sperm in the laboratory, and returning them to the woman's body or donating them to another woman. art has been associated with epigenetic syndromes, specifically bws and angelman syndrome. three groups have shown an increased rate of art conception in children with bws. a retrospective case control study from australia found a 1 in 4000 risk of bws in their in-vitro population, several times higher than the general population. another study found that children conceived by in vitro fertilisation (ivf) are three to four times more likely to develop the condition. no specific type of art has been more closely associated with bws. the mechanism by which art produces this effect is still under investigation. epidemiology beckwith–wiedemann syndrome has an estimated incidence of one in 13,700; about 300 children with bws are born each year in the united states. the exact incidence of bws is unknown because of the marked variability in the syndrome's presentation and difficulties with diagnosis. the number of reported infants born with bws is most likely low because many are born with bws, but have clinical features that are less prominent and therefore missed. bws has been documented in a variety of ethnic groups and occurs equally in males and females. children conceived through in vitro fertilization have a three to fourfold increased chance of developing beckwith–wiedemann syndrome. it is thought that this is due to genes being turned on or off by the ivf procedures. history in the 1960s, dr. john bruce beckwith, an american pathologist and dr. hans-rudolf wiedemann, a german pediatrician, independently reported cases of a proposed new syndrome. originally termed emg syndrome (for exomphalos, macroglossia, and gigantism), this syndrome over time became known as beckwith–wiedemann syndrome or wiedemann beckwith syndrome. originally, dr. hans-rudolf wiedemann (born 16 february 1915, bremen, germany, died 4 august 2006, kiel) coined the term exomphalos-macroglossia-gigantism (emg) syndrome to describe the combination of congenital abdominal wall defects as hernia (exomphalos), large tongues (macroglossia), and large bodies and/or long limbs (gigantism). over time, this constellation was renamed beckwith–wiedemann syndrome following the autoptical observations of prof. john bruce beckwith (born 18 september 1933, spokane, washington), who also observed a severe increase in the size of the adrenal glands in some of these patients.