A news investigation from the BBC uncovered failures in diagnosing serious medical issues during private baby scans.
More than 200 studies across the United Kingdom now sell ultrasound scans, and thousands are being carried out every year.
BBC found evidence of women not being told about the serious conditions and abnormalities of their infant.
The Care Quality Commission said that there is good quality care in the industry, but it has a growing concern. Private baby scanning studios offer different services.
Some diagnose medical issues, while other studios market themselves as providers of souvenir images or ultrasound videos. Most of the studios sell packages providing a reassurance scan to expectant mothers.
The growing popularity of gender reveals parties means that many women visit private baby scan studios to purchase confetti cannons and balloons that unveil the gender of their baby after the scan.
Many women that BBC News spoke to said that they had positive experiences at private studios, but there were also instances where women said they were failed.
Sonography is not as regulated as radiography or midwifery. It can lead some to question the quality of private baby scans and their interpretation.
Jeanette Dickson, the Royal College of Radiologists president, said that they are doing the most difficult scans at the trickiest time for the most anxious group of people with a workforce that they do not know.
Almost all sonographers are regulated separately as radiographers or midwives in the NHS, just like many private studios. However, Dr. Dickson said regulation of sonographers is needed because of the growth of the industry. She said that it matters now because of the massive increase in these companies.
Some baby scan studios say that they do not diagnose medical problems, but they still sell scans offering reassurance, which usually detect a heartbeat.
One of these companies, Meet Your Miracle, advertises scans which its website says visualize wellbeing. There are messages from the WhatsApp group of the company's management and sonographers, which shared and reviewed customer scans, sometimes during appointments.
One sonographer told the WhatsApp group that she felt guilty after letting a woman leave without telling her of a possible abnormality identified by her colleague as fetal hydrops, which has a low chance of survival.
Despite the studios not being a medical company, a former employee revealed to BBC News that women who were bleeding and in pain were still accepted for scans, instead of redirecting them to contact the NHS so they can get a proper check-up.
Meet Your Miracle says its scans are recreational. Under its registration, it cannot discuss any concerns unless connected to the baby's heartbeat or show a potential diagnosis that needs further tests done by the NHS.
The studio advises women who are bleeding and in pain to contact the NHS. According to the NHS, bleeding during pregnancy is common but advises women to get in touch with their midwife or GP if they are bleeding from their vagina.