Previous studies linking use of prescription drugs for asthma, epilepsy, diabetes and depression during pregnancy to birth defects have compelled researchers to look further into the issue.

In a study, expected to be published next year, European researchers are examining medical records of nearly four million births across the continent that have been linked to birth defects in newborns, including cleft palate, spina bifida and heart defects, and determining whether they are associated with prescription medications like asthma inhalers, artificial insulin, anti-epileptics and some anti-depressants.

More recently investigators found that pregnant women using asthma inhalers may risk their babies to be born with birth defects. 

The study had linked expecting mothers using preventative asthma inhalers to an increased risk of their babies being born with hormonal and metabolic disorders.

More research needs to be done use of budesonide, fluticasone and beclomethasone inhalers, researchers wrote in the American Journal of Respiratory and Critical Care Medicine.

“Since the Thalidomide disaster everyone thinks twice about taking medicines during pregnancy. It is, however, about balancing the risks of the medicine with the benefits,” Patrick O’Brien, of the Royal College of Obstetricians and Gynaecologists said in a statement, according to the Daily Mail.

Thalidomide, now under strict control and use to prevent birth defects, was introduced in the 1950s and was used to treat morning sickness.  However in the late 1950s and 1960s more than 10,000 in 46 countries with phocomelia, a rare congenital disorder that can result in serious malformation in various parts of the body. 

Researchers said while some prescriptions drugs have been linked to birth defects, pregnant women with chronic conditions like asthma must still take their medications, and the current research aims to figure out both the risks and benefits of taking those medications during pregnancy.

“It is very important work because for many drugs, the safety evidence has not been established yet. We are absolutely not saying to women to avoid all drugs during pregnancy but it should be very carefully weighed up because it is very difficult to establish safety in pregnancy,” said coordinator of the Euromedicat study, Dr. Marian Bakker of the University Medical Centre in Groningen, in the Netherlands in a statement, according to the Daily Mail.

Despite the investigation, the UK Royal College of Obstetricians and Gynaecologists on Sunday night stressed that women should still keep taking their medication, and to talk to their health care providers about any concerns.

“The national clinical guidelines are that inhalers are safe in pregnancy and we support that. We don’t want women to stop taking their medication,” Leanne Metcalf of Asthma UK said, according to Daily Mail.