Anne Flem Jacobsen og Hedvig Nordeng

Professor Hedvig Nordeng (right) with her favourite organ, the placenta, together with Head of Unit Anne Flem Jacobsen at Oslo University Hospital, Women and Children\'s Clinic. The two are close collaborators

– The Placenta is my favourite organ

Professor Hedvig Nordeng has been fascinated by the placenta ever since she as a young doctorate, even before having children of her own, participated in a birth for the first time. "The placenta is simply my favourite organ", she admits.

Professor Hedvig Nordeng has been fascinated by the placenta ever since she as a young doctorate, even before having children of her own, participated in a birth for the first time. She witnessed the birth of a healthy child which, just half an hour later, was followed by a discus shaped placenta weighing approximately half a kilo.

The bloody afterbirth had awoken her attention. Today, Nordeng is a professor at the School of Pharmaceutics at the University of Oslo (UiO) and head of a group of scientists examining how pharmaceuticals inside the mother’s body affect the fetus. We know these pharmaceuticals have to pass thorough the placenta which acts like link between mother and child.

“The Placenta is my favourite organ in the human body. It is an incredibly fascinating and important organ. It works so hard all through the pregnancy”, Nordeng explains.

If the placenta functions properly, then everything is in line for a healthy child. However, if the mother smokes, abuses alcohol or is dependent on certain harmful pharmaceuticals, these toxins may pass the placenta and harm the fetus.

Both lungs and kidneys

During the pregnancy, the main task of the placenta is to make sure that the fetus develops and grows. It transports oxygen and nutrition to the fetus while carbon dioxide and other waste are transported back to the mother. Consequently, making the placenta the fetus’s lungs and kidneys.

Furthermore, the placenta is a key endocrine organ that produces a series of pregnancy hormones – such as oestrogen and progesterone. The placenta is also the only organ that produces the hormone human chorionic gonadotropin, in short hCG. A hormone that is important during the pregnancy, but better known for being the hormone that is detected by the pregnancy tests that you buy at the pharmacy.

“Until the 1960s, both scientists and paediatricians believed that the placenta acted as a sort of protective barrier between mother and child. It was common to believe that you could smoke, drink and consume pharmaceuticals without affecting the child. Today however, we know this is wrong. There is actually quite an efficient exchange between the fetus through the placenta - because in-between there is just a couple of thin layers of cells. Consequently, nearly all ordinary pharmaceuticals will pass to the fetus provided the doses are high enough and that the usage is prolonged over time” explains Nordeng.


This considered, Professor Nordeng is convinced that it is of the outmost importance to study the safety and effect of different pharmaceuticals during the pregnancy; so that in the future one can give better advice on which pharmaceuticals are harmful during a pregnancy, and which are not.

Studying the brain of a foetus

Hedvig Nordeng is head of the faculty's new group of elite scientists called PharmaTox, where scientists from different backgrounds study how pharmaceuticals inside the mother can affect the development of a child’s brain.

“It can only happen if the pharmaceuticals pass both through both the placenta and across the blood/brain barrier in the fetus. We now know that some psychotropic drugs have abilities that make them able to pass across this barrier and connect themselves to receptors in the brain of the foetus. However, we still don't know what this exactly means for the development of the fetus, says Nordeng.

In 2012, Hedvig Nordeng and colleagues published an article based on data from nearly 700 pregnant women that had consumed anti-depressants during the pregnancy. Luckily, the results showed that these medicines didn't create a higher risk of malformations. The article received an award in 2011, as a result of its importance within clinical practice. However, it is possible to imagine other side effects than malformations, which means Nordeng is still examining these pharmaceuticals.

“Now we are trying to explore the possibility that some psychotropic drugs are safer than others. What is nevertheless certain is that some women have such a serious mental illness that using medicine during the pregnancy is in the best interest of both mother and child. A mother’s untreated depression will probably have a substantial negative effect on the foetus”, Nordeng points out.

The big toolbox

Additionally, Professor Nordeng and her colleagues at PharmaTox are in the process of testing if ordinary pain killers containing paracetamol can cause foster damage.

“The pharmaceutical is used by many pregnant women, so that just a slight increase in risk will have serious consequences for the public health”, Nordeng warns.

To get to the bottom of this issue, UiO has put together a PharmaTox-team that has a large toolbox at their disposal.

“Naturally, we cannot experiment on human fetuses. Instead we are testing on chicken fetuses and human stem cells. In this Strategic Research Initiative, four colleges at our faculty, consisting of neurotoxicologists, pharmacy epidemiologists, biologists, mathematicians and computer specialists, will cooperate to try to understand how pharmaceuticals can influence the development of the brain. Furthermore, we have established collaboration with 16 external health institutions both abroad and nationally - this includes hospitals, health authorities and other faculties and universities”.

Translated by Espen Haakstad


Professor Hedvig Nordeng, School of Pharmacy at University of Oslo

Read more:

About PharmaTox-project

The use of medicines during pregnancy: The challenges of disseminating research