Public defence: Sandra Larsen Sandra Larsen at Institute of Clinical Medicine will be defending the thesis “Placental weight ─ associations with maternal factors and preeclampsia” for the degree of PhD (Philosophiae Doctor).

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Photo: Erik Andreas Fonahn.

Trial Lecture – time and place

See Trial Lecture.

Adjudication committee

  • First opponent: Professor Karin Kalläén, Lund University
  • Second opponent: Senior Consultant Trond Melbye Michelsen, Oslo University Hospital
  • Third member and chair of the evaluation committee: Professor Asbjørn Årøen, University of Oslo

Chair of the Defence

Associate professor Stein Erik Utvåg, University of Oslo

Principal Supervisor

Professor II Anne Eskild, University of Oslo


During pregnancy, the mother supplies oxygen and nutrients to the fetus through the placenta. Birthweight and placental weight may be indicators of the intrauterine environment. Sandra Larsen has explored how placental weight may be associated with maternal factors such as maternal hemoglobin concentrations and maternal smoking, and preeclampsia. Data from Partus, the electronic patient delivery records at Akershus University Hospital, were used in one study and data from the Medical Birth Registry of Norway were used in two studies.

We found that placental weight decreased with increasing maternal hemoglobin concentrations. The high placental to birthweight ratio with low maternal hemoglobin concentrations suggests differences in placental growth relative to fetal growth across maternal hemoglobin concentrations.

In women who smoked throughout pregnancy, placental weight and birthweight decreased non-linearly by number of cigarettes in the first trimester. In women who stopped smoking in pregnancy, placental weight was higher than in non-smokers and increased linearly by number of cigarettes. Birthweight was almost similar to that of non-smokers. Placental to birthweight ratio was higher in all smokers, indicating a disproportionate growth between placenta and fetus.

The etiology of preeclampsia remains unclear and predicting which women will develop preeclampsia is difficult. We found that low placental weight in the first pregnancy was associated with increased risk of developing preeclampsia in the second pregnancy. Additionally, in women without preeclampsia in the first pregnancy, high placental weight increased the risk of developing term preeclampsia in the second pregnancy. Information about placental weight in the first pregnancy might help to identify women at risk of developing preeclampsia in a second pregnancy.

Additional information

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Published Jan. 27, 2020 10:03 AM - Last modified Feb. 6, 2020 9:55 AM