Due to copyright issues, an electronic copy of the thesis must be ordered from the faculty. For the faculty to have time to process the order, the order must be received by the faculty at the latest 2 days before the public defence. Orders received later than 2 days before the defence will not be processed. After the public defence, please address any inquiries regarding the thesis to the candidate.
Trial Lecture – time and place
See Trial Lecture.
Adjudication committee
- First opponent: Professor Bo Jacobsson, University of Gothenburg, Sweden
- Second opponent: Professor Pål Richard Romundstad, NTNU - Norwegian University of Science and Technology,
- Third member and chair of the evaluation committee: Professor Anna Bjerre, University of Oslo
Chair of the Defence
Associate Professor Elisabeth Qvigstad, University of Oslo
Principal Supervisor
Associate Professor Katariina Laine, University of Oslo
Summary
Preterm birth, defined as birth before gestational week 37 is a major challenge in obstetric and perinatal medicine.
The aim of this thesis was to assess associations between maternal country of birth, previous preterm birth and twin pregnancy, and extremely very and late preterm births among women in Norway. All three papers were population-based observational studies using data from the Medical Birth Registry of Norway and Statistics Norway. Associations were assessed by calculating frequencies, crude and adjusted odds ratios with 95 % confidence intervals.
Women born in sub-Saharan Africa and South Asia had 50–70% higher odds and women with unknown country of birth had 3 times higher odds of extremely preterm birth compared to women born in Norway.
Women with extremely preterm first birth had 13 times higher odds of extremely and very preterm second birth and 5 times higher odds of late preterm second birth compared to women with term first birth. Placental disorder was found to contribute to 33–40% of the recurrence risk in early preterm birth and 10–22% of the recurrence risk in late preterm birth.
Complications associated with preterm birth were distributed differently in twin and singleton pregnancies. Preterm birth rate was significantly higher in twin pregnancies than in singleton pregnancies in all gestational age categories. Preeclampsia was significantly more prevalent in singleton pregnancies ending in extremely preterm birth than in twin pregnancies ending in extremely preterm birth.
This thesis has revealed new insight in risk factor for preterm birth by studying different categories based on gestational age at birth and with extremely preterm birth as a separate category. Women with certain country of birth, a preterm first birth and twin pregnancies should be considered at risk and offered tailored antenatal care and relevant prophylactic treatment. Single embryo transfer should be used in in vitro fertilization.
Additional information
Contact the research support staff.