Multiple births in Iceland during 1997-2018

• Main Author: Jamie Ontiveros 1983-
• Other Authors: Háskóli Íslands
• Format: Thesis
• Language: English
• Published: 2021
• Subjects: Faraldsfræði; Iceland
• Online Access: http://hdl.handle.net/1946/38564

Introduction Multiple birth rates have been increasing globally since the 1980s and until the 2000s when regulations limited multiple embryo transfers during IVF treatments. Iceland passed similar regulations in 2009 and it is unknown whether these changes affected rates of multiple births in Iceland. The aim of the study was to assess the rates of multiple births and obstetrical interventions for multiples in Iceland during 1997-2018. Methods This study included multiple live births in Iceland during 1997-2018 identified from the Icelandic Medical Birth Registry. Multiple birth rates were calculated by birth year period overall and by grouped maternal age. Rates of cesarean delivery and induction of labor for multiples were calculated by birth year period. Logistic regression models were used to assess the risk of multiple birth and the risk of obstetrical intervention for multiple births according to birth year period. Results The study included 95 405 live births, of which 3314 (3.5%) were multiples. Multiple births rates decreased during the study period with the largest decrease from 2006 to 2009. The risk of multiple birth decreased in 2009-2013 (AOR=0.76, 95% CI=0.69-0.84) compared to 1997-2002 and was further decreased for maternal age 35+ (AOR=0.58, 95% CI=0.48-0.69). Induction of labor rates increased from 25% in 1997-2002 to 55% in 2009-2013 (AOR=4.25, 95% CI=3.40-5.33) whereas elective (AOR=0.62, 95% CI=0.48-0.80) and emergency cesarean (AOR=0.81, 95% CI=0.64-1.01) rates declined. Conclusion Multiple live births decreased during the study period with the largest decrease from 2006-2009 and for mothers aged 35+ years. These results indicate that international embryo transfer regulations published before the Icelandic regulations in 2009 may have had the largest effect on multiple birth rates in Iceland, but that the Icelandic policy introduced in 2009 may have had some effect on further reducing these rates, particularly for older mothers. Bakgrunnur Tíðni fjölburafæðinga hefur verið að aukast á ...