About the Authors
National Perinatal Epidemiology Unit, University of Oxford, Oxford, United Kingdom
Division of Perinatal and Reproductive Medicine, University of Liverpool, Liverpool Women's Hospital, Liverpool, United Kingdom
The authors have declared that no competing interests exist.
Conceived and designed the experiments: JJK ZA PS PB MK. Performed the experiments: MK. Analyzed the data: KF JJK ZA PS PB MK. Wrote the first draft of the manuscript: KF MK. Contributed to the writing of the manuscript: JJK ZA PS PB. ICMJE criteria for authorship read and met: KF JJK ZA PS PB MK. Agree with manuscript results and conclusions: KF JJK ZA PS PB MK.