1. Wilson RD. Society of obstetricians and gynaecologists of Canada genetics committee. Genetic considerations for a woman’s preconception evaluation. SOGC committee opinion 253. J Obstet Gynaecol Can. 2011;33:57–64.
2. Wilson RD, Davies G, Gagnon A, Desilets V, Reid GJ, Summers A, Wyatt P, Allen VM, Langlois S. Genetics committee of the society of obstetricians and gynaecologists of Canada. Amended Canadian guideline for prenatal diagnosis change to 2005–techniques for prenatal diagnosis. J Obstet Gynaecol Can. 2005;2005(27):1048–62.
3. American College of Obstetricians and Gynecologists. ACOG practice bulletin No. 4: prevention of Rh D alloimmunization. Int J Gynaecol Obstet. 1999;66:63–70.
4. Mujezinovic F, Alfirevic Z. Analgesia for amniocentesis or chorionic villus sampling. Cochrane Database Syst Rev. 2011;11:CD008580.
5. Young C, von Dadelszen P, Alfirevic Z. Instruments for chorionic villus sampling for prenatal diagnosis review. Cochrane Database of Syst Rev. 2013;1:CD000114.