Chorionic Villus Sampling at 11 to 13 Weeks of Gestation and Hypertensive Disorders in Pregnancy Asma Khalil, MD, Ranjit Akolekar, MD, Pranav Pandya, MD, Argyro Syngelaki, RM, and Kypros Nicolaides, MD OBJECTIVE: To estimate the potential association of chorionic villus sampling (CVS) with subsequent devel- opment of hypertensive disorders of pregnancy and to evaluate whether any such potential association remains significant after adjusting for maternal characteristics and components of first-trimester screening. METHODS: We included live singleton pregnancies at 11 0/7 to 13 6/7 weeks surviving to beyond 23 weeks of gestation with available measurements of free -hCG and pregnancy-associated plasma protein A. We ex- cluded pregnancies resulting in miscarriage or termina- tion before 24 weeks of gestation, women with no known pregnancy outcome, and women who had an amniocen- tesis. Multiple logistic regression analysis was used to determine whether CVS, in addition to factors in the maternal history and characteristics, made a significant contribution to the development of preeclampsia and gestational hypertension. RESULTS: Included in the study were 31,138 women, of whom 697 (2.2%) had preeclampsia subsequently de- velop, and 857 (2.8%) had gestational hypertension de- velop. In 2,278 (7.3%) individuals, a CVS was performed. Multiple logistic regression analysis demonstrated that although there were significant contributions from ma- ternal factors and serum biochemistry, a CVS in the first trimester did not contribute significantly to subsequent development of early preeclampsia (P.677), late pre- eclampsia (P.535), or gestational hypertension (P.848). CONCLUSION: There is no association between per- forming a CVS in the first trimester and subsequent development of hypertensive disorders of pregnancy. (Obstet Gynecol 2010;116:374–80) LEVEL OF EVIDENCE: II T here is conflicting evidence in the literature about whether chorionic villus sampling (CVS) in early pregnancy increases the risk of preeclampsia. A ran- domized study comparing the safety of CVS and early amniocentesis at 11 to 14 weeks reported that in the CVS group the rates of preeclampsia and/or gesta- tional hypertension were significantly increased and hypothesized that focal placental disruption may lead to subsequent development of maternal hyperten- sion. 1,2 Three subsequent case– control studies re- ported contradictory results. Adsumalli et al 3 com- pared 1,540 women who had CVS and 840 control women who did not have an invasive test and re- ported that, although the overall risk for hypertensive disorders was similar in the two groups, CVS was associated with an increase in the incidence of severe preeclampsia. Grobman et al 4 compared 152 women who had CVS and 653 control women who did not have an invasive procedure and reported that, al- though the overall risk for hypertensive disorders was similar in the two groups, in nulliparous women CVS was associated with an increase in the incidence of preeclampsia. Odibo et al 5 compared 5,096 women who had CVS with 4,002 women who did not have any invasive procedure and reported that, in the CVS group, the incidence of preeclampsia was decreased. These conflicting results may be the consequence of differences in study design, including the selection of control women and failure to adjust for some or all From the Department of Fetal Medicine, Institute for Women’s Health, University College Hospital, and Department of Fetal Medicine, Kings College Hospital, London, United Kingdom. Supported by a grant from The Fetal Medicine Foundation (UK Charity number 1037116). Corresponding author: Professor K. H. Nicolaides, Harris Birthright Research Centre for Fetal Medicine, King’s College Hospital, Denmark Hill, London SE5 9RS; e-mail: kypros@fetalmedicine.com. Financial Disclosure The authors did not report any potential conflicts of interest. © 2010 by The American College of Obstetricians and Gynecologists. Published by Lippincott Williams & Wilkins. ISSN: 0029-7844/10 374 VOL. 116, NO. 2, PART 1, AUGUST 2010 OBSTETRICS & GYNECOLOGY