American Journal of Obstetrics & Gynecology
Volume 197, Issue 2 , Pages 162.e1-162.e6, August 2007

Blood pressure dynamics during pregnancy and spontaneous preterm birth

  • Jun Zhang, PhD, MD

      Affiliations

    • Division of Epidemiology, Statistics and Prevention Research, National Institute of Child Health and Human Development, National Institutes of Health, Department of Health and Human Services, Bethesda, MD
  • ,
  • Jose Villar, MD

      Affiliations

    • Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Oxford, England, UK
  • ,
  • Wenyu Sun, MD, MS

      Affiliations

    • Division of Epidemiology, Statistics and Prevention Research, National Institute of Child Health and Human Development, National Institutes of Health, Department of Health and Human Services, Bethesda, MD
  • ,
  • Mario Merialdi, MD, PhD

      Affiliations

    • Development and Research Training in Human Reproduction, Department of Reproductive Health and Research, World Bank Special Programme of Research, World Health Organization, Geneva, Switzerland
  • ,
  • Hany Abdel-Aleem, MD

      Affiliations

    • Department of Obstetrics and Gynaecology, Assiut University Hospital, Assiut, Egypt
  • ,
  • Matthews Mathai, MD

      Affiliations

    • Department of Obstetrics and Gynecology, Christian Medical College, Vellore, India
  • ,
  • Mohamed Ali, PhD

      Affiliations

    • Development and Research Training in Human Reproduction, Department of Reproductive Health and Research, World Bank Special Programme of Research, World Health Organization, Geneva, Switzerland
  • ,
  • Kai F. Yu, PhD

      Affiliations

    • Division of Epidemiology, Statistics and Prevention Research, National Institute of Child Health and Human Development, National Institutes of Health, Department of Health and Human Services, Bethesda, MD
  • ,
  • Nelly Zavaleta, MD

      Affiliations

    • Instituto de Investigación Nutricional, Lima, Peru
  • ,
  • Manorama Purwar, MD

      Affiliations

    • Department of Obstetrics and Gynaecology, Government Medical College and Hospital, Nagpur, India
  • ,
  • Nguyen Thi Nhu Ngoc, MD

      Affiliations

    • Hung Vuong Hospital, Ho Chi Minh City, Vietnam
  • ,
  • Liana Campodonico, MSc

      Affiliations

    • Centro Rosarino de Estudios Perinatales, Rosario, Argentina
  • ,
  • Sihem Landoulsi, MSc

      Affiliations

    • Development and Research Training in Human Reproduction, Department of Reproductive Health and Research, World Bank Special Programme of Research, World Health Organization, Geneva, Switzerland
  • ,
  • Marshall Lindheimer, MD

      Affiliations

    • Departments of Obstetrics and Gynecology and Medicine, Pritzker School of Medicine, University of Chicago, Chicago, IL.
  • ,
  • Guillermo Carroli, MD

      Affiliations

    • Centro Rosarino de Estudios Perinatales, Rosario, Argentina

Received 25 October 2006; received in revised form 18 January 2007; accepted 13 March 2007.

Objective

The objective of the study was to examine whether blood pressure in early pregnancy and its rise in the second half of gestation are associated with spontaneous preterm birth in healthy, normotensive, nulliparous women.

Study Design

We included 5167 women with singleton gestation who participated in the World Health Organization Calcium Supplementation for the Prevention of Preeclampsia Trial. Systolic, diastolic, and mean arterial blood pressure and pulse pressure at baseline (12-19 weeks of gestation) and at the midthird trimester (30-34 weeks) were calculated. Rise in blood pressure was the difference between the midthird trimester and baseline. Preterm birth was defined as early preterm (less than 34 completed weeks) and late preterm birth (34-36 weeks).

Results

Women experiencing early or late preterm birth had over 10 mm Hg and 3 mm Hg higher rise, respectively, in systolic, diastolic, and mean arterial blood pressure than women delivering at term. A rise in systolic pressure over 30 mm Hg or diastolic pressure over 15 mm Hg was associated with a statistically significant 2- to 3-fold increase in risk of spontaneous preterm birth.

Conclusion

An excessive rise in either systolic or diastolic blood pressures from early pregnancy to the midthird trimester is associated with spontaneous preterm birth in a dose-response pattern.

Key words: blood pressure, preeclampsia, preterm birth

 

 Reprints not available from the authors.

 This work was supported in part by the National Institutes of Health Intramural Research Program (to J.Z., W.S., and K.F.Y.).

 Cite this article as: Zhang J, Villar J, Sun W, et al. Blood pressure dynamics during pregnancy and spontaneous preterm birth. Am J Obstet Gynecol 2007;197:162.e1-162.e6.

PII: S0002-9378(07)00419-X

doi:10.1016/j.ajog.2007.03.053

American Journal of Obstetrics & Gynecology
Volume 197, Issue 2 , Pages 162.e1-162.e6, August 2007