“Pregnancy has lasting adverse physiologic effects and may result in behavioral changes (i.e., physical activity), but studies have rarely provided longitudinal evidence directly linking pregnancy-related risk factor changes to disease onset,” Dr. Erica P. Gunderson and her associates write in the August issue of the American Journal of Obstetrics an Gynecology.
Dr. Gunderson, from the Division of Research at Kaiser Permanente Northern California in Oakland, and her associates addressed the dearth of strong evidence linking childbearing and metabolic syndrome by studying data from the Coronary Artery Risk Development in Young Adults (CARDIA) trial. Their analysis included 1451 women (61% white, 39% black).
Subjects were aged 18 to 30 years, nulliparous, and free of metabolic syndrome at baseline in 1985 and 1986. Metabolic syndrome was diagnosed if three of five factors were present: waist girth > 88 cm, fasting triglycerides 150 mg/dL or higher, HDL-cholesterol < 50 mg/dL, systolic blood pressure at least 130 mm Hg or diastolic blood pressure at least 85 mm Hg and/or treatment with antihypertensive medication, and fasting glucose at least 100 mg/dL and/or treatment with diabetes medications.
During the following 20 years, the authors identified 259 incident cases of metabolic syndrome (10.3/1000 person-years). In determining relative risk, the investigators adjusted for metabolic syndrome components and physical activity.
Compared with no births, adjusted relative hazards were 1.33 for one normal pregnancy (i.e., without gestational diabetes mellitus) and 1.62 for two or more normal pregnancies (p for trend = 0.02) for metabolic syndrome.
The authors also observed that the relative risk rose to 2.43 for even one birth in mothers with gestational diabetes.
“Both time-dependent physical activity and weight gain acted as mediators,” they note. Only about 5% of metabolic syndrome cases arose from the lowest quartiles of baseline BMI or waist girth.
“Postpartum screening of cardiometabolic risk factors may offer an important opportunity for primary prevention (e.g., structured lifestyle interventions) among women of reproductive age who might otherwise not receive early risk factor assessment,” Dr. Gunderson’s team suggests.
Reference: Am J Obstet Gynecol 2009.