Table 3.
Unadjusted and multivariable-adjusted association of number of pregnancies leading to live births and reproductive period duration with QTc interval (ms) in n=40 687 women in the Women’s Health Initiative and Clinical Trials
| Unadjusted effect (95% CI) |
Multivariable-adjusted effect* (95% CI) |
P values | |
| Number of live births and reproductive period duration are each in their own multivariable models | |||
| Number of live births (categorical with never pregnant as referent category) | P value for linear trend=0.008 | ||
| Never pregnant | Ref. | Ref. | |
| None (prior pregnancy, no live births) | 0.54 (−0.76 to 1.83) | 0.66 (−0.56 to 1.88) | |
| 1 | 0.29 (−0.60 to 1.18) | 0.15 (−0.71 to 1.02) | |
| 2–4 | 0.63 (−0.05 to 1.31) | 0.25 (−0.43 to 0.94) | |
| 5+ | 2.39 (1.59 to 3.19) | 1.15 (0.33 to 1.98) | |
| Reproductive period duration (continuous, years) | −0.09 (−0.12 to 0.06) | −0.04 (−0.07 to 0.01) | P value=0.01 |
*Covariates for number of live births analysis include age, baseline BMI, baseline hypertension status, history of diabetes, income, education, race/ethnicity, region, history/duration of breast feeding, lipid medication, oophorectomy status, hysterectomy status, hormone use history, heart rate and QRS duration. Covariates for reproductive period duration analysis include live births, age, baseline BMI, baseline hypertension status, history of diabetes, income, education, race/ethnicity, region, history of breast feeding, duration of breast feeding, lipid medication, oophorectomy status, hysterectomy status, hormone use history and QRS duration.
BMI, body mass index; HT, hormone therapy.