Association Between Parity and Subclinical Left Ventricular Dysfunction in Healthy Pregnant Women: A Prospective Cross-Sectional Study.

BACKGROUND

Pregnancy induces profound cardiovascular adaptations that may have cumulative effects with repeated pregnancies. However, the relationship between parity and subclinical myocardial dysfunction in healthy women remains unclear.

METHODS

This prospective cross-sectional study enrolled 605 healthy pregnant women without cardiovascular disease or risk factors. All participants underwent comprehensive echocardiographic assessment including speckle-tracking-derived global longitudinal strain (GLS) analysis during the third trimester (28-32 weeks gestation). The relationship between parity and GLS was described using multivariable linear regression analysis, adjusting for age, body mass index and blood pressure. Participants were stratified into two groups (≥ 4 vs. < 4 pregnancies) for comparative analysis.

RESULTS

Mean age was 30.9 ± 7.2 years with mean parity of 3.8 ± 2.4 pregnancies. Despite preserved ejection fraction across all women (63.2% ± 4.7%), each additional pregnancy was associated with a 0.21-unit worsening in GLS independent of age (β = 0.21, 95% CI: 0.13-0.29, p < 0.001). Women with ≥ 4 pregnancies had significantly worse GLS compared to those with fewer pregnancies (-19.1% ± 2.5% vs. -20.5% ± 4.1%, p < 0.001). In multivariable linear regression, high parity remained independently associated with reduced GLS (β = 1.18, 95% CI: 0.52-1.84, p < 0.001) after adjusting for confounders. The effect was more pronounced in older women and those with shorter interpregnancy intervals (< 18 months).

CONCLUSION

Higher parity is independently associated with reduced myocardial strain detected by GLS despite preserved ejection fraction, demonstrating a continuous relationship with each additional pregnancy. While GLS values remain within physiological ranges for pregnancy, the shift toward lower values suggests cumulative haemodynamic effects that warrant further investigation.