Pregnancy conditions and complications associated with the development of varicose veins.

Background: Pregnancy is a known risk factor for developing varicose veins (VV). However, pregnancy is often considered a homogeneous entity and few studies have examined if specific characteristics and complications of pregnancy may influence VV formation. This study sought to identify which pregnancy-specific factors are associated with the development of VV.

Methods: All women who gave birth (live or still) between 1998 and 2020 within a multicenter health care system were identified retrospectively and followed through all hospital encounters (inpatient and outpatient). The primary outcome was VV, defined as any encounter with a primary diagnosis code for VV or a procedure for VV. The study period for each woman was the time from the first to last encounter. Extended Cox regression modeling evaluated the association between VV and pregnancy-related factors as a time-varying covariates while controlling for patient comorbidities.

Results: There were 156,622 women with a median follow-up of 8.3 years (interquartile range, 2.7-16.6 years) included. During this time, 225,758 deliveries occurred. The 10- and 20-year freedom from VV was 97.0% (95% CI, 96.8%-97.1%) and 92.7% (95% CI, 92.4%-93.0%), respectively, from the estimated start of first pregnancy. Overall, 4028 patients (2.57%) developed VV during the follow-up period and 1594 (1.02%) underwent a procedure for VV. After risk adjustment, increasing parity was significantly associated with VV, with each subsequent pregnancy increasing hazard of developing VV (parity = 1: hazard ratio [HR], 1.78; 95% CI, 1.55-1.99; P < .001; parity ≥6: HR, 4.83; 95% CI, 2.15-1.99-10.9; P < .001), Other significant pregnancy factors included excessive weight gain in pregnancy (HR, 1.44; 95% CI, 1.09-1.91; P = .011), post-term pregnancy (HR, 1.12; 95% CI, 1.02-1.21; P = .021), pre-eclampsia (HR, 0.79; 95% CI, 0.70-0.90; P < .001), and postpartum transfusion of platelets, plasma, or cryoprecipitate (HR, 2.05; 95% CI, 1.19-3.53; P = .001).

Conclusions: Increasing parity, excessive weight gain in pregnancy, post-term pregnancy, and pre-eclampsia affect the development of VV after pregnancy. Although VV after pregnancy are likely underreported and true incidence is unknown, women should be counseled about the impact of these factors on VV development after pregnancy.