Trial of labor after cesarean delivery for estimated large for gestational age fetuses: A retrospective cohort study

Although ultrasonographic estimation of fetal weight ≥90th percentile is not associated with a greater risk for uterine rupture, trial of labor after cesarean delivery (TOLAC) is considered relatively contraindicated for macrosomic fetuses. Hence, when an estimated fetal weight of 4000 g is detected, TOLAC is usually avoided.Our aim was to evaluate the obstetrical outcome and safety of TOLAC in women with estimated large for gestational age fetuses (eLGA) (≥90th percentile).

Our retrospective cohort study encompassed all pregnant women with an estimated fetal weight ≥90th percentile for gestational age, admitted to a single tertiary care center between January 2012-July 2017 for TOLAC.

1949 women met the inclusion criteria; 78 (4%) eLGA and 1871 (96%) controls. Fifty-five (70.5%) women in the study group had experienced a successful vaginal delivery compared to 1506 (80.5%) of the controls (p = 0.03). The rate of obstetrical complications, including scar dehiscence, uterine rupture, a 3rd/4th degree perineal tear or shoulder dystocia were comparable. The rate of post-partum hemorrhage (PPH) increased in the study group compared to the controls (7.7 % vs.1.7%; p = 0.001).

TOLAC for eLGA fetuses can be considered safe, however, lower successful rates of vaginal births after a cesarean delivery and an increased PPH rate, may be expected.