Abstract
Objective The aim of the study is to examine whether an estimated fetal weight of the current
pregnancy greater than previous birth weight is associated with increased odds of
intrapartum cesarean delivery.
Study Design We conducted a retrospective cohort study of all women who had more than one singleton
pregnancy at 23 weeks' gestation or greater at a single labor and delivery unit. We
only analyzed the second pregnancy in the dataset. We excluded women who had preterm
birth in the second pregnancy. Women were categorized according to the difference
between estimated fetal weight and previous birth weight—estimated fetal weight close
to previous birth weight within 500 g (similar weight group); estimated fetal weight
significantly (more than 500 g) greater than previous birth weight (larger weight
group); and estimated fetal weight significantly (more than 500 g) lower than previous
birth weight (smaller weight group). The primary outcome was intrapartum cesarean
delivery. Multivariable logistic regression was performed to calculate adjusted odds
ratios (aORs) with 95% confidence interval (95% confidence interval [CI]) after adjusting
for predefined covariates.
Results Of 1,887 women, there were 1,415 (75%) in the similar weight group, 384 (20%) in
the greater weight group, and 88 (5%) in the smaller weight group. Individuals in
the larger weight group compared with those in the similar weight group had higher
odds of undergoing intrapartum cesarean delivery (11.2 vs. 4.5%; aOR 2.91; 95% CI
1.91–4.45). The odds of intrapartum cesarean delivery in the smaller weight group
compared with those in the similar weight group were not increased (3.4 vs. 4.5%;
crude OR 0.75; 95%CI 0.23–2.42).
Conclusion The difference between current estimated fetal weight and previous birth weight plays
an important role in assessing the risk of intrapartum cesarean delivery.
Key Points
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Estimated fetal weight compared with previous birth weight is an important factor.
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Cesarean delivery is infrequent if estimated fetal weight is similar to previous birth
weight.
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Larger estimated fetal weight greater than the previous birth weight is associated
with cesarean delivery.
Keywords
estimated fetal weight - intrapartum cesarean delivery - previous birth weight - proven
pelvis
