An investigation of the relationship between a heavy for gestational age infant and postpartum hemorrhage mainly from uterine atony.

Purpose To epidemiologically investigate the relationship between a heavy for gestational age infant (HGA) and postpartum hemorrhage (PPH) resulting mainly from uterine atony. Methods This retrospective observational study included Japanese women at a single tertiary obstetric hospital in Tokyo metropolitan area. The inclusion criteria were as follows: 1) vaginal delivery between 2007 and 2010, 2) single delivery at term, 3) primipara, and 4) maternal age of ≥20 years. HGA is defined as an infant with a birth weight greater than the 90th percentile of the new intrauterine growth curves in Japan. The primary outcomes were PPH (blood loss, ≥500 ml) and severe PPH (SPPH; blood loss, ≥1,000 ml). Multiple logistic regression analysis was performed to calculate the odds ratio (OR) and 95% confidence interval (CI) of PPH and SPPH in association with HGA. Results Of the 2,340 women studied, PPH and SPPH were found to occur in 593 (25.3%) and 63 (2.7%) women, respectively. The results of the multivariate analyses indicated that HGA was significantly associated with PPH (adjusted OR 2.34, 95% CI 1.71-3.19) and SPPH (adjusted OR 2.43, 95% CI 1.21-4.86). Conclusion HGA was considered an independent risk factor for PPH that results mainly from uterine atony. Thus, physicians and midwives could identify women at risk for PPH from uterine atony before delivery. [ABSTRACT FROM AUTHOR]