This prospective observational study aimed to compare the changes in placental vascular indices and placental volume using three-dimensional power Doppler (3DPD) ultrasound in pregnancies with small for gestational age (SGA) neonates. We enrolled 396 women with singleton pregnancies from September 2013 to June 2016. Placental vascular indices, including the vascularization index (VI), flow index (FI), and vascularization flow index (VFI), and placental volume were obtained using 3DPD ultrasound in the first and second trimesters. Of the enrolled women, 21 delivered SGA neonates and 375 did not. In the first trimester, the SGA group had a significantly lower mean FI (25.10 ± 7.51 versus 33.10 ± 10.97, p < 0.001) and VFI (4.59 ± 1.95 versus 6.28 ± 2.35, p = 0.001) than the non-SGA group. However, there was no significant difference in the placental volume between the two groups during the first trimester. In the second trimester, the SGA group also had a significantly lower mean FI (27.08 ± 7.97 versus 31.54 ± 11.01, p = 0.022) and VFI (6.68 ± 1.71 versus 8.68 ± 3.09, p < 0.001) than the non-SGA group. In addition, a significantly smaller placental volume was noted in the SGA group (104.80 ± 24.23 cm3 versus 122.67 ± 26.35 cm3, p = 0.003) than in the non-SGA group during the second trimester. The results showed that a decreased placental VFI occurred earlier than a decreased placental volume in SGA pregnancies.

Objective To investigate factors associated with obstetric anal sphincter injuries (OASIS) during vacuum delivery among Chinese women. Methods A retrospective cohort study of Chinese women who underwent vacuum‐assisted vaginal delivery at a tertiary referral hospital in Taiwan between January 2010 and December 2016. Logistic regression analysis was used to compare various factors (maternal, delivery, and neonatal factors) between women with and those without OASIS. Results Among 18 744 Chinese women with singleton vaginal delivery, 3141 (16.76%) had vacuum assistance and 2634 (83.86%) were primiparous. Of the women who had a vacuum delivery, 1073 (34.16%) sustained OASIS, of whom 967 (90.12%) were primiparous. The major independent risk factors for OASIS were primiparity (adjusted odds ratio [aOR], 2.93; 95% confidence interval [CI], 2.29–3.76) and use of midline episiotomy (aOR, 3.01; 95% CI, 1.74–5.17). However, epidural analgesia had a protective effect (aOR, 0.64; 95% CI, 0.54–0.75) against OASIS. In multivariate analysis for the primiparous subgroup, the independent significant risk factors for OASIS remained the same. Conclusion A high incidence of OASIS during vacuum delivery was observed among Chinese women. Midline episiotomy was found to be a modifiable risk factor for OASIS, whereas epidural analgesia had a protective effect.