Placental location, postpartum hemorrhage and retained placenta in women with a previous cesarean section delivery: a prospective cohort study

Figures & data

Table 1. Maternal, delivery, and infant characteristics in participants and non-participants.

	Participants (n = 400)	Non-participants (n = 129)
Age (years)
22–29	75 (18.8%)	28 (21.7%)
30–39	288 (72.0%)	90 (69.8%)
40–49	37 (9.2%)	11 (8.5%)
Parity (para)
1	272 (68.3%)	75 (58.1%)
>1	126 (31.7%)	54 (41.9%)
Previous cesarean section
1	337 (85.1%)	102 (79.0%)
>1	59 (14.9%)	27 (21.0%)
Body mass index
18–25	233 (58.8%)	77 (63.1%)
26–30	109 (27.6%)	27 (22.1%)
31–53	54 (13.6%)	18 (14.8%)
Smoking, Yes	15 (3.8%)	8 (6.3%)
Preeclampsia, Yes	10 (2.5%)	1 (0.8%)
Gestational week at delivery
31–36	22 (5.5%)	10 (8.1%)
37–42	376 (94.5%)	113 (91.9%)
Mode of delivery
Vaginal, non-instrumental	145 (36.3%)	50 (39.0%)
Vaginal, vacuum extraction	34 (8.5%)	8 (6.3%)
Caesarean section	221 (55.2%)	70 (54.7%)
Induction, Yes	66 (16.7%)	11 (8.7%)
Use of oxytocin, Yes	125 (31.4%)	34 (26.6%)
Birth weight (g)
Mean	3723	3589
Range	1687–5090	2010–4840
Myometrial thickness (mm)
Mean	5.5
Range	3.0–10.5
Vascularization index (%)
Mean	25.8
Range	2.5–63.0
Postpartum hemorrhage (mL)
<1000	356 (89.0%)	107 (85.6%)
≥1000	44 (11.0%)	18 (14.4%)
Retained placenta, Yes	14 (3.5%)	6 (4.7%)

Table 2. Placental location at 28 weeks.

Placental location	n	Percent
Anterior	195	48.7%
Low anterior	17	4.3%
Posterior	152	38.0%
Low posterior	7	1.7%
Fundal	21	5.3%
Anterior previa	6	1.5%
Posterior previa	2	0.5%
Total	400	100%

Table 3. Odds ratios for PPH (PPH > 1,000 mL) and retained placenta correlated to placental location.

	PPH				Retained placenta
			Odds ratio				Odds ratio
Placental location	n (total)	Rates, %	Crude	Adjusted	n (total)	Rates, %	Crude	Adjusted
Anterior	23 (195)	11.8	1.79 (P = 0.12)	1.94 (P = 0.10)	3 (195)	1.5	0.37 (P = 0.16)	0.34 (P = 0.13)
Posterior or fundal	12 (173)	6.9	reference	reference	7 (173)	4.0	reference	reference
Low anterior	1 (17)	5.9	0.34 (P = 0.51)	–	0 (17)	0	–	–
Low posterior	1 (7)	14.3	reference	reference	0 (7)	0	reference	reference
Anterior previa	5 (6)	83.3	–	–	3 (6)	50	1 (P = 1.0)	–
Posterior previa	2 (2)	100	reference	reference	1 (2)	50	1	–

Adjusted for: maternal age, parity, number of previous caesarean sections, gestational age at delivery, mode of delivery, induction, use of oxytocin, and birth weight.