Characteristics of pregnant women in the study in Matlab, Bangladesh
| Variable name | 2005 | 2006 | 2007 | 2008 | 2009 | P value* |
| n (%) | n (%) | n (%) | n (%) | n (%) | ||
| Age in year | <0.001 | |||||
| <20 | 266 (10.2) | 296 (11.4) | 269 (10.5) | 299 (11.2) | 279 (11.0) | |
| 20–24 | 826 (31.7) | 858 (33.1) | 678 (26.4) | 887 (33.1) | 845 (33.4) | |
| 25–34 | 1186 (45.5) | 1152 (44.4) | 1373 (53.5) | 1237 (46.2) | 1144 (45.3) | |
| ≥35 | 331 (12.7) | 290 (11.2) | 248 (9.7) | 257 (9.6) | 259 (10.2) | |
| Parity | <0.001 | |||||
| 0 | 904 (34.6) | 995 (38.3) | 965 (37.6) | 1002 (37.4) | 1000 (39.6) | |
| 1–2 | 1282 (49.1) | 1206 (46.5) | 1259 (49.0) | 1348 (50.3) | 1235 (48.9) | |
| ≥3 | 423 (16.2) | 395 (15.2) | 344 (13.4) | 330 (12.3) | 292 (11.6) | |
| Education in year | <0.001 | |||||
| 0 | 484 (18.6) | 546 (21.0) | 307 (12.0) | 581 (21.7) | 400 (15.8) | |
| 1–5 | 708 (27.1) | 639 (24.6) | 550 (21.4) | 796 (29.7) | 619 (24.5) | |
| ≥6 | 1417 (54.3) | 1411 (54.4) | 1711 (66.6) | 1303 (48.6) | 1508 (59.7) | |
| Asset quintiles | 0.013 | |||||
| 1-poorest | 409 (15.7) | 408 (15.7) | 363 (14.1) | 428 (16.0) | 374 (14.8) | |
| 2 | 467 (17.9) | 436 (16,8) | 442 (17.2) | 453 (16.9) | 429 (17.0) | |
| 3 | 504 (19.3) | 570 (22.0) | 523 (20.4) | 577 (21.5) | 474 (18.8) | |
| 4 | 623 (23.9) | 568 (21.9) | 594 (23.1) | 594 (22.2) | 557 (22.0) | |
| 5-richest | 606 (23.2) | 614 (23.7) | 646 (25.2) | 628 (23.4) | 693 (27.4) | |
| Mode of delivery | <0.001 | |||||
| Vaginal | 2431 (93.2) | 2373 (91.5) | 2255 (87.9) | 2310 (86.2) | 2066 (81.8) | |
| Caesarean | 178 (6.8) | 221 (8.5) | 309 (12.1) | 370 (13.8) | 461 (18.2) | |
| Pregnancy type | ||||||
| Twin | 69 (2.6) | 42 (1.6) | 22 (2.1) | 60 (2.2) | 79 (3.1) | 0.006 |
| Singleton | 2540 (97.4) | 2554 (98.4) | 2513 (97.9) | 2620 (97.8) | 2448 (96.9) | |
| Inter-pregnancy interval in month | ||||||
| <6 | 132 (8.1) | 86 (5.6) | 108 (7.1) | 120 (8.2) | 91 (6.8) | 0.001 |
| 6–11 | 94 (5.8) | 67 (4.4) | 77 (5.1) | 81 (5.6) | 78 (5.9) | |
| 12–17 | 110 (6.8) | 113 (7.4) | 98 (6.5) | 71 (4.9) | 73 (5.5) | |
| 18–23 | 133 (8.2) | 112 (7.3) | 106 (7.0) | 90 (6.2) | 91 (6.8) | |
| 24–47 | 598 (36.7) | 555 (36.2) | 547 (36.2) | 512 (35.1) | 430 (32.4) | |
| ≥48 | 562 (34.5) | 601 (39.2) | 575 (38.1) | 585 (40.1) | 566 (42.6) | |
| Previous preterm birth | ||||||
| <37 gestation weeks | 237 (17.8) | 243 (19.0) | 189 (15.0) | 194 (16.3) | 146 (13.7) | 0.003 |
| ≥37 gestation weeks | 1098 (82.2) | 1033 (81.0) | 1075 (85.0) | 999 (83.7) | 918 (86.3) | |
| Previous pregnancy outcomes | ||||||
| Induced miscarriage | 46 (2.8) | 25 (1.6) | 26 (1.7) | 29 (2.0) | 30 (2.3) | 0.35 |
| Spontaneous miscarriage | 165 (10.1) | 142 (9.3) | 145 (9.6) | 167 (11.4) | 172 (12.9) | |
| Stillbirth | 42 (2.6) | 49 (3.2) | 47 (3.1) | 42 (2.9) | 38 (2.9) | |
| Live birth | 1376 (84.5) | 1318 (85.9) | 1293 (85.6) | 1221 (83.7) | 1089 (81.9) |
*By χ2 tests.