Table 1 Maternal and neonatal characteristics of twin births in this study (2014–2017).
From: Birth weight percentiles by sex and gestational age for twins born in southern China
Variables | Male | Female | Total | ||||||
|---|---|---|---|---|---|---|---|---|---|
Monochorionic | Dichorionic | Total* | Monochorionic | Dichorionic | Total* | Monochorionic | Dichorionic | Total* | |
Number of mothers | 17384 | 8830 | 44130 | 15946 | 7952 | 39810 | 33330 | 16782 | 83940 |
Maternal age (years) | |||||||||
≤20 | 835(4.8) | 200(2.3) | 1327(3.0) | 906(5.7) | 175(2.2) | 1408(3.5) | 1741(5.2) | 375(2.2) | 2731(3.1) |
21–25 | 4383(25.2) | 1482(16.8) | 8278(18.8) | 4157(26.1) | 1376(17.3) | 7668(19.3) | 8540(25.6) | 2858(17.0) | 15947(19.0) |
26–30 | 6543(37.6) | 3459(39.2) | 16428(37.2) | 5922(37.1) | 3146(39.6) | 15026(37.8) | 12465(37.4) | 6605(39.4) | 31454(37.5) |
31–35 | 4038(23.2) | 2669(30.2) | 12850(29.1) | 3584(22.5) | 2343(29.5) | 11199(28.1) | 7622(22.9) | 5012(29.9) | 24051(28.7) |
36–40 | 1344(7.7) | 880(10.0) | 4294(9.7) | 1199(7.5) | 794(10.0) | 3798(9.5) | 2543(7.6) | 1674(10.0) | 8093(9.6) |
41–45 | 213(1.2) | 112(1.3) | 722(1.6) | 164(1.0) | 99(1.3) | 594(1.5) | 377(1.1) | 211(1.3) | 1316(1.6) |
≥46 | 28(0.2) | 28(0.3) | 231(0.5) | 14(0.1) | 19(0.2) | 117(0.3) | 42(0.1) | 47(0.3) | 348(0.4) |
Maternal ethnicity | |||||||||
Han | 16816(96.7) | 8469(95.9) | 41855(95.0) | 15434(96.8) | 7666(96.4) | 37857(95.1) | 32250(96.8) | 16135(96.1) | 79716(95.0) |
Minorities | 568(3.3) | 361(4.1) | 2275(5.0) | 512(3.2) | 286(3.6) | 1949(4.9) | 1080(3.2) | 647(3.9) | 4224(5.0) |
Parity | |||||||||
Nulliparous | 3951(22.7) | 2373(26.9) | 11461(26.0) | 3806(23.9) | 2140(26.9) | 10710(26.9) | 7757(23.3) | 4513(26.9) | 22172(26.4) |
Parous | 13433(77.3) | 6457(73.1) | 32669(74.0) | 12140(76.1) | 5812(73.1) | 29096(73.1) | 25573(76.7) | 12269(73.1) | 61768(73.6) |
Method of delivery | |||||||||
Caesarean section | 9912(57.0) | 5215(59.1) | 26335(59.7) | 8794(55.2) | 4624(58.2) | 23348(58.7) | 18706(56.1) | 9839(58.6) | 49684(59.2) |
Virginal | 3297(19.0) | 1095(12.4) | 7986(18.1) | 3440(21.6) | 1028(12.9) | 7666(19.3) | 6737(20.2) | 2123(12.7) | 15654(18.6) |
Un-know | 4175(24.0) | 2520(28.5) | 9809(22.2) | 3712(23.3) | 2300(28.9) | 8792(22.1) | 7887(23.7) | 4820(28.7) | 18602(22.2) |
Number of newborns | 34338 | 16720 | 84208 | 31567 | 15486 | 76868 | 65905 | 32206 | 161076 |
Gestational age (weeks) | |||||||||
25–27 | 102(0.3) | 68(0.4) | 372(0.4) | 45(0.1) | 46(0.3) | 238(0.3) | 147(0.2) | 114(0.4) | 610(0.4) |
28–32 | 1976(5.8) | 940(5.6) | 5160(6.1) | 1454(4.6) | 833(5.4) | 4075(5.3) | 3431(5.2) | 1773(5.5) | 9235(5.7) |
33–36 | 13160(38.3) | 6347(38.0) | 34426(40.9) | 11415(36.2) | 5740(37.1) | 30275(39.4) | 24575(37.3) | 12087(37.5) | 64701(40.2) |
37–42 | 19100(55.6) | 9365(56.0) | 44250(52.5) | 18653(59.1) | 8867(57.3) | 42280(55.0) | 37753(57.3) | 18232(56.6) | 86530(53.7) |
Birth weight (g) | |||||||||
Mean ± SD | 2436 ± 453 | 2506 ± 480 | 2457 ± 475 | 2361 ± 423 | 2400 ± 459 | 2373 ± 450 | 2400 ± 441 | 2455 ± 473 | 2417 ± 465 |
<1500 | 1094(3.2) | 481(2.9) | 2999(3.6) | 995(3.2) | 549(3.5) | 2926(3.8) | 2089(3.2) | 1030(3.2) | 5925(3.7) |
1500–1999 | 3852(11.2) | 1525(9.1) | 8855(10.5) | 4171(13.2) | 1835(11.9) | 9911(12.9) | 8023(12.2) | 3360(10.4) | 18766(11.7) |
2000–2499 | 11893(34.6) | 5311(31.8) | 28541(33.9) | 13048(41.3) | 6012(38.8) | 30876(40.2) | 24941(37.8) | 11323(35.2) | 59417(36.9) |
2500–2999 | 13954(40.6) | 7016(42.0) | 34028(40.4) | 11406(36.1) | 5760(37.2) | 27538(35.8) | 25360(38.5) | 12776(39.7) | 61566(38.2) |
≥3000 | 3545(10.3) | 2387(14.3) | 9785(11.6) | 1947(6.2) | 1330(8.6) | 5617(7.3) | 5492(8.3) | 3717(11.5) | 15402(9.6) |
