Bleker O P, Breur W, Huidekoper B L
Br J Obstet Gynaecol. 1979 Feb;86(2):111-8. doi: 10.1111/j.1471-0528.1979.tb10577.x.
A study was made of 1655 sets of twins born between 1931 and 1975 in two clinical centres. Compared to singletons, twins were born three weeks earlier, weighed less at birth from 33 weeks to term and had smaller placentae from 21 to 22 weeks to term. The influence on birth weight fo sex was smaller in twins, the influence of parity greater. Because, compared to singletons, lower placental indices were found in twins up to 37 to 38 weeks, the conclusion is drawn that the retardation of growth in twins is to some extent due to the placenta itself. When singletons and twins of the same gestational age were compared, the mortality was found to be similar, somewhat lower in twins up to 37 to 38 weeks and higher afterwards. Monochorial twins were found to be born earlier, weigh less at birth and have a higher mortality than dichorial twins. Placental weights were not different and the conclusion is drawn that the retardation of growth in monochorial twins is to some extent due to the higher incidence of marginal and velamentous insertions of the umbilical cord associated with lower birth weights.
一项针对1931年至1975年间在两个临床中心出生的1655对双胞胎进行的研究。与单胎相比，双胞胎早产三周，在孕33周足月时出生体重较轻，在孕21至22周足月时胎盘较小。双胞胎中性别对出生体重的影响较小，产次的影响较大。因为与单胎相比，孕37至38周前的双胞胎胎盘指数较低，所以得出结论，双胞胎生长发育迟缓在一定程度上是由于胎盘本身。当比较相同孕周的单胎和双胞胎时，发现死亡率相似，孕37至38周前的双胞胎死亡率略低，之后则较高。发现单绒毛膜双胞胎比双绒毛膜双胞胎出生更早、出生体重更轻且死亡率更高。胎盘重量没有差异，得出结论，单绒毛膜双胞胎生长发育迟缓在一定程度上是由于脐带边缘性和帆状附着的发生率较高，这与较低的出生体重有关。
