Hulvert J, Mardesic T, Müller P, Voboril J, Miková M, Hüttelová R, Becvárová V, Jirsová S
Sanatorium Pronatal, Praha.
Ceska Gynekol. 1999 Sep;64(5):295-9.
The goal of this study has been to determine frequency of occurrence of monochorial twins within the study group consisting of 521 pregnancies conceived through the In Vitro Fertilization (IVF) programme.
An observational study.
Sanatorium Pronatal, Na Dlouhé mezi 4/12, 147 00 Praha 4-Hodkovicky.
A condition to be included in the study group was that there was a gestation sac detected by ultrasound. The first ultrasound examination was performed transvaginally and was done between the fifth and the sixth week of each pregnancy. A multiple pregnancy has been classified as monochorial in case when gestation sac contains two yolk sacs and two fetuses.
Within the whole study group there were 13 monochorial twins which presents 2.5% of all pregnancies. The incidence of monochorionicity among all multiple pregnancies is 6.4%, in IVF cycles without micromanipulation techniques the occurrence of monochorial twins has been 0.9%, following cryoembryotransfer 3.9%, with micromanipulation (ICSI, AH) it reaches 5.7% of all pregnancies.
Monochorial twins were detected seven time more frequent in comparison within occurrence in ordinary population. The occurrence rises in connection with the number of fetuses in uterus. In comparison with simple IVF cycles we have proved higher occurrence of monochorionicity in connection with micromanipulation techniques and cryoembryotransfer.
本研究的目的是确定在由521例通过体外受精（IVF）计划受孕的妊娠组成的研究组中，单绒毛膜双胎的发生频率。
一项观察性研究。
布拉格4-霍德科维奇市纳德鲁赫4/12号14700号产前疗养院。
纳入研究组的条件是经超声检测到妊娠囊。首次超声检查采用经阴道超声，在每次妊娠的第5至6周进行。如果妊娠囊包含两个卵黄囊和两个胎儿，则多胎妊娠被分类为单绒毛膜性。
在整个研究组中，有13例单绒毛膜双胎，占所有妊娠的2.5%。所有多胎妊娠中单绒毛膜性的发生率为6.4%，在未采用显微操作技术的IVF周期中，单绒毛膜双胎的发生率为0.9%，冷冻胚胎移植后为3.9%，采用显微操作（ICSI、AH）时，占所有妊娠的5.7%。
与普通人群相比，单绒毛膜双胎的检出频率高出7倍。发生率随着子宫内胎儿数量的增加而上升。与单纯IVF周期相比，我们已证实在采用显微操作技术和冷冻胚胎移植时，单绒毛膜性的发生率更高。
