高个子女性更易生双胞胎
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Study by LIJ obstetrician confirms taller women are more likely to have twins
长岛犹太医疗中心的产科医生研究证实高个子女性更容易生双胞胎

NEW HYDE PARK, NY -- An obstetrician who specializes in multiple-birth pregnancies has confirmed that taller women are more likely to have twins. The suspected culprit is insulin-like growth factor, which has been positively linked to both height and twinning. By comparing the heights of women who had given birth to twins or triplets with the average height of women in the United States, Gary Steinman, MD, PhD, an attending physician at Long Island Jewish (LIJ) Medical Center, found that the multiple-birth mothers averaged more than an inch taller. The study was published in the September issue of the Journal of Reproductive Medicine.
纽约新海德公园的一名专攻多胎妊娠的产科医生研究证实高个子女性更容易生双胞胎，并且认为这很可能与类胰岛素生长因子有关，因为类胰岛素生长因子已被证实与身高和孪生有关。长岛犹太医疗中心的主治医师，博士（MD，PHD）Gary Steinman将美国那些生过双胞胎和三胞胎的妇女的平均身高和美国妇女的平均身高比较后发现，多胎妊娠妇女的平均身高要比美国妇女的平均身高高出1英寸多。这一研究结果发表在九月份出版的the Journal of Reproductive Medicine上。

"Any circumstance that affects the amount of available insulin-like growth factor so as to modify the sensitivity of the ovary to follicle-stimulating hormone appears to govern the rate of spontaneous twinning," said Dr. Steinman.
“任何能够影响可利用类胰岛素生长因子量的环境因素都可以改变卵巢对促卵胞生成激素的敏感性，进而控制自发性孪生的发生率，” Steinman博士说。

Insulin-like growth factor (IGF) is a protein that is released from the liver in response to growth hormone. It increases the sensitivity of the ovaries to follicle stimulating hormone, thereby increasing ovulation. Some studies also suggest that IGF may help embryos survive in the early stages of development.
类胰岛素生长因子（IGF）是肝脏在生长激素作用下释放的一种蛋白质，它增加了卵巢对促卵泡生成激素的敏感性，从而增加了排卵。也有研究表明在胚胎发育早期，IGF有助于胚胎的存活。

Among its many effects in the body, IGF stimulates cells in the shaft of long bones to grow. Previous studies have demonstrated that people with short stature have significantly lower levels of IGF. Countries with taller women have higher rates of twinning compared to countries with shorter women.
IGF对机体有许多作用，其中有一点就是它可以刺激长骨骨干中骨细胞的生长。以前的研究已证实身材矮小的人体内IGF水平明显较低。与女性平均身高较低的国家相比，在女性平均身高较高的国家孪生的发生率也较高。

In the current study, Dr. Steinman compared the heights of 129 women who gave birth to identical or fraternal twins or triplets -- 105 had twins and 24 had triplets -- with the average height of women in the United States, as reported by the National Center for Health Statistics. The multiple-birth mothers averaged 5 feet 5 inches tall, more than an inch taller than the U.S. average for adult females of about 5 feet 3 ?inches. While the effect of IGF on the ovaries likely involves fraternal, or dizygotic, twins, they were not distinguished from identical, or monozygotic, pregnancies in this study. Dizygotic twin pregnancies account for about two-thirds to three-quarters of all spontaneous multiple pregnancies in a random population, therefore the results of this study predominantly, but not exclusively, represent fraternal twins.本研究选择生产过同卵或异卵双胞胎或三胞胎的129名妇女——其中125名生过双胞胎，24名生过三胞胎，Steinman博士将129名妇女的平均身高和全国卫生统计中心报导的美国妇女的平均身高进行了比较，结果发现多胎妊娠妇女的平均身高为5英尺5英寸，比美国成年女性的平均身高5英尺3英寸高了1英寸多。 在本研究中，虽然IGF作用于卵巢可以引起异卵或双合子双胞胎妊娠，但是这种妊娠不能和同卵或单合子双胞胎妊娠相区别。因为在随机人群的自发性多胎妊娠中，双合子双胞胎妊娠占了大约2/3到3/4，所以本研究主要反映（但不是全部）了异卵双胞胎的情况。

In the previous study in his series on the mechanisms of twinning, Dr. Steinman found that women who consume animal products, specifically dairy, are five times more likely to have twins. Cows, like humans, produce IGF in response to growth hormone and release it into the blood, and the IGF makes its way into their milk.
在以前对孪生机制的一系列研究中，Steinman博士发现食用动物产品尤其是牛奶多的妇女生双胞胎的几率是一般妇女的5倍多。像人一样，奶牛在生长激素的作用下将IGF释放入血液，从而牛奶中含有较多的IGF。

Dr. Steinman has been invited to speak next month about IGF and twinning at the three-day workshop "Milk, Hormones and Human Health." The meeting, to be held in Boston from Oct. 23-25, is sponsored by the Harvard Center for Cancer Prevention at the Harvard School of Public Health and the McGill University Centre for Cancer Prevention.
Steinman博士被邀请参加下个月举办的关于IGF和孪生的为期3天的研讨会，并发表题为“牛奶，激素和人类健康”的演讲。这次会议将在10月23日到25日在波士顿举行，由哈佛大学公共卫生学院的癌症预防中心和Mcgill大学的癌症预防中心联合举办。