McLean F H, Boyd M E, Usher R H, Kramer M S
Department of Obstetrics and Gynecology, McGill University Faculty of Medicine, Montreal, Quebec, Canada.
Am J Obstet Gynecol. 1991 Feb;164(2):619-24. doi: 10.1016/s0002-9378(11)80035-9.
Concern over the postterm pregnancy has shifted from that of the difficult delivery of an excessively large fetus to the current concern with death in utero of an undernourished, small-for-date fetus. Studies of postterm pregnancy before the availability of ultrasonography may have included a large proportion of erroneous menstrual dates. The present study of 7000 infants was undertaken to reassess fetal growth in postterm pregnancies in which the expected date of confinement from last normal menstrual period dating was confirmed (+/- 7 days) by early ultrasonography. Results show a gradual shift toward higher birth weight and greater crown-heel length and head circumference between 273 and 300 days of gestational age. No evidence of postterm weight loss or lower weight for length could be demonstrated. Concern in postterm pregnancy should be for fetal macrosomia, not for intrauterine growth retardation.
对过期妊娠的关注已从过大胎儿难以分娩，转变为目前对营养不良、小于孕周胎儿宫内死亡的关注。在超声检查出现之前对过期妊娠的研究，可能包含了很大比例错误的末次月经日期。本研究对7000名婴儿进行了调查，以重新评估过期妊娠中的胎儿生长情况，其中通过早期超声检查确认了根据末次正常月经日期推算的预产期（±7天）。结果显示，在孕龄273至300天之间，出生体重逐渐增加，顶臀长度和头围也逐渐增大。没有证据表明过期妊娠会出现体重减轻或身长体重比降低的情况。过期妊娠应关注的是巨大儿，而非胎儿生长受限。
