Mouri MIchelle, Hall Heather, Rupp Timothy J.
DRMC
Garden City Hospital and Michigan State University
A pregnancy loss or "miscarriage" generally is defined as pregnancy failure before 20 weeks of gestation. A threatened miscarriage also called a "threatened abortion" or "threatened early pregnancy loss," typically refers to vaginal bleeding and uterine cramping in an otherwise viable pregnancy before 20 weeks of gestation, though more commonly occurring in the first trimester. A viable pregnancy is a pregnancy with the potential outcome of a live birth. First-trimester vaginal bleeding and cramping are also common symptoms of early pregnancy loss and incomplete miscarriage. However, characteristic clinical findings of a threatened miscarriage are a closed cervical os, without passage of products of conception, and no evidence of fetal or embryonic demise on pelvic ultrasound. Approximately 25% of pregnancies have some degree of vaginal bleeding during the first trimester, and approximately half of these patients progress to early pregnancy loss. The bleeding during a threatened miscarriage is typically mild to moderate; heavier bleeding that is more than typical menstrual flow is associated with an increased risk of pregnancy loss. Intermittent cramping, suprapubic pain, pelvic pressure, or lower back pain are also common. Evaluation of threatened miscarriage depends on the pregnancy's gestational age. At early gestational ages, it is important to establish the location of the pregnancy to rule out an ectopic pregnancy, which can also present with vaginal bleeding and lower abdominal pain. Once an intrauterine pregnancy has been established, the clinician must determine the viability of the pregnancy, which is accomplished through a pelvic examination and ultrasound. If fetal cardiac activity is not seen, serial ultrasound examinations may be required to differentiate an early viable pregnancy from a pregnancy loss. Historically, the term "abortion" has been used to refer to any pregnancy loss before 20 weeks, though many leading professional organizations now recommend using variations of the terms "miscarriage" or "pregnancy loss" (eg, threatened miscarriage, threatened pregnancy loss) as patients prefer these terms.
妊娠丢失或“流产”通常定义为妊娠在孕20周前失败。先兆流产也称为“先兆流产”或“先兆早期妊娠丢失”，通常指在孕20周前原本可存活的妊娠出现阴道出血和子宫收缩，不过更常见于孕早期。可存活妊娠是指有可能分娩活婴的妊娠。孕早期阴道出血和子宫收缩也是早期妊娠丢失和不全流产的常见症状。然而，先兆流产的典型临床表现是宫颈口闭合，无妊娠产物排出，盆腔超声检查无胎儿或胚胎死亡迹象。大约25%的妊娠在孕早期会出现某种程度的阴道出血，其中约一半患者会发展为早期妊娠丢失。先兆流产时的出血通常为轻度至中度；出血量超过正常月经量的大量出血与妊娠丢失风险增加有关。间歇性子宫收缩、耻骨上疼痛、盆腔坠胀或下背部疼痛也很常见。对先兆流产的评估取决于妊娠的孕周。在妊娠早期，确定妊娠位置以排除异位妊娠很重要，异位妊娠也可表现为阴道出血和下腹痛。一旦确定为宫内妊娠，临床医生必须确定妊娠的存活情况，这通过盆腔检查和超声来完成。如果未见到胎儿心搏，可能需要进行系列超声检查以区分早期可存活妊娠和妊娠丢失。过去，“流产”一词一直用于指孕20周前的任何妊娠丢失，不过现在许多主要专业组织建议使用“流产”或“妊娠丢失”的变体术语（如先兆流产、先兆妊娠丢失），因为患者更喜欢这些术语。
