竹中 慎, 長谷川 潤一, 三村 貴志, 松岡 隆, 市塚 清健, 大槻 克文, 岡井 崇

Shin TAKENAKA, Junichi HASEGAWA, Takashi MIMURA, Ryu MATSUOKA, Kiyotake ICHIZUKA, Katsufumi OTSUKI, Takashi OKAI

昭和大学医学部産婦人科学教室

Department of Obstetrics and Gynecology, Showa university school of medicine

キーワード : oligohydramnios, NRFS, cesarean section, amniotic pocket

目的：妊娠末期における経時的羊水量変化と分娩前の羊水量測定が急速遂娩の予測に有用であるかを知ること．対象と方法：2006‐2008年に分娩した単胎（妊娠37‐41週）の内，予定帝王切開症例と前期破水症例を除いた966症例を対象とした．対象を羊水過少群と正常羊水量のコントロール群に分け，さらに羊水過少群を，外来時で羊水過少と診断された群（A群），陣発入院時に初めて羊水過少が認められた群（B群）に分類した．各群のおける急速遂娩率，急速遂娩を予測する羊水量（羊水ポケット：AP），妊娠末期羊水量の経時的変化について検討した．結果：A群26例（2.7％），B群75例（7.8％），コントロール群865例（89.5％）であった．急速遂娩は，コントロール群7.9％に対し，A群26.9％（p＜0.001），B群16.0％（p＝0.015）であった．緊急帝王切開は，コントロール群2.6％に対し，A群14.3％（p＜0.001），B群2.7％（ns）であった．急速遂娩を予測するAPのカットオフ値は21mmであった．羊水過少症例でのAPがその1，2週間前に20‐30mmの範囲に含まれる確率は，それぞれ83％，65％であった．考察：分娩前の羊水量測定は，急速遂娩の予測に有用であることが示唆された．さらに，妊娠末期のAPが30mm未満の症例は注意してフォローアップするのが望ましいと思われた．

Purpose: To evaluate the significance of amniotic pocket (AP) measurements after 37 weeks of gestation for assessing the possibility of occurrence of non-reassuring fetal status (NRFS) during labor. Methods: The study population consisted of term patients (37-41 weeks of gestation) with singleton pregnancy, excluding admissions due to preterm rupture of membrane and for elective cesarean section (n=966). Subjects were divided into the following three groups; Group A: diagnosed as oligohydramnios during outpatient check-up, Group B: diagnosed as oligohydramnios at admission with onset of labor, and a control group. Frequencies of prompt delivery (emergent C/S or instrumental delivery) due to NRFS in each group were evaluated, and cutoff values of AP to predict prompt delivery were calculated. We also assessed sequential changes in AP before diagnosis of oligohydramnios. Results: The number of cases in Group A, Group B, and control were 26 (2.7%), 75 (7.8%), and 865 (89.5%), respectively. Frequencies of prompt delivery due to NRFS in Group A and B were 26.9% (p<0.001) and 16.0% (p=0.015), respectively, which were higher than control (7.9%). Frequencies of emergency cesarean section in Group A and control were 14.3% and 2.6%, respectively, and these were significant difference between them (p<0.001). A cutoff value of AP for predicting prompt delivery was calculated as 21 mm based on ROC curve. In the group diagnosed with oligohydramnios, AP was in the range of 20-30 mm 2 weeks and 1 week before the diagnosis in 65% and 83% of the cases, respectively. Conclusion: Measurement of AP is useful for predicting non-reassuring fetal status during labor in not only outpatients but also inpatients with onset of labor. Our results suggest that cases in which AP is less than 30 mm at outpatient check-up require intensive follow-up.