本間 千夏, 西村 陽子, 伊藤 薫, 古谷 菜摘, 倉崎 昭子, 近藤 春裕, 長谷川 潤一, 鈴木 直

Chika HOMMA, Yoko NISHIMURA, Kaoru ITO, Natsumi FURUYA, Akiko KURASAKI, Haruhiro KONDO, Junichi HASEGAWA, Nao SUZUKI

聖マリアンナ医科大学産婦人科学

Department of Obstetrics and Gynecology, St. Marianna University School of Medicine

キーワード : single umbilical artery, intra-uterine fetal death, lung hypoplasia, oligohydramnios

30歳，初産婦．既往歴は24歳時にパニック障害があったが，家族歴に特記すべきことはない．自然妊娠後，最終月経より予定日が決定された．妊娠19週に－1.8 SDの胎児発育不全，AFI 4.6 cmと羊水過少のため当院に紹介となった．胎児超音波所見では単一臍帯動脈を認める他には明らかな胎児形態異常を認めなかった．胎盤の位置，形態，大きさも特記すべきことはなかった．羊水検査を施行したが正常核型であった．妊娠経過中は－1.8～－2.0 SD程度の胎児発育不全を認めていたが胎児発育はあり，また経過中，徐々に羊水過少は軽快し羊水ポケットは2 cm以上を推移し，Biophysical Profiling Score （BPS）は10点であった．妊娠36週の胎児ドプラ所見は正常範囲内で，BPSは10点であった．妊娠37週4日胎動減少を主訴に来院した．胎児超音波で羊水ポケットは1 cm未満であった．同日のNon stress testはreactive patternであったが，翌日には最下点が55 bpmの高度遷延一過性徐脈を認め，胎盤機能不全の診断で同日帝王切開分娩とした．在胎37週5日2,481 g （－0.55SD）の女児であった．Apgar Scoreは1分値5点，5分値6点で，出生直後には啼泣を認めたがそのあと呼吸状態が悪化，左肺の含気が悪く，一酸化窒素，高頻度振動換気を行った，呼吸状態の改善を認めず，日齢3に死亡となった．剖検では肺低形成（左10g，右14g，正常値：左45g，右33g），腎低形成（左1.4g，右4.1g，正常値：左18g，右18g）が認められた．長期間の羊水過少を認めず，肺低形成を認め新生児死亡となったが臨床的にはその原因は分からなかった．剖検を施行したことで腎低形成，肺低形成を診断し，組織像では肺胞は小さく，隔壁も厚く未成熟な肺組織像を認め，肺低形成のメカニズムの可能性を示すことができた．本症例のように妊娠の早い時期に一時的に羊水過少を認めていた場合は，その後羊水量が維持されていたとしても，根本的に肺の成熟が悪い可能性を念頭に置く必要があると考えられた．

A 30-year-old primiparous woman was referred to our perinatal center because of fetus growth restriction at 19 weeks of gestation with estimated fetal weight -1.8 SD, AFI 4.6 cm, and oligohydramnios. Fetal morphological assessment revealed normal findings, except for single umbilical artery. A karyotype of 46,XX was found at amniocentesis. During the course of pregnancy, fetal growth was estimated at between -1.8 and -2.0 SD, but the fetus was developing. The amount of amniotic fluid remained at 2 cm or more in the amniotic fluid pocket, and the Biophysical Profiling Score was 10 points. She visited our hospital because of decreased fetal movements at 37+4 weeks of gestation. The amniotic fluid index was less than 1 cm, and severe prolonged deceleration was observed. Thus, caesarean section was performed due to diagnosis of non-reassuring fetal status. A female infant weighing 2481 g (-0.55 SD) with 5/6 (1/5 min) Apgar score was delivered. Absence of peripheral malformation and a normal placenta were observed. The infant's breathing state deteriorated after birth, and neonatal death due to respiratory failure resulted despite immediate intensive care. Autopsy revealed left hypoplastic lung and bilateral hypoplastic kidneys. After temporal oligohydramnios around 19 weeks of gestation, long-term oligohydramnios was not observed. The cause of death was not clinically determined, but the autopsy revealed renal hypoplasia and lung hypoplasia. Further, the alveoli were small and the septum was thick and immature. Even when temporal oligohydramnios occurs during early-mid gestation, this case suggests that lung immaturity can occur.