張女士懷孕 39週，入院待產中，產程進度情形為：子宮頸擴張 4 cm，變薄 40%，高度為 0，胎兒監測器顯示如下圖。根據此圖形，下列何者正確？ ![圖片描述][The image displays a cardiotocograph (CTG) tracing, which consists of two graphs: Upper Graph (Fetal Heart Rate - FHR): The baseline Fetal Heart Rate (FHR) is approximately 130-140 beats per minute (bpm). There are recurrent, smooth, U-shaped decelerations in the FHR. The onset of these decelerations is gradual and occurs after the beginning of a uterine contraction (shown in the lower graph). The nadir (lowest point) of each deceleration occurs after the peak of the corresponding contraction. The FHR returns to baseline after the contraction has ended. Labels in Chinese, "減速開始" (deceleration start) and "減速結束" (deceleration end), mark one such event, illustrating this delayed timing relative to the contraction. Lower Graph (Uterine Contractions): This graph shows uterine activity, with regular contractions occurring.The label "晚期開始" (late onset) is noted near the beginning of a contraction, likely referring to the late onset of the FHR deceleration in relation to the contraction. Interpretation:The pattern observed in the FHR tracing, characterized by decelerations that begin after the onset of uterine contractions, reach their nadir after the peak of contractions, and recover after the contractions end, is defined as late decelerations.](https://bgvxfcrmbdvefjhuvrmt.supabase.co/storage/v1/object/public/image/questions/NU-4101/108/content/1a486122-52d4-4550-8913-32bbb96d9f22.webp)

護理師 - 分娩過程與產科急症考古題解析 - 民國108年 | ExamWise

產科臨床常用胎兒監視器(Cardiotocography, CTG)同時記錄胎心率(FHR)及宮縮強度，以早期偵測胎兒缺氧。判讀重點包含：

題目影像顯示： • 基準線約 130–140 bpm，屬正常
• 隨每次宮縮出現平滑 U 型下降
• 減速起點在宮縮開始之後，最低點落在宮縮高峰之後，恢復亦在宮縮結束後

此為「晚期減速(Late deceleration)」的典型時序。

A. 胎頭受壓
‧ 典型圖形：Early deceleration——與宮縮幾乎鏡像，於宮縮開始就下降，宮縮末即回復
‧ 屬正常生理反應，常見於第一產程後期及第二產程
‧ 與題目所見時序不符 ➜ 錯

B. 胎盤功能不良
‧ 又稱子宮胎盤功能不足(Uteroplacental insufficiency)
‧ 造成胎兒在宮縮時血氧供應不足，FHR 於宮縮高峰後才下降，即 Late deceleration
‧ 與圖形完全相符 ➜ 正確

C. 臍帶受壓
‧ 典型圖形：Variable deceleration——下降快速、呈 V／W

...（解析預覽）...