Space
Interval, Gap
noun
I'd like to isolate this interval of time. Take it, make it separate, and then look at it. Now there is a space there. An interval, if you will.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
生理痛程度の陣痛が15分から20分ぐらいの間隔で始まって、今行った方がいいのか病院に電話をしました。
Mild contractions are starting in 15 to 20 minutes intervals and I called the hospital to see if we should go now.