産痛の記憶に関する縦断的研究—産後の産痛強度の上昇・下降に影響する因子

A Longitudinal Study on the Intensity of Memorized Labor Pain: Factors affecting ascent and descent of memorized labor pain intensity

　196人（初産婦101人・経産婦95人）に対して，産後の4時期（出産直後・5日後・1か月後・産後1年以降）に，産痛強度の記憶とその影響因子を調査し，とのような因子が産後に産痛強度の記憶を上昇・下降させるかを，相関や数量化Ⅱ類を用いて分析した。

　産後1年以降よりも出産直後の産痛強度が強い下降群は40.8％と多く，出産直後よりも1年以降の産痛強度が強い上昇群は12.2％で，下降群の1/3を示した。経産婦は初産婦よりも，上昇群が有意に高率であった。上昇群は，下降群よりも有職率が低く，妊娠や出産に伴う離職率が高率を示し，児の栄養では母乳が有意に低率で，人工栄養が有意に高率を示した。また，上昇群の産痛強度は出産時の自己制御や夫の年齢と有意な負の相関を，育児時期とは有意な正の相関を示した。すなわち，自己制御が悪くなるほと，夫の年齢が若くなるほど，妻の産痛強度は強くなった。また，育児で大変な時期の開始・終了時期が遅く，育児で大変な期間の持続が長く，育児に慣れた時期が遅延するほど，産痛強度は強くなった。数量化Ⅱ類でも正診率は，初産では88.1％，経産でも81.5％ときわめて高値を示した。

　産後の産痛強度の記憶には，職業や夫などの社会・家族因子や育児因子の影響が大きく，特に産痛強度の記憶の強調化（上昇）は育児の危機的状況であり，親子関係や夫婦関係に悪影響を及ぼすことが示唆された。

　This longitudinal study was designed to investigate how physical, psychological and living environmental factors affect the intensity of memorized labor pain measured with the Visual Analogue Scale (VAS). The subjects were 101 primiparas and 95 multiparas. The surveys were conducted within 24 hours, 5 days, 1 month and 1-2 years at postpartum period.

　The rate of ascent group, whose intensity of memorized labor pain was more intense on 1-2 years postpartum than within 24 hours, was 12.2%. The rate of descent group, whose intensity of memorized labor pain was less intense on 1-2 years postpartum than within 24 hours, was 40.8%.

　The subjects in the ascent group had such characteristics as follows; the rate of persons in occupation was lower than that in the decent group. There was a significant difference in the rate between the ascent and the decent groups. The end of hard period for childcare came later in the ascent group than in the descent group and longer time was needed before the ascent group became accustomed to childcare. Strong negative correlation to couple's ages and birth weight were found in the ascent group as for the length of hard period for childcare and that of time before they became accustomed to childcare. There was no significant correlation for other factors in the descent group.

　These data suggest that the ascent of memorized labor pain intensity creates a critical phase in childcare and has a negative effect on parent-child relation.