Morning sickness

Morning sickness is a syndrome caused by pregnancy that develops in the early stages of pregnancy, mainly with digestive symptoms. In other words, it refers to a condition that begins around the fifth week of pregnancy, when the expected menstrual period has not yet begun for 7-14 days, during which loss of appetite, changes in mood and tastes, increased saliva secretion, nausea and vomiting when hungry at night, etc., appear, and is said to affect 60-80% of all pregnant women. The mechanism of onset is unknown, but it is thought that factors include the endocrine environment during pregnancy, especially chorionic gonadotropin, which is secreted in large amounts in the early stages of pregnancy, as well as psychological factors such as emotional disorders and anxiety associated with pregnancy.

In addition to the symptoms mentioned above, morning sickness can also include heartburn, palpitations, insomnia, and increased sensitivity to smell, hearing, taste, and vision, as well as extreme aversion to odors that normally don't bother you. Symptoms usually last until around the 14th to 16th week of pregnancy and then improve, but they can continue throughout the entire pregnancy.

Generally, severe morning sickness is called hyperemesis gravidarum, but there is no clear line between morning sickness and hyperemesis gravidarum. Usually, when the symptoms do not improve even after four or more months of pregnancy, they gradually become stronger and cause general symptoms such as weakness, eventually becoming life-threatening. This condition is also known as early pregnancy toxemia, and has also been called early pregnancy toxemia.

Regarding morning sickness, it is important to understand that it is a symptom of pregnancy, and instead of sticking to three meals a day, eat easily digestible, nutritious foods in small amounts several times a day. Also, try to stay physically and mentally rested and regulate bowel movements and urination. In addition, pregnant women at this stage tend to be nervous and emotionally unstable, so it is important to adjust the environment and try to keep a relaxed mood. Also, because nervous effects are significant, it is best not to think of yourself as a sick person or be too conscious of morning sickness. In the case of hyperemesis gravidarum, consult a doctor and take appropriate measures, but in severe cases hospitalization is required.

[Masao Arai]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

妊娠が原因となって妊娠初期に発症する消化器系の症状を中心とした症候群を一般に「つわり」とよんでいる。すなわち、予定月経の発来がみられずに7～14日過ぎた妊娠五週ころから、食欲不振、気分や嗜好(しこう)の変化、唾液(だえき)分泌の亢進(こうしん)、夜間など空腹時の悪心(おしん)や嘔吐(おうと)などがみられるものをいい、全妊婦の60～80％に発症するといわれる。発症の機序は不明であるが、妊娠時の内分泌環境、とくに妊娠初期に大量に分泌される絨毛(じゅうもう)性ゴナドトロピンをはじめ、妊娠に伴う情動障害や不安などの心理的因子などが要因として考えられている。

　つわりの症状には、前述のほかに、胸やけ、心悸(しんき)亢進、不眠などもあり、通常では気にもならないにおいに極度の嫌悪を感ずるなど、嗅覚(きゅうかく)をはじめ、聴覚、味覚、視覚などの感受性亢進もみられる。普通は妊娠14～16週ころまで続いて軽快するが、妊娠期間中続くこともある。

　一般に、つわりの重くなったものを妊娠悪阻(おそ)とよんでいるが、つわりと妊娠悪阻との間に明確な一線が画されているわけではない。通常、妊娠4か月以上になっても症状が軽快せず、しだいに強くなって衰弱などの全身症状が顕著となり、ついには生命に危険を及ぼすような場合を妊娠悪阻といい、妊娠中毒症の一つとして早期妊娠中毒症とよばれたこともある。

　つわりに対しては、妊娠による症状であることをよく理解したうえで、食事は1日3回にこだわらず、消化のよい栄養に富んだものを少量ずつ数回に分けてとるほか、肉体的、精神的安静を心がけ、排便や排尿を調整する。また、一般にこの時期の妊婦は神経質になり、感情も不安定になりがちであるから、環境を調節するとともに、気持ちをゆったりと保つように努力するほか、神経的な作用も大きいので、病人のように思い込んだり、つわりを意識しすぎないほうがよい。なお、妊娠悪阻の場合は医師に相談して適切な処置をとるが、重症例では入院治療が必要となる。

［新井正夫］

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