01、三十而已?生殖衰老已经开始
和男性几乎一生都在制造精子不同,传统学术观点认为女性一生能排出的卵子是有定数的——卵母细胞从女性出生前仍在母亲子宫内之时便已贮存在卵巢内,在初潮后、绝经前以一个相对稳定的速率排出、衰减[1]。
尽管近年来的一些新研究发现卵母细胞能由干细胞分化而来,并且可以通过骨髓干细胞补充[2],也许属于“可再生资源”。但是,女性的生育能力从30-35岁达到高峰之后开始逐渐下降却是不争的事实[3,4]。
比起卵细胞的损耗,激素变化才是女性生殖衰老最大的原因——女性的生殖衰老目前主要归因于卵泡活力和卵巢功能不断下降。当有活力的卵泡减少到了一定范围,卵泡分泌的抑制素B水平明显下降,失去抑制素B的抑制后,腺垂体分泌的卵泡刺激素(FSH)水平升高。
FSH升高和卵巢功能衰退导致雌二醇分泌水平高低起伏后再降低,排卵和月经直到50岁还能相对维持正常。而排卵后黄体期的孕酮浓度更早就会明显较年轻女性降低,这就是很多40岁左右的“高龄产妇”需要艰难打针保胎的原因[5]。
02、绝经——女性必由之路的终点
由于上述的这些激素变化,从生育期晚期到绝经后早期,女性需要经历数年(平均4年)的月经不规则,通常表现为月经周期间隔延长,经量减少,这段时期被称为围绝经期(perimenopause)。在不追求严谨定义的情况下,基本等同于我们平时常说的“更年期(climacteric)”[6]。
在更年期末尾的某个时刻,月经将永久停止,一旦12个月内没有再来月经,便意味着绝经(menopause)。据统计,女性自然绝经的中位年龄是51.4岁,开始进入更年期出现月经不规则的中位年龄是47岁[7]。
40岁以前发生的停经是绝对不正常的。很有可能遭遇了卵巢早衰;如果怀疑自己开始进入更年期,可以选择到医院测定血清雌二醇(E2)、卵泡刺激素(FSH)和抗苗勒管激素(AMH)的浓度来估计发生绝经的年龄范围[8,9]。
03、“易燃易爆炸”的更年期症状
围绝经期的激素改变会带来多个生理系统改变,引起许多典型症状。更年期既是女性自身的一道坎,也是身边人的一场劫,正确认识更年期症状,多一些包容与理解。
>>潮热
更年期女性常会出现面部和上胸部的突然发热,之后迅速转变为全身发热,伴随有出汗、心悸、寒战、焦虑感,每次持续2-4分钟。
这是更年期最常见的症状,60%-80%的更年期女性都会出现潮热[10],却只有20%-30%的女性会选择就医干预,潮热与甲亢典型症状极为相似,也需要通过医院的实验室检查来鉴别。
>>泌尿生殖系统萎缩与性功能下降
持续性雌激素缺乏会导致阴道萎缩、阴道壁褶皱消失、阴道干涩,外阴皮肤弹性和饱满度下降、阴道口狭窄,阴毛稀疏[11]。
阴道萎缩和阴道干涩容易引起性交疼痛,让女性被动回避性行为,是更年期女性性功能下降的最主要原因[12]。
>>情绪障碍与睡眠障碍
女性在更年期新发抑郁的风险显著升高2.5倍[13],有潮热症状的更年期女性更容易抑郁[14]。
除了抑郁,更年期女性还很容易出现焦虑、易激惹等其他情绪障碍,这些情绪障碍加之雌激素减退对认知功能造成的影响,使得更年期女性记忆力减退,并且注意力难以集中[15]。
潮热容易在夜间发生,会让患者从睡梦中热醒;加之更年期高发的抑郁、焦虑、原发性睡眠障碍四者联合作用,导致38%-46%的更年期女性晚上睡不着,白天打瞌睡[16]。
>>体重增加
女性在中年时体重通常都会增加,尽管这并不都是绝经造成的,但雌激素减少会加重脂肪重分布,引起向心性肥胖,使“梨形身材”越发明显[17]。
>>偏头痛与乳房疼痛
更年期女性在月经期偏头痛的发作频率和发作强度都会加重,严重时头痛欲裂[18]。乳房疼痛和压痛在更年期也肯常见,很可能与雌激素水平波动有关[19]。
04、撤走的不止是月经,还是“免病金牌”
由于卵巢内卵泡耗竭,卵巢雌二醇的生成和分泌下降,在绝经后完全停止。雌激素缺乏有许多长期影响,主要包括骨质疏松症、心血管疾病、痴呆和皮肤老化加速。
女性从绝经过渡期开始发生骨量丢失,骨密度的年丢失率可能在最后一次月经前的1-2年间是最高的[20]。
美国心脏病学会(AHA)认为绝经后状态是心血管疾病(CVD)的一个独立危险因素[21],自然绝经更早(早于44岁)的人心血管病风险更高[22]。
内源性雌激素还有助于保护总体认知功能[23],避免骨关节损伤[24],维持女性皮肤厚度和胶原含量[25]。因此绝经后雌激素缺乏可能导致痴呆、骨关节炎和皮肤皱纹风险升高。
05、跨越更年期,如何才能继续乘风破浪?
>>更年期症状对症处理
80%的更年期女性都可能出现潮热的症状,非常影响日常生活。
对于一天仅发作1-2次的轻度潮热,可以考虑减少穿衣层次、降低室温、使用风扇、避免刺激(如辛辣食物和使人紧张的场景)来缓解[26]。
对于差不多每个小时都要发作的中重度潮热的患者来说,她们通常需要的是药物治疗。
常用的非激素类药物是5-羟色胺再摄取抑制剂(SSRI),这类药物一般用于抑郁和焦虑的治疗,美国FDA批准用于潮热治疗的唯一SSRI类药物是低剂量帕罗西汀(7.5mg/d)[27]。SSRI治疗数日后即可缓解潮热症状,数周后可以改善更年期的抑郁和焦虑障碍[28]。
另一个广泛困扰更年期女性,却又是难言之隐的大问题是绝经期泌尿生殖系综合征(外阴阴道萎缩)。互联网调查显示,在40岁以上女性中,多达85%有阴道干涩,29%-59%报告性交痛,26%-77%报告阴道瘙痒和刺激感[29,30]。
对于外阴阴道萎缩,目前的一线治疗主张在性交时使用阴道润滑剂来缓解阴道干涩症状[31]。润滑剂无效时则考虑使用阴道内雌激素制剂[32],但阴道内雌激素使用不当有被伴侣吸收的风险。
传统观念让大家总是回避“人到中年的性”,但在不干预雌激素的情况下,持续的性活动便有助于预防阴道缩短或狭窄,阴道壁弹性下降[33]。在自愿、私密、安全的前提下,中年人也有享受自己性生活的权利。
>>激素替代治疗——谨慎触碰的“双刃剑”
美国内分泌学会的临床实践指南推荐年龄在60岁以下或绝经不到10年,更年期症状(潮热、外阴阴道萎缩)特别严重且没有禁忌证(如乳腺癌、冠心病、脑卒中、静脉血栓、肝病等)的健康女性,可以考虑雌孕激素替代治疗,通常是口服短效避孕药,来缓解更年期症状[34]。
值得一提的是,目前学界普遍认为激素替代治疗不宜用于预防绝经后雌激素缺乏导致的心血管疾病、骨质疏松和痴呆[35-38]。
妇女健康行动(WHI)雌孕激素联合治疗试验显示,激素替代治疗后冠心病、脑卒中、静脉血栓栓塞症和乳腺癌风险提高[39-41]。选择激素治疗必须权衡利弊,慎之又慎。
>>生活方式调节——贵在坚持
饮食宜清淡忌辛辣,多吃蔬菜、水果和全谷物,减少饱和脂肪、红肉和精制糖的摄入。避免摄入咖啡因,咖啡因一方面可能引发潮热,另一方面会进一步降低睡眠质量[42]。
戒烟,降低心脑血管病和骨质疏松风险;限酒,避免干扰睡眠和导致疾病。
定期在白天进行体育锻炼,有助于缓解更年期症状和预防老年相关疾病。练习深呼吸放松调节、进行肌肉拉伸训练、做点按摩和水疗都是不错的选择。
人均寿命越来越长的今天,更年期是广大女性同胞的必经之路。平稳地跨过这一关,更年期后还有更加悠长而美好灿烂的人生。
本文转载自时光派公众号,作者RingoKuma,原标题《心烦易怒、失眠变胖竟是生殖衰老的锅?8成女生必备的回春指南来了》
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