本文來自微信公眾號： 環(huán)球科學科研圈 ，作者：領研網(wǎng)，原文標題：《精子，被嚴重低估了｜科學60秒》

生殖醫(yī)學門診里，擠滿了因生育困難而焦慮的夫妻。在這場漫長而艱難的努力中，女性往往承受著更多的生理與心理壓力。即便通過試管嬰兒等輔助生殖技術成功受孕，依然有近20%的妊娠以流產(chǎn)告終，而流產(chǎn)帶來的身心創(chuàng)傷，絕大部分要由女性獨自承受。

一次成功的妊娠中，精子與卵子的結合只是起點，后續(xù)還要經(jīng)歷胚胎發(fā)育、著床等重重考驗，直至誕下健康胎兒。人們常常以為，一旦受孕成功，后續(xù)的一切就只和母體有關，但近幾年的研究表明，即便夫妻成功受孕，精子的質(zhì)量會持續(xù)影響整個妊娠過程。

男性精子及其攜帶的DNA對妊娠結局的影響，遠超人們的想象。學界已經(jīng)證實，精子DNA碎片化（DNA fragmentation）——即精子攜帶的遺傳信息發(fā)生斷裂或損傷——與流產(chǎn)之間存在相關性，還與較低的體外受精活產(chǎn)率（成功分娩存活嬰兒的比例）有關。針對這一問題的檢測技術其實早在幾十年前就已問世。更令人鼓舞的是，在部分病例中，僅須一些簡單的干預即可大幅提高生育成功率，如戒酒、改善飲食、增加運動、補充特定營養(yǎng)素等。

可在現(xiàn)實中，夫妻尋求生殖醫(yī)學幫助時，精子問題一直沒有得到應有的重視。在中國，不孕不育配套的標準檢查中，女性一方要完成10余項常規(guī)檢查，涵蓋激素、卵巢儲備、輸卵管、子宮、免疫、染色體等多個維度；男性一方則通常只有2~3項，其中最核心的僅有精液常規(guī)分析，主要檢測精子數(shù)量與活力——簡言之，就是看它們能否順利抵達卵子。

在美國，直到2026年，美國生殖醫(yī)學學會（ASRM）14年以來首次更新了《復發(fā)性妊娠丟失評估與處理》委員會意見，才將精子DNA碎片化檢測正式納入推薦范圍，且僅限于流產(chǎn)組織遺傳學評估與子宮結構檢查均未發(fā)現(xiàn)其他原因的情況，不適用于所有經(jīng)歷過反復流產(chǎn)的患者。

這不禁讓人追問：既然精子DNA如此重要，為什么不一開始就檢測，非要等到女方的檢查全部排處之后？

這些問題的答案或許并不完全根源于科學。男性在生育過程中承擔著不可替代的角色，胎兒的DNA有一半來自父親。在所有不孕不育案例中，男性因素貢獻的比例可高達50%。其中約20%的病例完全因為精子存在某種問題；另有30%~40%的病例是精子問題與卵子問題或女方其他因素并存的結果。

然而，生殖醫(yī)學界真正意識到精子可能與流產(chǎn)相關，也不過是最近幾十年的事。臨床上有一個反復出現(xiàn)的現(xiàn)象引起了醫(yī)生們的注意：一些經(jīng)歷過多次流產(chǎn)的女性，在更換伴侶后順利懷孕并生下了健康的孩子。全球生殖醫(yī)學集團旗下波士頓IVF（Boston IVF）的首席科學官丹尼·薩卡斯（Denny Sakkas）表示，“從這一點出發(fā)，人們隱約發(fā)覺，反復流產(chǎn)可能與男方有關?！?/p>

丹尼正是這一領域的開拓者之一。他在1990年代分析了不孕男性的精子DNA，首次發(fā)現(xiàn)其分子結構中存在“微小斷裂”。這一觀察正是后來精子DNA碎片化檢測誕生的科學基礎。圍繞“男性不孕不育”，目前仍有大量科學問題有待探索。好在隨著醫(yī)學研究與文化討論的同步升溫，精子健康逐漸被推向公眾視野的中心。

學術層面，相關研究正在獲得越來越多的關注，臨床醫(yī)生也開始更認真地對待男性不孕不育因素。文化層面上，歐美社媒近期興起了一場名為“精子最大化”（sperm maxxing）的風潮：越來越多的男性開始為改善生殖健康而調(diào)整生活方式，包括但不限于認真吃飯、減少飲酒、戒掉成癮物質(zhì)等。

對于備孕女性而言，最痛苦的莫過于反復流產(chǎn)。在這一過程中，精子究竟發(fā)揮著怎樣的作用？

如果精子攜帶的DNA本身就存在損傷，受精卵的正常發(fā)育就可能受到干擾。精子DNA碎片化檢測正是針對這一問題而設計的：它通過量化DNA雙螺旋鏈上微小斷裂點的比例，評估精子遺傳物質(zhì)的完整程度。醫(yī)生可以據(jù)此告訴一位男性，他的精子DNA損傷處于輕度、中度還是重度。

丹尼給出過一個形象的比喻：“DNA就像一本使用說明書。如果說明書里存在大量拼寫錯誤，你或許仍然可以懷孕，但當妊娠發(fā)展到某個關鍵階段，比如某個‘拼寫錯誤’恰好落在心臟組織發(fā)育的說明上，妊娠就無法繼續(xù)?！边@同時解釋了一個此前令人困惑的臨床現(xiàn)象：為什么一些精子DNA受損的男性能夠讓伴侶受孕，胚胎卻在幾周之后停止發(fā)育。

得到檢測結果后，醫(yī)生可以采取相應干預手段，比如針對某類特定病因（如精索靜脈曲張）的外科手術方案。但這項檢測更具普遍意義的臨床價值在于，它可以促使男性主動思考：自己能做些什么改善精子的健康狀況？是否可以更均衡地飲食、多吃蔬果？是否可以堅持運動，保持健康生活習慣？此外，學界也有大量文獻探討各種維生素與營養(yǎng)補充劑對精子質(zhì)量的改善作用。

從這個角度而言，精子DNA碎片化檢測也是一次健康提示，它讓男性直面精子狀態(tài)不理想的現(xiàn)實，告訴他們這可能正是不孕不育的根源所在，必須作出改變。

如果說DNA碎片化揭示的是精子“硬件層面”的損傷，近年來另一個更顛覆性的發(fā)現(xiàn)，指向了精子的“軟件層面”……[查看全文]

New recommendations spotlight sperm’s role in recurrent miscarriage

Rachel Feltman:For?Scientific American’s?Science Quickly,I’m Rachel Feltman.

When heterosexual couples struggling to conceive seek medical assistance,sperm often don’t get as much attention as they should.Standard tests measure sperm count and motility,but this ultimately just shows how likely a sperm is to make it to the egg.And that moment of conception is just the first of many steps to the implantation of a growing embryo,let alone the gestation of a healthy fetus.

We now know that,even if couples manage to conceive,problems with sperm can interfere with the pregnancy.Research has shown a connection between DNA fragmentation,which is when the genetic information stored within sperm is broken or otherwise damaged,and miscarriage.It’s also been linked to lower IVF live birth rates,which makes sense:in vitro fertilization gets the sperm through the door,so to speak,but if half of the resulting embryo’s DNA is potentially damaged,it’s less likely to develop normally and progress into a healthy pregnancy once implanted.

The good news is that there are tests for DNA fragmentation in sperm.In fact,they’ve been around for decades.And the even better news is that,at least in some cases,successful intervention can be as simple as cutting out alcohol,improving your diet and exercise and taking a few supplements.

Earlier this year,the?American Society for Reproductive Medicine updated its recommendations?for assessing and treating recurrent pregnancy loss for the first time since 2012.Sperm DNA fragmentation testing was finally recommended but not for all patients who’ve had repeated miscarriages—only in cases where genetic evaluations of miscarriage tissue and tests on the structure of the uterus haven’t revealed another cause.Which begs the question,why aren’t people hoping to conceive being taught about the importance of sperm DNA and offered testing for it from the start?

Here to unpack this for us is freelance science journalist Sarah Elizabeth Richards,the author of a recent story on the subject?for?Scientific American.

Thanks for joining us today.So for listeners who don’t have as much,you know,experience reading about writing about this field,just how big is the disparity between the research and even conversation around female infertility issues and those same conversations and studies related to sperm?

Sarah Elizabeth Richards:Well,that’s a great question.So the background,and people don’t really know about this,is that men contribute to 50 percent of infertility problems.And I think there was a quote in the story,it’s like I think 20 percent of cases are just the sperm alone,and then another 30 to 40 percent are the sperm and the egg alone,or the sperm and women—whatever they’re dealing with.

So men obviously play a huge role;they have to give half of the DNA they have to make the baby,but they also,there’s a lot that can go wrong or a lot to explore on,you know,why they might be experiencing infertility as a couple.

So there’s a lot of science behind it,and it’s getting a lot more recognition.A lot more doctors are paying a lot more attention to it.Culturally,there’s another piece:[it]is that I think more,you know,people are recognizing the role of sperm.You’ve got this trend of“sperm maxxing”and men doing all of these things to have the optimal sperm and eating well,drinking less,smoking less pot,which are obviously really important things.So at the same time,you’ve got a lot more medical and scientific research.You’ve got,culturally,a lot more people paying attention to sperm.

Feltman:Yeah.So what do we know,currently,about the ways in which sperm can contribute to,you know,this risk of recurrent miscarriage?

Richards:So for this test specifically,which measures what they call DNA fragmentation,and that’s the idea that on a piece of DNA,there’s these little breaks,and these little breaks can mess up the instruction booklet,right,when you,you make a baby.And so what this test does is:it measures that level.So a doctor can go back to a man and say,you know,“You’ve got a high level of sperm damage,”which is measured in this DNA fragmentation,“You’ve got a light level,”“You’ve got a high level.”And then,based on that,you know,there are certain surgical techniques they can do.But,like,the bigger message or one way it can be helpful in the clinic is that it sends the message to men as like,“Okay,well,what things can I do to improve the health of my sperm?”You know,“Can I eat better,eat more fruits and vegetables?Can I drink less,smoke less pot,exercise?”I think there’s a whole list of different vitamin supplements you can take,this is beyond my knowledge,but apparently there’s a whole literature on things you can do to improve your sperm.I think,in that way,it can be useful to say,like,“Look,your sperm actually ain’t great,and it could be causing the problem.So it’s something you might wanna pay attention to.”...[full transcript]