美国国家公共电台 NPR--COVID during pregnancy may alter brain development in boys

COVID during pregnancy¹ may alter brain development in boys

Transcript²

Boys born to mothers who got COVID-19 while pregnant appear nearly twice as likely as other boys to be diagnosed with subtle delays in brain development.

That's the conclusion of a study of more than 18,000 children born at eight hospitals in Eastern Massachusetts. Nearly 900 of the children were born to mothers who had COVID during their pregnancy.

In the study, boys, but not girls, were more likely to be diagnosed with a range of developmental disorders⁴ in the first 18 months of life. These included delays in speech and language, psychological development and motor function, as well as intellectual disabilities.

In older children, these differences are often associated with autism spectrum⁵ disorder³, says Dr. Roy Perlis, a co-author of the study and a psychiatrist⁶ at Massachusetts General Hospital.

But for the young children in this study, "it's way too soon to reliably diagnose autism," Perlis says. "All we can hope to detect at this point are more subtle sorts of things like delays in language and speech, and delays in motor milestones⁸."

The study, which relied on an analysis of electronic health records, was published in March in the journal JAMA Network Open.

The finding is just the latest to suggest that a range of maternal⁹ infections can alter fetal brain development, especially in male offspring. For example, studies have found links between infections like influenza¹⁰ and cytomegalovirus, and disorders like autism and schizophrenia.

"Male fetuses¹² are known to be more vulnerable to maternal infectious exposures during pregnancy," says Dr. Andrea Edlow, the study's lead author and a maternal-fetal medicine specialist at Massachusetts General Hospital.

But the effect from COVID-19 appears to be modest, Perlis says. "Most children of moms who have COVID during pregnancy won't have neurodevelopmental consequences even if there is some increase in risk."

A research opportunity

The study came about because Perlis and Edlow — both of whom are on the faculty¹³ at Harvard Medical School — saw an opportunity when COVID-19 arrived.

They had been looking for ways to use electronic health records to study factors that might affect the brain development of a fetus¹¹. That meant identifying pregnancies¹⁴ involving diabetes¹⁵, high blood pressure, or an infection like influenza, then following the offspring as they grew up.

"When the COVID pandemic started, we pivoted¹⁶ to try to look at fetal brain development and how it might be impacted by SARS-CoV-2 infection," Edlow says.

So the team began comparing the offspring of infected and uninfected mothers. And when they had a large enough group to look for sex differences, they found one.

"If a mom had SARS-CoV-2 infection in pregnancy and had a male child, her 12-month-old was 94% more likely to have any neurodevelopmental diagnosis¹⁷," Edlow says.

Keep in mind that the virus that causes COVID-19 rarely infects a fetus, Edlow says. That makes it similar to influenza viruses, but very different from Zika virus, which directly attacks a developing brain.

With influenza or COVID-19, the risk to a fetus appears to come primarily from the mother's immune response to an infection, not the infection itself.

As part of the body's effort to fight the virus, it produces proteins known as cytokines, which regulate the immune system.

"These are cytokines that are really important for that initial immune response," says Kim McAllister, a professor at the University of California, Davis and director of the school's Center for Neuroscience. "They make you feel really bad. And that's a good thing because that's your immune system fighting off the pathogen."

But cytokines, unlike most pathogens, can cross the placenta and cause inflammation in a fetal brain. And animal studies suggest that this inflammation has a greater impact on the brains of male fetuses than female fetuses, and results in different behavioral abnormalities after birth.

"There's no doubt from the animal models that there is a link between maternal immune activation¹⁸, changes in gene⁷ expression in the brain, changes in brain development, and long-lasting changes in behaviors," McAllister says.

The Harvard researchers plan to continue assessing the children in their study for several more years. That will allow them to see whether the early delays in boys persist or result in a diagnosis like autism spectrum disorder.

"I hope these effects go away," Perlis says. "I would be far happier if at the two year and three year follow-up there's no effect."

1 pregnancy   

n.怀孕，怀孕期

参考例句：

• Early pregnancy is often accompanied by nausea.怀孕早期常有恶心的现象。
• Smoking during pregnancy increases the risk of miscarriage.怀孕期吸烟会增加流产的危险。

2 transcript   

n.抄本，誊本，副本，肄业证书

参考例句：

• A transcript of the tapes was presented as evidence in court.一份录音带的文字本作为证据被呈交法庭。
• They wouldn't let me have a transcript of the interview.他们拒绝给我一份采访的文字整理稿。

3 disorder   

n.紊乱，混乱；骚动，骚乱；疾病，失调

参考例句：

• When returning back,he discovered the room to be in disorder.回家后，他发现屋子里乱七八糟。
• It contained a vast number of letters in great disorder.里面七零八落地装着许多信件。

4 disorders   

n.混乱( disorder的名词复数 )；凌乱；骚乱；（身心、机能）失调

参考例句：

• Reports of anorexia and other eating disorders are on the increase. 据报告，厌食症和其他饮食方面的功能紊乱发生率正在不断增长。 来自《简明英汉词典》
• The announcement led to violent civil disorders. 这项宣布引起剧烈的骚乱。 来自《简明英汉词典》

5 spectrum   

n.谱，光谱，频谱；范围，幅度，系列

参考例句：

• This is a kind of atomic spectrum.这是一种原子光谱。
• We have known much of the constitution of the solar spectrum.关于太阳光谱的构成，我们已了解不少。

6 psychiatrist   

n.精神病专家；精神病医师

参考例句：

• He went to a psychiatrist about his compulsive gambling.他去看精神科医生治疗不能自拔的赌瘾。
• The psychiatrist corrected him gently.精神病医师彬彬有礼地纠正他。

7 gene   

n.遗传因子，基因

参考例句：

• A single gene may have many effects.单一基因可能具有很多种效应。
• The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。

8 milestones   

n.重要事件( milestone的名词复数 )；重要阶段；转折点；里程碑

参考例句：

• Several important milestones in foreign policy have been passed by this Congress and they can be chalked up as major accomplishments. 这次代表大会通过了对外政策中几起划时代的事件，并且它们可作为主要成就记录下来。 来自《简明英汉词典》
• Dale: I really envy your milestones over the last few years, Don. 我真的很羡慕你在过去几年中所建立的丰功伟绩。 来自互联网

9 maternal   

adj.母亲的，母亲般的，母系的，母方的

参考例句：

• He is my maternal uncle.他是我舅舅。
• The sight of the hopeless little boy aroused her maternal instincts.那个绝望的小男孩的模样唤起了她的母性。

10 influenza   

n.流行性感冒，流感

参考例句：

• They took steps to prevent the spread of influenza.他们采取措施
• Influenza is an infectious disease.流感是一种传染病。

11 fetus   

n.胎，胎儿

参考例句：

• In the fetus,blood cells are formed in different sites at different ages.胎儿的血细胞在不同时期生成在不同的部位。
• No one knows why a fetus is not automatically rejected by the mother's immune system. 没有人知道为什么母亲的免疫系统不会自动排斥胎儿。

12 fetuses   

n.胎，胎儿( fetus的名词复数 )

参考例句：

• DNA was extracted from fetuses at mid-gestation, about 10 days past conception. DNA从受孕大约10天后的中期妊娠胚胎中提取。 来自互联网
• Brucellosis is a disease that causes fetuses to abort in cattle. 普鲁士菌病是一种可以导致牲畜胎儿夭折的疾病。 来自互联网

13 faculty   

n.才能；学院，系；(学院或系的)全体教学人员

参考例句：

• He has a great faculty for learning foreign languages.他有学习外语的天赋。
• He has the faculty of saying the right thing at the right time.他有在恰当的时候说恰当的话的才智。

14 pregnancies   

怀孕，妊娠( pregnancy的名词复数 )

参考例句：

• Since the wartime population needed replenishment, pregnancies were a good sign. 最后一桩倒不失为好现象，战时人口正该补充。
• She's had three pregnancies in four years. 她在四年中怀孕叁次。

15 diabetes   

n.糖尿病

参考例句：

• In case of diabetes, physicians advise against the use of sugar.对于糖尿病患者，医生告诫他们不要吃糖。
• Diabetes is caused by a fault in the insulin production of the body.糖尿病是由体內胰岛素分泌失调引起的。

16 pivoted   

adj.转动的，回转的，装在枢轴上的v.（似）在枢轴上转动( pivot的过去式和过去分词 )；把…放在枢轴上；以…为核心，围绕（主旨）展开

参考例句：

• His old legs and shoulders pivoted with the swinging of the pulling. 他一把把地拉着，两条老迈的腿儿和肩膀跟着转动。 来自英汉文学 - 老人与海
• When air is moving, the metal is pivoted on the hinge. 当空气流动时，金属板在铰链上转动。 来自辞典例句

17 diagnosis   

n.诊断，诊断结果，调查分析，判断

参考例句：

• His symptoms gave no obvious pointer to a possible diagnosis.他的症状无法作出明确的诊断。
• The engineer made a complete diagnosis of the bridge's collapse.工程师对桥的倒塌做一次彻底的调查分析。

18 activation   

n. 激活，催化作用

参考例句：

• A computer controls the activation of an air bag.电脑控制着气囊的启动。