如何预防新生儿先天性出生缺陷

文/菲奥雷·萨尔瓦托·约里奥（Fiore S. Iorio） 译/杨帆 贾潇潇

（Fiore S. Iorio，意大利），医学博士，河北省儿童医院外籍心脏外科专家。前意大利耶稣圣婴儿童医院心脏中心主任，“燕赵友谊奖”获得者。

2015年3月3日，“世界出生缺陷日”被首次确立，其主要目的是提高全世界对先天性缺陷的认识，促进并整合有关预防和治疗先天性畸形的行动。“世界出生缺陷日”的设立是为改善生育质量，以及提升产妇、新生儿、儿童和青少年的健康所采取的举措。

并非所有出生缺陷都可以预防，但可以通过采取一些措施来帮助每一位母亲拥有一个健康的孕期。

在世界各地，数以千计的出生缺陷病例都与公共卫生相关状况有着紧密联系。特别是在工业化社会，以及在不断涌现的新兴工业化国家中，出生缺陷是婴儿在一岁以内发病和死亡的主要原因之一。

先天性出生缺陷的种类及治疗模式

每年，全世界约有800万婴儿出生时患有严重的先天缺陷，并且其中约有300万会在五岁之前死亡。考虑到所有情况，先天性缺陷的发生率估计约为5%：每20个婴儿中就会有1个患有畸形。

：例如，先天无脑畸形、左心发育不全综合征等。此类缺陷能导致死产或新生儿和婴儿死亡，经产前诊断后一定比例的病例可能终止妊娠。

：如唇裂等。此类病例需要早期医疗干预以避免死亡或临床状况严重恶化。

如先天性髋关节脱位、隐睾。此类病例仍需医疗介入，但预期寿命良好。

致命和严重的先天缺陷是主要的先天性异常，而非轻微先天缺陷。

此文中非常值得注意的是海德格尔对非真理的描述。非真理包括遮蔽与迷误。对于遮蔽，海德格尔认为，遮蔽比显现、开放更为古老，更为本源。这种遮蔽并非是存在及其真理发生之后才随后产生，也并非由于人对于存在的认识的不足与匮乏，而是因为，存在者整体的遮蔽状态作为根本性的非真理，比任何一种存在者和存在的敞开状态更古老，比“让存在”亦即存在的真理更本源。存在的真理自行遮蔽，存在在此就被遗忘了，因为人总是固执于“方便可达的和可控制的东西”。

导致出生缺陷的原因

预防出生缺陷，即在怀孕前或怀孕期间消除或减轻一些风险因素，从而使孩子出生时健康无缺陷。至少在理论上，所有原因或风险因素是已知的，最重要的是具有可更改性的，出生缺陷也可以被防治。

我们都知道，给孕期母亲服用叶酸可以减少神经管缺损的发生，我们也知道母亲年龄较大是产儿患有21—三体综合征（唐氏综合征）的一个重要因素。但由于我们不能改变母亲的年龄，因此对该风险因素的预防是无用的。

有效控制风险因素可以降低该缺陷或疾病的发生率。在出生前对缺陷的早期诊断可以让父母衡量是否需要人工流产。但是，如果是这种情况，我们阻止的是胎儿的出生而不是缺陷本身。换句话说，我们抹去的是患者生命而不是疾病本身。因此，我们不能将其定义为一种预防，甚至这是一种错误的预防。

导致新生儿先天性缺陷主要有以下三点原因：

一是遗传因素（25%），包括染色体（21—三体综合征、18—三体综合征、13—三体综合征）或单基因异常（小儿手—心畸形综合征）。造成这些缺陷的两个主要原因是母亲年龄较大（35岁以上）和近亲结婚。

二是环境因素（15%）。怀孕母亲不健康的饮食习惯，比如酗酒、吸烟、接触有害物质，如铅、农药、致畸药物、辐射、污染物；或是母亲患有传染性病原体，如水痘、巨细胞病毒、传染性红斑、疱疹病毒、风疹、梅毒、弓形体病、寨卡病毒等；再或产妇健康紊乱，如妊娠期糖尿病、肥胖、营养不良等。

三是多方面因素（60%），如环境因素引发怀孕母亲的健康问题。

出生缺陷的预防

先天性异常往往发病最早且完全康复的机会有限。因此，治疗这类疾病的最佳医疗策略是预防。

一是戒烟戒酒。二是提倡多样化和均衡的饮食，从孕前阶段开始补充叶酸和维生素，避免营养不足、肥胖和妊娠期糖尿病。三是在母亲患有慢性疾病（癫痫、糖尿病、抑郁症、甲状腺疾病）时，有必要与医生一起规划怀孕事项，调整相关的治疗方案。四是减少接触有害物质，如铅、农药、药物、辐射、污染物。五是接种疫苗应对风疹、水痘和流感。六是注意危险的传染性病原体，如水痘、巨细胞病毒、传染性红斑、疱疹病毒、风疹、梅毒、弓形体病、寨卡病毒等。七是杜绝近亲结婚。八是年龄较大的父母生育的新生儿基因突变或异常的风险更大，因此建议母亲的生育年龄在35岁前。

二级预防包括早期诊断和及时有效的治疗，例如通过新生儿手术治疗复杂的先天性心脏缺陷，如导管依赖性左心或右心发育不全综合征或大动脉转位。

最常见的先天性出生缺陷影响：骨骼、关节及肌肉（马蹄内翻足、先天征兆性脱位、先天性膈疝、脐疝、多指畸形、有两个或两个以上的指融合在一起）；脑与脊柱（先天无脑畸形、小头畸形、脑积水、脊柱裂）；消化道（唇腭裂、食道闭锁、肛肠直肠闭锁）；心脏（导管依赖性左心或右心发育不良、大动脉转异位、法洛四联症、主动脉缩窄）；泌尿道和生殖器（肾发育不全、囊性肾、膀胱外露、尿道下裂和上裂、隐睾）；唐氏综合征。

在孕前和怀孕早期要为即将成为父母的双方提供有针对性的建议、开展健康教育活动，为减少环境污染作出努力，更重要的是，我们需要更多的医疗监测和持续的研究来进行改进，使出生缺陷的预防变得更加有效。

On March 3, 2015, for the first time, “World Birth Defect Day” (WBDD) was celebrated with the main objective to raise awareness all around the world about birth defects and to promote and integrate actions for the prevention and treatment of congenital malformations and, in general, for the improvement of reproductive, maternal, neonatal, childhood and adolescent health.

Not all birth defects can be prevented, but you can take steps to help the mother have a healthy pregnancy.

There are thousands of birth defects representing a relevant condition in public health anywhere in the world. In industrialized societies, and increasingly also in emerging societies, they are one of the leading causes of infant morbidity and mortality within the first year of life.

Every year, about eight million babies worldwide are born with a serious birth defect, and about three millions of them will die before their fifth birthday. Considering all cases, the frequency of congenital defects can be estimated at around 5%: one in 20 babies born has a malformation.

when they may cause stillbirth or neonatal and infant death, or when pregnancies may be terminated in a relevant proportion of cases after prenatal diagnosis (anencephaly, hypoplastic left heart syndrome).

when they need early medical intervention to avoid death or major impairment of clinical conditions (cleft lip).

when they still need medical intervention, but life expectancy is good (congenital dislocation of the hip, cryptorchidism).

Lethal and severe defects represent significant congenital anomalies instead of minor ones.

Prevention of birth defects means elimination or mitigation of the causes or risk factors before or during pregnancy, thus allowing the child to be born healthy and without defects. All birth defects whose causes or risk factors are known and, most of all, modifiable can also be prevented, at least in theory.

For example, the administration of folic acid reduces neural tube defects to the mother, and we also know that the older age of the mother is a risk factor for the birth of a neonate with trisomy 21 (Down syndrome). But since we cannot modify that mother's age, this risk factor is useless for prevention.

Effective control of a cause or risk factor of a birth defect will result in a percentage reduction of the incidence of that defector disease. The early diagnosis of the defect in prenatal age allows the parents to evaluate whether to terminate the pregnancy. But, if this is the case, we prevent the birth of the fetus, not the defect itself. In other words, we eliminate the patient, not the disease. We cannot define this as prevention but false prevention.

The causes of congenital birth defects are:

including chromosomal (trisomy 21 Down syndrome, trisomy 18 Edwards syndrome, trisomy 13 Patau syndrome) or single gene anomaly (Holt-Oram syndrome). The two major risk factors for these defects are the older age of the mother (＞35 years) and consanguineous marriages.

due to unhealthy habits of the mother like alcohol abuse and smoking; exposure to harmful substances such as lead, pesticides, teratogenic drugs, radiation, pollutants; infectious agents (chickenpox, cytomegalovirus, infectious erythema, herpes virus, rubella, syphilis, toxoplasmosis, Zika virus, etc.); maternal health disorders (gestational diabetes, obesity, nutritional deficiencies).

: when environmental risk factors trigger the mother's predisposition.

Congenital abnormalities have the earliest onset and a limited chance for complete recovery; therefore, the best medical strategy to approach these types of diseases is prevention.

Primary prevention of congenital defects is a priority for the consequences in the social and health field as a cause of mortality and infant morbidity. Many birth defects can be avoided by taking preventive actions before and during pregnancy. It is therefore strategic to offer any woman of childbearing age extensive counseling to promote healthy lifestyles, with particular reference to the following aspects.

elimination of alcohol and smoking., promotion of a varied and balanced diet, also through folic acid and vitamins supplementation from the preconceptional phase to avoid nutritional deficiencies, obesity, gestational diabetes.in the presence of chronic diseases of the mother (epilepsy, diabetes, depression, thyroid disease), it is necessary to plan the pregnancy with the doctors to manage the related treatment.reduction of exposure to harmful substances such as lead, pesticides, drugs, radiation, pollutants.favor a vaccination strategy against rubella, chickenpox and flu.beware of dangerous infectious agents (chickenpox, cytomegalovirus, infectious erythema, herpes virus, rubella, syphilis, toxoplasmosis, Zika virus, etc.).avoid marriages between relatives for the risk of inbreeding.try to favor the mother's age ＜35 years as genetic factors such as gene mutations or abnormalities may occur more frequently in older parents.

Secondary prevention includes early diagnosis and prompts effective treatment, e.g., neonatal surgical treatment of complex congenital heart defects such as ductus-dependent hypoplastic left or right heart syndrome or transposition of the great arteries.

The most common congenital birth defects affect:s (clubfoot, congenital dislocation of the hint, congenital diaphragmatic hernia, omphalocele, polydactyly, syndactyly);(anencephaly, microcephaly, hydrocephaly, spina bifida);(cleft lip/palate, esophageal atresia, anorectal atresia);(ductusdependent hypoplastic left or right heart, transposition of the great arteries, tetralogy of Fallot, coarctation of the aorta);(renal agenesis, cystic kidney, bladder exstrophy, hypospadias, epispadias, undescended testis);

Tailored advice to future parents during preconceptional and early pregnancy consultations, health education campaigns for prospective parents, international efforts to reduce environmental pollution. But, most of all, medical surveillance and continuous research are needed to improve and make birth defects more and more effective in the future.