**3. Causes of congenital anomalies**

Fifty percent of birth defects have no clear identifiable cause and in the other 50% there are factors that considered as the cause. The causes can be broadly classified in to 3:

• Pre-conception

perinatal deaths and 13–16% of neonatal deaths in India [8]. Reliable data from lowincome countries on fetal anomalies like data from other health indices is difficult to come by and even where available it is generated from institutional studies rather than from population based studies. Yet most congenital anomalies and their severe consequences are seen in developing low-income. In developed countries common causes of perinatal and neonatal have been dealt with and congenital anomalies are now seen as causes of perinatal and neonatal death. In developing countries, the reverse is the case and this may be the reason why the contributions of congenital anomalies in perinatal and neonatal mortality is well appreciated. So the augment goes in view of the presence of commoner causes of perinatal and neonatal mortality it will not be appropriate to allocate resources trying to reduce mortality from congenital anomalies. The is question now is, can we wait to achieve health transition in which common causes of perinatal and neonatal mortality are eliminated before addressing the issue of congenital anomalies and their contribution to perinatal and neonatal mortality? The answer is no. What we fail to realize is in developing countries congenital anomalies indirectly contribute to maternal mortality. Imagine a situation where a pregnant woman goes in to labor with a fetus with an undiagnosed congenital anomaly that preclude vaginal delivery and as we know more than half of pregnant women in developing countries labor and deliver at home. In this scenario the labor be prolonged and with time obstructed, membranes would have ruptured, chorio-amnionitis would have set in and as consequence develop postpartum hemorrhage or puerperal sepsis and die or she develop ruptured uterus and die. Congenital fetal anomalies can lead to both perinatal and

*Congenital Anomalies in Newborn Infants - Clinical and Etiopathological Perspectives*

In this chapter, I will discuss congenital anomalies, their causes, prenatal diagnosis, treatment and prevention with the peculiarities of the African environment

Multitudes of factors determine the overall quality of health and pregnancy

Illiteracy and poverty are factors that directly or indirectly influence health and pregnancy outcome in Africa. In Sub-Saharan Africa proportion of workers living in extreme poverty is 57% [9]. Other factors are ignorance, superstitious beliefs, bad cultural practices and poorly developed health infrastructure. The rate malnutrition in Sub-Saharan Africa is 23% [10]. In many countries in Africa utilization of antenatal care services is low and it is at this critical time pregnant women are screened for various diseases and ultrasound screening is done for fetal anomalies. In Nigeria only 2/3 of pregnant women attend antenatal care and only 40% deliver under the care of skilled birth attendants [10]. Utilization of the antenatal and delivery services in other African countries is much lower. Sub-Saharan Africa has the lowest contraceptive prevalence 13% and highest unmet need for family planning 28% [10]. Infections and infestations, lack of immunization against diseases that may be harmful to pregnancy and exposure to various potentially harmful substances increase the risk for fetal anomalies in Sub-Saharan African women. Lack of reliable data collection and recording means that the prevalence of congen-

ital anomalies in the region is based on institutional estimates not the actual numbers. This is the background to understanding the causes, management and prevention of congenital anomalies in Africa. It is with this background in mind that this chapter will discuss the causes, management and prevention of congenital

maternal mortality and morbidity.

safety and outcome in Africa.

in view.

**2. Background**

anomalies in Africa.

**198**


The pre-conception causes of birth defects are those causes that have their origin before conception and are genetic or partly genetic in origin [Genes and Chromosomes]. They found in families and can be inherited e.g. Sickle cell disease. They can also be seen as isolated incident in a particular pregnancy. The post-conception causes of birth defects are those anomalies that arise after conception or but before parturition. The last category of birth defects are those whose cause is unknown. The prevalence of birth defects based on the cause as shown in the above table is a broad division based on what is found in developed countries. If population based studies are conducted the findings differ from those above. This is because in developed countries concerted efforts were made to reduce environmental exposure to teratogens in pregnancy, institute preconception care to optimize medical conditions before pregnancy, immunize against infections that may affect the fetus in utero, offer pregnancy termination to where anomalies are identified etc. These measures reduce the prevalence of congenital anomalies of genetic origin or environmentally induced. In Africa environmental factors may play a role in causing birth defects. These may be from diseases [Viral, Bacterial and Protozoan/parasitic] or from exposure to teratogens [Alcohol, Cigarette, Pesticides and traditional medications who chemical constituents are unknown]. There is a difference in the annual numbers of birth defects, annual deaths from birth defects and annual under-5 deaths between Low-income, Middle-income and High-income countries.


#### **Table 1.**

*Percentage of birth defects by cause in high income countries.*


long run be linked to the actual cause. Some common viral infections associated with congenital birth defects include; **Zika** virus, **Cytomegalovirus**, **Rubella** virus. **Zika virus:** Infection Zika virus was first recorded in East Africa in 50s [Uganda and Tanzania]. It has recently caused epidemic in the Americas and travel advisory was issued with regard to this infection. The virus causes microcephaly and other congenital abnormalities known as Zika syndrome. It is also associated with other

**Cytomegalovirus [CMV]:** Women with cytomegalovirus infection have 1 in 3 chance of transmitting the infection to their fetus through the placenta. Not all exposed babies present with disease or its complications. There some ultrasound features detectable during prenatal screening which include; microcephaly, intracranial calcifications, ventriculomegally, ascites, hepato-splenomegally, intestinal, periventricular or hepatic echo densities and fetal hydrops. One or more of these

**Rubella virus:** Rubella is one the most dangerous viral infection that lead to serious complications in the fetus. Approximately 25% of infant born to mothers who contract rubella in the first trimester of pregnancy have congenital rubella syndrome [CRS] [4]**.** In countries with successful rubella immunization programs, CRS has been eliminated. In the remaining 50% of countries, more than 100,000 infants are born with CRS annually [13]. The common birth defects from CRS include; cataract, heart defects, low birth weight, skin rash at birth, deafness, and intellectual disabilities. Others include glaucoma, brain damage, thyroid and other

Drugs of various types are known to cause congenital birth defects. In Africa most drugs are bought over the counter as there are strict regulations. Because of poverty low medications are preferred by patients and such drugs may have potential side effects including embryo toxicity. As most pregnancies are unplanned women on treatment for some medical conditions may become pregnant and continue taking treatment with drugs that are teratogenic to the fetus. As antenatal care patronage is low women on such drugs may not be discovered until damage has been. Diseases requiring drug treatment either singly or in combination are common in Africa, ranging from infections, endocrine diseases such as diabetes and

**Misoprostol:** This is common drug used to induce abortion and is cheap, readily available and is sold over the counter in most African countries. Girls who have unwanted resort to its use without recourse to doctor's prescription. In approximately 80% of cases it fails to induce abortion and the pregnancy continue to term [14]**.** Misoprostol even though of low teratogenicity it is known to cause facial nerve paralysis, with or without limb defects, probably due to vascular disruption of the

Drugs such as Phenytoin and sodium valproate are known to cause birth defects. **Phenytoin**: This is known to cause fetal hydantoin syndrome; IUGR, Microcephaly, Limb defects, Hypoplastic nails and distal phalanges, Heart defects and cleft lip [18]. Up to 1 in 10 of babies whose mothers take sodium valproate are at risk of having a birth defect and up to 1 in 40 have developmental problems as they

thyroid diseases, haemoglobinopthies, Epilepsy, leprosy, etc.

subclavian artery and an ischemia in the embryonic brain stem [15–17].

pregnancy complications including preterm birth and miscarriages.

*Fetal Congenital Anomalies in Africa: Diagnostic and Management Challenges*

may indicate congenital CMV.

*DOI: http://dx.doi.org/10.5772/intechopen.91994*

**5. Drugs and birth defects**

hormone problems.

**6. Anti-epileptics**

**201**

#### **Table 2.**

*Estimated numbers and percentage of annual total birth defects, early deaths due to birth defects, and under-5 deaths for low-, middle-, and high- income countries.*

This is a demonstration of the impact of strategies put in place to control birth defects based on the level of economic development and investments made in health care infrastructure and health care provision and prevalence of modifiable risk factors for birth defects (**Table 2**).

#### **4. Chromosomal abnormalities as cause of birth defects**

These account for 6% of birth defects in developed countries in industrialized countries [11]. The most common example of is Down syndrome which is characterized by an extra chromosome and is also called trisomy 21. This is condition is now diagnosed early [Thickened Nuchal translucency, absent or hypoplastic nasal born etc.] and pregnancy can be terminated. Other defects in this category include Edward's syndrome and patau syndrome. Many infants are born with Down syndrome in Africa because early diagnosis and termination is not possible. Lots of resources are expended by families and communities on caring for the affected infants which constitute a burden for the family.

Single gene defects an estimated 7.5% of birth defects [11]. They are caused by alteration gene structure and more than 6000 single gene defects were described.

Environmental factors as cause of birth defects.

#### **Intrauterine infections;**

**Bacterial infections**: Example, Syphilis which in Sub-Saharan Africa is seen 6– 16% of pregnant women [12]. Currently most countries in Africa screen for Syphilis during antenatal care and provide treatment for those affected. Those affected present with features of the disease in the first 3 months of life which include; Vesiculobullous eruptions or macular copper-colored rash on the palms and soles and popular lesions around the nose and mouth as well as petechial lesions.

**Protozoan infection:** Congenital toxoplasmosis occurs as a result of maternal vertical transmission to the fetus. It is a cause of severe fetal complications that may manifest in the early neonatal period but may manifest later and lead to life-long complications. Diagnosis is through laboratory tests, however ultrasound is helpful and can be used to assess prognosis. The classical triad of congenital Toxoplasmosis are; chorioretinitis, hydrocephalus and intracranial calcifications.

**Viral infections:** Many viral infections are implicated as cause of several birth defects. Some viral diseases present with non-specific clinical features and many other infections have similar features. In Africa with poor health infrastructure screening and diagnosis for most diseases is challenging. Thus viral diseases may affect pregnant women and cause fetal congenital anomalies which may not in the

#### *Fetal Congenital Anomalies in Africa: Diagnostic and Management Challenges DOI: http://dx.doi.org/10.5772/intechopen.91994*

long run be linked to the actual cause. Some common viral infections associated with congenital birth defects include; **Zika** virus, **Cytomegalovirus**, **Rubella** virus.

**Zika virus:** Infection Zika virus was first recorded in East Africa in 50s [Uganda and Tanzania]. It has recently caused epidemic in the Americas and travel advisory was issued with regard to this infection. The virus causes microcephaly and other congenital abnormalities known as Zika syndrome. It is also associated with other pregnancy complications including preterm birth and miscarriages.

**Cytomegalovirus [CMV]:** Women with cytomegalovirus infection have 1 in 3 chance of transmitting the infection to their fetus through the placenta. Not all exposed babies present with disease or its complications. There some ultrasound features detectable during prenatal screening which include; microcephaly, intracranial calcifications, ventriculomegally, ascites, hepato-splenomegally, intestinal, periventricular or hepatic echo densities and fetal hydrops. One or more of these may indicate congenital CMV.

**Rubella virus:** Rubella is one the most dangerous viral infection that lead to serious complications in the fetus. Approximately 25% of infant born to mothers who contract rubella in the first trimester of pregnancy have congenital rubella syndrome [CRS] [4]**.** In countries with successful rubella immunization programs, CRS has been eliminated. In the remaining 50% of countries, more than 100,000 infants are born with CRS annually [13]. The common birth defects from CRS include; cataract, heart defects, low birth weight, skin rash at birth, deafness, and intellectual disabilities. Others include glaucoma, brain damage, thyroid and other hormone problems.
