Introduction
Child marriage is a formal marriage or informal union entered into by an individual before reaching the age of 18. The legally prescribed marriageable age in some jurisdictions is below 18 years, especially in the case of girls; and even when the age is set at 18 years, many jurisdictions permit earlier marriage with parental consent or in special circumstances, such as teenage pregnancy. In certain countries, even when the legal marriage age is 18, cultural traditions take priority over legislative law. Child marriage affects both boys and girls, though the overwhelming majority of those affected are girls, most of who are in poor socioeconomic situations.
Child marriage is related to child betrothal, and it includes civil cohabitation and court approved early marriages after teenage pregnancy in many cases, only one marriage-partner is a child, usually the female. Causes of child marriages include poverty, bride price, dowry, cultural traditions, laws that allow child marriages, religious and social pressures, regional customs, fear of remaining unmarried, illiteracy, and perceived inability of women to work for money.

Child marriage is a harmful practice1 which severely affects the rights of a child and further deprives the child from attaining other aspirations like education.
Every year, about 14 million adolescent and teen girls are married, almost always forced into the arrangement by their parents.
There is a correlation between poverty and child marriage. Girls from the poorest households are three times as likely to get married before age 18 as girls from the richest households.6 However, correlation does not always mean causation, - in contexts where the practice is almost universal, the level of education and location have found to be major determinants, above wealth. While poverty may be a factor, there are also two other important factors that drive child marriage: 1) Gender based violence and; 2) Gender discrimination.
Firstly, in many communities and countries, gender based violence specifically violence against the girl-child is very high with adolescent girls at risk of rape, even while walking to school. Given the prevalence of violence against the girl-child, parents may offer a daughter's hand marriage in the belief this will help protect her from a sexual assault that could leave her stigmatized in the community. The paradox is that parents are often wrong. Girls who marry before 18 are more likely to experience domestic violence including marital rape than their peers who marry later. Moreover, child brides often show signs symptomatic of sexual abuse and post-traumatic stress such as feelings of hopelessness, helplessness and severe depression.
Secondly, underlining these forms of violence and abuse against the girl-child is pervasive gender discrimination that frequently causes girls to be regarded as less worthy of care and protection. In patriarchal cultures, where girls lack the same perceived value as boys right from birth; families and communities may discount the benefits of educating and investing in their daughters’ development. Child brides are a strong reflection of pervasive gender discrimination.

Effects of child marriage
The leading cause of maternal mortality and morbidity for girls age 15 to 19 is pregnancy and childbirth. Child brides are almost always married to older men, and lack the standing or skills to negotiate over sex or birth control. That means many girls get pregnant soon after marriage, when their bodies are too underdeveloped. Among the disabilities associated with early childbirth is obstetric fistula, an injury which leaves girls in constant pain, vulnerable to infection, Sexually Transmitted Diseases including HIV, incontinence, and are often shunned by their husbands, families and communities.
According to UNICEF the child of a mother aged below18 years also has a 60-percent greater chance of dying in his/her first year. Married girls are often under pressure to become pregnant immediately or soon after marriage, although they are still children themselves and know little about sex or reproduction. A pregnancy too early in life before a girl’s body is fully mature is a major risk to both mother and baby.
The society and the country also suffer the consequences of child marriage. Child marriage undermines development efforts. The World Bank has calculated the cost of girls dropping out of school — as almost all child brides do — and reducing their future earning power. The World Bank finds billions in lost GDP and productivity for countries like India, Brazil and Kenya; and the report notes this does not include the broader social costs when half a nation's population is uneducated.
Child marriage also affects girls’ education, child brides usually drop out of school and are denied the opportunity to complete their education, significantly reducing their ability to earn an income and lift themselves and their children out of poverty. Conversely, if girls are able to stay in school and avoid early marriage, the benefits are widely felt. Educated girls are more likely to understand and advocate for their rights and they are more likely to raise healthy, educated children.
Education can also be one of the most powerful tools to enable girls to avoid early marriage and fulfil their potential. When a girl in the developing world receives seven or more years of education, she marries on average four years later.
Girls who live in countries facing humanitarian crises face the greatest risk of forced marriage, when communities are in need of security for their girls this can also result into child marriage. Where in conflict areas, girls may be taken as brides by warlords or offered by their families to authority figures in exchange for protection from violence or death. Innocent girls are given away to the warriors as a way of negotiating peace and harmony among the conflicting communities. Due to the conflict environment, girls are often left physically and emotionally scarred with no way out and no-one to help them.

Conclusion
In conclusion it is importance to mention birth registration to the protection of children from child marriage. Birth registration is the act of recording the birth of a child by a government authority. It establishes the existence in law of a child, and sets the foundation for the recognition of the child as a legal person. Birth registration of a child provides a proof of his/her age against various child abuses such as trafficking, sexual abuse, early marriage, child labour and enrollment in armed forces.

References
UNICEF, 2014. The State of the World’s Children 2015: Reimagine the future.

UNFPA, 2012. Marrying too Young: End Child Marriage.
UNICEF, 2014. Ending child marriage: Progress and prospectss an urgent task