Child marriage, also referred to as early marriage, is a serious human rights violation and detrimental practice that exposes children to increased risk of violence, exploitation, and abuse. It requires serious deliberation and action. Child marriage refers to formal marriages and informal unions in which one or both parties are under 18 years of age and live with a partner as if married ^[1][2][1,2]. Child marriage affects girls and boys, but disproportionately and negatively affects girls, who are more likely to be married off earlier in life than boys, especially in South Asia and Africa. This forced alliance is rooted in harmful pre-existing traditional norms and practices passed down through generations with debilitating effects on the girl child, their families, and society at large [3]. This harmful practice significantly undermines the best interests of the girl child at the individual, societal and national levels [4]. Besides being a human rights issue, child marriage has dire reproductive and sexual health consequences for girls, impeding their overall development and wellbeing [4].

Globally, more than 12 million girls marry at a young age (under 18 years) each year, that is, around 21% of young women marry before the age of 18 [1]. About 37% of these child marriages occur in sub-Saharan Africa, and 30% in South Asia [1]. In 2010, nearly 46% of women aged 20–24 years in South Asia reported being married before the age of 18. This translates to about 24.4 million women in the region, with projections that about 130 million girls are likely to be victims of child marriage between 2010 and 2030 [5].

In recent years, South Asia has experienced a significant decline in child marriage, especially among girls under 15 years ^[1][2][1,2]. This decline is driven predominantly by India, where child marriage rate declined from 47% in 2005 to 27% in 2016 [6]. However, despite the observed decline in child marriage in South Asia from 63% in 1985 to 45% in 2010 and 32% to 17% for girls under 15 years of age [1], this practice continues to be widespread and often concentrated in certain geographic regions or among specific cultural groups, necessitating more targeted efforts to protect adolescents from marriage. These targeted efforts must consider the predisposing factors associated with child marriage within the region.

Previous studies conducted in countries outside South Asia have reported some individual-level factors as being associated with child marriage, including place of residence (mostly rural) ^[7][8][9][7,8,9], low education level ^[7][8][9][7,8,9], poverty ^[7][8][7,8], culture [3], lack of exposure to mass media ^[7][8][7,8], low decision-making capacity ^[10][11][10,11], and religion ^[7][12][7,12]. Besides these associated factors, several other factors have also been reported to result from child marriage such as increased school dropouts [12], increased marital violence ^[10][13][10,13], increased maternal morbidity and mortality ^[14][15][14,15], increased risk of unintended pregnancies [16], decreased utilization of antenatal care and postnatal care services ^[17][18][17,18], decreased institutional delivery in health care facilities ^[17][19][17,19], and decreased deliveries assisted by skilled birth attendants ^[4][17][19][4,17,19]. However, no study has collectively and systematically analyzed the most consistent factors across the entire South Asia region to guide region- and country-specific interventions, which could lead to a decline in child marriage within each South Asian country and across the region. 

2. Child Marriage and Socio-Demographic Factors

Studies conducted in Bangladesh ^[20][23], Nepal ^[21][25] and India ^[22][26] reported an association between no/low exposure to mass media and child marriage. In India ^[22][23][21,26], Bangladesh ^{[20][24][25][26]}[23,27,28,33], and Nepal ^[21][27][25,30], children from low SES households were found to be more susceptible to child marriage. Studies conducted in Bangladesh ^[20][24][28][23,27,29], India ^[22][26], and Pakistan ^[29][31] reported an association between rural residence and child marriage. In contrast, a study conducted in Nepal ^[21][25] found that child marriage was prevalent among children in urban areas. Studies conducted in Nepal ^[27][30][22,30], Bangladesh ^{[20][25][28][31][32]}[23,28,29,34,35], India ^[22][23][21,26], and Pakistan ^[29][31] reported low educational attainment among most children, their parents and husbands exposed to child marriage. On the other hand, a study from Nepal ^[21][25] showed that early married women had husbands with a secondary or higher education level, and two studies conducted in Nepal ^[21][25] and Bangladesh ^[24][27] reported child marriage among women with a secondary or higher level of education. Five studies from Nepal ^[21][27][25,30] and Bangladesh ^[24][28][31][27,29,34] reported child marriage as prevalent among Hindus and Muslims.

3. Child Marriage and Maternal Health Service

Studies carried out in Bangladesh ^[20][33][23,32], India ^[33][34][24,32], Pakistan ^[29][33][31,32], and Nepal ^[33][32] reported that the number of ANC visits attended by early married women were less than four, which is the minimum recommended number of visits. Contrary to this, a study conducted in Nepal ^[21][25] reported that a higher percentage of early married women had four or more ANC visits. Most studies in India ^[26][33][34][24,32,33], Bangladesh ^[20][33][23,32], Nepal ^[21][33][25,32], and Pakistan ^[29][33][31,32] found that early married mothers reported few or no health facility-based deliveries. Studies conducted in Bangladesh ^[20][33][23,32], India ^[33][34][24,32], and Pakistan ^[29][33][31,32] reported low levels of delivery assistance by skilled birth attendants. On the other hand, a study conducted in Nepal ^[21][25] showed that delivery for early married mothers was mostly conducted by skilled birth attendants.

4. FaDisctors iussion Child Marriage

In countries where child marriage is prevalent, it is also reported that the practice is not equally distributed, being geographically clustered and more pervasive in rural areas ^[25][31][28,34]. In rural settlements, child marriage is mostly seen among girls with low educational attainment and from poor households, which predisposes them to early childbearing and less access to the health system ^[27][30]. The interplay between place of residence, socio-economic status, educational attainment, and uptake of health services as it relates to child marriage is quite complex. Applying the principle of intersectionality ^[35][36], it could be inferred that economically disadvantaged girls, with no/low educational attainment, and residing in rural areas are more susceptible to being married off at an early age compared to their more affluent, better-educated counterparts living in urban areas. Rural residence was reported as being associated with child marriage. This could be associated with limited access to education due to fewer educational facilities in rural areas. Fewer schools restrict the number of children who can obtain proper education. In addition, most rural areas have fewer job opportunities ^[36][37], coupled with reduced access to education, which indirectly impacts the economic stability of most families, leading to parents marrying off their daughters at an earlier age for economic security ^[37][38]. However, contrary to this finding, a study from Nepal reported that most child marriages occur in urban areas irrespective of the number of educational facilities available ^[21][25]. This points to the need for interventions to prevent child marriage in both rural and urban areas. Religion was associated with child marriage. Every religion has teachings and doctrines which are upheld within the family. In South Asia, the most common religions are Hinduism, Islam, and Buddhism ^[38][39]. In this rentryview, Hindu and Muslim religions were reported as being associated with child marriage. However, this is inconclusive, as studies which reported this were conducted in Nepal and Bangladesh which practice predominantly Hindu and Muslim religions respectively. Similarly, a study conducted in the United States of America (USA), a predominantly Christian country, reported the Christian religion to be associated with child marriage ^[39][40]. Another consistent factor associated with early marriage is education. The lack of adequate educational opportunities is a significant contributor to child marriage, especially in developing countries. Most often, families facing significant financial hardship resort to marrying off their daughters to relieve some financial burden, instead of paying costly school fees. This practice prevents the girl child from attaining future independence and autonomy through proper education and income-earning jobs. This practice is also prevalent in situations where the parents and the husband have low levels of educational attainment. Education enhances decision-making capacity ^[40][41] and has been known to help delay the age of marriage. The education level of parents influences their disposition towards child marriage to a great extent, and their willingness to marry off their young daughters [12]. Parents and husbands with low level of education do not seem to understand the detrimental impact child marriage could have on maternal and neonatal health outcomes. In addition, research has shown that marital violence increases in cases of child marriage where husbands are illiterate ^[41][42][42,43]. In line with ouresearchers' entry review are studies conducted in Nepal, Zambia, Indonesia, and Bangladesh that showed an inverse association between education and child marriage ^[7][9][43][7,9,44].