At the end of 2020, approximately 38 million people were living with human immunodeficiency virus (HIV) and of these, 1 million were children aged 0 to 9 years . In the same year, 1.5 million people became newly infected with HIV around the world and this included 160,000 children under the age of nine .
Approximately 1.3 million women living with HIV got pregnant in 2018  and Mother- to- Child Transmission of HIV (MTCT) in-utero or through breastfeeding is responsible for over 90% of all paediatric HIV infections . Prevention of Mother-to-Child Transmission of HIV (PMTCT) is therefore critical in the prevention of paediatric HIV infection. To prevent HIV infection occurring in children, the World Health organisation (WHO) recommends a range of strategies, namely: the prevention of HIV in women of childbearing age, the prevention of unwanted pregnancies, PMTCT with anti-retroviral therapy (ART) in HIV positive pregnant women and infant prophylaxis for HIV exposed infants . Antenatal care (ANC) plays a vital role in one of these strategies, namely, PMTCT, since it is the entry point for pregnant women into health care services. Women, who for various reasons fail to utilise ANC, would unfortunately have missed the opportunity to fully utilize PMTCT services and are at high risk for maternal HIV transmission.
Antenatal care refers to the ongoing health services provided to women during pregnancy in the formal health system. It is meant to screen out pregnant women for potential obstetric complications, non-communicable and infectious diseases and provide therapeutic and preventive interventions to minimise maternal and fatal adverse pregnancy outcomes . In 2002, the WHO issued a set of ANC guidelines for developing countries which incorporated what was proposed in relation to the prevention of mother to child transmission of HIV .
Henceforth, ANC became the focal point for access to PMTCT services by pregnant women . Unfortunately, about 14% of pregnant women worldwide have no access to a single ANC visit with trained healthcare workers . In Zimbabwe, the HIV prevalence among pregnant women is 16.7% and about 7% of all pregnant women in Zimbabwe fail to access ANC services throughout pregnancy for various reasons . These women, un-booked for ANC, unfortunately miss the opportunity to fully utilise PMTCT services and those with HIV become very high risk for MTCT. Without intervention, the risk for MTCT is 15 to 45%  but can be as low as below 1% with PMTCT .
Many factors have been described which affect access to antenatal care. They include women’s perceptions on the importance of ANC and health problems during pregnancy. It has been suggested that marital status, parity, health worker – related factors, the costs of ANC and the fear of HIV testing were some of the factors influential in the utilisation of antenatal care services .
A systematic review by Simkhada (2008) further identified maternal education, husband’s education, availability of ANC services, household income, women’s employment status, media exposure and having a history of obstetric complications along with a women’s marital status, as factors affecting access to ANC. Cultural beliefs and ideas about pregnancy also influenced ANC utilization . Many studies have shown that poor socio-economic status is associated with poor use of antenatal services [13,14,15]. For example, attending ANC is associated with costs even in facilities where the service is offered free. Such costs include those required for transport and the time spent at the ANC clinic.
Women who have completed secondary school or those with a tertiary education are noted, in many studies, as better utilisers of antenatal care services compared to those with no education and those who did not complete primary or secondary education [16,17,18]. Educated women may have a better perception of the importance of ANC, have a better understanding of health education messages and are less intimidated to approach health care workers . Similarly, it has been noted that professional women are good users of antenatal care services compared to unemployed women [12, 17]. Women who get pregnant at ages less than 20 are usually not financially independent, unmarried and have not yet completed secondary or tertiary education and have been identified as poor utilisers of antenatal care services. In some settings, this can be worsened by poor pregnancy disclosure and social stigma [11, 16].
Researchers have noted that lower parity, a planned pregnancy, and past pregnancy complications were associated with better utilisation of ANC [16, 17].
.Interestingly, most studies focusing on the risk factors associated with poor utilisation of ANC tend to focus on the comparison between early bookers and late bookers and do not focus on the risk factors for not booking at all. Galvin (2001) showed that non-bookers were likely to be of lower socio-economic status compared to booked women in Harare, Zimbabwe. However, this study was done at a referral hospital where most of the non-bookers had been referred from rural areas which does not represent the urban Chitungwiza population .
Despite the fact that anti-retroviral drugs have been made available free of charge in the public health sector since 2002 and that HIV care is decentralized so that PMTCT services are available at all maternity health centres in Zimbabwe, some pregnant women appear to still find it difficult to access these services . These women either present at maternity clinics as unbooked clients during labour or well after giving birth without having had a single contact with antenatal care services prior to the labour or delivery. Those newly diagnosed with HIV would then have missed taking ART during pregnancy and one of the obvious results of this is the children born are at high risk (15–45%) of contracting HIV , when such could have been prevented.
Whilst there is the Harare provincial data showing an un-booked proportion of 6% , the local burden of un-booked women in the city of Chitungwiza is not readly available. The proportion of these un-booked women who also have HIV, is again not readily available. Even though the data are collected and are present in maternity records, they are not available as aggregate data. A study by Chadwick et al., which recruited a population of unbooked postpartum women with HIV, indicated that the proportion of unbooked women in Chitungwiza could be way higher than the 6% estimated for Harare province where Chitungwiza is located .
This study therefore aimed at determining the proportion of women un-booked for antenatal care and among them, the proportion of women who were HIV positive, and to identify some of the risk factors for un-booking in the city of Chitungwiza. Determining the local burden of non-utilisation of ANC services is essential in identifying what local health promotion strategies and health service actions and resources are needed to bring such pregnant women into care. Determining the proportion of pregnant women both unbooked for ANC and living with HIV is important in assessing the risk of vertical HIV transmission in the city and what effort is still needed for the elimination of paediatric HIV.