OBJECTIVE To describe the adoption of at least four early ANC (ANC4+) visits among women of reproductive age in Zambia between 2007 and 2019. METHODS We used Zambia Demographic and Health Survey data gathered between 2007 and 2019. Early ANC4+ was the desired result and was defined as having at least four ANC visits with the first ANC visit occurring during the first four months of pregnancy. Weighted univariate, bivariate, and multivariate logistic regression analyses were performed. RESULTS A total of 11633 (56%) of the 20661 women enrolled in our study had received early initiation of ANC4+. We saw an increase in the proportion of women who started ANC4+ early, from 55% in 2007 to 63% in 2018/19. There was a decreasing trend in the odds of early ANC4+ initiation with parity, but an increasing trend in the odds of early ANC4+ initiation with a higher level of education. Being a member of a wealthier household was associated with a lower risk of ANC4+ (OR= 0.81, 95%CI: 0.66-0.99, P=0.03). 27% of the 12,333 women who had at least four ANC visits, regardless of the timing of their first visit, reported being late for ANC. CONCLUSION Early ANC4+ uptake increased in Zambia between 2007 and 2019. We found that 27% of women who were misclassified as having at least ANC4+ using conventional analysis were actually late for ANC. We provide some key considerations for ensuring that Zambia and other similar settings achieve universal antenatal care coverage by 2030.

The authors have declared no competing interest.

No funding for this analysis.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The individual consent was conducted by Zambia Statistical Agency (ZSA) during the DHS 2007, 2013-14 and 2018 We obtained permission to use these data from the MEASURE DHS. The Zambia DHS datasets were downloaded from https://www.dhsprogram.com/data/available-datasets.cfm. As this study used secondary anonymised data, individual informed consent was not required.

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Yes