Study setting and design
The study was done in eastern zone of Tigray regional state, North Ethiopia which was financially funded by Adigrat University with registration number of AGU/CMHS/033/10. Unmatched case–control study design was employed to generalized the determinates of late ANC for all age groups, residences and other related issues from January 2018 to April 2018. Time of first ANC attendance was considered as an outcome variable. Participants were categorized as cases and controls based their time of first ANC as an outcome variable to identify the determinants of late ANC due to the fact that the WHO recommends pregnant women need to start ANC first visit with in the first trimester (in the first 4 months), second visit 20–24 weeks, third visit 28–32 weeks and fourth visit at 36 weeks or after. Accordingly, Participants who visited first ANC after 16 weeks of gestation were considered as cases and participants attended first visit of ANC within the first 16 weeks were considered as controls. All pregnant women who were doing their schedule of first visit in all of the health facilities were included as sources of population. However pregnant women who were severely ill and mentally ill during the data collection were excluded due to they might not give appropriate information.
Sampling size and techniques
Sample size was calculated using EPI INFO Version 7 by considering proportion of mothers who had good knowledge on advantage of early ANC among cases was 58.2% (main exposure variable with AOR = 2.1) from previous study done in Ethiopia . In addition 95% CI, 80% power and 1:1 control to case ratio was taken. Accordingly by adding 10% none response rate the final sample size was 201 cases and 201 controls (total of 402 participants). To obtain the required sample size 12 health facilities were selected randomly from the total 44 health facilities of the Zone. Thus, eligible Participants were shared proportionally to population size of each health facilities. Finally participants were selected using systematic sampling technique from the total pregnant mothers attending ANC first visit in the selected health facilities.
Data collection tools and analysis
The determinants of late ANC was assessed using structured and pre tested questionnaires by face to face interview. Questionnaires were developed in English, and then it was translated to local language to check its completeness, consistence, accuracy and finally applied the English version. The actual data was collected during their first ANC visit. Twelve Midwifery professional data collectors and three Bachelor of Science in Nursing Supervisors were recruited. Two days training was given for data collectors and supervisors. The preliminary data was coded and checked for completeness, consistent and managed accordingly. Data clean up and cross-checking was also done before the analysis. Data was entered to SPSS version 20 for analysis. Cross tabulation was done to see the distribution of cases and controls by frequency, percentage and mean. Bivariate and multivariate logistic regression was done. Each variable with the outcome of interest at p < 0.05 in the bivariate analysis was transported to multivariable analysis. Each independent variable at p < 0.05 was declared as determinate factors in the final model. Multi-collinearity using VIF (Variance Inflator Factor) at the cut of point 10 and Model goodness of fit using Hosmer–Lemeshow test at p value > 0.05 was done. The overall design, data collection and analysis was followed and checked by the funding agency (Adigrat University). Finally the finding of the study was presented to Adigrat University and respected districts.
Part I: Socio demographic characteristics and obstetric history of participants
In the current study, 199 controls and 199 cases were participated making a response rate of 98.7%. Majority, 54 (27.1%) control and 53 (26.6%) case were in the age group of 25–29 years with the mean age of 27 years (SD ± 6.3). The highest 113 (56.8) controls and 109 (54.8) case were house wives. Only 19 (9.5%) controls and 15 (6.5%) case were governmental employed. In educational status, the highest 89 (44.7%) controls and 72 (36.1%) cases were attended 7–10 grade (Table 1).
Most of the participants, 67 (49.6%) controls and 58 (35.4%) cases had 2–4 births. Regarding the number of alive children they had, 69 (53.1%) controls and 77 (47%) cases had 1–2 alive children, and 25 (21.2%) controls and 29 (18.8%) cases had history of abortion. Out of the total participants 53 (26.6%) controls and 84 (42.4%) controls their current pregnancy were unplanned. Concerning the time of previous ANC follow up, 35 (53.3%) controls and 71 (51.1%) case were attended after 16 weeks. Participants were asked if they know when ANC visit will be started, accordingly, 42 (21. 1%) controls and 116 (58.3%) case replied it should start after 16 weeks (Table 2).
Part II: Determinates of late ANC among pregnant women in Eastern Tigray, North Ethiopia
The current study identified pregnancy status, Time of previous ANC attendance, accompanied by their partner for ANC, time of recognized their pregnancy and provided adequate time for their previous ANC by health professionals were found the determinates of Late ANC follow up. Participants whose pregnancy was unplanned were 4 times more likely attending late (AOR = 4.03, 95% CI 1.56–5.67). Women whose previous first ANC was after 16 weeks were 3.9 times attended late compared to those whose previous ANC was before 16 weeks (AOR = 3.9, 95% CI 1.98–7.68). Pregnant who recognized their pregnancy after the first 3 months were 4.7 times attending late as compared with those who recognized with in the first 2 months (AOR = 4.75, 95%, CI 1.495–9.042). However participants who provided adequate time for their previous ANC visit by health professionals were about 53% attending early compared to those who did not provided adequate time (AOR = 0.461, 95% CI 0.342–0.875) (Table 3).
The current study revealed that women with unplanned pregnancy were 4 times more likely attending late compared to women their pregnancy was planned. Similar finding was shared from studies in Arbaminch and Addis Ababa, Ethiopia [6, 12]. Bayou et al., also reported intention of pregnancy was found as a predictor of late ANC . Another study in South western Ethiopia explained, late attendance of ANC was higher among women with unplanned pregnancy . An evidenced from South Africa and Kenya indicated, unplanned pregnancy was an independent determinant factor for late ANC [10, 15]. This could be due to pregnant women with unplanned pregnancies might miss supports from partner or family, so they might not recognized their pregnancy early. In contrary if they recognized their pregnancy early, they can alert about the disadvantage attending late and they may give more care for their pregnancy themselves and from spouses.
We found women who attended ANC first after 16 weeks for past pregnancy was showed significant determinant for late attending. Similarly, Girmatsion et al. stated women who attended early ANC for past pregnancy were less likely to start late compared to those attended late for the past pregnancy . This might be the fact that women who attended ANC with in the first 4 months for the past pregnancy are expected to have better awareness on the advantage of early ANC visit. In addition, the odds of late ANC among women who did not accompanied by their partner were 1.2 times higher than those who accompanied. Similar report was observed in a study done in Tanzania  and in Ethiopia .
Again the odds of late ANC at first visit were 1.2 times higher among women who gave birth 2–4 children than primigravida. Tolefac et al. reported, the odds of late ANC were high among women who had ≥ 4 children . Manzi et al. and Ochako et al. also share similar finding [15, 18]. The same evidence was also shared from a study done in Bhutan . Ideally, as the size of children increases, the likelihood of attending ANC visit early will be dropped. It might be due to in developing countries especially in Ethiopia mothers are responsible and preoccupied in routing house hold activities and giving care for their kids, so they may get difficult in representing another person who gives care for the kids and the house hold activities. This evidence was confirmed by time constraint with household activity was one of the main reason for late ANC in Ethiopia . In the other hand the current study identified women who recognized their pregnancy at third months or late were attending late than those who recognized their pregnancy before 3 months. This finding was supported by a study done in south eastern Tanzania .
Hence, the study identified women need to have planned pregnancy, they should recognized their pregnancy early and the health providers should give them adequate time. Tigray regional health bureau and the respective health facilities in collaboration with other stake holders should give due emphasis on community awareness in family planning, sign and symptoms of pregnancy.