There were 555 women in their post-partum period that were screened and all questionnaires were filled using structured interview until the sample was accumulated. The participants were from 6 districts of Southern province of Rwanda and from 12 health facilities. The participants were distributed with respect to age, education level, employment status, social economic status. The mean age was 27.35 (SD = 5.2) ranging from 18 to 35 years. Most participants (n = 338, 60.9%) were in the age range of 26–35 years, 47.6% had primary education, 38.7%, had secondary education, 7% had tertiary education and 6.7% had no formal education. The majority of the study participants, (n = 513, 92.4%) are from rural setting, 63.2% are farmers and 55.5% are in category 3 of “Ubudehe”/ social economic status as categorized in Rwanda national categories. Table 1
Table 1
Demographic characteristics of participants
Variables | Frequency (n) | Percent (%) |
Age category | 16–25 | 217 | 39.1 |
26–35 | 338 | 60.9 |
Education level | No formal education | 37 | 6.7 |
Primary | 264 | 47.6 |
Secondary | 215 | 38.7 |
Tertiary | 39 | 7 |
Residence | Urban | 42 | 7.6 |
Rural | 513 | 92.4 |
| Farmers | 351 | 63.2 |
Employment status | Employed | 71 | 12.8 |
| Students | 32 | 5.8 |
| Not employed | 101 | 18.2 |
| Category 1 | 56 | 10.1 |
Economic status | Category 2 | 191 | 34.4 |
| Category 3 | 308 | 55.5 |
Factors associated with preterm low birth weight among pregnant women attending antenatal care clinics
To assess if there is a relationship between women who had periodontal diseases and those who had health gingiva in relation to preterm low birth weight, in our sample we had 370 women with normal gestation and normal birth weight babies (controls). On another group we had 185 (cases) women who had given birth prematurely and with low birth weight babies. Among the women with normal gestational age and normal weight babies, 229 (61.8%) had healthy periodontium while 141(38%) had periodontitis. On the other hand, among women with preterm low birth weight, 31 (16.7%) had healthy periodontium and 154 (83.2%) had periodontitis, chi-square test revealed that periodontal disease is significantly associated with preterm and low birth weight (x2 = 100.902, p < 0.001). There was also a significant association between preterm low birth weight and mothers’ weight where by mothers with less weight were found to be with high chances of having periodontitis compared to those with normal weight (x2 = 29.198, p < 0.001), Last pregnancy was also found to be significantly associated with preterm low birth weight where by the mothers who got pregnant before 24 months after delivery were found to be with high risk of preterm low birth weight compared to those who got pregnancy 24 months and above after previous delivery (x2 = 19.474, p < 0.001), Women who had experienced premature deliveries before had higher chances of preterm low birth weight (x2 = 47.989, < 0.001), stress during pregnancy was also found to be associated with preterm low birth weight, where by the mothers who reported stress during pregnancy had high risk of preterm low birth weight compared to those who reported no stress (x2 = 15.711, p < 0.001), some illnesses during pregnancy were also associated with preterm low birth weight like Malaria (x2 = 5.686, p = 0.021), Urinary tract infection (x2 = 5.382, p = 0.020). On the other hand, violence during pregnancy was also found to be significantly associated with preterm low birth weight (x2 = 20.321, p = < 0.001). Age, education level and residence are not associated with preterm low birth weight (x2 0.639, p = 0,2), (x2 5.862, p = 0.1), (x2 1.855, p = 0.2) respectively. Chi-square test revealed association between tobacco and preterm low birth weight. Women who had ever used tobacco had high chances of having preterm low birth weight compared to those who had never used tobacco (x2 = 4.630, p < 0.04). Table 2 (Placed at the end of the text)
Table 2
Variables | Sub-variables | Control/ Normal | Case/ PTLBW | X2 | P-value |
Age category | 17–25 | 149 | 68 | 0.639 | 0.2 |
26–35 | 221 | 117 |
Education level | No formal | 23 | 14 | 5.864 | 0.1 |
Primary | 168 | 96 |
Secondary | 147 | 68 |
Tertiary | 32 | 7 |
Residence | Urban | 32 | 10 | 1.855 | 0.2 |
Rural | 338 | 175 |
Employment status | Farmers | 221 | 130 | 7.635 | 0.054 |
Employed | 56 | 15 |
Students | 23 | 9 |
Not employed | 70 | 31 |
Socio-Economic status | Category 1 | 38 | 18 | 0.401 | 0.8 |
Category 2 | 124 | 67 |
Category 3 | 208 | 100 |
Ever used tobacco | No | 368 | 180 | 4.63 | 0.04 |
Yes | 2 | 5 |
Recorded periodontal case | Healthy | 229 | 31 | 100.902 | 0.001 |
Periodontitis | 141 | 154 |
Mother’s weight | 30–50 | 20 | 37 | 29.198 | < 0.001 |
51–75 | 332 | 143 |
76 & above | 18 | 5 |
Last pregnancy | 12–24 Months | 52 | 55 | 19.474 | < 0.001 |
Above 24 Months | 318 | 130 |
ANC Visits | No visits | 0 | 1 | 5.015 | 0.08 |
1–4 Visits | 364 | 184 |
5–8 Visits | 6 | 0 |
Malaria during pregnancy | Yes | 78 | 56 | 5.686 | 0.021 |
No | 292 | 129 |
UTI during pregnancy | Yes | 32 | 28 | 5.382 | 0.02 |
No | 338 | 157 |
RTI during pregnancy | Yes | 5 | 6 | 2.272 | 0.193 |
No | 365 | 179 |
Other illnesses during pregnancy | Yes | 6 | 5 | 0.742 | 0.519 |
No | 364 | 180 |
Previous premature delivery | Yes | 3 | 28 | 47.989 | < 0.001 |
No | 367 | 157 |
Stress during pregnancy | Yes | 57 | 55 | 15.711 | < 0.001 |
No | 313 | 130 |
Physical trauma | Yes | 12 | 10 | 1.515 | 0.25 |
No | 358 | 175 |
Violence | Yes | 19 | 31 | 20.321 | < 0.001 |
No | 351 | 154 |
Other causes of stress | Yes | 36 | 30 | 4.953 | 0.026 |
No | 334 | 155 |
During bivariate analysis using chi square test, 11 variables namely; employment status, ever used tobacco, periodontitis, mothers’ weight, last pregnancy, malaria during pregnancy, urinary tract infection during pregnancy, experienced premature delivery before, experienced stress during pregnancy and violence during pregnancy were associated with Preterm low birth weight therefore, eligible for multivariate logistic regression. Multivariate regression analysis was done and the variables were hierarchically grouped into three groups: where by demographic variable of employment status was put first in the regression model as step 1 and followed by other potential factors of ever used tobacco, mothers’ weight, last pregnancy, whether experienced premature delivery before, where experiences stress before, Malaria during pregnancy, urinary tract infection during pregnancy, physical trauma during pregnancy and violence during pregnancy. On the third step of regression model, the researcher put periodontal diseases as it was hypothesized as predictor variable.
Employment status and ever used tobacco lost their significance after controlling for other variables (p = 0.4, 95% CI 0.3, 1.2), (P = 0.2, 95% CI 0.5,15.8) respectively but some other variables remained significant. After building the regression model, the results were as follows; the logistic regression revealed that mothers’ weight was still significant after controlling for other variables, mothers with less weight had higher chances of giving birth to preterm and low birth weight babies compared to mother with normal weight where by the odds of giving birth to preterm low birth weight baby was 6 times for underweight compared to those with normal weight mothers (p = 0.002) (95% CI 1 1.5, 27.9). Also the results from logistic regression revealed that women with history of giving birth to premature babies before, had higher chances of preterm low birth weight babies where by the odds of preterm low birth weight when you had ever experienced premature delivery was 14 times higher compared to those who had no history of premature deliveries (p < 0.001) (95% CI 3.4, 45.9). It was also found out that women who had experienced violence during pregnancy had 6 times the odds of having preterm low birth weight compared to those who did not experience any violence during pregnancy (p = 0.007) (95% CI 1.6, 20.0). Also interval between pregnancies was found to be associated with preterm low birth weight where by women who got pregnancy before 24 months after last delivery had 2 times odds of having preterm low birth weight compared to women who got pregnant 24 months above after previous delivery (p < 0.008) (95% CI 1.2, 3.6). Finally, logistic regression revealed strong association between periodontitis and preterm low birth weight where by women who had periodontitis had 6 times the odds of giving birth to preterm low birth weight babies compared to women who had no periodontitis (p < 0.001) (95% CI 3.9, 10.4). Table 3
Table 3
Multivariate analysis of Preterm low birth weight and associated factors
Variables | Categories | Wald | p-value | Odds | 95% C.I |
Employment status | Farmers | 2.9 | 0.403 | | |
Employed | 1.6 | 0.203 | 0.7 | 0.3–1.2 |
Students | 1.9 | 0.169 | 0.6 | 0.2–1.3 |
Not employed | 1.5 | 0.218 | 0.5 | 0.1–1.6 |
Ever used tobacco? | No | | | | |
Yes | 1.4 | 0.233 | 2.8 | 0.5–15.8 |
Mothers’ weight | 30–50 | 12.9 | 0.002 | | |
51–75 | 6.3 | 0.012 | 6.4 | 1.5–27.9 |
76 & above | 1 | 0.299 | 2 | 0.5–7.7 |
Had Malaria | Yes | 2.8 | 0.096 | 1.5 | 0.9–2.5 |
No | | | | |
Had UTI | Yes | 1.2 | 0.271 | 1.4 | 0.8–2.8 |
No | | | | |
Had RTI | Yes | 0.4 | 0.522 | 1.6 | 0.3–6.3 |
No | | | | |
Other illnesses | Yes | 0.09 | 0.761 | 0.7 | 0.1-5.0 |
No | | | | |
Previous premature delivery | Yes | 14.3 | < 0.001 | 12.4 | 3.4–45.9 |
No | | | | |
Stress during pregnancy | Yes | 0.1 | 0.723 | 0.8 | 0.2-3.0 |
No | | | | |
Physical trauma | Yes | 0.9 | 0.332 | 0.5 | 0.1–1.9 |
No | | | | |
Violence | Yes | 7.2 | 0.007 | 5.6 | 1.6–20.0 |
No | | | | |
Other causes of stress | Yes | 0.5 | 0.457 | 1.6 | 0.4–6.2 |
No | | | | |
Last pregnancy | 12–24 Months | 7 | 0.008 | 2.1 | 1.2–3.6 |
Above months | | | | |
Periodontitis | Yes | 58.3 | < 0.001 | 6.5 | 3.9–10.4 |
No | | | | |