4.6.4 Presence of antenatal depression and participant household food security status
The frequency of participants that belong to the lower 50% EPDS category and those who belong to the higher 50% EPDS according to their HFIAS score classification is shown in table 4.21. The majority of participants with a low EPDS score were food secure whilst those at risk for food insecurity or were food insecure had higher EPDS scores. Levene’s test for equality of variances and an independent samples t-test was conducted to compare the EPDS scores to the HFIAS scores. The Levene’s test produced a p-value > 0.05 for HFIAS. It can therefore be concluded that the variances in EPDS scores between the HFIAS scores are equal. The independent samples t- test results however, indicate that there is no significant difference between the EPDS scores and the HFIAS scores (p- value > 0.05).
Table 4.21: EPDS score versus HFIAS
Table 4.22: Infant gender and related birth outcomes
4.7.1 Infant birth weight in relation to socio-demographic characteristics.
Results generated by the Pearson correlation coefficient results showed that there was no correlation between IBW and maternal age (r = -0.06; p = 0.42), relationship status (r = 0.03; p = 0.74), living arrangements (r= -0.026; p = 0.73), first time or not first time pregnancy (r = -0.12; p = 0.09), education (r = -0.106; p = 0.17), education level (r = 0.06; p = 0.46), employment status (r = -0.34; p = 0.08), household income (r = 0.08;
p = 0.29), access to a social grant (r = 0.10; p= 0.19), pre-existing health condition (r = -0.02; p= 0.76), GDM ( r = 0.08; p = 0.29), high blood pressure (r = 0.11; p < 0.16) and anaemia during pregnancy (r = - 0.05; p= 0.51).
The mean weight gain and mean IBW according to the maternal pre-pregnancy BMI classification is presented in table 4.23. The mean weight gain for the participants with an underweight, normal weight, overweight and obese pre-pregnancy BMI shows that overall, the majority of these participants had adequate weight gain throughout pregnancy according to the WHO classification and IOM guidelines for weight gain during pregnancy. The mean IBW for each maternal pre-pregnancy BMI group indicated that the majority of infants had an ideal IBW.
Characteristics of Infants Frequency Percentage (%) Infant Gender
Male 81 47
Female 91 53
Birth weight classification
Normal weight ( ≥ 2.5 kg ≤ 4.0 kg) 148 86
LBW (< 2.5 kg) 8 5
PTB ( <37 weeks < 2.5 kg) 7 4
PTB (normal weight) (< 37 weeks >2.5 kg) 4 2
LGA (> 4.0 kg) 5 3
Table 4.23: Mean weight gained and infant birth weight according to maternal pre- pregnancy BMI
BMI Classification Weight gain range Mean weight gained (±SD)
Mean IBW (± SD) Underweight (<18.5 kg/m2) 9 kg – 28 kg 16.2 ± 8.06 3.01 ± 0.35 Normal weight (18.5 – 24.9 kg/m2) 4 kg – 27.5 kg 12.75 ± 4.45 3.13 ± 0.44 Overweight (25.0 – 29.9 kg/m2) 5 kg – 28 kg 10.83 ± 4.55 3.11 ± 0.71 Obese (≥ 30 (kg/m2) -9 kg – 20.8 kg 8.37 ± 6.03 3.14 ± 0.44
In table 4.24, the frequency and percentage of normal weight, LBW, PTB and LGA infants born to women who had an underweight, normal weight, overweight and obese pre-pregnancy BMI is reported. The table shows that all infants born to women with an underweight pre-pregnancy BMI had infants with a normal birth weight. Equal numbers of LBW infants were born to women with normal and overweight pre- pregnancy BMI. Most LGA infants were seemingly born to women with an overweight pre-pregnancy weight.
Table 4.24: Frequency Birth weight classification vs. maternal pre-pregnancy BMI
Approximately 80% of women with LGA had excessive weight gain during pregnancy.
Seventy-five percent of women with PTB (normal weight) infants had excessive weight gain and 20% of them had inadequate weight gain during pregnancy. Approximately 71% of women with PTB infants had inadequate weight gain, 14% had adequate weight gain whilst another 14% had excessive weight gain. An estimated 25% of women with LBW infants had adequate weight gain, 50% had inadequate weight gain
Birthweight Classification Underweight pre-pregnancy
BMI
Normal weight pre-pregnancy
BMI
Overweight pre-pregnancy
BMI
Obese pre-pregnancy
BMI Normal weight (n = 148) 3% (n = 5) 43% (n = 64) 31% (n = 46) 22% (n = 33)
LBW (n = 8) 0% (n= 0) 38% (n = 3) 38% (n = 3) 25% (n = 2)
PTB (n = 7) 0% (n = 0) 43% (n = 3) 57% (n = 4) 0% (n= 0)
PTB (normal weight) (n = 4) 0% (n = 0) 0% (n = 0) 50% (n = 2 ) 50% (n= 2)
LGA (n = 5) 0% ( n = 0) 0% (n = 0) 80 % (n = 4) 20% (n = 1)
and 25% had excessive weight gain during pregnancy according to the WHO classification and IOM guidelines.
There was no statistically significant association between IBW and maternal pre- pregnancy weight, height, BMI and MUAC (see Table 4.25). There was however a positive correlation between maternal delivery weight and IBW (r =0.17; p = 0.02) as well as a statistically significant positive correlation between the total weight gained during pregnancy and IBW (r = 0.32; p = 0.00).
Table 4.25: Birth weight correlation with maternal anthropometric measurements
Pre-
pregnancy weight
(kg) (N = 172)
Height from clinic (m)
(n = 168)
Height measured
by fieldworkers
(m) ( N = 172)
BMI using clinic height
kg/m2 (n = 168)
BMI using height measured by fieldworkers
kg/m2 (N = 172)
MUAC
(n = 113)
Delivery Weight
(kg)
(N = 172)
Total weight gained
(N = 172)
Birth Weight (kg)
Pearson Correlation
0.013 -0.053 -0.036 0.042 0.039 0.016 .174 .317
p-value 0.878 0.491 0.644 0.593 0.608 0.869 0.023* 0.000**
* P-value < 0.05; **. P-value < 0.01; Pearson Correlation
4.7.2 Infant birth weight and dietary diversity
Table 4.26: Birth weight classification in relation to DDS classification
Birth weight DDS Classification P- value #
Low DDS (n= 14)
Medium DDS (n = 76)
High DDS (n = 82)
Normal weight ( ≥ 2.5 kg ≤ 4.0 kg) 71% (n = 10) 88% (n = 67) 87% (n = 71) NS LBW (≥ 37 weeks, < 2.5 kg) 7% (n = 1) 3% (n = 2) 6% (n = 5) NS PTB ( <37 weeks, < 2.5 kg) 0% (n = 0) 20% (n =4) 4% (n = 3) NS PTB (normal weight) (< 37 weeks, >2.5kg) 7% (n = 1) 5% (n = 1) 2% (n = 2) NS
LGA (> 4.0 kg) 14% (n = 2) 3% (n = 2) 2% (n = 2) NS
#Chi-square; p < 0.05 considered significant; NS = non-significant
Table 4.26 presents the relationship between birth weight classification and DDS classification. Participants with high DDS had the largest number of LBW infants and those with a medium DDS had the most PTB infants. Participants with medium and high DDS had an equal number of LGA infants. The Chi-square test showed that there was no significant association between the IBW and DDS scores. A Pearson correlation coefficient between the two variables was computed to analyse the relationship between dietary diversity and IBW. This rendered a weak negative correlation (r = -0.16; p = 0.04) with the correlation being significant at the p-value <
0.05 level.
4.7.3 Infant birth weight and household food security
The relationship between birth weight and HFIAS scores is represented in table 4.27.
The table indicates that the same percentage of participants with both low and high HFIAS scores had normal birth weight infants. Low birth weight infants were born to mostly women with higher HFIAS scores.
Table 4.27: Birth weight classification in relation to HFIAS classification
Birth weight HFIAS P- value #
Lower 50%
(n = 96)
Higher 50%
(n = 76)
Normal weight ( ≥ 2.5 kg ≤ 4.0 kg) 86% (n = 83) 86%(n = 65) NS
LBW (≥ 37 weeks, < 2.5 kg) 2% (n = 2) 8% (n = 6) NS
PTB ( <37 weeks, < 2.5 kg) 4% (n = 4) 4% (n = 3) NS
PTB (normal weight) (< 37 weeks, >2.5 kg) 3% (n = 3) 1% (n = 1) NS
LGA (> 4.0 kg) 4% (n = 4) 1% (n = 1) NS
# Chi-square test; p < 0.05 considered significant; NS = non-significant
The association between IBW and HFIAS was tested by performing a Pearson correlation coefficient. There was no correlation between the two variables (r = -0.07;
p = 0.39). A scatter plot summarises the results (Figure 4.5).
Figure 4.5 Correlation between infant birth weight and HFIAS
4.7.4 Infant birth weight and presence of possible antenatal depression
Table 4.28 shows the birth weight classification in relation to EPDS scores. The table indicates that the majority of participants with normal birth weight infants, LBW, PTB, PTB (normal weight) and LGA had lower EPDS scores. The majority of those with higher EPDS scores had normal birth weight infants, equal number of LBW and fewer PTB, normal weight PTB and LGA when compared to participants with lower EPDS scores.
Table 4.28: Birth weight classification in relation to EPDS score category
# Chi-square test; p < 0.05 considered significant; NS = Non significant 0
1 2 3 4 5 6 7
0 5 10 15 20 25 30
Birth weight
HFIAS Score
Infant birth weight versus HFIAS Score
Birth weight EPDS P- value #
Lower 50%
(n = 116)
Higher 50%
(n = 56)
Normal weight ( ≥ 2.5 kg ≤ 4.0 kg) 85% (n = 99) 86% (n = 49) NS
LBW (≥ 37 weeks, < 2.5 kg) 3% (n = 4) 7% (n = 4) NS
PTB ( <37 weeks, < 2.5 kg) 5% (n = 6) 2% (n = 1) NS
PTB (normal weight) (< 37 weeks, >2.5 kg) 3% (n = 3) 2% (n = 1) NS
LGA (> 4.0 kg) 3% (n = 4) 2% (n = 1) NS
A Pearson correlation coefficient was performed to analyse the relationship between IBW and EPDS. The results showed that there was no correlation between IBW and EPDS scores (r = 0.01; p= 0.95). Figure 4.6 summarises the results of the association between the variables.
Figure 4.6: Correlation between infant birth weight and EPDS.