Table 3.
Description of study population by HIV status
| HIV-positive | HIV-negative | p valueh | |||
|---|---|---|---|---|---|
| Social-demographic factors | n | No (%) | n | No (%) | |
| Mother's age in yearsa | 662 | 25 (21-29) | 217 | 23 (19-28) | 0.003 |
| More than 7 yrs (primary school) education | 647 | 369 (57.0) | 213 | 133 (62.44) | 0.28 |
| Married | 665 | 116 (17.4) | 218 | 42 (19.3) | 0.54 |
| Household income (ZAR/month) a | 553 | 700 (400-1200) | 172 | 910 (640-1600) | < 0.0001 |
| Socio-economic scorea,c | 640 | -0.298 (-1.6-1.4) | 213 | 0.273 (-1.6-1.97) | 0.08 |
| Ever disclosed HIV status | 665 | 275 (41.4) | 218 | 9 (4.1) | < 0.0001 |
| Discussed infant feeding with someone other than health staff | 648 | 186 (28.7) | 216 | 71 (32.9) | 0.25 |
| Knew about MTCT in general | 528 | 419 (79.4) | 197 | 159 (80.7) | 0.69 |
| Knew about MTCT though breastfeeding | 661 | 454 (68.7) | 215 | 158 (73.5) | 0.18 |
| Site | 665 | 218 | |||
| Paarl | 149 (22.4) | 51 (23.4) | |||
| Rietvlei | 191 (28.7) | 74 (33.9) | |||
| Umlazi | 325 (48.9) | 93 (42.7) | |||
| Health system factors | |||||
| Counseling scorea,d, h | 663 | 24 (9-28) | 215 | 0 (-4-0) | |
| Medical factors | |||||
| Log viral load b,e | 553 | 3.75 (0.7) | |||
| No. ANC visits a | 655 | 5 (3-8) | 213 | 5 (3-7) | |
| Pregnancy complicationsf | 665 | 211 (31.7) | 218 | 68 (31.2) | 0.88 |
| Post-partum complicationsg | 665 | 145 (21.8) | 218 | 33 (15.1) | 0.03 |
| Type of delivery | 658 | 218 | 0.60 | ||
| Vaginal | 455 (69.2) | 149 (68.4) | |||
| Elective C/S | 73 (11.1) | 23 (10.6) | |||
| Emergency C/S | 130 (19.8) | 46 (21.1) | |||
| Infant factors | |||||
| Nevirapine to baby | 609 | 596 (97.9) | |||
| Baby's birth weight (g) | 651 | 3016 (547) | 211 | 3088 (527) | 0.15 |
| Infant feeding | |||||
| Feeding intention antenatally | 653 | 210 | < 0.0001 | ||
| Exclusive formula feeding | 309 (47.3) | 19 (9.0) | |||
| Exclusive breastfeeding | 313 (47.9) | 142 (67.6) | |||
| Mixed breastfeeding | 28 (4.3) | 49 (23.3) | |||
a: median (Q1-Q3) One ZAR = approx 14US cents b: mean and standard deviation
c. Socioeconomic score (SES) - estimated using principal component factor analysis using six household assets (refrigerator, radio, television, stove, telephone/cell phone, car) and questions about food security. A weighted average was produced - items with greater variability (e.g. television) contributed to more score than items with lesser variability (e.g. radio). High socioeconomic score denotes people with more assets and food security
d. Counseling score - a composite measure of reported antenatal infant feeding counseling. For HIV-positive women: was ever discussed antenatally? (+4 if yes, -4 if no and 0 if don't know), number of times discussed (0 -none, 1 - once only, 2 - twice, 3-3 times and 4 if > 3 times) and whether the following topics were mentioned: risks of MTCT and breastfeeding (+4 if yes), different formula feeding and breastfeeding options (+4 if yes), risk of giving formula feeds (+4 if yes),, how to make best feeding choice (+4 if yes), if the mother intended to breastfeed, then avoiding mixed feeding and stopping breastfeeding early (+4 for each), how women were helped to make a choice - if women were helped to make an appropriate choice (score = +12); if health staff recommended a suitable option (score = +8); if little/no help or guidance provided with choice (score = +4). If health staff simply told women to breastfeed, score = -4. Thus maximum score was +44 and minimum was -8. For HIV-negative women the scores were as follows: if the counsellor reportedly discussed the risks of giving formula feeds (+4), advised against mixed feeding (+4), discussed the risks of MTCT (-4), discussed different formula feeding options (-4), advised the mother to stop breastfeeding by 6 months (-4) and discussed feeding options, helping the mother to make a choice (-4). Thus the maximum score was +8 and minimum was -16
e: Maternal HIV viral determined using finger-prick dried blood spots on Guthrie cards collected during the 3 and 36 week home visit. Mean maternal viral load was computed when both 3 and 36 week maternal viral load were available; otherwise maternal viral load was determined using whichever of the two was available. In cases where a mother recorded as being HIV-positive had no detectable viral load, a repeat laboratory enzyme-linked immunosorbent assay was carried out [Uniform 2 HIV-1 Assay (bioMe'rieux) followed by Biorad HIV-1 Assay (Hercules, California, USA)]
f. Pregnancy complication as documented in the antenatal card, including any of the following: anaemia, hypertension, eclampsia, sexually transmitted infection, vaginal bleed, pre-term labour, amniocentesis, TB, diarrhea, pneumonia, thrush, skin lesions, fever, excessive weight loss or gain, abnormal pap smear, fever of unknown origin, any other infection
g. Postpartum complication in hospital (endometritis, fever, post-partum haemorrhage, eclampsia, sepsis, mastitis)
h. p-Value only reported if comparison between HIV and positive women is sensible e.g. the counseling score is made up of different elements for HIV-positive versus negative women and thus no p-value is reported