Infant feeding practices at routine PMTCT sites, South Africa: Results of a prospective observational study amongst HIV exposed and unexposed infants – birth to 9 months

Background: We sought to investigate infant feeding practices amongst HIV-positive and -negative mothers (0-9 months postpartum) and describe the association between infant feeding practices and HIV-free survival.Methods: Infant feeding data from a prospective observational cohort study conducted at three (of 18) purposively-selected routine South African PMTCT sites, 2002-2003, were analysed. Infant feeding data (previous 4 days) were gathered during home visits at 3, 5, 7, 9, 12, 16, 20, 24, 28, 32 and 36 weeks postpartum. Four feeding groups were of interest, namely exclusive breastfeeding, mixed breastfeeding, exclusive formula feeding and mixed formula feeding. Cox proportional hazards models were fitted to investigate associations between feeding practices (0-12 weeks) and infant HIV-free survival.Results: Six hundred and sixty five HIV-positive and 218 HIV-negative women were recruited antenatally and followed-up until 36 weeks postpartum. Amongst mothers who breastfed between 3 weeks and 6 months postpartum, significantly more HIV-positive mothers practiced exclusive breastfeeding compared with HIV-negative: at 3 weeks 130 (42%) versus 33 (17%) (p < 0.01); this dropped to 17 (11%) versus 1 (0.7%) by four months postpartum. Amongst mothers practicing mixed breastfeeding between 3 weeks and 6 months postpartum, significantly more HIV-negative mothers used commercially available breast milk substitutes (p < 0.02) and use of these peaked between 9 and 12 weeks. The probability of postnatal HIV or death was lowest amongst infants living in the best resourced site who avoided breastfeeding, and highest amongst infants living in the rural site who stopped breastfeeding early (mean and standard deviations: 10.7% ± 3% versus 46% ± 11%).Conclusions: Although feeding practices were poor amongst HIV-positive and -negative mothers, HIV-positive mothers undertake safer infant feeding practices, possibly due to counseling provided through the routine PMTCT programme. The data on differences in infant outcome by feeding practice and site validate the WHO 2009 recommendations that site differences should guide feeding practices amongst HIV-positive mothers. Strong interventions are needed to promote exclusive breastfeeding (to 6 months) with continued breastfeeding thereafter amongst HIV-negative motherswho are still the majority of mothers even in high HIV prevalence setting like South Africa. © 2012 Goga et al; licensee BioMed Central Ltd. Data are from a prospective observational cohort study (September 2002-August 2003) conducted to determine the operational effectiveness of the Routine National South African PMTCT programme. Three sites were purposively selected [24]: Paarl, a well-resourced commercial farming area with 11% antenatal HIV prevalence, infant mortality rate (IMR) at 40 per 1000 live births; Rietvlei, a poverty-stricken deep rural area with 26% antenatal HIV prevalence, IMR 99/1000 and Umlazi, a peri-urban area with 36% antenatal HIV prevalence, IMR 60/1000 [25,26]. The 2002-2003 routine PMTCT programme included single-dose nevirapine, delayed rupture of membranes and infant feeding counselling. In Paarl, five lay counsellors received eight hours of in-service training on HIV and infant feeding; in Umlazi and Rietvlei nurses and lay counsellors were trained in a standardised five-day PMTCT and infant feeding training course[13]. In Umlazi one of the three lay counsellorsspecialised in infant feeding. For HIV-positive women post-test counselling and post-natal PMTCT visits included infant feeding counselling. Non-breastfeeding HIV-positive women received free commercial infant formula from routine health services for six months. HIV-negative women received infant feeding counselling during post-test counselling sessions, and were scheduled to receive infant feeding support postpartum from routine child health services. Quality of PMTCT and infant feeding counselling was poorest in Paarl, and best in Umlazi [13]. Highly active antiretroviral treatment was not national policy in 2002-3. Maternal HIV status was determined by the routine PMTCT programme [24]. Consecutive HIV- positive and -negative pregnant women were enrolled (3:1) and followed up until 36 weeks postpartum. Trained data collectors conducted home interviews at recruitment, 3, 5, 7, 9, 12, 16, 20, 24, 28, 32 and 36 weeks. The recruitment interview gathered data on socio-demographics, perceived quality of antenatal feeding counselling, feeding intention and knowledge of PMTCT. From 3 to 36 weeks, data collectors asked whether the infant received any of 15 food and liquid items 'yesterday' (from sunrise yesterday until sunrise today) and for 3 days prior to 'yesterday'. During the 3 week interview, data on feeding during the first postnatal week were gathered. At 3, 24 and 36 weeks check questions asked whether infants had 'ever breastfed'. Data collectors did not counsel about feeding or PMTCT. No diaries were used to remind mothers about infant feeding practices. Table ​Table22 explains how we operationalized the World Health Organization feeding definitions. Socioeconomic score (SES) was 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. Counseling score was a composite measure created from reported antenatal infant feeding counseling. For HIV-positive women: was feeding 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. Operationalising the WHO feeding definitions during data analysis Pregnancy complication was defined using information documented in the antenatal card. It included 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. Postpartum complication was defined using information documented in the hospital medical record included endometritis, fever, post-partum haemorrhage, eclampsia, sepsis and mastitis. Data were entered into MS ACCESS using double data entry at a central site (MRC Durban). After validation, databases were exported to SAS version 9.1 (SAS Institute Inc., Cary NC, USA) for data management and analysis. HIV-positive and -negative women were compared using χ2 tests for categorical variables (Fisher exact test if expected cell count < 5) and t-tests or Wilcoxon rank sum tests for normally and non-normally distributed continuous variables respectively. We identified whether an infant was "ever" or "never" breastfed. Table ​Table22 explains the cross-sectional and longitudinal feeding variables generated during analysis. The proportion of HIV-positive women practicing EBF was calculated of those HIV-positive women who reported any breastfeeding, while for HIV-negative women the denominator was all negative women. To examine associations between feeding variables and infant HIV-free survival we fitted Cox proportional hazards models, using the midpoint between the last negative and first positive test as the time of infection and Efron's method for adjusting for tied survival times. We excluded HIV-positive infants at 3 weeks as early transmission is not dependent on feeding. We verified that the proportionality of hazards assumption holds. Sample size was too small in each feeding group to do analysis that explained the differences in feeding practices between HIV-positive and -negative women. To compare with the South African Demographic and Health Survey we also looked at cumulative assessment of repeated measures of feeding at birth, 3, 5, 7, 9 and 12-16 weeks to obtain proportion ever breastfed, exclusively breastfed (0-12 weeks) and not breastfed (0-16 weeks). For cross sectional analysis on the association between feeding variables and HIV-free survival feeding practices at 5 weeks were chosen, on the assumption that by 5 weeks feeding practices would have stablised. Nelson R Mandela Medical School Research Ethics Committee approved the cohort study protocol (20 November 2002, Ref: E095/02). The Institutional Review Board, Columbia University granted approval for this analysis. All participating women had signed consent forms.