This is one of the first studies of IVH in LBW neonates in a LIC in sub-Saharan Africa and the first in east Africa. We found that more than a third of neonates born weighing ≤2000g had any IVH and 15% had high grade IVH. The majority of IVH had occurred by day 7. Vaginal delivery, GA <32 weeks, resuscitation in the NU and being SGA (<10th centile) increased the odds of having IVH.
Our findings show a higher prevalence of IVH than two studies from Nigeria, but are comparable to one study from Zambia. This prospective study of neonates weighing <1500g found an IVH prevalence of 34.2%, comparable to our finding of 38.7% (10). Neonates were only scanned up to day 7 however, and our study showed 9.8% of IVH occurred after day 7. In contrast, the studies from Nigeria, both of neonates <1500g found lower rates of IVH. One found a 24.1% prevalence of IVH, however each infant was only scanned once within the first week (range 60 hours to 7 days)(9). The second found 29.7% had IVH, 7.5% of which were high grade(12). This is likely to be an underestimation as many eligible neonates were not scanned as they died within 72 hours of birth. No studies in LICs in sub-Saharan Africa have examined IVH in neonates weighing 1500-2000g. Our data showing that in this subgroup almost one in three have IVH and one in 10 have high grade IVH are therefore the first in this area.
On analysis by gestation, in neonates of 28-31 weeks GA we found rates of IVH of 31.6%, comparable with findings from another Nigerian study of 33.3%(11). However, in the 32-42 week GA group we found much higher rates (34.2% vs 6.3%). Of note, this study had much lower rates of SGA neonates than ours (21.8% vs 42.5%) which may contribute to this difference, although the relationship of SGA with IVH varies between studies(28,29).
Overall and in all subgroups for any IVH and high grade IVH, our rates are higher than in HICs. The difference is smallest in the <1500g and <28 week gestation groups and largest in neonates of >1500g or >37 weeks, suggesting in our setting the higher weight and GA neonates may benefit most from modification of risk factors(13,14,16,18,30).
Our results show that 34% of all IVH had occurred on day 1, 58.5% by day 3 and 90.2% by day 7. In the Zambian study, 68.7% of IVH had occurred by 72 hours of age, however as they only scanned up to day 7 this may be an overestimation of the total proportion(10). Evidence from HICs shows that approximately 50% of IVHs occur in the first 24 hours after birth and almost all by 72 hours(31). This could be due to different aetiologies for IVH in our settings, with more influence from postnatal risk factors due to the standard of neonatal care available.
Our results show that neonates with GA of <32 weeks had increased odds of having both mild and severe IVH, in keeping with other studies from HICs and LICs(9–11,13,20,32). Birthweight was not shown to be associated with IVH, which is contrary to most findings from HICs but in keeping with some studies in Africa(5,11,12,19). This lack of association of weight with IVH is possibly due to the high prevalence of SGA neonates (42.5%) giving a higher GA than expected for birthweight, thus comparatively reducing risk of IVH.
Vaginal delivery was associated with increased odds of IVH compared with Caesarean delivery. It was not shown to be associated with low grade IVH, however the sample was too small to determine the relationship with high grade IVH. Whilst vaginal delivery is a recognised risk factor for high grade IVH in HICs, this finding has not been replicated in studies from LICs in sub-Saharan Africa(9–11,33,34). This may be related to the timing and indications for Caesarean differing.
Resuscitation in the NU was associated with an increased probability of any IVH and high grade IVH. Resuscitation at birth is a risk factor for IVH however this was not demonstrated in our results(35). This is likely due to poor documentation and limited accessibility of adequate neonatal resuscitation. We found that the prevalence cPVL (2.4%) was comparable with expected rates from HICs; there are no comparable data currently available from LICs in Africa(36).
We found that SGA neonates had increased odds of low grade IVH, however this finding should be interpreted with caution. Comparable studies in LICs in sub-Saharan Africa found no association with SGA and IVH, and in HICs the relationship of SGA with IVH varies between studies(11,12,28,29). Whilst our study had both a larger sample size and much higher rates of SGA than other African studies which may explain why we identified an association, this finding is not supported by any relationship with high grade IVH (11,12). Low grade IVH can be difficult to detect using cUS, so it is possible that some were missed in these studies(37). Many risk factors for SGA are present in our population, including maternal malnutrition, infections and PET and their prevalence and relationship with IVH in this setting is an area of future interest(38).
Whilst no relationship between exposure to 1 or 2 doses of antenatal steroids and IVH was shown possibly due to the small sample, of the 6 neonates who received 2 doses of antenatal steroids, none had IVH. Interestingly, this group had few additional risk factors for IVH (see Supplementary Table 3). Antenatal corticosteroids are protective against IVH in HICs, however current evidence suggests that in LICs antenatal steroids can increase the risk of neonatal death(14,39,40). Although it is possible that the low rates of steroid exposure in our study (only 47%) may have contributed to the high rates of IVH, further data on the impact of antenatal steroids on IVH and other preterm complications are needed; use of antenatal steroids in this setting remains controversial and needs further exploration.
We did not find IVH to be an independent predictor of survival. There is little evidence on survival after IVH in LICs, but in this cohort there was a much lower mortality in neonates with IVH than in a Nigerian study (41.7% vs 66.7%)(9). This is likely due to the relatively high standard of care at our centre(22).
Over a quarter of neonates in the study died by day 28, the large majority before discharge. Of neonates ≤2000g who had IVH, a third died, compared with a quarter of those who did not, a difference not found to be statistically significant. Of the neonates that died, more than three quarters weighed <1500g and of neonates weighing <1500g, just under half died, findings which are in keeping with data from a meta-analysis of neonatal mortality in East Africa(41).
Strengths of this study included that the cUS were performed by well-trained investigators and that image analysis was undertaken prospectively and independently by 2 blinded, experienced, senior clinicians. Outcomes are known for a high proportion of participants (115/120, 95.8%) and 71/81 (87.7%) babies alive at day 28 underwent a day 28 cUS.
Limitations include challenges with reliable capture of obstetric and perinatal data. Additionally, 26 neonates died very early before recruitment, to which IVH could have contributed, therefore the occurrence, particularly of severe IVH may be underestimated. This could also cause an underestimation in the mortality associated with IVH. Furthermore, 10/81 surviving neonates (12.3%) were unable to attend for day 28 scans so it is possible that some findings such as cPVL were underestimated. Due to the date of women’s last menstrual period being rarely known, assessment of GA was by Ballard scoring which is accurate to +/- 2 weeks and has inter user variability. The assessment of haemodynamic significant of PDA was made using only LA/Aortic root diameter as measurement of other parameters of haemodynamic significance were not available, therefore it is possible that may have been underestimated in some neonates due to offloading of the LA through a patent foramen ovale. Assessing potential risk factors for IVH was a secondary analysis and therefore the sample size may have been too small to determine relationships for some risk factors. Additionally, clinical data was collected retrospectively from the medical notes.