Neural tube defect diagnosis and outcomes at a tertiary South African hospital with intensive case ascertainment (original) (raw)
South African Medical Journal
Neural tube defects (NTDs) include anencephaly, encephalocele and spina bifida (SB). Anencephaly is a lethal condition, whereas encephalocele and SB, which may cause long-term disability, are a considerable burden to families and the healthcare system, [1,2] and are relatively common birth defects. In South Africa (SA), studies give estimated population prevalence rates of 0.99-3.8 per 1 000 live-born infants. [3-6] Folic acid supplementation in the peri-conceptional period [7] or fortification of staple foods [8] has been shown to reduce the prevalence of NTDs. In SA, the introduction of folic acid fortification of maize and wheat products in 2003 was associated with a 31% reduction in NTD prevalence at sentinel sites, from 1.41 to 0.98/1 000 births. [9] Another preventive option is prenatal diagnosis by ultrasound, with the choice of termination of pregnancy (TOP), which has become increasingly available in parts of SA. Despite these changes, there are minimal data on NTD prevalence after 2003. Effective surveillance of NTDs and other birth defects is important for various reasons, e.g. to establish burden of disease, monitor trends in birth prevalence, assess impact of preventive measures and detect outbreaks. The last role is highlighted by the recent link between maternal Zika virus infection and microcephaly in offspring, [10] and the possible link between maternal use of the antiretroviral drug dolutegravir and NTDs. [11] The National Department of Health (NDoH) has a populationbased birth defect surveillance system, which appears to be ineffective. [12] Hospital-based surveillance is an easier alternative, but less optimal because of lack of a defined denominator. It therefore works best where it captures most of the population of interest in a geographical region. [13] We anticipated this to be largely true in Western Cape Province, SA, for NTDs, or at least for SB, given that both prenatal diagnosis and paediatric management are centralised at tertiary hospitals with defined catchment areas. Furthermore, most NTDs are readily visible at birth. We therefore aimed to assess the detection of NTDs at a tertiary hospital using a range of prenatal, perinatal and postnatal data sources, and to estimate the impact of prenatal diagnosis and birth prevalence for the referral area. Methods The study was conducted at Tygerberg Academic Hospital (TAH), a tertiary public hospital in the Western Cape. It is a referral centre for This open-access article is distributed under Creative Commons licence CC-BY-NC 4.0.