Abstract Body

Neural tube defects (NTDs) are one of the most common congenital malformations affecting births worldwide. The estimated NTD prevalence in Africa is 12 per 10,000 live births [95% confidence interval (CI) 5-75]; but data are limited. The impact of antiretroviral therapy (ART) during pregnancy on the risk for birth defects is unknown; therefore, ongoing surveillance is needed for pharmacovigilance.

A hospital-based surveillance program was established at four hospitals in Kampala, Uganda to provide estimates of the baseline prevalence of selected birth defects and assess potential associations with HIV status and ART use. All live births and stillbirths, regardless of gestational age, were included. Data were collected from hospital records, maternal interviews, photographs, and narrative descriptions of birth defects (BD). Births were examined by trained midwives and confirmed by a BD specialist. Prevalence (Wilson 95% CI) and adjusted odds ratio (AOR) estimates for potential risk factors of NTDs using logistic regression with site as an effect modifier are reported for births from August 2015-December 2017.

A total of 69,767 births were included in surveillance. Median maternal age was 26 years (IQR=22-30), 51.3% had their first antenatal visit after the first trimester, 9.6% (6,725/69,767) were HIV-infected with 95.2% (6,399/6,725) on ART. The majority of HIV-infected women were on an efavirenz-based ART (80%), 16% on nevirapine-based ART and 4% received other ART regimens. Overall, 62 births were affected with NTDs, giving a prevalence of 8.9 (6.8-11.4) per 10,000 live births. Spina bifida (n=34) was the most common type of NTD with prevalence (95%CI) of 4.9 (3.4-6.8) per 10,000 live births, followed by anencephaly (n=16) with 2.3 (1.3-3.7) and encephalocele (n=12) with 1.7 (0.9-3.0). There was no significant difference in NTD prevalence (95%CI) among HIV-infected [5.9 (0.1-11.8)] and HIV un-infected women [9.2 (6.8-11.6)]; AOR 0.75 (95% CI:0.2-2.2), p= 0.61. NTDs were not significantly associated with maternal age, HIV status, ART, or parity. Anencephaly was more common among females compared to males with site as an effect modifier [AOR of 5.9 (95%CI:1.9-17.9), p=0.002].

NTDs are a common congenital malformation affecting births in Kampala. These findings are similar to the current estimates for Africa. ART was not associated with an increased risk for NTDs. With the introduction of new ART regimens during pregnancy, ongoing BD surveillance is critical.