[1] Univ KwaZulu Natal, Fac Hlth Sci, Dept Obstet & Gynaecol, Subdept Fetal Med, Durban, South Africa
[2] Univ Witwatersrand, Fac Hlth Sci, Dept Obstet & Gynaecol, Johannesburg, South Africa
[3] Univ Pretoria, Dept Obstet & Gynaecol, Fac Hlth Sci, Pretoria, South Africa
[4] Univ Witwatersrand, Fac Hlth Sci, Dept Obstet & Gynaecol, Div Fetal Med, Johannesburg, South Africa
[5] Stellenbosch Univ, Div Fetal Med, Dept Obstet & Gynaecol, Cape Town, South Africa
[6] Univ Pretoria, Dept Paediat Neurol, Fac Hlth Sci, Pretoria, South Africa