Extreme Gestational Discordance in Twins: A Probable Case of Superfoetation in a Resource Limited Setting

Abstract

Background:
Superfoetation, defined as the fertilization of a second ovum and subsequent implantation of its conceptus during an ongoing pregnancy, is an exceedingly rare and controversial phenomenon in humans. Diagnostic challenges are particularly pronounced in resource-limited settings where access to early obstetric ultrasound and advanced investigations is limited.

Case presentation: 
A case of naturally conceived preterm twins delivered at 34 weeks gestation to a 28-year-old multiparous mother with severe pre-eclampsia. Marked anthropometric and gestational age discordance was observed; The male twin weighed 1600 g and a female twin 650 g and their gestational ages by clinical assessment using the New Ballard Score were respectively 35 and 27.2 weeks suggesting a difference in estimated gestational age of approximately eight weeks. The larger twin had a favourable clinical course, while the smaller twin developed complications of extreme prematurity and died on day 5 of life. Alternative explanations, including twin-to-twin transfusion syndrome and isolated intrauterine growth restriction, were considered unlikely.

Conclusion:
The case suggests the clinical plausibility of superfoetation and emphasizes the importance of careful clinical evaluation in resource-limited settings. Improved awareness and diagnostic capacity are needed to better characterize and understand this rare phenomenon.