This was a 30 year old lady who came for a scan around 20 weeks of gestation. She had already undergone a scan about 4 weeks ago when she was told to have twins.

At present the scan showed mono chorionic and di amniotic twin pregnancy .The sac on the left side was filled with turbid amniotic fluid .

turbid amniotic fluid seen in the sac on the left side

2 d view of the heads seen below

normal head on the rt side of screen and abnormal “frog eyed appearance of anencephaly on the left side

fetus A with normal cranial vault

fetus B with absent cranial vault

3 d images of anencephalus

4 d image of anencephalus

sagittal view of normal fetal head 3 d view

anencephalus fetus on the left side and the normal fetus on the right side

management strategy

Dichorionic twins discordant for anencephaly are best managed with serial ultrasound examinations for early diagnosis of polyhydramnios, which can then be treated either by amniodrainage or selective feticide.

In monochorionic twins it is uncertain whether the best management is expectant or by cord occlusion.and expectant management is probably more favoured.