DUTY OF CARE AND THE FORESEEABILTY TEST OF A PREGENANT MOTHER.

The duty of care in tort tends to wonder whether a duty of care was owned to a child damaged by anothers negeligence before its birth..
In Burton v Islington Health Authority,it was held that a duty is owned to the unborn child ,but that duty does not crystallise until the live birth of the child.Also The 1976 Congential Disabilities (civil liability ) Act 1976 went futher to stress  that law applies in respect of children born with disiabilty ;and disability is defined in terms of any deformity,diseae or abnormaliy including predispostion (whether or notsusceptible of immediate prognosis)to physical or mental defect in the future.

The intresting thing about the Act and the case law in relation to the matter in issue,is that the mothers are expressely immuned from the general liability attached to the law.Majority of the mother smokes or drinks during pregenancy inspite of the health implications to the unborn baby.This run contray to the law of holding a woman liable to damages to her child inflicted by her negligent driving of a motor vechicle when she knows or ought to know herself to be pregnant.
I stand to be corrected ,does it also not run contray to the foreseability test  which creat a duty of care?