The original british criminal law (from the 1860's) that existed before the passage of the referendum remained in force until 2013.

While the referendum was intended to copper fastened the pre existing criminal law in some ways it was more restrictive.

The State acknowledges the right to life of the unborn and, with due regard to the equal right to life of the mother, guarantees in its laws to respect, and, as far as practicable, by its laws to defend and vindicate that right.

Recognising the right to life of the unborn and placing it as being equivalent to the mother and then placing a positive duty on the state to defend and vindicate as far as practicable that right has knock on effects.

Like for example on maternal consent (or ability to consent/refuse consent) to treatment in pregnancy and labour. Or on the ability of doctors to induce women earlier than term in cases of maternal ill health or where the unborn would not survive birth.

Some of those questions weren't raised or considered before hand, some such as care of women facing diagnosis of a fatal fetal abnormality didn't arise as prenatal diagnosis was not possible.

It didn't make an immediate practical effect but over time more and more issues, unintended effects arose.