The married woman's "Stamp", NI contributions stopped in 1977. Think some employers were aware of the changes, I had a "brief" marriage in the 70's and was told it wasn't advisable.
If you had or have Child Benefit you can: apply for credits missing from your National Insurance record. However, now it only applies until the child is 12 year old.
I have a friend who didn't work for years bringing up her children, she had big gaps between her 3, she gets the full pension, as her "family allowance" contributions counted.