Emma Robbins from Bristol gave birth to four boys by caesarean section within six minutes of each other earlier this week.
Zachary, Rueben, Joshua and Samuel were all born on Wednesday, 29 February, at St Michael's maternity hospital and are all believed to be doing well.
The babies range in weight from 2lb 8oz to 3lb 1oz and two are identical twins.
All four were conceived naturally, which a consultant said is ‘exceedingly rare’.
They were born after 29 weeks and one day of pregnancy.
Emma has set up a blog called Emma’s Quad Diary
to document her experiences.
Her husband, Martin, wrote a post yesterday (Thursday) breaking the news of the birth.
It says: ‘They are all healthy and happy and doing really well.
‘Rueben and Zachary have been given a few doses of Surfactant to help their lungs cope being with being born premature, which makes breathing easier and prevents the lungs from collapsing.
‘They have also been on mechanical ventilation to avoid respiratory distress and maintain oxygen levels and air pressure which they will be weaned off within 48 hours after birth.
‘Otherwise the hospital is really happy with their condition and we have been told to expect them to be in care for 6/8 weeks. They are so small yet so perfect!’