So your baby was a gorgeous, pink little bundle, perfect in every way - and then, a few days in, they did something rather strange and turned yellow. It's a condition very common among newborns called jaundice.
What is it?
Jaundice occurs when the blood contains excess levels of bilirubin (a chemical produced in the body as old red blood cells break down) and it causes a noticeable yellowing of the skin and eyes.
Many little babies are affected by it (in fact, more than 50% will develop it within a few days of being born) because they have high amounts of oxygen-laden red blood cells, and also because their immature livers are less able to break down the bilirubin as it is produced.
Premature babies are more likely to get jaundice and may take a little longer to get over it, but for most newborns, a bout of jaundice will be over within around a week or 10 days.
The most obvious symptom of jaundice is a yellowing of the skin which will start at the head and face and move down to the chest and back, and possibly on to the limbs. If you are unsure whether your baby has it, try applying a little pressure to the skin on their forehead and then letting go - if you see a yellow tinge just before the blood flows back to the area you pressed, then jaundice is present.
In babies with dark skin, jaundice will be easier to detect by examining the eyes, and also possibly the palms of the hands and soles of the feet. One other giveaway sign is pale coloured poo.
Although jaundice looks rather strange it is, in the vast majority of cases, no major cause for concern and it should have gone completely by the time your baby is two weeks old.
What can I do?
Babies tend to develop jaundice a few days after birth and so you will probably still be seeing your midwife or health visitor by the time you notice. Mention it, and ask them to check your baby, or otherwise go to your GP.
In many cases, the advice is to feed frequently and to allow your baby to lie in an area of bright daylight (note, this does not mean in direct sunshine) because ultra violet light helps the body to break down bilirubin.
If your baby's jaundice is more severe, you might need to take them back to hospital (possibly the special care baby unit) for some phototherapy treatment. They may be placed into a cot or incubator with an ultra violet bulb. Although it looks strange to see your baby like this, swathed in purple light, rest assured they will be extremely warm and comfortable in there! And the treatment can be stopped every few hours for feeding.
Some babies, particularly premature ones, might be given fibre optic therapy, where they are wrapped in a special blanket that shines UV light directly on to the skin. If the doctor suspects your baby has very high levels of bilirubin, they might need to do a blood test and, in severe cases, will suggest a transfusion to rid your baby's body of the excess bilirubin. That scenario is rare, however, and the majority of cases can be treated at home or with a short hospital stay.
What else could it be?
While most jaundice cases are nothing to worry about, there are some instances which would require urgent attention. If your baby shows signs of jaundice within 24 hours of birth, contact a doctor straight away. If jaundice appears more than seven days after birth, if it is still present after two weeks, or if your baby's poo is chalky white, contact a GP immediately, as these things may signify a more serious underlying problem with your baby's liver.
The NHS website has more details.