The below information was taken from The Royal College of Psychiatrists. You can visit their website here
Postpartum (puerperal) psychosis
This is the most severe type of mental illness that happens after having a baby. It affects around 1 in 1000 women and starts within days or weeks of childbirth. It can develop in a few hours and can be life-threatening, so needs urgent treatment.
There are many symptoms that may occur. Your mood may be high or low and there are often rapid mood swings. Women often experience psychotic symptoms. They may believe things that are not true (delusions) or see or hear things that are not there (hallucinations).
This illness always needs medical help and support. You may have to go into hospital. Ideally, this should be to a specialist mother and baby unit where your baby can go with you.
Women who have had previous episodes of severe mental illness, particularly bipolar disorder, are at a high risk of postpartum psychosis. Women, who have had a severe episode of illness following a previous delivery, are also at very high risk. Let your doctor or midwife know about this. You can discuss with them ways to increase the chances of you staying well.
Although puerperal psychosis is a serious condition, the vast majority of women make a full recovery.
Other mental health problems after childbirth
You may have had a mental illness before pregnancy. Your symptoms may get worse or return after your baby is born. Just as at other times, women can experience many types of mental health problems. If you are worried about any type of mental illness, discuss this with your GP. They can make sure you get the help and support you need.