Normal and healthy newborns tend to wake for feedings every couple of hours and most babies don't begin sleeping through the night until they're at least three months old . This in itself means that most new mothers — who nearly always find themselves the primary carer during the night, especially if they are also breastfeeding — end up getting less sleep than they really need during the postpartum period.
Being sleep deprived during this time of immense existential transition places new mothers in a vulnerable position. Some get sucked into a chicken-or-egg like situation: sleeplessness is strongly associated with depression, and depression is in turn associated with sleeplessness. "Am I depressed because I can't sleep, or can't I sleep because I'm depressed?", would be an apt question to ask. The same holds true for mothers who find themselves excessively sleepy during the day after staying up all night. Determining whether the sleepiness is caused by depression, or the other way round, is no easy task.
Detangling The Web: Do You Have Postpartum Insomnia?
While insomnia is commonly understood to refer to a condition in which the sufferer finds it exceedingly difficult to fall asleep or remain asleep , the National Sleep Foundation adds the qualifier "even when a person has the chance to do so" . Using this definition, a new mother who has trouble falling and staying asleep because her baby keeps waking her up is not suffering from insomnia, but rather from baby-induced sleep deprivation.
Should you find it difficult to sleep even when your baby is not keeping you up, however, you may be dealing with true chronic insomnia — which is indeed one of the signs of postpartum depression , along with excessive sleeping, which we will look at later.
The other signs of postpartum depression are:
- A depressed mood — feeling low, lost, sad, moody, numb, hopeless.
- Persistent feelings of worthlessness and guilt.
- Loss of interest and pleasure in activities you previously found meaningful.
- Appetite changes and accompanying weight fluctuations.
- Fatigue and low energy.
- An inability to concentrate.
- Thoughts about death and dying, with or without active suicidal plans and/or thoughts about harming your baby.
Since it is estimated that around 60 percent of new mothers suffer from insomnia at eight weeks postpartum  while a lower rate of between 10 and 20 percent of mothers will suffer from postpartum depression , it is important to look at the entire clinical picture of postpartum depression before assuming you have found the cause of your problem.
Hypersomnia: The Other Side Of The Postpartum Sleep Disturbances Coin
Hypersomnia  is the opposite of insomnia — a condition in which a person find themselves excessively sleepy during the day, or in fact sleeping too much.
Given the fact that new mothers' sleep is frequently disturbed during the night and many new mothers are not able to get the seven to eight hours of sleep that is considered healthy, it is hardly surprising that one study found that 81 percent of mothers experience some degree of postpartum sleepiness, with 10 percent of mothers falling into the pathological sleepiness range .
So, Do I Have Postpartum Depression?
Mothers who can't sleep at night will suffer from sleep deprivation, causing them to suffer from fatigue and low energy in the day time, which could in turn lead to excessive sleeping while they have the chance. While both insomnia and hypersomnia are indeed possible postpartum depression signs, they are not in themselves enough to conclude that you are suffering from depression.
Sleep deprivation itself leads to many of the symptoms associated with postpartum depression, including a lack of concentration and a depressed mood, with its associated symptoms of sadness, hopelessness, numbness, and feeling like crying all the time.  Paying off your "sleep debt" may make you feel so much better that you no longer wonder whether you could be suffering from postpartum depression.
If, on the other hand, your sleep disturbances merely form part of a greater whole, and you recognize some of the other symptoms of postpartum depression as well — particularly if you feel that you are not bonding with your baby, have suicidal thoughts, thoughts of harming your baby, or feel completely unable to look after yourself or your baby — it is time to seek help.
Should you indeed have postpartum depression, research shows that psychotherapy, particularly cognitive behavioral therapy, is the best treatment. Where necessary, this can be combined with antidepressant medication, which you will be advised to continue to use between six to 12 months to optimize your odds of a full recovery.