The mothers of baby boys are more prone to postnatal depression than those who give birth to girls, a study has found.
University of Kent research into postnatal depression (PND) found the odds of developing this condition increased by 71 to 79 per cent in the mothers of male babies.
And women whose births had complications were 174 per cent more likely to experience PND compared with those women who had no complications.
Dr Sarah Johns and Dr Sarah Myers in the University’s School of Anthropology and Conservation hope their findings will help health professionals to identify and support women who may be more likely to develop this condition.
Their research also found that while women with a tendency towards depression, anxiety and stress were always at increased risk of PND, they had reduced odds of developing it after experiencing birth complications.
This is because these women receive greater post-birth support due to their known mental health concerns.
It means greater support can prevent PND from developing.
Watch below: Everything you need to know about postnatal depression
Dr Johns said: "PND is a condition that is avoidable, and it has been shown that giving women at risk extra help and support can make it less likely to develop.
"The finding that having a baby boy or a difficult birth increases a woman's risk gives health practitioners two new and easy ways to identify women who would particularly benefit from additional support in the first few weeks and months."
What is postnatal depression?
The NHS says PND is a type of depression that can start at any point in the first year after giving birth and can develop suddenly or gradually.
Many women feel a bit down, tearful or anxious in the first week after giving birth.
This is often called the 'baby blues' and is so common that it’s considered normal. But this doesn't last for more than two weeks after giving birth.
If your symptoms last longer or start later, you could have postnatal depression.
The main symptoms include:
a persistent feeling of sadness and low mood
loss of interest in the world around you and no longer enjoying things that used to give you pleasure
lack of energy and feeling tired all the time
trouble sleeping at night and feeling sleepy during the day
feeling that you're unable to look after your baby
problems concentrating and making decisions
loss of appetite or an increased appetite (comfort eating)
feeling agitated, irritable or very apathetic (you "can't be bothered")
feelings of guilt, hopelessness and self-blame
difficulty bonding with your baby with a feeling of indifference and no sense of enjoyment in his or her company
frightening thoughts – for example, about hurting your baby; these can be scary, but they're very rarely acted upon
thinking about suicide and self-harm
The NHS says that if you think you may be depressed, talk to your GP or health visitor as soon as possible so you can access the support you need.
Don't struggle on alone and hope the problem will go away. It can continue for months or years if not addressed.
Fathers and partners can also become depressed after the birth of a baby. You should seek help if this is affecting you.
For more on treatment of postnatal depression, click here
So why is the birth of baby boys linked to postnatal depression?
Dr Johns and Dr Myers say there is a known link between inflammatory immune response and the development of depressive symptoms.
And the gestation of male foetuses and the experience of birth complications are both associated with increased inflammation.
The new study indicates this inflammation can go on to trigger postnatal depression.
Depression is increasingly accepted as a "neuroprogressive and inflammatory process", reports ScienceDirect .
It's thought that immune inflammatory responses are at the root of depression, which is supported by the fact that most antidepressants have anti-inflammatory effects.
So inflammation is thought to come before the emotional distress of depression, rather than be caused by it.
There are suggestions that depression is an evolutionary adaptation to help prevent and fight infection.