Mothers who give birth to boys are almost twice as likely to suffer from postnatal depression، a study has found، daily mail reported.
Their risk of being diagnosed with the common mental health condition is up to 79 per cent higher if they have a son.
But the trigger is not disappointment at having a son – it is far more scientific، the researchers say.
The University of Kent team claim having a son increases levels of inflammation in the immune system of mothers، which is thought to change chemical balances in the brain.
The same research also found women who have complications during their child's birth are nearly three times more likely to get postnatal depression (PND).
PND is common and affects as many as one in every 10 women after they give birth، causing feelings of sadness، tiredness and difficulty bonding.
The new study quizzed 296 mothers to discover those with sons or who experienced complications are more likely to suffer from PND.
However، the risk of PND after complications among women with existing mental health problems is lower – potentially because they are already receiving help.
'PND is a condition that is avoidable،' said lead researcher Dr Sarah Johns.
'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.'
Dr Johns's study found PND risk increases by between 71 and 79 per cent in women giving birth to boys، and by 174 per cent among women with complications.
The scientists suggest the rises for these two groups may be down to inflammation – swelling of internal tissues caused by increased blood flow and an influx of white blood cells – in the body.
Growing a baby boy or having complications during a birth – such as the baby being in the wrong position، or labour failing to progress normally – both increase inflammation.
And scientific evidence has linked inflammation to depressive symptoms because it can change chemical balances in the brain.
The research was published in the journal of Social Science and Medicine.
WHAT IS POSTNATAL DEPRESSION? Postnatal depression is a form of the mental-health condition that affects more than one in 10 women in the UK and US within a year of giving birth.
As many men can be affected as women، research suggests.
Many parents feel down، teary and anxious within the first two weeks of having a child، which is often called the 'baby blues'.
But if symptoms start later or last longer، they may be suffering from postnatal depression.
Postnatal depression is just as serious as others form of the mental-health disorder.
Persistent sadness Lack of enjoyment or interest in the wider world Fatigue Insomnia Struggling to bond with your baby Withdrawing from others Difficulty concentrating and making decisions Frightening thoughts، such as hurting your baby Sufferers should not wait for their symptoms to just go away.
Instead they should recognise that it is not their fault they are depressed and it does not make them a bad parent.
If you or your partner may be suffering، talk to your GP or health visitor.
Treatments can include self-help، such as talking to loved ones، resting when you can and making time to do things you enjoy. Therapy may also be prescribed.
In severe cases where other options have not helped، antidepressants may be recommended. Doctors will prescribe ones that are safe to take while breastfeeding.
Postnatal depression's cause is unclear، however، it is more common in those with a history of mental-health problems.
Lack of support from loved ones، a poor relationship with the partner and a life-changing event، such as bereavement، can also raise the risk.