Postnatal depression (PND), also known as postpartum depression, is the most common psychiatric pregnancy complication and manifests as a serious long-term mood disorder that interferes with familial relationships, sleep, appetite, emotional regulation and newborn bonding. Historically, post-birth changes resulted in PND being labelled as ‘baby blues’ and women’s concerns being dismissed. This is a separate condition that causes a mild low mood in 50-80% of new mothers, that is often resolved a week after birth and seldom sustained over a fortnight.
Symptoms can include excessive and compulsive thoughts, crying, mood swings, difficulty concentrating, memory problems, doubt, dread, guilt and melancholy, although this is not an exhaustive list A key misconception is that PND leads to wanting to harm the infant, when in fact this is very rare. It is much more likely that individuals with PND will overprotect or avoid the child and desire to harm themselves, in their minds to keep the baby safe.
(PND can occur in men but is not the focus of this blog since they would not have the associated post-birth hormonal changes. It is acknowledged that individuals who do not identify as female can give birth, but their hormonal changes may be different, with little research available, and so this blog may only be partially applicable to them.)
The widely advertised statistic is 10-15% of mothers experience PND, but this has been found to be largely underestimated in recent years, with numbers rising. When self-report measures have been used, PND ranged from 4% in Japan to 64% in America. It has been suggested that this lack of openness is due to fear of being stigmatised as a ‘bad mum’ or minimising symptoms to healthcare professionals. Most women diagnosed with PND, have no prior history of depression or mental health concerns, but it is estimated only 25% of those with moderate to severe PND seek treatment.
Throughout pregnancy and postnatally, there are fluctuating levels of various hormones that causes imbalance inside the body. The following changes should subside after two months, but in those with PND these are more severe and often prolonged.
Within four hours of giving birth, two hormones: oestrogen and progesterone, drastically decline within the body after being at record high levels and create a vulnerable time frame. Specifically, oestrogen decrease means the body no longer has its natural biological defence against depression. Proteins become ineffective since the number of sites that can receive information is reduced and cannot synchronise with gene expression. This can trigger changes in how DNA molecules are built throughout the body. Lack of progesterone leads to certain signalling networks becoming uncontrolled as progesterone stops unneeded signals. Ultimately, causing an imbalance in multiple brain areas of overactivity and failure to maintain emotional stability. As a potential exacerbating factor, the ovaries do not resume progesterone production until the first period after childbirth.
Breastfeeding had been shown to aid adaptation with lower levels of oestrogen, by releasing serotonin and oxytocin (known as the happy hormones) as a stress response, which alleviates depression symptoms. However, if breastfeeding is not an option physically or psychologically, this prevents the natural protective defences against PND and additionally, the depleted serotonin causes temperature and sleep disruption. Oxytocin and PND create a paradox. Oxytocin reduces volumes of maternal brain structures to ‘fine tune’ and create connections that assist adaptability and emotional regulation. For this to occur, oxytocin levels must increase through mother-child interactions. But if suffering from PND, parental bonding may be impossible and therefore oxytocin resilience to aid PND recovery cannot happen.
During pregnancy, the body becomes immunosuppressed through adaptations in tissue, cells and molecules. The foetus can then grow without being identified as a foreign material and the hormonal shifts after birth reactivate the immune system. The immune system can overcompensate, alongside increased cortisol and prolactin levels and can aggravate autoimmune conditions or complications. This can result in inflammation which dysregulates the pathways that transport serotonin and dopamine further. Central brain regions become imbalanced with these cells under intensifying stress, which dampens their ability to strengthen or regrow. This creates vulnerability to PND, especially if external factors are also present.
In addition, the thyroid gland has high demand during breastfeeding but if too many thyroid hormones are released, this can facilitate panic disorder and PND symptoms.
Having multiple risk factors is not a definitive predictor of PND but does increase the susceptibility of an individual during the postnatal period. These comprise of antenatal depression or anxiety, unplanned pregnancy, low self-esteem, gender preference, low socioeconomic background, poor familial ties, teenage pregnancy, intimate partner violence, chronic illness and breastfeeding difficulties.
Oestradiol and allopregnanolone are steroid hormones derived from oestrogen and progesterone respectively. These modulate the same networks that the original hormones would, thereby resuming balance of underactive and overactive brain regions to aid in heightening mood state and emotional regulation. If thyroid dysfunction is prolonged, iodine can be taken to compensate for increased demand of thyroid hormone required for breastfeeding.
Antidepressants, with the most common when postnatal including Fluoxetine, Citalopram and Venlafaxine, can be prescribed. However, for medical professionals, the optimum hormonal treatments are those which aid PND recovery whilst not causing harm to the infant. These can also be of benefit over typical antidepressants for mothers, who may feel overly guilty indirectly passing negative side effects. The first specifically PND hormonal therapy drug approved in America (2019) was Brexanolone. This is used to correct the underlying sensitivity to hormones rather than just flattening hormonal responses and is given in an IV as a protective measure. Whilst not currently available on the NHS, if continued positive results are seen then funding could be sought. This has sparked conversations that postnatal care needs to be treated at an individual level based on brain hormone sensitivity rather than one standard treatment pathway.
There are also a number of options for alternative treatments that can be used in conjunction with others or standalone. Incorporating bright light therapy, electroconvulsive therapy, acupuncture, exercise, talking therapies and nutritional support.
Whilst PND is not treated specifically at Smart TMS, the depression and anxiety symptoms can be addressed. This provides a great alternative to antidepressants or other medication that could impact breastfeeding. This could be utilised in tandem with hormonal supplemental treatments to address biological and psychological aspects of PND, hopefully becoming successful in restoring balance between the overactive and underactive brain regions.
Written by Georgie, Smart TMS Southampton practitioner
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