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Susan, a 27-year-old single mother, had an unplanned pregnancy. She was worried about how she would cope with another baby. She had recently left her partner because of domestic abuse. Six weeks after her baby was born, she started to feel low, was unable to get to sleep and lost her appetite. She had less interest in her children and found everything a struggle. She felt guilty that she did not love her baby. She considered taking an overdose but did not want to harm herself because there was nobody else to look after her children.
Her health visitor asked her how she was feeling, but she was scared to tell her – she thought it would show she was a bad mother and that her children would be taken away. When she took her baby to her general practitioner (GP), she burst into tears and told the GP how she felt. The GP referred her to a psychologist and her health visitor invited her to a support group for mothers with postnatal depression. She found this really helpful and gradually recovered.
Postnatal depression (PND) is an illness that affects 10–15% of women who have a baby. It often starts 1–2 months after birth, but can begin several months later. For a third of women with postnatal depression, their symptoms start in pregnancy.
Some women feel ashamed or guilty about feeling depressed when everyone expects them to be happy about having a baby. PND is nobody's fault. It can happen to anyone. Having a baby is one of the biggest life changes women experience and can be stressful. Women often feel under pressure to live up to their own or others’ expectations.
There are many causes of PND; previous mental illness, lack of support, previous abuse, domestic abuse, stressful life events (e.g. relationships ending) and physical illness (e.g. underactive thyroid) can all contribute. Many different mental health problems can affect women in pregnancy and after birth, not just PND. It is important to get the diagnosis right so that the right treatment can be obtained.
We analyzed the long-term evolution of two active regions (ARs), NOAA 7978 and 8100, from their emergence through their decay using observations from several instruments on board SoHO (MDI, EIT and LASCO) and Yohkoh/SXT. We computed the evolution of the relative coronal magnetic helicity from one central meridian passage to the next, combining data from MDI and SXT with linear force-free models of the coronal magnetic field. Next, we calculated the injection of helicity by photospheric differential rotation using MDI magnetic maps and a mean differential rotation profile. To estimate the depletion of magnetic helicity we counted all the CMEs of which these ARs were the source, and we evaluated their helicity assuming a one to one correspondence with magnetic clouds (MCs) with an average helicity content; this value was computed for a sample of 18 clouds using a cylindrical linear force-free model. Out of our three helicity estimates (variation of coronal magnetic helicity, injection by differential rotation and ejection via CMEs) the one with the largest uncertainty is the amount of helicity ejected via CMEs. However, we determined, by modeling a particular MC using three different approaches in cylindrical geometry (two force-free models and a non force-free model with constant current), that its magnetic helicity content was nearly independent of the model used to fit in situ field observations (Dasso et al. 2003, in preparation). This result justifies our use of the average magnetic helicity value considering only a single MC model. Comparing the three components in the helicity balance (see Table 1), we find that photospheric differential rotation is a minor contributor to the AR magnetic helicity budget. CMEs carry away at least 10 times more helicity than the one differential rotation can provide. Therefore, the magnetic helicity flux needed in the global balance should come from localized photospheric motions that, at least partially, reflect the emergence of twisted flux tubes. Taking into account the magnetic flux in the ARs and the number of turns that a uniformly twisted flux tube should have to survive its rise through the convection zone, we have found that the total helicity carried away in CMEs is approximately equal to the end-to-end helicity of the flux tubes that formed these two ARs. Therefore, we conclude that most of the helicity ejected in CMEs is generated below the photosphere and emerges with the magnetic flux. Extended versions of this work were published in Demoulin et al. (2002, Astronomy & Astrophys. 382, 650) and in Green et al. (2002, Solar Phys. 208, 43), while in Mandrini et al. (2003, Astrophys. & Space Sci., 290, 319) and van Driel-Gesztelyi et al. (2003, Adv. Space Res., 32, 1855) the helicity computations were revised to include the underestimation of magnetic flux density found in MDI data. After this revision, we confirmed our former results.