After giving birth three years ago, I suffered what I now think was undiagnosed postnatal depression. For the first nine months of motherhood my world was black and I struggled to cope with the simplest of challenges. I recovered on my own, with the help and support of my family. Now I'm three months pregnant with my second child and part of me is dreading my baby being born in case the same thing happens again. Can anything be done to prevent a relapse?

Some 1 in 10 mothers are diagnosed with postnatal depression, but according to a recent survey the true number is probably closer to 1 in 2. Previous history of depression is a factor, as well as changing hormone levels - low progesterone following childbirth depletes levels of serotonin, the feel good hormone. Luckily there are measures you can take during pregnancy to lessen the risk, and afterwards if you start feeling low.

Essential fats are depleted during pregnancy and breastfeeding, which negatively affects brain function and mood as well as hormone balance. Boosting these reduces the likelihood of PND, so start taking a good quality fish or flaxseed oil, and eat plenty of nuts, seeds, oily fish and green vegetables. Avoid saturated and hydrogenated fats, which block the uptake of essential fats, and keep sugary foods and stimulants to a minimum as these also disrupt hormone levels.

Low Zinc is also associated with PND, so boost levels during pregnancy by eating plenty of wholegrains and taking a good pregnancy multivit formula. Extra Zinc is often needed after birth, try Biocare's Nutrisorb Zinc drops.

5-HTP can be used to raise serotonin levels and is sometimes recommended after birth; however its safety during breastfeeding has not been established. Instead, eat plenty of foods containing tryptophan, an amino acid the body uses to make serotonin. These include bananas, porridge oats, turkey, cottage cheese, eggs, beans and wholegrains. Tryptophan foods also aid restful sleep, enabling you to cope better.

If you still find yourself feeling low after the birth, homeopathy can really help. A possibility is Sepia, where there is exhaustion and irritability towards loved ones, or Aurum, where there is a feeling of failure or not being the "perfect mum". However I would strongly advise consulting a qualified homeopath as PND needs careful professional support - see the Society of Homeopaths www.homeopathy-soh.org

Stella New RSHom is a registered homeopath and dietary therapist based in West Sussex. Prior to her training she spent many years as an expedition leader, taking groups into some of the most challenging parts of the world, where she was inspired by the use of natural remedies for treating all manner of ailments. Email stella@stellanew.co.uk