Mother nature: A pregnant Brooke Shields.

Pregnancy has long been assumed to be a time of expectant joy, at least for women whose pregnancies are planned and who look forward to motherhood. And indeed, it is a happy time for most. But not all. A significant minority ? 10 to 20 per cent, depending on who is counting ? suffer moderate to severe depression during pregnancy. All too often the problem goes unrecognised by the women and their doctors.

Some depression symptoms ? fatigue, change in appetite and lack of energy ? overlap normal signs of pregnancy, prompting some women to ignore them. Others are embarrassed to mention their depressed feelings to their doctors since they’re supposed to be thrilled to be pregnant.

But even when pregnancy-related depression is recognised and acknowledged, women and their doctors can find themselves in a dilemma. After decades of warnings to avoid all manner of drugs, alcohol, nicotine and caffeine, pregnant women are often reluctant to take anti-depressants even if their doctors will prescribe them.

New studies examining possible effects of anti-depressants on the foetus as well as the risks involved in failing to treat depression during pregnancy are likely to make decisions even harder. The decision to treat or not to treat must involve a careful assessment of known risks and benefits based on the best medical information available.

A depressed woman is more likely to be delinquent about prenatal care. She may miss doctor appointments, eat and sleep poorly, fail to take vitamins, have difficulty forming a healthy attachment to her unborn child, and experience stress that can expose the foetus to harmful levels of hormones and neuro-transmitters. To alleviate depressed feelings, some women may turn to alcohol or cigarettes, which themselves can harm an unborn child.

Untreated depression during pregnancy has been linked to higher rates of miscarriage, stillbirths, premature deliveries, intra-uterine growth restriction and low-birth-weight babies. Though they often catch up early in life, babies born smaller than they should be for their gestational age face higher than average rates of high blood pressure and heart disease as adults.

The untreated depression can also damage a woman’s relationship with her spouse and other children. The inability of a depressed person to cope well with stresses, however small, can result in undue irritability and impatience.

Finally, depression is unlikely to end once the baby is born. As Dr. Shaila Kulkarni Misri noted in her recent book, Pregnancy Blues, “If depression goes untreated during pregnancy, it will worsen and more than likely continue postpartum.”

Postpartum depression not only robs a woman of the joy of having a new baby, it can seriously impair her ability to nurse and care for the infant, and it prompts some women to harm the baby.

A woman taking antidepressants before becoming pregnant may assume that the safest course is to stop the medication until the baby is born or after she stops nursing. But a study published in The Journal of the American Medical Association found that such an interruption greatly increased the chance that major depression would recur during the pregnancy.

Stress in mothers is risky for foetuses.

Even stopping treatment only for the first 12 weeks, when the baby’s organs are forming, increased the chance of a relapse, the researchers, headed by Dr. Lee S. Cohen, perinatal psychiatrist at Massachusetts General Hospital, found.

An earlier study by the University of Pittsburgh found that about one per cent of babies exposed to antidepressants in the last third of pregnancy developed serious respiratory problems.

Misri emphasises that pregnancy, “far from being protective against psychiatric illness, as many continue to believe, can actually trigger depression for the first time, exacerbate an already existing condition, or cause the relapse of a depression that had previously been under control.”

She calls pregnancy-related depression “an equal-opportunity illness” that can strike any woman, rich or poor, socially well-connected or isolated, previously healthy or suffering from years of recurrent depressions. Two new studies have raised questions about the safety of leading anti-depressants during pregnancy, the selective serotonin reuptake inhibitors, or SSRI’s, likr Prozac and Zoloft.