Shortening days during third trimester of pregnancy may add to risk of postpartum depression
September 27, 2018
Women in late pregnancy during darker months of the year may have a greater risk of developing postpartum depression once their babies are born. This is consistent with what is known about the relationship between exposure to natural light and depression among adults in the general population.
Although reduced exposure to natural light has been associated with depression among adults in the general population, there is not yet a consensus about whether light exposure or seasonality influences the development of depression during and after pregnancy.
In this study, Goyal and her colleagues at the University of California San Francisco analysed available information from 293 women who participated in one of two randomized controlled clinical trials about sleep before and after pregnancy. The participants were all first-time mothers from the US state of California. Data included the amount of daylight during the final trimester of their pregnancy, along with information about known risk factors such as a history of depression, the woman's age, her socioeconomic status and how much she slept.
Overall, the participants had a 30 per cent risk of depression. The analysis suggested that the number of daylight hours a woman was exposed to during her final month of pregnancy and just after birth had a major influence on the likelihood that she developed depressive symptoms.
The lowest risk for depression (26 per cent) occurred among women whose final trimester coincided with seasons with longer daylight hours. Depression scores were highest (35 per cent) among women whose final trimester coincided with "short" days and the symptoms continued to be more severe following the birth of their babies in this group of women. In the northern hemisphere, this timeframe refers to the months of August to the first four days of November (late summer to early autumn).
"Among first-time mothers, the length of day in the third trimester, specifically day lengths that are shortening compared to day lengths that are short, long or lengthening, were associated with concurrent depressive symptom severity," Goyal explains.
The findings suggest that using light treatment in the late third trimester when seasonal day length is shortening could minimize postpartum depressive symptoms in high-risk mothers during the first three months of their children's lives. Goyal says that women with a history of mental health problems and those who are already experiencing depressive symptoms in the third trimester might further benefit from being outdoors when possible, or using devices such as light boxes that provide light therapy.
"Women should be encouraged to get frequent exposure to daylight throughout their pregnancies to enhance their vitamin D levels and to suppress the hormone melatonin," adds Goyal, who says that clinicians should also advise their patients to get more exercise outdoors when weather and safety permit. "Daily walks during daylight hours may be more effective in improving mood than walking inside a shopping mall or using a treadmill in a gym. Likewise, early morning or late evening walks may be relaxing but would be less effective in increasing vitamin D exposure or suppressing melatonin."
Fish-rich diets in pregnancy may boost babies' brain development
September 20, 2018
Women could enhance the development of their unborn child's eyesight and brain function by regularly eating fatty fish during pregnancy. This is the suggestion from a small-scale study. The research supports previous findings that show how important a prospective mother's diet and lifestyle choices are for the development of her baby.
According to Laitinen, a mother's diet during pregnancy and breastfeeding is the main way that valuable long-chain polyunsaturated fatty acids become available to a fetus and infant brain during the period of maximum brain growth during the first years of a child's life. Such fatty acids help to shape the nerve cells that are relevant to eyesight and particularly the retina. They are also important in forming the synapses that are vital in the transport of messages between neurons in the nervous system.
In this study, Laitinen and her colleagues analysed the results of 56 mothers and their children drawn from a larger study. The mothers had to keep a regular food diary during the course of their pregnancy. Fluctuations in their weight before and during pregnancy were taken into account, along with their blood sugar level and blood pressure. Aspects such as whether they smoked or developed diabetes related to pregnancy were also noted.
The team recorded the levels of nutritional long-chain polyunsaturated fatty acid sources in the mother's diet and blood serum, and the levels in the blood of their children by the age of one month. Their children were further tested around their second birthday using pattern reversal visual evoked potentials (pVEP). This sensitive and accurate, non-invasive method is used to detect visual functioning and maturational changes occurring within a young child's visual system.
The subsequent analyses of the visual test results revealed that infants whose mothers ate fish three or more times a week during the last trimester of their pregnancy fared better than those whose mothers ate no fish or only up to two portions per week. These observations were further substantiated when the serum phospholipid fatty acid status was evaluated.
"The results of our study suggest that frequent fish consumption by pregnant women is of benefit for their unborn child's development. This may be attributable to long-chain polyunsaturated fatty acids within fish, but also due to other nutrients like vitamin D and E, which are also important for development," explains Laitinen.
"Our study therefore highlights the potential importance of subtle changes in the diet of healthy women with uncompromised pregnancies, beyond prematurity or nutritional deficiencies, in regulating infantile neurodevelopment," adds Laitinen, who believes that their results should be incorporated into counselling given to pregnant women about their diets.