Researchers studied 441 pregnant women in China who were overweight or had obesity before getting pregnant. They found that about one-third of these women experienced depression during their last three months of pregnancy. The good news? Things like eating healthy foods, exercising regularly, getting good sleep, and learning about health can help protect against depression. The study suggests that making lifestyle changes early in pregnancy might help prevent depression in women who start pregnancy at a higher weight.

The Quick Take

  • What they studied: Whether pregnant women who were overweight or obese before pregnancy experience more depression in their final three months, and what lifestyle habits might help or hurt their mental health.
  • Who participated: 441 pregnant women in their third trimester (last three months) from two large hospitals in Guangdong, China. Most (93%) were overweight, and a smaller group (7%) had obesity before becoming pregnant.
  • Key finding: About 35% of these pregnant women experienced some level of depression—24% had mild depression, 10% had moderate depression, and less than 1% had severe depression. Healthy eating, exercise, good sleep, and health knowledge were protective, while processed foods and poor sleep increased depression risk.
  • What it means for you: If you’re pregnant and were overweight before pregnancy, paying attention to diet quality, staying active, sleeping well, and learning about health may help protect your mental health. However, this study shows connections, not definite cause-and-effect, so talk to your doctor about your individual situation.

The Research Details

Researchers recruited 441 pregnant women who were overweight or obese before pregnancy from two major hospitals in Guangdong, China. All participants were in their third trimester (last three months of pregnancy). Each woman completed several questionnaires about her depression symptoms, eating habits, physical activity, sleep quality, and health knowledge. The researchers then used statistical analysis to identify which factors were connected to depression.

This type of study is called ‘cross-sectional,’ which means researchers collected all the information at one point in time rather than following women over months or years. This approach is useful for identifying patterns and connections but cannot prove that one thing directly causes another.

Understanding which pregnant women are at higher risk for depression is important because depression during pregnancy can affect both the mother’s health and the baby’s development. By identifying modifiable factors—things women can actually change like diet and exercise—researchers can suggest practical interventions that might help prevent depression in this vulnerable group.

This study has several strengths: it included a reasonably large sample size (441 women), used validated questionnaires that are recognized in medical research, and examined multiple lifestyle factors. However, because it’s cross-sectional, we can’t be certain whether lifestyle habits cause depression or whether depression causes changes in lifestyle habits. The study was conducted in one region of China, so results may not apply equally to all populations worldwide.

What the Results Show

Among the 441 pregnant women studied, 289 (about 66%) reported no depression symptoms. However, 152 women (about 34%) experienced some level of depression: 107 had mild depression, 44 had moderate depression, and 1 had severe depression.

The researchers found that several factors were connected to depression risk. Women with higher education levels, those who worked, those with higher family income, and those who were not pregnant for the first time had lower depression rates. These socioeconomic and demographic factors appeared to be protective.

Regarding lifestyle factors, women who ate a balanced diet with whole foods had lower depression rates, while those who frequently ate highly processed foods had higher depression rates. Women who exercised regularly and got good quality sleep also had lower depression rates. Additionally, women with better health literacy—meaning they understood health information and could apply it to their lives—had lower depression rates.

Sleep quality emerged as particularly important. Women with sleep disorders had significantly higher depression rates. Health literacy also played a meaningful role—women who better understood health concepts and could use that knowledge in daily life were more protected against depression. The study found that these lifestyle factors appeared to be more directly connected to depression than some demographic factors.

Previous research has shown that depression is common during pregnancy, especially in the third trimester. This study adds to that knowledge by showing that women who start pregnancy at a higher weight may be at even greater risk. The finding that lifestyle factors like diet, exercise, and sleep are protective aligns with other research showing these behaviors support mental health in general populations.

The biggest limitation is that this study captured information at one moment in time, so we cannot determine whether lifestyle habits cause depression or whether depression causes people to change their habits. The study was conducted only in Guangdong, China, so results may not apply equally to pregnant women in other regions or countries with different healthcare systems and cultural factors. Additionally, the study relied on women’s self-reported information about their habits and symptoms, which may not always be completely accurate.

The Bottom Line

If you’re pregnant and were overweight before pregnancy, consider: (1) eating a balanced diet with whole foods rather than processed foods (moderate confidence), (2) engaging in regular physical activity as approved by your doctor (moderate confidence), (3) prioritizing good sleep habits (moderate confidence), and (4) learning about pregnancy and health to increase your health literacy (moderate confidence). These changes may help protect your mental health during pregnancy.

This research is most relevant to pregnant women who were overweight or obese before pregnancy, especially those in their third trimester. It’s also important for healthcare providers caring for this population. Women with normal pre-pregnancy weight may still benefit from these lifestyle recommendations, but this study doesn’t specifically address their risk. Anyone experiencing depression during pregnancy should speak with their healthcare provider regardless of these findings.

Lifestyle changes typically take several weeks to show effects on mood and mental health. You might notice improvements in sleep quality within 1-2 weeks of better sleep habits, but mood improvements may take 4-8 weeks of consistent lifestyle changes. If depression symptoms are severe or worsening, seek help from your healthcare provider immediately rather than waiting for lifestyle changes to work.

Want to Apply This Research?

  • Track daily mood using a simple 1-10 scale, along with three lifestyle factors: (1) meals eaten (noting if balanced or processed), (2) minutes of physical activity, and (3) sleep quality rating. Review weekly trends to see if improvements in lifestyle correlate with mood improvements.
  • Set one specific goal: choose one meal per day to make with whole foods instead of processed options, aim for 30 minutes of approved pregnancy-safe activity most days, and establish a consistent bedtime 30 minutes earlier than current routine. Use the app to log these daily and celebrate weekly consistency.
  • Create a weekly dashboard showing mood scores alongside lifestyle metrics. Set reminders for meal planning, activity breaks, and bedtime routines. If mood scores don’t improve after 4 weeks of consistent lifestyle changes, or if depression symptoms worsen, use the app to schedule a healthcare provider appointment.

This research shows connections between lifestyle factors and depression in pregnant women who were overweight before pregnancy, but cannot prove direct cause-and-effect relationships. Depression during pregnancy is a serious condition that requires professional medical care. If you’re experiencing depression, anxiety, or thoughts of self-harm during pregnancy, contact your healthcare provider, midwife, or mental health professional immediately. Do not rely solely on lifestyle changes to treat depression—combine them with professional medical support. This information is for educational purposes and should not replace personalized medical advice from your healthcare team.