Body Weight is An Important Health Factor During Pregnancy, Regardless of Country of Birth

Being overweight is a major factor in complications during pregnancy and childbirth – this applies to both women born in Sweden and women who have moved here, which has not been well researched so far. Measures to promote a healthy weight have the potential to prevent complications in all women, the researchers conclude. The study was conducted by researchers at Linköping University and the Karolinska Institute and published in The Lancet Public Health.

The Risk of Complications

In Sweden and similar high-income countries, there are inequalities in women’s health during pregnancy and childbirth. Women who have migrated to Sweden from other countries are more affected by various serious complications compared to women born in Sweden. The risk of complications is particularly high for women born in certain parts of the world. It is not clear why, but many different factors that affect health may contribute to this disparity. One possible factor is body weight. Women immigrants from certain regions are more likely to be underweight, overweight or obese (a condition where the person is overweight and has a BMI of 30 or more) when they become pregnant.

“We know that overweight and obesity among women born in Sweden are associated with many complications during pregnancy and childbirth. Therefore, we wanted to investigate whether the inequalities in pregnancy complications between women born in different countries can be explained to some extent by differences in body weight. When you know that there are health inequalities, you want to find out why that is, so that you can then do something about them,” says Pontus Henriksson, senior adjunct professor at Linköping University’s Institute of Health, Medical and Care Sciences, who led the study.

What is new about this study is that the researchers were able to estimate the extent to which complications such as gestational diabetes could be avoided if all women were of a normal weight when they became pregnant. For example, they concluded that about half of all cases of gestational diabetes could potentially be prevented. This applies to both women born in Sweden and women born abroad.

How Body Weight Promotes Pregnancy Complications

The researchers believe that efforts to promote healthy body weight could help all women, regardless of where in the world they were born. A healthy weight is good for everyone. The earlier in life, the better, because once obesity has manifested itself, it is difficult to treat. The study paints a complex picture. The importance of body weight differs depending on the complication. For example, high body weight contributes more to gestational diabetes than to other complications. But what about being underweight in early pregnancy, how does this affect risks? To the researchers’ surprise, being underweight does not appear to contribute significantly to the complications studied.

In their study, the researchers followed nearly two million pregnancies – basically all births in Sweden from 2000 to 2020. The researchers looked at eight complications that can affect the mother or child during pregnancy or during and after childbirth. These included preeclampsia, gestational diabetes, infant mortality in the first year of life, preterm birth (before 37 weeks of gestation) and extremely preterm birth (before 28 weeks of gestation), low Apgar score (a measure of the vitality of the newborn), large baby (in relation to gestational age) and small baby (in relation to gestational age).

Using data from several national registries, they were able to examine the association between a woman’s BMI at the first prenatal visit and complications, depending on the region of the world in which the mother was born. In their analyses, the researchers took several factors into account, including socioeconomic data. However, some factors that could affect a woman’s health during pregnancy and childbirth, such as the quality of healthcare treatment, communication barriers, stress associated with migration, and differences in health-promoting behaviors, could not be examined in the current study because it used registry data. Therefore, further research is needed to examine more factors that may affect health during pregnancy in different groups.