Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Gaining Weight in Between Pregnancies Could Lead to Pregnancy Complications

A new large-scale study from researchers at the Harvard School of Public Health in Boston and the Karolinska Institutet in Stockholm, Sweden, found that an increase in body mass index (BMI) between first and second pregnancies was associated with adverse outcomes. The findings support for the first time a possible causal relationship between obesity and pregnancy complications, and are published in The Lancet.

Obesity is a growing problem worldwide. The World Health Organization considers it a major global health threat. In Sweden, during the years of the study (1992-2001), the percentage of pregnant women either overweight or obese increased from 25 percent to 36 percent. In the U.S., the prevalence of obesity in women aged 20-39 years jumped from 9 percent in 1960-1962 to 28 percent in 1999-2000.

A number of studies over the years have found an association between obesity and pregnancy complications but there was little evidence of a direct cause-and-effect relationship. The researchers, Eduardo Villamor, Assistant Professor of International Nutrition at HSPH and Sven Cnattingius, Professor of Epidemiology at Karolinska Institutet, looked at a study population of more than 150,000 Swedish women having their first and second births between 1992 and 2001. They calculated BMI at the first prenatal visit of each pregnancy (BMI is weight in kilograms divided by the square of height in meters). The researchers then calculated the difference between BMI at the beginning of the first and second pregnancies. The adverse outcomes that Villamor and Cnattingius looked at during the second pregnancy included maternal complications, such as pre-eclampsia, gestational diabetes, gestational hyptertension and caesarean delivery, and perinatal complications, such as stillbirth and large-for-gestational-age birth.

The results showed that weight gain between first and second pregnancies was associated with an increased risk of all these overweight and obesity-related adverse outcomes. A gain of one to two BMI units increased the risk of gestational diabetes, gestational hypertension or large-for-gestational age birth an average of 20 to 40 percent. A gain of three or more BMI units showed a 63 percent greater chance of stillbirth compared to a gain of less than one BMI unit and also a greater effect on all other complications.

Additionally, the researchers found that the risk of adverse outcomes increased even in women who were not overweight, but who gained a modest amount of weight between pregnancies. For example, if a woman who was 5 ft., 5 in., tall and weighed 139 lbs. (giving her a BMI of 23, not considered overweight) gained 6.6 lbs. (1 BMI unit) between her first and second pregnancies, her average risk of gestational diabetes would increase by more than 30 percent. If she gained 12.2 pounds (2 BMI units), her risk would increase 100 percent. The risk would continue to climb if she gained more weight and became obese. And opposite: weight loss before pregnancy in overweight women appeared to lower their risk of pregnancy complications.

“Previous studies have looked at the risk of pregnancy complications in relation to a snapshot measure of pre-pregnant weight”, says Dr. Sven Cnattingius. “These studies of course found that obesity appeared to increase the frequency of such complications. But in our study we went further back in time, to look at how women arrived to that pre-pregnant weight.

One limitation of the study was the possibility that other risk factors or illnesses could be associated with both weight gain and adverse pregnancy outcomes. Whether weight gain between pregnancies could have been due to lack of weight loss after the first pregnancy or to excessive weight gain during that initial pregnancy, was difficult to differentiate. But overall, the authors believe the results provide strong evidence that weight gain before pregnancy could lead to a number of complications of pregnancy.

“Women of normal weight should avoid gaining weight between pregnancies, that is a key public health message from our study”, says Dr Cnattingius. “Overweight and obese women are likely to benefit from weight loss if they are planning to become pregnant. But additional research is needed to find the most effective interventions that prevent interpregnancy weight gain and postpartum weight retention.”

The study was supported by grants from the Karolinska Institutet; Dr. Villamor is supported in part by the National Institute of Child Health and Development.

For further information, please contact:

Dr. Sven Cnattingius, Karolinska Institutet
Phone: +46 8 52486190
Katarina Sternudd, Press Officer, Karolinska Institutet
Phone: +46 8 524 838 95 or +46-70-224 38 95
Todd Datz, Assistant Director for External Communications, HSPH
Phone: +1 617-432-3952

Katarina Sternudd | alfa
Further information:

More articles from Health and Medicine:

nachricht Resolving the mystery of preeclampsia
21.10.2016 | Universitätsklinikum Magdeburg

nachricht New potential cancer treatment using microwaves to target deep tumors
12.10.2016 | University of Texas at Arlington

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>