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Excess weight gain during pregnancy could raise the risk of death from heart disease and diabetes, according to a new study. Cavan Images/Getty Images
  • Researchers report that weight gain over the recommended amount during pregnancy can lead to heart disease or diabetes later in life.
  • In the study, women who were underweight at the start of their pregnancy and gained more than the recommended weight during pregnancy increased their risk of death by heart disease by 84%.
  • Experts note that excessive weight gain during pregnancy can also affect the baby’s health.

Women who gain more than the recommendations for weight gain during pregnancy have a higher risk of death from heart disease or diabetes in the decades that follow.

That’s according to a study completed at the Perelman School of Medicine at the University of Pennsylvania and published on October 19 in The Lancet.

In their study, researchers analyzed health information for more than 45,000 women who gave birth in the 1950s and 1960s. The data included body mass index (BMI) and weight changes during pregnancy and compared those numbers to current recommendations.

Health records were linked to mortality data through 2016 – about 50 years later.

Researchers reported that about 39% of the women in the study had died by the final follow-up date. They were classified as death by any cause, cardiovascular disease, and death by diabetes-related causes.

Researchers said the death rate correlated with pre-pregnancy BMI. Those with the lowest BMI died at a lower rate than women with higher BMIs.

Some of the specific findings included:

  • Women who were considered underweight before pregnancy and gained more than the now-recommended weight had an 84% higher risk of death by heart disease.
  • Women considered to have average weight before pregnancy and gained more than the current recommended weight had the all-cause death rate increase by 9% and death by heart disease increase by 20%
  • Women considered overweight had a 12% increased risk of dying if they gained more weight than what is now recommended.

“[I am] unsure as to why those who were underweight had a greater risk of death than those who were already overweight,” said Dr. Kecia Gaither, OB-GYN, the director of Perinatal Services/Maternal Fetal Medicine at NYC Health + Hospitals/Lincoln in the Bronx who was not involved in the study.

“A hypothesis — those who were underweight and suddenly had an increase in BMIm — perhaps had more of a ‘hit’ from the amount of inflammation which occurred — a hit where the body didn’t compensate as well — compared with those obese women whose bodies had already compensated over time with the levels of bodily fat and thus a steady state of inflammation,” Gaither told Medical News Today.

The researchers did not find a correlation between high weight gain during pregnancy and the subsequent death rate in women classified as having obesity.

The study showed a significant variation in risk between women who were underweight (84% higher risk) compared to those who were overweight (12% higher risk).

“At first glance, the 84%t increase in risk for women who are underweight vs. the 12% increase for those who are overweight seems surprising,” said Dr. Ashley Parr, an OB-GYN at The Women’s Hospital at MemorialCare Saddleback Medical Center in California, who was not involved in the study.

”It is counterintuitive to have the underweight population see the largest increase in risk of death. But upon further consideration, this data makes sense. The individuals at a lower weight to start were starting with very low risk. As they gained weight above and beyond recommendations, they became higher and higher risk. The obese population starts at a higher baseline risk of death, so even with higher than recommended weight gain, their risk classification does not have as much room to change. Overall, it shows that high weight is a high risk, some patients started there, and some ended there, but either way, those with high weight had a higher risk of death.”

— Dr. Ashley Parr, OB-GYN

The study’s authors indicate the increased risk of mortality from cardiovascular disease later in life, but experts note there are more immediate dangers as well.

“Excessive weight gain during pregnancy can also lead to several other health complications,” said Dr. Meleen Chuang, the medical director of women’s health at the Family Health Centers at NYU Langone in New York, who was not involved in the study.

According to Dr. Chuang, health risks of high pregnancy weight gain may include:

“Increased weight gain also causes larger babies, which can make complications related to delivery higher risk- increasing need or having a cesarean section after failed labor,” Dr. Chuang added.

According to the Office of Women’s Health, excessive weight during pregnancy can also affect the baby. They are more at risk for:

“They are also at risk for low calcium,” said Dr. G. Thomas Ruiz, an OB-GYN lead at MemorialCare Orange Coast Medical Center in California who was not involved in the study.

“Another concern is macrosomia — a baby who is much larger than average. Shoulder dystocia is the inability of the shoulders to pass through the birth canal. The biggest problem is this occurs after the head is delivered. It is associated with injury to the clavicle and brachial plexus,” Ruiz told MNT.

Ruiz cautions that there can also be long-term health issues for mothers and their babies when the mother gains excess weight during pregnancy.

“It is linked to gestational diabetes and may result in insulin resistance or diabetes in the child as they age,” he said.

Other factors could also contribute to the difference.

“For example, women who were underweight prior to pregnancy may already have had certain health vulnerabilities that could increase their risk,” Dr. Chuang said.

“On the other hand, women who were normal weight or overweight before pregnancy could potentially have different metabolic profiles or other underlying conditions that contribute to the varying risks,” she told Medical News Today.

The scientists note that gaining weight during pregnancy within the current guidelines provides short-term health benefits for the mother and baby and may protect against possible adverse impacts later in life.

“This is a well-researched and thorough epidemiologic study,” said Dr. Monte Swarup, an OB-GYN in Chandler, AZ, and founder of the HPV information site HPV HUB who was not involved in the study.

Dr. Gaither agreed and said she hopes it provides a way forward to healthier pregnancies and lower mortality for the pregnant person and the baby.

“Fascinating and well-grounded research will hopefully come from this novel study, which will point conclusively as to the best diet to achieve the right amount of healthy weight — without the inflammation — resulting in more positive perinatal outcomes,” she said.

Dr. Chuang agreed, noting, “Maintaining a healthy weight during pregnancy is crucial for both the mother and the baby’s well-being.”

The suggested total weight gain during pregnancy is based on BMI, according to the American Congress of Obstetricians and Gynecologists.

Early in pregnancy — up until about 12 weeks — pregnant people might gain anywhere from 0 to 5 pounds during the whole trimester. After that, between half a pound and 1 pound per week is average.

“A woman’s caloric needs need to change after the first 12 weeks of pregnancy,” Dr. Swarup told MNT.

“It’s important for her to consult with her OB/GYN to determine the BMI at the initial prenatal visit. You need to discuss appropriate weight gain, diet, and exercise from the initial visit and throughout your pregnancy.”

Still, the amount of weight a pregnant person should gain may vary based on an individual’s health circumstances.

“The recommended weight gain during pregnancy depends on a woman’s prepregnancy weight,” Dr. Chuang said. “Gaining too much weight during pregnancy can pose certain health risks.”

The Centers for Disease Control and Prevention (CDC) recommends the following parameters for weight gain during pregnancy:

Weight Gain Recommendations For Women Pregnant With One Baby

BMI less than 18.5
28-40 pounds
Normal Weight
BMI 18.5-24.9
25-35 pounds
BMI 25.0-29.9
15-25 pounds
BMI greater than or equal to 30.0
11- 20 pounds

“Pregnancy is a state characterized by many changes — hormonal, metabolic, structural, physiologic — all to ensure the normal development of the growing fetus, to house the fetus in a sterile expansible environment, and ensure that the maternal component of the maternal-fetal dyad will be able to birth and feed the newborn safely,” Dr. Gaither said.

“Adequate consumption of nutrients allows for these processes to take place — for the mother and for the enlarging and developing fetoplacental unit. As such, adequacy of caloric intake is necessary — and there is a proportional increase corresponding to whether there is a singleton pregnancy vs. one with multiples,” Dr. Gaither added.

Dr. Gaither noted that a healthy pregnant person carrying a singleton should consume about 2,000 calories per day on average.

“The rationale for this limitation for weight gain is to preclude a number of complications like hypertension, diabetes, increased incidence of operative delivery, preterm birth, and infants noted to be too small or too large for gestational age,” she added. “Excessive weight gain is correlated with excessive adverse outcomes.”

— Dr. Kecia Gaither, OB-GYN