If a woman is obese during pregnancy, she will probably use more health-care services and stay in hospital longer, a new study says.

The study, published in The New England Journal of Medicine, was a joint effort between the Centers for Disease Control (CDC) and the Kaiser Permanente Northwest Center for Health Research.

Scientists analyzed more than 13,000 deliveries that resulted in a live birth or stillbirth between 2001 and 2004. They found that pregnant women who were obese were more likely than women of normal weight to stay in hospital longer, have more obstetrical ultrasounds, take out-patient medications and be seen by a physician rather than a nurse or midwife.

Obese women had more pre-natal appointments with physicians primarily due to the fact that they had a Caesarean section delivery rate that was twice that for women of normal weight.

"The increased health care use by obese pregnant women will have substantial cost implications," explained Susan Chu, lead scientist on the study, in a statement.

The study's findings support previous studies that indicate obesity during pregnancy can increase a woman's risk of various complications, such as high blood pressure, gestational diabetes and Caesarean delivery.


Abstract

Background In the United States, obesity during pregnancy is common and increases obstetrical risks. An estimate of the increase in use of health care services associated with obesity during pregnancy is needed.

Methods We used electronic data systems of a large U.S. group-practice health maintenance organization to identify 13,442 pregnancies among women 18 years of age or older at the time of conception that resulted in live births or stillbirths. The study period was between January 1, 2000, and December 31, 2004. We assessed associations between measures of use of health care services and body-mass index (BMI, defined as the weight in kilograms divided by the square of the height in meters) before pregnancy or in early pregnancy. The women were categorized as underweight (BMI <18.5), normal (BMI 18.5 to 24.9), overweight (BMI 25.0 to 29.9), obese (BMI 30.0 to 34.9), very obese (BMI 35.0 to 39.9), or extremely obese (BMI 40.0). The primary outcome was the mean length of hospital stay for delivery.

Results After adjustment for age, race or ethnic group, level of education, and parity, the mean (�SE) length of hospital stay for delivery was significantly (P<0.05) greater among women who were overweight (3.7�0.1 days), obese (4.0�0.1 days), very obese (4.1�0.1 days), and extremely obese (4.4�0.1 days) than among women with normal BMI (3.6�0.1 days). A higher-than-normal BMI was associated with significantly more prenatal fetal tests, obstetrical ultrasonographic examinations, medications dispensed from the outpatient pharmacy, telephone calls to the department of obstetrics and gynecology, and prenatal visits with physicians. A higher-than-normal BMI was also associated with significantly fewer prenatal visits with nurse practitioners and physician assistants. Most of the increase in length of stay associated with higher BMI was related to increased rates of cesarean delivery and obesity-related high-risk conditions.

Conclusions Obesity during pregnancy is associated with increased use of health care services.