Background
Obesity is prevalent among reproductive-aged women and is associated with increased obstetric complications. Weight gain recommendations exist; however, knowledge of these recommendations is low, and few women gain appropriate weight during their pregnancies. Excessive gestational weight gain is common and is associated with adverse outcomes. Little is known about the relationship between knowledge of gestational weight gain recommendations and actual weight gain.
Objectives
Our objectives were to assess knowledge of weight gain recommendations in pregnancy and to determine its association with actual weight gain among women who seek care at an urban, regional perinatal center. We hypothesize that low levels of knowledge will predict inappropriate weight gain in this population.
Study Design
This is a cross-sectional study with linked chart review of 338 women who sought routine obstetric ultrasound scans at an urban, regional perinatal center that serves a largely low-income population of predominately black women. Descriptive statistics, chi-square test, and analysis of variance were performed.
Results
This population has low rates of accurate knowledge of weight gain recommendations in pregnancy (27%) and low rates of appropriate gestational weight gain (30%). Inappropriate gestational weight gain was highest among women who were obese before pregnancy. Accurate knowledge of gestational weight gain recommendations was associated with appropriate weight gain in pregnancy ( P = .02), as was prepregnancy weight category ( P = .004) and correct identification of prepregnancy weight category ( P = .005).
Conclusion
These findings support the need for improvements in educational efforts about weight gain in pregnancy for high-risk, low-income women in an urban setting, which may improve compliance with the recommendations.
More than one-half of reproductive-aged women (20-39 years old) are obese or overweight; the rates are highest among non-Hispanic black and Mexican American women. Obesity in pregnancy is associated with maternal illnesses that include gestational diabetes mellitus and preeclampsia, the need for cesarean delivery, anesthetic and surgical risks during delivery, and postpartum complications such as wound infections or thromboembolic events. Fetal risks include prematurity, stillbirth, congenital anomalies, macrosomia, birth injury, and childhood obesity.
The increasing burden of the obesity epidemic in the United States and evidence of the effects of inappropriate gestational weight gain prompted the Institute of Medicine (IOM) to publish updated guidelines for weight gain in pregnancy in 2009. The 2009 IOM weight gain recommendations are 18–40 pounds for underweight women (body mass index [BMI], <18.5 kg/m 2 ), 25–35 pounds for normal weight women (BMI, 18.5–24.9 kg/m 2 ), 15–25 pounds for overweight women (BMI, 25–29.9 kg/m 2 ), and 11–20 pounds for obese women (BMI, ≥30 kg/m 2 ).
However, evidence suggests that pregnant women are gaining weight outside these recommendations. According to the Center for Disease Control and Prevention, only one-third of women (32%) had appropriate weight gain during their pregnancy in 2012–2013. Not only are weight gain recommendations not being followed, but studies have also found high rates of excessive gestational weight gain. Johnson et al found 73% of a large cohort of nulliparous women (n = 8293) gained more weight than recommended by the IOM. Risk factors for excessive gestational weight gain include obesity, low socioeconomic status, being overweight before pregnancy, and underestimating one’s prepregnancy weight class. Excessive gestational weight gain has been associated with an increased risk of hypertensive disorders during pregnancy, cesarean delivery, large for gestational age infants, and postpartum maternal weight retention. Excessive gestational weight gain has also been associated with increased childhood obesity, which suggests that focus on gestational weight gain may be important for health at the individual, familial, and societal levels.
There are few studies that have assessed maternal knowledge of the 2009 IOM recommendations for gestational weight. Previous studies reported accurate knowledge of these recommendations that ranged from 31–48%. However, it is unclear whether knowledge of the recommendations is associated with actual weight gained during pregnancy. This study sought to assess knowledge of recommended weight gain in pregnancy and the association between this knowledge and gestational weight gain in the women who attended an urban hospital-based clinic.
Materials and Methods
The study is a cross-sectional survey with linked chart review. Women who sought routine dating or anatomy ultrasound scans in an urban, regional perinatal center that is affiliated with two academic institutions were identified as potential participants and screened for eligibility. Exclusion criteria included non-English speaking and reading, unable to provide informed consent, reported age of <18 years old, known multiple gestation, and history of bariatric surgery. Participants who met inclusion criteria and expressed interest in participation underwent informed consent and the Health Insurance Portability and Accountability Act authorization. Participants completed a survey using audio computer-assisted self-interview software. A chart review was later performed to collect participant characteristics of interest and to ascertain actual weight gained during the index pregnancy. The study received Emory University Institutional Review Board expedited approval and Grady Memorial Hospital Research Oversight Committee approval.
A power analysis was performed, and a sample size of 340 women was determined to be sufficient to detect a 33% prevalence of accurate knowledge of recommended weight gain with a 95% confidence level and 5% confidence limit.
Our key outcome of interest was accurate knowledge of weight gain recommendations during pregnancy. This outcome was determined by categorization of the participant’s weight category from her BMI (calculated from her self-reported prepregnancy weight and height) according to the World Health Organization definitions. We then compared how much weight the woman thought that she should gain during pregnancy to the IOM 2009 guidelines for her determined weight category. For the women who did not report their height in the survey, this value was obtained from the chart review. There were 11 participants with no or implausible prepregnancy weights reported in the survey. Ten of these women had a first recorded weight from early in pregnancy, and this weight was used as their prepregnancy weight. One participant’s data were excluded because of having an earliest recorded weight at 36 weeks of gestation.
Appropriate weight gain during pregnancy was our second outcome of interest. Weight gain during pregnancy was calculated as the difference between the last recorded weight in the chart before delivery and the prepregnancy weight reported in the survey. Those who did not deliver at our institution were not included in this portion of the analysis. Total weight gain was categorized as appropriate or inappropriate based on whether this value falls within the IOM recommended weight gain for the participants’ weight category by BMI that was calculated from self-reported height and weight.
The survey included participant reports of prepregnancy weight, perceived weight class, knowledge of weight gain recommendations, intentions regarding eating and exercise during pregnancy, and screening for disordered eating. The chart review abstracted the following information: demographics, medical and obstetric history, prenatal course, and recorded weights throughout pregnancy. Past medical problems were recorded individually and as a collapsed variable of any medical history. Previous mental health illnesses were reported individually for depression and anxiety and as a collapsed variable of any mental health illness. Documentation of alcohol, tobacco, or illicit drug use in the participant’s medical chart or a positive urine drug screen identified substance use.
Survey answers and chart review data were merged and deidentified for analysis. Descriptive analyses were performed with the use of frequencies to characterize the study sample and their survey responses. To determine factors that were associated with accurate knowledge of weight gain in pregnancy, bivariate analyses were performed with chi-square analysis for categoric variables, Fisher’s exact test, and analysis of variance, when appropriate. A probability value of <.05 was considered statistically significant. Statistical analyses were performed using SPSS statistical software (version 23; IBM Corporation, Armonk, NY).
Results
Between October 31, 2014, and March 4, 2015, a convenience sample of 769 women was approached regarding completion of the survey: 4500 women are seen in this perinatal center annually; 555 women were screened for eligibility; and 339 women met eligibility criteria and completed the informed consent process and survey. The most common reason for exclusion was being non-English speaking or reading (16%), followed by 11% who did not want to participate, and 6% who reported their age as <18 years old. One subject who did not report a prepregnancy weight in the survey and had a single recorded weight measured at 36 weeks of gestation was excluded. This analysis includes 338 women.
Baseline demographic and participant characteristics are reported in Table 1 . Most of the participants were black, had Medicaid insurance, were overweight or obese, and received prenatal care from a medical doctor. The mean age at the time of recruitment was 26 years. One participant reported she was 18 years old when screened for eligibility for participation in the study but was found to be 17 years old during the chart review. Inclusion of this participant in this analysis was reviewed with and approved by our institutional review board. Nearly two-thirds of the women were multiparous. Prepregnancy medical problems were common (38%). Approximately 10% each had a history of mental illness and substance use.
| Characteristic | Frequency |
|---|---|
| Mean age at study recruitment, y ± SD (range) | 26.24 ± 5.58 (17-45) |
| Mean prepregnancy body mass index, kg/m 2 ± SD (range) | 27.61 ± 7.76 (15-60) |
| Prepregnancy weight category by body mass index, n (%) a | |
| Underweight (<18.5 kg/m 2 ) | 16 (4.7) |
| Normal weight (18.5–24.9 kg/m 2 ) | 139 (40.9) |
| Overweight (25–29.9 kg/m 2 ) | 69 (20.3) |
| Obese (≥30 kg/m 2 ) | 114 (33.5) |
| Black race, n (%) | 295 (87.3) |
| Uninsured, n (%) | 58 (17.2) |
| Multiparous, n (%) | 210 (62.1) |
| Previous pregnancy affected by hypertensive or diabetic disorder of pregnancy b | 44 (21.0) |
| History of cesarean delivery b | 65 (31.0) |
| Prenatal care with resident, fellow, or attending physician c | 225 (66.6) |
| Any medical history, n (%) d | 128 (37.9) |
| Hypertension | 48 (14.2) |
| Pregestational diabetes mellitus | 13 (3.8) |
| Asthma | 43 (12.7) |
| HIV positive | 13 (3.8) |
| Mental health disorder, n (%) | 33 (9.8) |
| Depression | 6 (1.8) |
| Anxiety | 16 (4.7) |
| Substance use in pregnancy, n (%) | 33 (9.8) |
a Determined by self-reported height and weight to calculate body mass index
b Frequencies calculated as percentages of those who were multiparous, n = 210
c Other prenatal care was provided by certified nurse midwives
d A significant medical history included women with chronic hypertension, pregestational diabetes mellitus, asthma, thyroid disorders, sickle cell disease, HIV, congenital heart disease, seizure disorders, or medical conditions considered to be significant by the study team.
Addressing our primary outcome, 90 women in this sample (27%) correctly identified their gestational weight gain goal. Moreover, >20% of the women not only incorrectly identified their recommended range of gestational weight gain but also reported an amount of weight gain that is not recommended by the IOM for any woman of any weight category; 18% of the women believed that they should lose weight or gain less than 10 pounds; 4% of the women thought they should gain >40 pounds during pregnancy.
Additional survey responses ( Table 2 ) revealed that fewer than one-half of the women (48%) could correctly identify their weight category. Of those who could not, the majority (92%) underestimated their weight category. Nine percent of the women screened positive for an eating disorder. Nearly two-thirds of the women had been informed about how much weight they should gain in pregnancy; the majority of those women (80%) received this information from their healthcare provider. Few women (8%) thought that all women should gain the same amount of weight in pregnancy. Twenty-one percent of the women planned to eat twice as much during their pregnancy, and more than one-half of the women (57%) planned to increase their exercise regimen during pregnancy.
| Survey item | Frequency (n = 338), n (%) |
|---|---|
| Self-reported weight category by body mass index | |
| Underweight (<18.5 kg/m 2 ) | 23 (6.8) |
| Normal weight (18.5–24.9 kg/m 2 ) | 202 (59.8) |
| Overweight (25–29.9 kg/m 2 ) | 97 (28.7) |
| Obese (≥30 kg/m 2 ) | 16 (4.7) |
| Identification of own weight category | |
| Correct | 162 (47.9) |
| Underestimated | 162 (47.9) |
| Overestimated | 14 (4.1) |
| Screen positive for disordered eating | 31 (9.2) |
| Informed about gestational weight gain during current pregnancy | 214 (63.3) |
| Received this information from healthcare provider a | 172 (80.4) |
| Believe all women should have the same amount of gestational weight gain | 28 (8.3) |
| Accurate knowledge of gestational weight gain goal | 90 (26.6) |
| Dietary plans for this pregnancy | |
| Eat twice as much or “eat for 2” | 71 (21.0) |
| Eat a little more | 121 (35.8) |
| Eat the same amount | 107 (31.7) |
| Eat less | 39 (11.5) |
| Plans for exercise this pregnancy | |
| Exercise more | 194 (57.4) |
| Exercise the same amount | 98 (29.0) |
| Exercise less | 46 (13.6) |
a Frequency calculated as a percentage of those who had received this information (n = 214).
In bivariate analysis ( Table 3 ), only a history of cesarean delivery was associated significantly with accurate gestational weight gain knowledge. Knowledge did not vary by trimester at the time of completion of the survey.
| Characteristic | Accurate knowledge (n = 90) | Inaccurate knowledge (n = 248) | P value |
|---|---|---|---|
| Mean age at study recruitment, y ± SD (range) | 25.84 ± 5.1 (18-42) | 26.39 ± 5.7 (17-45) | .430 a |
| Mean prepregnancy body mass index, kg/m 2 ± SD (range), | 26.96 ± 7.1 (14.84-60.0) | 27.85 ± 8.0 (17.03-51.76) | .347 a |
| Prepregnancy weight category by body mass index, n (%) | .085 | ||
| Underweight (<18.5 kg/m 2 ) | 1 (1.1) | 15 (6.0) | |
| Normal weight (18.5–24.9 kg/m 2 ) | 45 (50.0) | 94 (37.8) | |
| Overweight (25–29.9 kg/m 2 ) | 18 (20.0) | 51 (20.5) | |
| Obese (≥30 kg/m 2 ) | 26 (28.9) | 88 (35.5) | |
| Self-reported weight category by body mass index, n (%) | .259 | ||
| Underweight (<18.5 kg/m 2 ) | 10 (11.1) | 13 (5.2) | |
| Normal weight (18.5–24.9 kg/m 2 ) | 52 (57.8) | 150 (60.5) | |
| Overweight (25–29.9 kg/m 2 ) | 23 (25.6) | 74 (29.8) | |
| Obese (≥30 kg/m 2 ) | 5 (5.6) | 11 (4.4) | |
| Correctly identified weight category, n (%) | 49 (54.4) | 113 (45.6) | .149 |
| Underestimated their weight category, n (%) | 39 (43.3) | 123 (49.6) | .308 |
| Uninsured, n (%) | 14 (15.6) | 44 (17.7) | .637 |
| Multiparous, n (%) | 59 (65.6) | 151 (60.9) | .434 |
| Previous pregnancy affected by hypertensive or diabetic disorder of pregnancy, n (%) | 11 (12.4) | 33 (13.4) | .810 |
| History of cesarean delivery | 24 (26.7) | 42 (16.9) | .046 |
| Prenatal care with resident, fellow, or attending physician | 66 (73.3) | 159 (64.1) | .112 |
| Any past medical history, n (%) | 27 (30.3) | 101 (40.9) | .079 |
| Chronic hypertension | 8 (9.0) | 40 (16.1) | .098 |
| Pregestational diabetes mellitus | 2 (2.2) | 11 (4.4) | .526 b |
| Asthma | 7 (7.9) | 36 (14.6) | .104 |
| HIV positive | 3 (3.3) | 10 (4.0) | 1.00 b |
| Mental health disorder, n (%) | 7 (8.0) | 26 (10.5) | .495 |
| Substance use in pregnancy, n (%) | 8 (10.4) | 25 (11.6) | .768 |
| Screen positive for disordered eating, n (%) | 8 (8.9) | 23 (9.3) | .914 |
| Previously informed about appropriate gestational weight gain, n (%) | 60 (66.7) | 154 (62.1) | .441 |
| Informed about gestational weight gain by their healthcare provider, n (%) | 49 (54.4) | 123 (49.6) | .819 |
| Believe all women should gain the same amount of weight in pregnancy, n (%) | 8 (8.9) | 20 (8.1) | .808 |
| Dietary plans for this pregnancy, n (%) | .559 | ||
| Eat twice as much or “eat for 2” | 23 (25.6) | 48 (19.4) | |
| Eat a little more | 32 (35.6) | 89 (35.9) | |
| Eat the same amount | 27 (30.0) | 80 (32.3) | |
| Eat less | 8 (8.9) | 31 (12.5) | |
| Plans for exercise this pregnancy, n (%) | .336 | ||
| Exercise more | 47 (52.2) | 147 (59.3) | |
| Exercise the same amount | 27 (30.0) | 71 (28.6) | |
| Exercise less | 16 (17.8) | 30 (12.1) |
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
