Forty-seven percent of U.S. women exceed the 2009 Institute of Medicine's (IOM) gestational weight gain guidelines, and overweight and obese women are even more likely to exceed the guidelines than are normal-weight women.1 Inaccurate physician gestational weight gain advice is one predictor of excessive gestational weight gain.2 However, women likely have other sources from whom they receive information and encouragement for gestational weight gain, including family and friends.3 It is unclear how accurate the gestational weight gain information received from their social network is (eg, “you need to be eating for two,” advice about dangers of being active during pregnancy4) and how much it influences gestational weight gain. In addition, understanding a woman's own expectations for gestational weight gain and her views of “healthy” gestational weight gain are important because they are likely to influence her adherence to the guidelines as was found in a recent study,5 which demonstrated that expectations were a significant predictor of self-reported gestational weight gain.
The current study examined pregnant women's views of “healthy” gestational weight gain, their expectations for weight gain, their family and friends' gestational weight gain expectations, and their perceived specificity of their physician's advice about weight gain. We hypothesize that overweight and obese women are more likely to rate as “healthy” weight gains that exceed the guidelines, to have self-expectations of excessive weight gain, to have family and friends who expect them to gain over guidelines, or to report that they did not receive specific advice about weight gain from their physician. Furthermore, we hypothesize that they will be more likely to have measured weight gain over guidelines compared with women with expectations or advice for weight gain within or below the guidelines.
MATERIALS AND METHODS
In this secondary analysis, we examined gestational weight gain expectations and advice received from various sources (ie, self, family and friends, physician) in 230 pregnant women at 12 weeks of gestation, who took part in a study examining the effects of maternal body composition on neonatal birth weight, growth, body composition, and risk of overweight at 2 years old (clinicaltrial.gov #NCT01131117). Women were considered eligible for the study if their measured body mass index (BMI, calculated as weight (kg)/[height (m)]2) was between 18.5 and 35, if they were 21 years of age or older, and if they were planning to become pregnant or, if already pregnant, at less than 10 weeks of gestation. To avoid the potentially confounding effect of parity, only those who were pregnant with their second child were enrolled. Exclusion criteria included: conception with the use of fertility treatments, multiple gestations, pre-existing medical conditions (eg, diabetes mellitus, hypertension, sexually transmitted diseases), complications in their first pregnancy (eg, gestational diabetes, preeclampsia, preterm labor), use of medications known to influence fetal growth (eg, glucocorticoids, insulin, thyroid hormones), and tobacco or alcohol use during the pregnancy. Participants were recruited from the community in 2011–2014 using both print and social media advertisements. We targeted women and children's magazines, physician offices, daycare centers, and local health fairs. Participants received routine prenatal care from health care providers throughout the community. All study procedures were determined to be in compliance with the ethical research standards set by the institutional review board of the University of Arkansas for Medical Sciences, and all participants provided informed consent.
All study visits occurred in a research office. All participants received information on the IOM's gestational weight gain guidelines6 tailored to their BMI category at an individual session which was conducted at 4–10 weeks of gestation as well as the maternal and child health rationale for gestational weight gain guidelines during pregnancy. Trained research staff with a Bachelor or Master degree in psychology, public health, or nutrition introduced and explained a gestational weight gain graph (tailored to BMI category) that would be used to track the participant's gestational weight gain at each session throughout her pregnancy. During pregnancy, all participants received six behavioral intervention sessions (at 4–10 weeks, 12 weeks, 18 weeks, 24 weeks, 30 weeks, and 36 weeks of gestation) designed to promote healthy gestational weight gain based on a previous intervention7 as well as motivational interviewing and evidence-based strategies for weight management including daily weight self-monitoring, goal setting, and problem-solving.8 Intensified intervention with additional intervention sessions and dietary self-monitoring with feedback was offered to women with excessive gestational weight gain. The intervention and the outcomes have been described in detail elsewhere.9
Age, race, ethnicity, marital status, education, and household income were determined by self-report at 4–10 weeks of gestation. Weight was measured in a hospital gown without shoes to the nearest 0.1 kg using a tared calibrated standing digital scale at every study visit. Height was measured to the nearest 0.1 cm standing against a wall-mounted stadiometer. All measures were obtained in duplicate (if both weights were within 0.1 kg and both heights were within 0.1 cm) or triplicate (if the first two weights or heights were not within the limits); agreeing measures were averaged. Body mass index was calculated from these measures using the standard formula.10 A categorical BMI variable was created using standard BMI weight categories (normal [18.5–24.9], overweight [25.0–29.9], and obese [30.0 or greater]).
Similar to previous research,11 at 12 weeks of gestation, each participant answered the following questions: 1) How many pounds do you think it is healthy for a woman of your weight to gain during pregnancy? 2) How many pounds do you expect you will gain during your pregnancy? 3) How many pounds do your friends and family tell you they think you should gain during your pregnancy? Response categories for each question provided on the questionnaire were: 1) 35–50 pounds, 2) 28–40 pounds, 3) 25–35 pounds, 4) 15–25 pounds, and 5) 10–20 pounds. We chose these response categories because they were consistent with the IOM's recommendations for each BMI category as well as one higher gestational weight gain range (ie, 35–50 pounds). These weight category responses then were classified with respect to the IOM's recommendations for the individual participant based on her prepregnancy weight as consistent with guidelines, over the guidelines, or under the guidelines. Women also were asked “how specific has your physician been in telling you how much weight to gain during your pregnancy?” and rated their perception of the advice on a 7-point scale (0=not at all specific to 6=very specific).
The total amount of gestational weight gain was calculated as the difference in weight between the first prenatal study visit (ie, 4–10 weeks of gestation) and the final study prenatal visit (ie, 36 weeks of gestation). A variable was created to indicate whether the participant gained above, within, or below the 2009 IOM's gestational weight gain guidelines for her prepregnancy BMI category adjusted for gestational age because the final weight measurement was at 36 weeks of gestation.
Continuous variables were summarized as means and standard deviations; differences between means were compared using Student t tests. Categorical variables were summarized as counts and percentages; differences between proportions were compared using Fisher exact tests. Differences between groups were considered significant when the P value was ≤.05. Comparisons were made between participants who completed the 36-week study visit (ie, “completers”) and those who did not complete this study visit (ie, “noncompleters”) for demographic variables, perceived healthy gestational weight gain, self-expectation of gestational weight gain, expectations of gestational weight gain from family and friends, and specificity of physician gestational weight gain advice. Comparisons were also made among normal weight, overweight, and obese participants for perceived “healthy” gestational weight gain, self-expectation of gestational weight gain, expectations of gestational weight gain from family and friends, and specificity of physician gestational weight gain advice. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were computed for the association between participants being above the IOM's recommended guidelines for gestational weight gain and each of the perception and expectation questions using logistic regression; models were adjusted for covariates including maternal age, race, education, household income, and marital status. All statistical analysis was performed with R software 3.2.3 using the “rms” package.
A total of 287 participants met the inclusion criteria and were enrolled in the study. Of these participants, the 14 who had miscarriages, preterm births, or a hysterectomy and the 13 who were diagnosed with gestational diabetes were not included in these analyses. Of the remaining 260 participants, 230 (88%) completed the 36-week data collection visit. Of the 30 participants who did not complete the 36-week data collection visit, 14 were lost to follow-up, 14 voluntarily withdrew, and 2 were not able to attend the 36-week study visit. Completers of the 36-week data collection visit (N=230) were not significantly different from the noncompleters of this visit (n=30) on sociodemographic characteristics, BMI categorization, or responses to the various gestational weight gain expectation and advice questions. All completers were included in the current analyses and sociodemographic data are presented in Table 1. The proportion of participants by BMI category who endorsed each weight range for perceived healthy gestational weight gain and self-expectations for gestational weight gain is presented in Table 2.
Consistent with the data presented in Table 2, the majority of women (56.5%) selected gestational weight gain goals that they viewed as “healthy” that were within the IOM's guidelines for their BMI category (Table 3). However, significantly more overweight (35.7%) and obese women (58.5%) reported gestational weight gain goals that they viewed as “healthy” that exceeded guidelines compared with normal-weight women (10.8%). In addition, more normal-weight women (21.5%) reported gestational weight gain goals that they viewed as “healthy” that were below guidelines compared with overweight (9.5%) and obese women (1.9%) (Table 3). No sociodemographic characteristics (ie, race, education, marital status, household income, maternal age) were significantly associated with perception of “healthy” gestational weight gain goals.
In comparison with the proportion of women reporting as “healthy” gestational weight gain goals within the IOM's guidelines (56.5%), a smaller proportion of women (45.2%) expected that they would gain within the guidelines. In addition, significantly more overweight (47.6%) and obese women (56.6%) reported expecting to gain more than the guidelines compared with normal-weight women (22.6%). Participants showed significantly different expectations for gestational weight gain based on marital status; specifically, 48.3% of participants married to the biologic parent expected gains within guidelines, whereas only 18.8% cohabitating with the biologic parent and 14.3% divorced, single, or cohabitating with the nonbiologic parent expected gains within guidelines. Race, education level, household income, and maternal age were not significantly associated with gestational weight gain self-expectations.
Although 55.9% of normal-weight participants reported that their family and friends expected them to gain within guidelines, a significantly lower proportion of overweight and obese women (31.0% and 28.3%, respectively) reported that their family and friends expected them to gain within guidelines compared with normal-weight participants (Table 3). Participants reported significantly different family and friend expectations for gestational weight gain based on marital status and household income; specifically, 42.5% of participants married to the biologic parent reported family and friends expected gains within guidelines, whereas 0.0% divorced, single, or cohabitating with the nonbiologic parent reported family and friends expected gains within guidelines. In addition, 48.1% with household incomes between $50,000 and $89,000 reported family and friends expected gains within guidelines, whereas 22.2% of participants with household income less than $50,000 and 32.5% with household incomes greater than $90,000 reported family and friends expected gains within guidelines. Race, education level, and maternal age were not significantly associated with family and friend expectations for gestational weight gain (P values >.05).
Overall, 59.4% of participants reported receiving not very specific gestational weight gain advice (ie, score of 0 or 1) from their physician. No participant characteristics were significantly associated with the specificity of physician gestational weight gain advice.
We examined the effect of gestational weight gain expectations and advice on actual gestational weight gain at 36 weeks of gestation (Tables 4 and 5). Notably, women who reported expecting to gain in excess of the guidelines were significantly more likely to gain excessively (52%; OR 3.19, 95% CI 1.77–5.77) than those who expected to gain within the guidelines (36%; reference). There were no significant associations between actual gestational weight gain and perceived “healthy” gestational weight gain, specificity of physician gestational weight gain advice, and family and friend expectations (Tables 4 and 5). Similar results were observed after adjusting the models for maternal age, race, education, household income, and marital status.
Given that gestational weight gain in the first pregnancy might be associated with expectations of gestational weight gain among these participants who were currently pregnant with their second child, we examined our intervention notes to determine whether gestational weight gain in the first pregnancy was recorded for the majority of participants. Although this variable was not part of the measurement protocol, we determined that self-reported gestational weight gain in the first pregnancy was captured for 208 of 230 (90%) participants (after removing one outlier, a participant who reported a weight loss of 27 pounds). Although the strength of the association between gestational weight gain expectations and actual gestational weight gain was lower after adjusting for gestational weight gain in the first pregnancy and sociodemographic characteristics, women who reported expecting to gain in excess of the guidelines were still significantly more likely to gain excessively (51%; OR 2.22, 95% CI 1.08–4.56) than those who expected to gain within guidelines (37%).
This study demonstrates the substantial association between self-expectations of excessive gestational weight gain expressed early in the pregnancy and actual measured gestational weight gain. These findings are consistent with previous research using self-reported gestational weight gain5 and extend the literature by using objectively obtained weights and by adjusting for gestational weight gain in the first pregnancy. This is particularly striking because 40% of participants had self-expectations for gaining in excess of the IOM's guidelines, similar to previous studies.5,11 It appears that many women may not fully accept the IOM's recommendations or believe that the health outcomes associated with excessive gestational weight gain are unlikely to affect them based on the large proportion of participants who indicated expectations of excessive gestational weight gain or indicated perceived “healthy” gestational weight gain in excess of the guidelines.
In contrast to previous research,2,12 we did not find an association between the perceived specificity of physician advice and actual gestational weight gain. This lack of association may be the result of the lower level of health care provider advice received in this sample or a lack of recollection by the participants regarding the information they were given. Either way, only 40% of participants reported receiving at least somewhat specific health care provider advice about gestational weight gain compared with 67–73% in previous studies.2,12 However, these studies assessed physician advice in the third trimester compared with the first trimester in the current study, a methodologic difference that might contribute to the different rates observed. Nonetheless, given the evidence indicating the importance of first-trimester gestational weight gain on overall weight gain,13,14 assessment of health care provider advice in the first trimester offers important information, and the lack of association between health care provider advice reported by women and prospectively obtained measured gestational weight gain is troubling and offers an opportunity for improvement. We also did not find a link between family and friend expectations or “healthy” gestational weight gain perceptions and actual gestational weight gain.
Overweight and obese women were significantly more likely to report perceived “healthy” gains that exceeded the guidelines and to expect their gains would exceed the guidelines compared with normal-weight women, consistent with previous research.5,11 In addition, fewer overweight and obese women reported that their family and friends expected them to gain within the guidelines compared with normal-weight women. Taken together, it would appear that overweight and obese women may be particularly vulnerable to expectations that may contribute to unhealthy gestational weight gain.
There are several strengths of this study including measured weight throughout pregnancy and adjustment for gestational weight gain recommendations at the final measurement point (36 weeks of gestation). We also measured gestational weight gain expectations several weeks after participants had received tailored gestational weight gain recommendations, minimizing concerns that we might be assessing pre-existing knowledge rather than expectations per se. In addition, we assessed numerous potential influences on gestational weight gain expectations as well as controlled for self-reported gestational weight gain in the first pregnancy. However, there are also several limitations, including the potential generalizability of findings given that the participants were predominantly Caucasian, well-educated, older than average, and married with higher than average household incomes, and all were in their second pregnancy. Furthermore, we did not assess family and friend expectations or physician advice directly; rather, we relied on the participant's perspective of these expectations and advice. One might argue, however, that the participant's perspective of these expectations and advice may be more influential than the actual expectations and advice. Furthermore, because the study took place in a research setting and all participants received a behavioral weight gain intervention, the results may not generalize to routine prenatal care. However, one might assume that women who have not received clearly discussed gestational weight gain recommendations at 4–10 weeks of gestation may be even more likely to have expectations for excessive gestational weight gain. Finally, because experience with gestational weight gain during the first pregnancy appears to have influenced expectations, it is possible that findings would differ among nulliparous women.
Given the robust association with women's self-expectations for gestational weight gain and the fairly minimal association with early health care provider advice and family and friend expectations, at least in this sample, it may be beneficial to develop interventions that positively influence women's own expectations for gestational weight gain, particularly for overweight and obese women. Furthermore, increased understanding of what sources and factors (eg, self-efficacy for controlling one's weight, food cravings) contribute to women's self-expectations for gestational weight gain may be useful in the design of gestational weight gain interventions.
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