The authors identified 13 initial search queries that included keywords and phrases related to weight gain during pregnancy based on clinical experiences with pregnant patients (ie, “Am I gaining enough weight during pregnancy?,” “Healthy weight gain during pregnancy,” and “Am I gaining too much weight during pregnancy?”). To help ensure the queries used by our study reflected how people actually search on this topic, we expanded the initial set of 13 queries into 114 variants based on query suggestions produced by Google’s autocomplete feature (see Multimedia Appendix 1). The autocomplete feature suggests similar queries that have been typed before by Google users, or that occur as content on the Web [21].

Each query was entered into the Google search engine to yield a list of webpages on August 8, 2014. A website is defined as a set of webpages typically served from a single Web domain [22]. A Windows 8 Pro (64-bit) machine using the US English locale and running Google Chrome (v46) from Ann Arbor, Michigan, was used for all search results retrieval and processing. A new Google account was used with personalization not activated, so that search history did not influence the results. Safe search was also not activated.

The first 10 webpages that resulted from each search were included in this study, as these represent the websites most likely to be viewed by actual users; webpages ranked 11 or greater on a Google search received less than 5% of overall traffic [23]. Paid advertisements/webpages at the top of the Google search result were not included. Duplicate websites were removed to create the list of the most commonly accessed websites resulting from Google searching for information on weight gain during pregnancy.

The majority of webpages assessed in our study do not reflect the latest IOM guidelines and either present inaccurate or incomplete information, or provide no recommendations. Additionally, for-profit websites currently dominate this online sphere, and these were most likely to contain inaccurate, incomplete, or no specific recommendations compared to other website types. Our study suggests that despite established guidelines for healthy weight gain in pregnancy, many women may not access these guidelines when searching the Internet, potentially increasing their risk of adverse maternal or fetal outcomes from too much or too little weight gain.

Among inaccurate webpages, most recommendations either were within a few pounds of the IOM recommendations or incorrectly defined prepregnancy BMI categories by just 1-2 points (kg/m²). However, some webpages combined recommendations for overweight and obese women. This is concerning because obese women may be at highest risk of obstetric complications from excessive gestational weight gain. More concerning may be that nearly one-third of webpages had no recommendations despite appearing in the top 10 results of a Google query for information regarding weight gain during pregnancy. This creates a significant knowledge gap for pregnant women and can have long-term health consequences for mother and baby.

Patients may receive no or inaccurate information on weight gain in pregnancy not just from the Internet, but also from their clinicians, friends, and family. Studies have shown that patients want specific information on weight gain during pregnancy, and they trust and rely on information given by clinicians [32,33]. Clinicians also have the advantage of providing face-to-face information to their patients. However, clinicians are often incomplete information sources regarding weight gain during pregnancy because they fail to address the topic or provide information that is not aligned with the IOM guidelines [34,35]. Perhaps the same reluctance among clinicians to discuss the sensitive subject of weight may also apply to online contributors who may not want to offend their pregnant readers by discussing specific weight gain guidelines on their websites. This lack of information, from both clinicians and the Internet, may be compounded by misinformation, such as the widespread cultural belief of “eating for two,” that is often perpetuated and reinforced by pregnant women’s friends and family members [36-39].

Our findings underscore the inadequacy of online resources—key sources of health information for pregnant women—in addressing weight gain in pregnancy [10]. These findings also suggest two specific ways to improve awareness of the IOM weight gain guidelines, for both pregnant women and the people who influence them:

1. Clinicians and caregivers need to fill the knowledge gap. At this time, clinicians and those that provide support and care for pregnant women cannot depend on the Internet to transmit accurate information about healthy weight gain during pregnancy. As a trusted and preferred source of health information, clinicians, nurses, and public health workers should anticipate a knowledge gap about this topic and strive to discuss healthy weight gain with every pregnant woman [32,33]. Robust data from systematic reviews and meta-analyses have demonstrated the efficacy of motivational interviewing, behavioral self-monitoring, goal setting, structured moderate physical exercise programs, and dietary counseling [40-44]. Ideally, providers of prenatal care should address healthy diet and exercise habits early in pregnancy, including discussions of individualized goals for total weight gain across the pregnancy. The frequency of prenatal visits allows for revisiting this topic and drawing on clinical support resources, such as nurses, nutritional counselors, and social workers, to augment the clinician’s efforts.

In addition, because of the known challenges in patient-clinician communication regarding weight gain during pregnancy, research should also investigate effective communication approaches that work for both clinicians and at-risk patients. These approaches could include how the topic should be framed, what information should be presented, and the optimal timing of this counseling.

2. Accurate webpages must be more accessible. For-profit webpages dominate online search results because they know how to market their websites. Academic and government websites, on the other hand, do not seem to be using the techniques that ensure a webpage appears as a top result in Google searching. These techniques include optimizing the keywords used in the website, so that they are in the file name and headings and are used throughout the page, especially in the beginning of the first sentence; creating sitemaps (ie, a list of pages of a website accessible to crawlers or users); and including related links that can be detected and indexed to create greater visibility for the website and the health message [45]. By employing these techniques, websites with accurate information can become more accessible by appearing higher in Google searching, something shown to improve Web traffic to those sites [23]. These techniques can have an exponential effect as other sites can link to them and spread the accurate and usable knowledge. Furthermore, visible and easily searchable sites can help to educate not only pregnant women, but other influential people, such as family and friends who often search on behalf of their friends and loved ones [46].

This study describes the text that is contained in the webpage, not whether a patient understood the text, as we did not evaluate the presentation or readability of the information. Also, the specific characteristics and motivations of contributors on Crowdflower are unknown and may bias their judgments, though we believe this bias is limited by the multiple layers of quality control described in the Methods. We also did not analyze the accuracy of online calculators, though they were a small proportion of webpages (8/181, 4.4%). Finally, only the Google search engine results were evaluated in this study, which may limit the generalizability of our findings.

In conclusion, frequently accessed online information regarding weight gain during pregnancy does not reflect the latest IOM guidelines, with a large proportion of webpages displaying inaccurate or incomplete information, or no recommendations. Accurate information regarding healthy weight gain during pregnancy is vital during the prenatal period to prevent long-term morbidity in mother and baby. Our study adds insight into a potential modifiable factor that may contribute to a large proportion of US women gaining an unhealthy amount of weight during pregnancy and the vital role of clinicians and medical organizations in educating and supporting women during this critical window for maternal and child health.