Obstetrician Practice Patterns and Recommendations for Physical Activity During Pregnancy

Abstract

Background and Methods:

Many women do not attain minimum American College of Obstetricians and Gynecologists (ACOG) recommendations for physical activity during pregnancy. This study assessed the self-reported practice patterns and recommendations of 384 obstetricians working in Texas through a mailed survey on physical activity during pregnancy.

Results:

The most common exercise elements routinely collected from pregnant women included types of exercise (81%), history of exercise before pregnancy (79%), and frequency of exercise (76%). Fewer obstetricians collected duration (68%) or intensity (69%) of exercise. The percentage of obstetricians recommending avoidance of nine household activities and exercises (including lifting groceries, starting a new exercise program, or participating in walking, jogging, or bicycling) was significantly higher with each successive trimester. Most obstetricians agreed that pregnant women would gain some benefit from mild exercise (99.5%), but fewer agreed that moderate (74%) or vigorous exercise (6%) would be beneficial. Sixty-two percent of obstetricians reported that women who have never exercised could begin an exercise program during pregnancy. Almost all participants agreed that physical activity might make a woman feel more energetic (98%) and improve her labor and delivery (89%), but fewer agreed that exercise during pregnancy causes lower weight babies (23%) or could trigger labor (18%).

Conclusions:

Dissemination of current recommendations and discussion about the benefits and risks of physical activity during pregnancy, such as through continuing education, appear warranted. Future research could address the causes of disparities between self-reported practice patterns and current ACOG guidelines.

Introduction

In the United States, the American College of Obstetricians and Gynecologists (ACOG) provides exercise recommendations for pregnant women, which have changed over time. In 1985, ACOG recommended that heart rate during exercise should not exceed 140 beats/minute and that vigorous activity should last no longer than 15 minutes.¹ In addition, exercise in the supine position (lying on one's back) was not recommended after the fourth month of gestation. A 1994 update of the recommendation was less restrictive, with the heart rate limit removed.² In the most recent update in 2002, ACOG recommended that pregnant women should engage in moderate intensity exercise for at least 30 minutes on most, if not all, days of the week in the absence of any contraindications.³ The guideline indicated that information on vigorous activity was scarce and that women who engage in such activity require close medical supervision. Those with complications and previously inactive women should be evaluated before starting an exercise program. They also recommended that pregnant women avoid supine positions during exercise in the second and third trimester, as well as motionless standing. They also indicated a potential link between vigorous physical activities and the development of intrauterine growth restriction.

Subsequent to the ACOG position statement, in 2008 the U.S. government released physical activity guidelines for Americans, including recommending specifically that pregnant women attain at least 150 minutes of moderate intensity aerobic activity per week if not already highly active or doing vigorous intensity activity.⁴ Healthy pregnant women who engaged in vigorous aerobic activity before pregnancy were encouraged to continue physical activity, but there was no basis to recommend vigorous aerobic exercise to inactive women. This guideline indicated that moderate intensity activity done by healthy women during pregnancy does not increase the risk of low birth weight. Physical activity may reduce the length of labor and the risk of preeclampsia and gestational diabetes, although the evidence was not conclusive.

Physical activity is any bodily movement produced by skeletal muscles that causes increases in energy expenditure above that of rest, and exercise refers to a form of physical activity that is planned, repetitive, structured, and performed with the goal of improving fitness or health.⁴ Benefits of physical activity or, specifically, exercise for pregnant woman may include a reduction in risk of preeclampsia, gestational diabetes, and depressive symptoms, as well as more appropriate gestational weight gain and improved mood.^5,6 However, many pregnant women are not meeting either the ACOG or governmental recommendations for physical activity.^7
–9 National U.S. data from 1999 to 2006 indicated that among pregnant women, only 57% reported that they engaged in at least some moderate to vigorous leisure activity, and 54% reported any moderate to vigorous household activity, both in the past month.⁹ Other studies suggest that physical activity, particularly recreational activity, may decline with each trimester.^10
–12

The mismatch between physical activity recommendations and actual behavior of pregnant women may be due to patient-centered intrapersonal or interpersonal factors, such as motivation, concern about injury, or lack of support.^13,14 Provider-centered factors during pregnancy may also contribute to poor compliance.¹⁵ Surveys of obstetricians and other providers indicate that a significant proportion of providers report not discussing exercise with their pregnant patients.^16

–19 Reports from pregnant women also support a lack of counseling at times with regard to physical activity and exercise.^20
–22

This study sought to assess self-reported practice patterns and recommendations of obstetricians on physical activity and exercise during pregnancy by querying them through a mailed survey. Because the ACOG recommendations have changed over the past decade, we explored whether obstetricians' recommendations differed (1) by the number of years they practiced obstetrics and (2) by whether or not they reported engaging in continuing education on the topic in the past 5 years.

Materials and Methods

Source population

This study was approved by the University of Texas Health Science Center at Houston's Institutional Review Board. A survey was mailed to obstetricians in Texas who were registered through their State Medical Board in summer 2007. Currently licensed physicians with a specialty listed as obstetrician (n = 55) or obstetrician/gynecologist (n = 2987) were initially selected for study inclusion. Physicians registered as inactive, who did not provide direct care, or who did not practice medicine in Texas were excluded (n = 962) from the mailed sample. Forty-eight percent (n = 1000) of the 2080 currently licensed and practicing Texas obstetricians and obstetrician/gynecologists were randomly selected. The study questionnaire, cover letter describing the study purpose, and $1.00 attached to the cover letter were sent to their business addresses. Because we included physicians registered as obstetrician/gynecologist, physicians who did not provide prenatal care were asked in the cover letter to give their survey to a colleague in their practice or professional community who did provide prenatal care. Dillman's²³ mail survey techniques were employed to improve the response rate, which included sending a reminder postcard 2 weeks after the survey, sending nonresponders a second survey 4 weeks after the initial survey was mailed, and sending a final postcard reminder 4 weeks later.

Questionnaire

A two-step process for survey development was employed. We initially conducted key informant interviews with two obstetricians and four occupational medicine physicians to learn about the types of information they collected from patients on their physical activities during pregnancy, their recommendations for activities by trimester, and specific activities they recommended that women avoid during pregnancy. These physicians were also asked to review a draft of the mailed survey for content and readability and to provide comments about additional questions they thought should be included.

The final distributed survey is available elsewhere (www.unc.edu/∼kevenson/_TXSurvey.pdf). Physicians were asked questions about household and exercise information routinely collected during the prenatal period either by completing a triage/history form or verbally asking and about activities pregnant women should avoid by trimester. One question ascertained whether in the past 5 years the physicians had attended any continuing education classes or research presentations at a professional conference that addressed recommended levels of exercise during pregnancy (continuing education). Thirteen questions ascertained obstetricians' opinions about physical activity and exercise during pregnancy by responding to whether they agreed or disagreed with the statements provided. Twelve of the 13 questions were asked verbatim from a separate survey of 1306 pregnant women participating in the Pregnancy, Infection, and Nutrition Study 3 (PIN3) in order to make comparisons to the ACOG guidelines.²⁰ The remaining questions asked about work activities and are reported elsewhere.²⁴

Several descriptive characteristics of the obstetricians and their practice were collected. Professional practice information was ascertained, including how long the physician had practiced as an obstetrician (including residency and fellowship), their type of professional practice (private, academic, public health), geographical setting (urban, rural), and estimated percentage of patients from lower socioeconomic groups (Medicaid, indigent, undocumented migrant worker).

Statistical analysis

Descriptive analyses were used to characterize the population of obstetricians who responded to the survey and the frequency of their responses to the questions. The proportion of missing responses by question was <4%, and usually <1%, so we did not report missing values as a separate category. We used chi-square tests, or Fisher's exact test when cell sizes were small, to examine differences in response (1) by the number of practice years (≥15 years or <15 years) and (2) by attending continuing education on recommended levels of exercise during pregnancy in the past 5 years (yes or no). We used binomial regression models with generalized estimating equations, with compound symmetry working correlation for repeated counts, to test if reports of activities to avoid differed by the three trimester periods.^25,26 These models provided appropriate p values to assess the relationships between trimesters, given that the obstetricians responded for each of these periods. In all cases, significance was set at p < 0.05. We explored the possibility of selection bias with our sample of obstetricians by examining differences in response rates by age, type of medical practice, location, and gender using t tests for continuous variables and chi-square tests for categorical variables. All statistical analyses were conducted using SAS version 9.1.3 (Cary, NC).

Results

Description of sample

Of the 1000 mailed surveys, 84 were returned because of an incorrect address and, therefore, were not counted in the response rate. Of the 916 remaining surveys, 427 (47%) physicians responded, with 7 indicating they no longer practiced medicine, 13 who did not provide prenatal care, and 23 who returned the survey unanswered. A total of 384 (42%) completed surveys were included in the analyses. More than half of the responding obstetricians reported practicing ≥15 years (55%). Overall, physicians were primarily in private practice (90%) or a combination of appointments including academic (5%) rather than in academics only (4%) or public health only (1%). Most (84%) were located in urban settings, defined as a population of at least 50,000 persons. Almost one fifth (18%) reported serving a majority (>50%) population of patients of low socioeconomic status (SES). One quarter (25%) of responding obstetricians reported attending continuing education that addressed recommended levels of exercise during pregnancy in the past 5 years; this percent did not differ by the number of practice years.

Routinely collected information

The most commonly collected information about household activity and exercise during pregnancy included types of exercise (81%), history of exercise before pregnancy (79%), frequency of exercise (76%), and children or elderly to care for (74%) (Table 1). Elements not often collected included stair climbing (19%), lifting at home (28%), and average heart rate during exercise (35%). Obstetricians in practice for ≥15 years were more likely to collect information on stair climbing and problems with pregnancy as a result of domestic responsibilities. Obstetricians who attended continuing education were more likely to report collecting each of the 12 data elements listed in Table 1.

Table 1.

Household and Exercise Information Routinely Collected by Obstetricians from Women During Prenatal Period Either by Completing a Triage/History Form or Verbally Asking, Overall, by Years of Obstetric Practice, and by Training

			Years of obstetric practice			Continuing education on recommended exercise during pregnancy in past 5 years
	Overall (n = 384) ^a		<15 years (n = 172)	≥15 years (n = 206)		Yes (n = 94)	No (n = 285)
	% Yes	n	% Yes	% Yes	p value ^b	%	%	p value ^b
Household activities during pregnancy
Children/elderly to care for	74	283	74	73	0.75	86	70	0.002
Types of domestic responsibilities	38	147	34	42	0.09	55	33	<0.0001
Frequency and amount of lifting at home	28	108	24	31	0.15	44	23	<0.0001
Frequency and amount of stair climbing at home	19	72	13	24	0.01	31	15	0.0005
Problems with pregnancy because of domestic responsibilities	55	209	47	61	0.01	68	50	0.002
Exercise during pregnancy
History of exercise before pregnancy	79	304	81	78	0.36	95	74	<0.0001
Types of exercise	81	310	83	79	0.31	97	75	<0.0001^c
Frequency of exercise	76	292	77	76	0.81	93	70	<0.0001
Duration of exercise	68	259	70	66	0.37	86	62	<0.0001
Intensity of exercise	69	263	68	70	0.70	85	63	<0.0001
Symptoms associated with exercise	60	229	57	62	0.30	76	54	0.0002
Average heart rate during exercise	35	133	36	35	0.96	45	32	0.03

Sample size may not add to 384 because of missing values.

p value from chi-square test.

p value from Fisher's exact test because of small cell sizes.

Recommendations about physical activity and exercise

Obstetricians were asked if they recommended avoidance of nine household activities and exercises by trimester for an otherwise healthy woman having a normal pregnancy (Table 2). In all cases, the percent of obstetricians recommending against specific activities was higher with each successive trimester. Among the nine activities, the percent of obstetricians recommending against them in the first trimester was highest for starting a new exercise program (35%), jogging (30 minutes five times/week) (22%), and biking (19%). In the second and third trimesters, the most common activity to avoid was exercise while supine (63% in second trimester and 83% in third trimester).

Table 2.

Obstetrician's Report of Household Activities and Exercise to Be Avoided for Otherwise Healthy Women Having a Normal Pregnancy (n = 384)

Activities to avoid	First trimester %	Second trimester %		Third trimester %
Household activities
Carry toddler	7	19	<0.0001	43	<0.0001
Lift heavy groceries	15	30	<0.0001	53	<0.0001
Climb stairs	3	9	<0.0001	17	<0.0001
Lift laundry basket	5	11	<0.0001	28	<0.0001
Exercise
Starting new exercise program	35	53	<0.0001	73	<0.0001
Walking 30 minutes five times/week	4	5	0.02	11	<0.0001
Jogging 30 minutes five times/week	22	43	<0.0001	70	<0.0001
Biking	19	47	<0.0001	68	<0.0001
Exercise while supine (on back)	12	63	<0.0001	83	<0.0001

p value test from binomial regression models with generalized estimating equations to test difference from the preceding trimester (1 vs. 2 and 2 vs. 3).

Obstetricians practicing ≥15 years were more likely to recommend against lifting heavy groceries (58% vs. 48%, p = 0.05) and doing laundry (33% vs. 21%, p = 0.01) than were obstetricians practicing for <15 years, both in the third trimester only. Obstetricians practicing longer were also more likely to report avoidance of jogging for 30 minutes five times/week (29%, 51%, 80% by trimester, p < 0.01 for each comparison) compared with obstetricians practicing for less time (13%, 34%, 57% by trimester). Obstetricians practicing longer were less likely to report avoidance of supine exercise in the second trimester (58% vs. 70%, p = 0.02) but more likely to report avoidance of walking 30 minutes five times/week in the third trimester (14% vs. 7%, p = 0.02) compared with obstetricians practicing for less time. There were no other differences by practice years for the remaining activities queried in Table 2 by trimester (data not shown).

In all cases, avoidance of household activities by trimester and, in most cases, avoidance of exercise queried in Table 2 did not significantly differ by continuing education (data not shown). The exceptions were, in the first trimester, when obstetricians reporting continuing education were more likely to recommend avoidance of jogging 30 minutes five times/week (24% vs. 14%, p = 0.05). In the second trimester, obstetricians reporting continuing education were more likely to recommend avoidance of jogging 30 minutes five times/week (32% vs. 46%, p = 0.01) and biking (37% vs. 49%, p = 0.04).

Report of obstetrician opinions about physical activity and exercise during pregnancy are detailed in Table 3, based on responses to 13 statements. Most obstetricians agreed that for pregnant women, regular exercise is better than irregular exercise (98%), that it was acceptable to continue their regular exercise during pregnancy (94%), and that long periods of standing in one place should be avoided (92%). Eighty-five percent agreed that pregnant women should not exercise while on their back in the third trimester, and fewer reported that women who have never exercised could begin an exercise program during pregnancy (62%). All participants reported that pregnant women will gain some benefit from mild exercise (100%), but fewer reported this for moderate exercise (74%) and vigorous exercise (6%). Almost all participants agreed that it might make a woman feel more energetic (98%) and could improve a woman's labor and delivery (89%). Slightly less agreed that physical activity and exercise could improve the health of the baby (70%). Less than one quarter of the obstetricians agreed that exercise during pregnancy causes lower weight babies (23%) or could trigger labor (18%).

Table 3.

Obstetrician's Opinions About Physical Activity and Exercise During Pregnancy, Overall, by Years of Obstetric Practice, and by Training

			Years of obstetric practice			Continuing education on recommended exercise during pregnancy in past 5 years
	Overall (n = 384) ^a		<15 years (n = 172)	≥15 years (n = 206)		Yes (n = 94)	No (n = 285)
Do you agree or disagree?	% agree	n	% agree	% agree	p value ^b	% agree	% agree	p value ^b
Exercise during pregnancy:
Most women can continue their regular exercise during pregnancy	94	360	96	92	0.15	96	94	0.46
Most women who have never exercised can begin an exercise program during pregnancy	62	233	61	62	0.77	62	62	0.91
During pregnancy, regular exercise done at least 3 times per week is better than activity done irregularly or less often	98	372	98	97	0.52^c	99	98	NA
Exercise to avoid during pregnancy:
Pregnant women should not exercise while lying down on their back during the third trimester	85	324	90	81	0.03	82	86	0.33
Long periods of standing in one place without moving should be avoided while pregnant	92	354	90	94	0.12	92	93	0.72
Benefits of exercise and physical activity during pregnancy:
Pregnant women will gain some benefit from:
mild exercise that feels fairly light	100	380	99	100	NA	99	100	NA
moderate exercise that feels somewhat hard	74	282	79	70	0.04	79	73	0.25
vigorous exercise that feels hard or very hard	6	24	9	4	0.08	5	7	0.40
Physical activity and exercise during pregnancy:
might make a woman feel more energetic	98	376	98	99	NA	99	98	NA
will improve a woman's labor and delivery	89	337	90	88	0.55	89	89	0.98
will improve the health of the baby	70	263	74	67	0.16	80	67	0.02
Risks of exercise during pregnancy:
Exercise during pregnancy causes lower weight babies	23	85	28	18	0.02	25	22	0.47
Exercise during pregnancy can trigger labor	18	66	13	22	0.03	20	17	0.50

Sample size may not add to 384 because of missing values.

p value is from chi square test.

p value from Fisher's exact test due to small cell sizes.

NA, not calculated because of cell sizes.

In most cases, years in practice were not associated with whether obstetricians agreed with the 13 statements about physical activity and exercise (Table 3). The exceptions included that those practicing <15 years were more likely than obstetricians practicing longer to agree that pregnant women should not exercise while lying on their back in the third trimester, that pregnant women will gain some benefit from moderate exercise, and that exercise during pregnancy can cause lower weight babies. Obstetricians practicing for less time were also less likely than obstetricians practicing longer to report that exercise during pregnancy could trigger labor. Only 1 of the 13 statements differed by continuing education; obstetricians reporting continuing education were more likely to agree that physical activity and exercise during pregnancy would improve the health of the baby.

Exploration of non-responders

We explored the potential for selection bias with our sample. No differences in response status were observed with regard to mean age (responders, mean 48.5 years, vs. nonresponders, mean 49.3 years, p = 0.23 from t test) or type of medical practice (e.g., academics, private solo, private group, other) (p = 0.30). The majority of obstetricians in Texas practice in large urban areas, and we found no significant differences in response rates by Texas cities (e.g., Austin, Dallas, El Paso, Fort Worth, Houston, San Antonio) (p = 0.68). However, we did find differences in response rates between eligible male (38%) and female (48%) obstetricians (p = 0.004).

On further exploration, no significant differences were observed in how male and female obstetricians responded to survey questions pertaining to household and exercise information gathered from patients (Table 1). In addition, no differences in recommendations for avoiding household and exercise activities by gender were found, with two exceptions (Table 2): male obstetricians were more likely than female obstetricians to recommend that women avoid jogging during pregnancy across trimesters (e.g., avoid in third trimester: males 77%, females 58%, p < 0.0001). Conversely, female obstetricians were more likely to recommend that women avoid supine exercise in the second and third trimester (e.g., avoid in third trimester: males 79%, females 89%, p = 0.01).

Discussion

This survey of obstetricians provides current information on routinely collected data relating to physical activity, recommendations about exercise during pregnancy, and the potential benefits, as well as activities to avoid and potential risks.

Routinely collected information

In this study, most (>70%) obstetricians reported collecting information on their patients' physical activity history, including type, frequency, and history of exercise and children or elderly to care for. Fewer reported collection of the duration and intensity of exercise and lifting at home. In order to formulate an appropriate exercise prescription, information on the type, frequency, intensity, and duration of activity, as well as prepregnancy exercise levels, should be considered. Although we did not query about specific heart rate recommendations provided to patients, several studies^16,21,27 indicate that some healthcare providers are still providing advice based on the outdated 1985 ACOG guideline,¹ which included heart rate restriction at 140 beats/minute. Our survey indicated that only 35% of obstetricians asked about average heart rate during exercise.

The Canadian Society for Exercise Physiology developed an intake form, with sections for both the patient and provider to complete, to help screen pregnant women systematically and provide appropriate exercise counseling.^6,28 Development and use of an intake form congruent with current guidelines could help standardize collection on key data elements and improve appropriate screening and recommendations for more patients.

Recommendations about exercise during pregnancy

In Table 2, 12 of the 13 questions were asked verbatim from a survey of 1306 pregnant women participating in the PIN3 Study in order to make comparisons. These pregnant women were recruited between 2001 and 2005 and were <20 weeks' gestation and were seeking prenatal care at clinics associated with the University of North Carolina Hospitals. Women were not enrolled if they were non-English speaking, <age 16, carrying multiple gestations, and not planning to continue care or deliver at the study hospital or did not have a telephone from which they could complete the phone interviews. The women completed a take-home questionnaire that included these questions at 27–30 weeks' gestation.²⁰

Most obstetricians agreed that pregnant women can continue their regular exercise during pregnancy (94%), congruent with current ACOG guidelines,³ whereas a lower percentage of pregnant women (78%) agreed with this statement. For pregnant women wanting to start a new exercise program, ACOG encourages them to first be evaluated;³ the Canadian guideline suggests that starting a new exercise program is acceptable through the second trimester.^6,28 For women who were not exercising before pregnancy, approximately one third (35%) of physicians recommended avoiding starting a new exercise program in the first trimester, which increased to 53% and 73% in the second and third trimesters, respectively. Most obstetricians (98%) and pregnant women from the PIN3 Study (89%) agreed that regular exercise was better than irregular exercise during pregnancy.²⁰

Benefits of exercise and physical activity

Almost all obstetricians reported that pregnant women will gain some benefit from mild exercise, but fewer agreed with the benefit of moderate exercise (74%). The fact that more than one quarter of the obstetricians did not agree that moderate exercise produced benefit for pregnant women may partially explain why women may not be counseled on an exercise program.^20
–22 Moreover, only 6% of obstetricians agreed that vigorous exercise produced benefit. The most recent ACOG statement recommends moderate intensity activity but does not make a recommendation about vigorous intensity activity,³ which may be a contributory factor to the low number agreeing to the benefits of vigorous exercise. These reports from obstetricians are in agreement with reports from the pregnant women participating in the PIN3 Study.²⁰ When asked about agreement on the benefits of exercise for pregnant women, 98%, 73%, and 13% agreed to the benefit of mild, moderate, and vigorous intensity exercise, respectively. Other studies also have found that pregnant women report that lighter intensity exercise or physical activity is safer than more vigorous intensity activities during pregnancy.^29,30

Most obstetricians agreed that physical activity and exercise during pregnancy might make a woman feel more energetic (98%) and improve her labor and delivery (89%), but fewer agreed that it would improve the baby's health (70%). Each of these benefits has at least some support in the literature.^31

–37 Pregnant women in the PIN3 Study answered the same questions and agreed that physical activity and exercise during pregnancy might make a woman feel more energetic (94%), improve her labor and delivery (94%), and improve the baby's health (75%).²⁰ For both the PIN3 Study²⁰ and another study of pregnant women living in Mississippi,²¹ participants reporting such benefits (e.g., improved energy, labor and delivery) were more likely to report engaging in exercise during their pregnancy.

Physical activities to avoid and risks

A higher proportion of obstetricians reported recommending avoidance of specific physical activities for each progressive trimester. Only in a few instances were these reports of activities to avoid associated with continuing education training in the past 5 years. However, those practicing longer were more conservative in some of their recommendations; they were more likely than obstetricians practicing <15 years to report recommending avoidance of lifting heavy groceries, doing laundry, and walking in the third trimester and regular jogging in all three trimesters.

ACOG³ recommends that women avoid supine exercise during the second and third trimesters because of the risk of hypotension caused by exercising in the supine position from compression of the inferior vena cava by the uterus.⁶ Consistent with this position, few obstetricians indicated that they recommended against supine exercise in the first trimester (12%), but more reported it in the second (63%) and third (83%) trimesters. These reports were generally similar among the PIN3 women, wherein 17%, 64%, and 81%, agreed that they should avoid supine exercise in the first, second, and third trimesters, respectively.²⁰ Most (92%) of the obstetricians agreed that long periods of standing in place without moving should be avoided while pregnant. This opinion again concurred with that of PIN3 pregnant women, among whom 93% agreed with the same statement.

Almost one fourth (23%) of the obstetricians agreed that exercise during pregnancy could cause lower weight babies, in contrast to only 5% of PIN3 pregnant women reporting it. Those who were in practice for <15 years were more likely to agree with this statement. However, the literature to date seems to support no association of lower birth weight babies with moderate activities but a small reduction in birth weight associated with vigorous activities.^38,39

Only 18% of obstetricians agreed that exercise during pregnancy could trigger labor, with a higher percentage agreeing with this statement among those in practice longer. We expected this percent to be higher, as in clinical practice women are often encouraged to participate in physical activity to help stimulate labor or are advised to be inactive in an attempt to postpone labor. There are biological mechanisms suggesting that exercise could trigger labor, as it increases catecholamines, which can induce uterine contractions.⁴⁰ At present, more work is needed to determine if this is true, with few studies examining physical activity as a potential trigger of labor.⁴¹

Findings related to practice time and continuing education

Our understanding of the risks and benefits of physical activity during pregnancy grew considerably over the past two decades and is partially reflected in the number of updated guidelines during that time. ACOG recommendations for physical activity during pregnancy were first introduced in 1985¹ and updated in 1994² and 2002.³ In addition, in 2008, U.S. governmental guidelines⁴ were released that also targeted pregnant women. It is possible that obstetricians may not have kept up with these changing recommendations and rapidly growing body of literature. In this study, we explored whether responses differed by time in practice, as it may be that some obstetricians in practice longer refer to outdated ACOG guidelines³ or are not aware of the ACOG guidelines for physical activity. We found that for several types of activities, obstetricians in practice longer were more conservative in their recommendations to healthy pregnant women, such as with lifting (third trimester), jogging (each trimester), and walking (third trimester). They were also less likely to recommend against supine exercise during the second trimester, as recommended by ACOG.³

In this study, we explored whether the findings differed by attendance at continuing education, as this is a strategy to increase physician knowledge about current recommendations, and other studies indicate a need for training.^15,27 Obstetricians who attended continuing education on recommended exercise in the past 5 years were more likely to collect information on each of the 12 items on exercise and household information (Table 1). It may be that those attending continuing education were more interested in the topic and, therefore, more likely to collect this information routinely or that they collect this information because they attended continuing education. We cannot discern this because of the cross-sectional study design. In this study, obstetricians who attended continuing education were more likely to recommend that pregnant women avoid jogging (first and second trimester) and biking (second trimester). These findings are somewhat unexpected, and further exploration, including an understanding of the content of continuing education obstetricians receive, could help us understand why this is so.

Limitations

Several limitations of this study should be considered. The source population was limited to obstetricians practicing in Texas; confirmation in other states would be desirable. The response rate for our random survey was 47% and is a conservative estimate because our sampled population (denominator) most likely included some gynecologists who do not provide prenatal care whom we were not able to exclude from the outset. No differences in response status were observed by obstetrician's age, type of medical practice, or location of practice within Texas. Female obstetricians were more likely than males to respond, but few differences were observed with regard to their recommendations to avoid certain leisure time activities during pregnancy.

Our comparisons between reports from the PIN3 Study participants²⁰ and the obstetricians completing this survey were useful, but there may be some mismatch. Whereas the obstetricians practiced in Texas, the PIN3 participants lived in North Carolina. In addition, the responses to the survey are subject to reporting bias because of social desirability. We do not know how well the responses from the obstetricians represent their actual day-to-day practice. It is important to note that we only surveyed obstetricians and not midwives or nurse practitioners, who also provide care and information to patients. We asked about routinely collected information, but we cannot determine if obstetricians subsequently counseled women on appropriate amounts of physical activity and exercise. This counsel is important, as women advised by a physician on exercise may be more likely to report exercising during pregnancy.²¹

Conclusions

Several differences observed in this study between practice patterns and current ACOG guidelines³ point to topics for future exploration. Dissemination of current recommendations and discussion about what is known and not known regarding the benefits and risks of physical activity during pregnancy, such as through continuing education, appear warranted. The development of standardized intake and counseling tools for physicians and other healthcare providers, such as those developed elsewhere,²⁸ could assist in appropriate screening and provision of recommendations for more pregnant women.

Footnotes

Acknowledgments

This study was funded by the National Institute for Occupational Safety and Health Centers for Disease Control and Prevention through the Southwest Center for Occupational and Environmental Health Educational Resource Center (grant T42CCT610417). The content is solely the responsibility of the authors and does not necessarily represent the official views of NIOSH or the CDC. We acknowledge Elizabeth Foster for assisting with data collection and management of the project, Fang Wen for assisting with the statistical analyses, and the anonymous reviewers.

Disclosure Statement

No competing financial interests exist.

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