It is now clear that the rate and absolute number of late preterm births (34–36 weeks of gestation) and early term births (37–38 weeks of gestation) are increasing.1–3 It is also quite clear that, compared with neonates born at 39–40 weeks of gestation, as the gestational age at birth decreases, the risks of an adverse outcome increases.4–7 Births occurring as late as 38 weeks of gestation are still at increased risk compared with those occurring 1 week later. For example, in a recently published article on elective cesarean deliveries, as compared with births at 39 weeks of gestation, those occurring at 37–38 weeks of gestation were associated with an increased risk of adverse neonatal outcomes, including mechanical ventilation, newborn sepsis, hypoglycemia, admission to the neonatal intensive care unit, and hospitalization for 5 days or more.8 For this reason, the American College of Obstetricians and Gynecologists’ guidelines caution against elective delivery by induction or cesarean delivery before 39 weeks of gestation.9,10
The reasons for the increases in preterm and early term births are not entirely clear, but spontaneous preterm and early term births after spontaneous labor or spontaneous membrane rupture do not appear to account for the increase.11 Instead, births after induction of labor and cesarean delivery before labor appear responsible for much of the increase in preterm and early term births.1,12–14 The reasons for the choice of timing of these deliveries have not been well studied. In cases of severe maternal or fetal distress, the choice of delivery timing by the physician is often obvious. However, we suspect that in many other cases, these deliveries, while not entirely elective, are performed for indications not generally considered sufficient to warrant an early delivery.15 In these less emergent situations, why a specific time point is chosen is often not clear either from the medical record or from interviews with the physician or patient. In addition, while the obstetric provider usually begins the path to delivery by ordering an induction or scheduling a cesarean delivery, it is often not clear whether the driver of that decision was the obstetric provider or the pregnant woman herself. While studies have examined providers’ attitudes toward timing of delivery,16–18 little research has been done on women’s understanding of the implications of the gestational age at delivery.19 One study that examined general perceptions about prematurity found that most women considered a neonate born 7 weeks early or more to be preterm.20 Furthermore, the majority of women interviewed in that study did not consider preterm birth to be a serious problem.
When choosing when to deliver, neither the provider nor the patient is likely to be totally responsible for the decision, and there may be an interaction between the two that results in the selection of a specific day and time for induction or cesarean delivery. The women’s perception of the gestational age that defines preterm and whether prematurity poses a health risk are likely to be important factors. In a recent survey commissioned by a national health benefits provider to estimate women’s attitudes related to cesarean and induced delivery, several questions were asked related to women’s beliefs about the definition of full term and the safety of delivery at various gestational ages. Our objective was to estimate women’s understanding of the definition of full term and the gestational age at which it is safe to deliver an otherwise healthy pregnancy. These data are presented here.
The survey was commissioned by UnitedHealthcare, a national health benefits provider, with a goal of better understanding consumer’s knowledge and attitudes related to cesarean delivery and induced deliveries. The survey was developed based on information gleaned from a series of 2-hour focus groups conducted in July 2008. The final version of the survey took approximately 20 minutes to complete either online or by telephone. The survey collected demographic information of the participants and questioned their perceptions of the gestational age at which a birth becomes full term and the earliest gestation age they believed the baby could be delivered safely.
Prospective participants were first time mothers aged 21–45 years selected for the survey at random from a national database of women who had delivered within the past 18 months. Clustering or stratification by any characteristic was not utilized in the original sampling plan. Participation was voluntary, and all responses were anonymous. Because the initial sample contained few Hispanic women, additional Hispanic women also aged 21–45 were recruited at random from a national phone list of about 2,000 Hispanic women. They were surveyed using the same instrument by telephone by a Spanish/English speaking interviewer either in Spanish or English depending on the preference of the subject. Before the invitation to participate in the survey, prospective participants were screened to meet the following inclusion criteria: they were women who had given birth within the last 18 months, were first time mothers of singleton infants, currently had health insurance coverage either through their employer or spouse’s employer, with at least some high school education, and delivered their child at a hospital or medical facility. Those who had diabetes, hypertension/preeclampsia, or obesity or had any other medical condition that would put them at high risk for a cesarean delivery were excluded from the study. The online survey was conducted August 16–19, 2008, while the telephone portion of the survey was conducted August 18–29, 2008.
Descriptive statistics were calculated for all demographic variables and survey measures. These include frequencies for categorical variables and measures of central tendency (mean, standard deviation) for continuous variables. A Pearson product moment correlation was conducted to explore the relationship between the respondents’ perception of gestational age that could be considered full term for their child and the earliest gestation age they perceived was safe to deliver their child. A multivariate logistic regression analysis was conducted to assess whether participants’ selection of 34–36 weeks of gestation as a response to the question regarding the gestational age they considered “full term” and “safe to deliver” varied by their sociodemographic characteristics. The level of significance for all the tests was set at an alpha of 0.05. With 650 participants, the maximum margin of error associated with the estimation of proportions from this survey was 4%.
Six hundred fifty women completed the survey. Of these, 504 women responded to the online version while 146 Hispanic women participated via telephone. Sociodemographic characteristics of the participants are summarized in Table 1. The respondents were reasonably diverse in regional representation, ethnicity, education, income, marital status, and type of employment. The majority of the participants were white (n=379, 58.3%), most were married or partnered (n=602, 92.7%), and most were aged 30–39 years (n=374, 57.5%). Only 146 (22.6%) had a yearly family income less than $50,000. Full-time employment was held by 324 (49.8%), and 447 (68.7%) were at least college graduates. All participants received health insurance either through their employer (n=317, 48.8%) or through their spouses’ employer (n=333, 51.2%). All the women were first-time mothers with infants aged 6–12 months (n=334, 51.4%) or 13–18 months (n=316, 48.6%).
Participants were asked “At what gestational age do you believe the baby is considered full term?” with possible responses ranging from 34 to 40 weeks of gestation. As seen in Figure 1, 24.1% (n=156, 95% confidence interval [CI] 20.8–27.4%) of the respondents chose 34–36 weeks, and 50.8% (n=330, 95% CI 46.9–54.6%) chose 37–38 weeks, while only 25.2% (n=164, 95% CI 22–28.7%) chose 39–40 weeks as full term. The overall mean choice was 37.7 weeks (standard deviation 1.6, 95% CI 37.6–37.8) with no significant differences (P>.05) in the mean score by age of mother, ethnicity, marital status, education, region of the country, or income levels. We also evaluated the distribution of responses by maternal characteristics. In a multivariate regression analysis, adjusting for the characteristics in Table 1, compared with women aged 21–29, women aged 30–39 were more likely to choose 34–36 weeks of gestation as the definition of full term (odds ratio [OR] 1.6, 95% CI 1.0–2.6) as were single women compared with married women (OR 3.3, 95% CI 1.6–7.0). Compared with employed women, homemakers were less likely to choose 34–36 weeks of gestation as the definition of full term (OR 0.47, 95% CI 0.28–0.82).
The women were also asked “What is the earliest point in the pregnancy that it is safe to deliver the baby, should there be no other medical complications requiring early delivery?” also with the range of choices from 34 to 40 weeks of gestation. As seen in Figure 2, more than half of the new mothers selected 34 to 36 weeks of as their response, (N=336, 51.7%, 95% CI 47.9–55.5%). In contrast, fewer than one in four women selected either 37 weeks (N=140, 21.5%, 95% CI 18.3–24.7%) or 38 weeks (N=125, 19.2%, 95% CI 16.2–22.2%). Fewer than 10% chose 39–40 weeks as their response (N=49, 7.6%, 95% CI 5.6–9.6%). The overall mean response was 36.5 weeks (standard deviation 1.5, 95% CI 36.4–36.8) with no significant differences (P>.05) in mean scores or distribution of scores by ethnicity, maternal age, region, education, marital status, or income level. In a multivariate regression analysis adjusting for the characteristics in Table 1, compared with white women, Asian women were less likely to choose 34–36 weeks of gestation as being safe to deliver (OR 0.55, 95% CI 0.31–0.96) as were homemakers compared with those who were employed (OR 0.57, 95% CI 0.36–0.89). Compared with women from the Central United States, women from the Northeast were more likely to believe it was safe to deliver at 34–36 weeks of gestation (OR 1.7, 95% CI 1.1–2.7) as were women with a high school education (OR 2.1, 95% CI 1.0–4.1) or a college education (OR 1.6, 1.1–2.4) compared with women with a graduate education.
We also evaluated the relationship between the gestational age at delivery of the mother’s last birth with her perceptions about full term and safety. In this analysis, the gestational age of the prior delivery significantly (P<.05) correlated with the gestational age mothers considered their child full term and the gestational age mothers considered it safe to deliver their child. However, the correlation coefficients were r=0.28 and 0.22, respectively, suggesting a relatively weak association between the variables. We also evaluated the relationship between the gestational age that respondents considered their child full term and the earliest gestation age that they considered it safe to deliver their child. There was a significant correlation (P<.001) showing a moderately strong relationship (r=0.40).
The increasing numbers of late preterm and early term births, together with the recent demonstrations of an associated increase in adverse neonatal outcomes, are troublesome. Many of these births appear to follow a completely elective induction of labor or cesarean delivery while others are likely elective in that they are associated with findings or symptoms not generally considered an indication for immediate delivery.15 Why the increases in elective deliveries are occurring and whether the obstetric provider or the pregnant woman herself is driving the decision toward earlier delivery are often not clear. In many cases it is likely a joint decision. While there are undoubtedly many facets to this interaction,11 one of these may be the information brought to the decision by the pregnant woman herself.
The responses to the survey questions reported here strongly suggest that pregnant women carry varying definitions of “full term” and hold different opinions regarding the safety of delivery at various gestational ages. As even healthy pregnancies often become increasingly uncomfortable for the pregnant women near term and as anxiety about the labor and delivery increases, many women want the baby delivered as soon as possible. Misinformation about the safety of early deliveries, especially those that are perceived to be “only a little early,” combined with the desire for the pregnancy to be over, likely contributes to a patient “push” for early delivery. One source of this misinformation may be the many news stories about the increased survival of preterm babies receiving newborn intensive care. The stories do not generally dwell on the small increases in mortality and short- and long-term morbidity associated with decreasing gestational age at birth.8
There are several potential weaknesses to this study. First, despite surveying women from different geographic areas with varying characteristics, the survey was targeted at women with private insurance who recently delivered. The results may therefore not be able to be generalized to women without private insurance and to women before their first delivery. This study also is a secondary analysis of data in a survey collected primarily for other purposes. We also understand that the study participants might interpret words such as “full term” and “safe” differently, especially because no definitions were provided by the survey itself. However, because delivery is never entirely safe at any gestational age, the safety question implies a comparison with those births occurring at earlier gestational ages. Recent data confirm that compared with neonates born at 39 weeks of gestation, those born earlier are at increased risk of a number of adverse outcomesf and are not as “safe.”7,8
In several recent studies, educational efforts primarily aimed toward providers have shown promise in reducing the rate of elective preterm or early term deliveries.16,17 The role of the patient, although alluded to in some of these studies, has not been a focus of research to delay or reduce elective late preterm and early term deliveries. However, in one study, women defined a preterm birth as one occurring on average more than 7 weeks early and considered late preterm and early term births not to be associated with much of an increase in risk.20 We are not sure why women with certain characteristics were more likely to choose 34–36 weeks of gestational age as the definition of full term (single, older, and working women) or when it was safe to deliver (those from the Northeast, with lower education, working and non-Asian). However, these observations may be a fruitful starting place for further research or targeted educational efforts.
With the trend of an increased patient role in medical decision-making, ensuring that women understand the implications of the timing of delivery may be an important component of interventions to reduce the number of elective or semi-elective late preterm and early term deliveries. Further studies of women’s knowledge regarding the safety of early delivery as well as the impact of women’s influence on the timing of elective and semi-elective late preterm and early term deliveries are crucial if we are to properly address the expanding number of these deliveries.
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