Background
Preterm birth (PTB) remains a significant cause of neonatal morbidity and mortality. Women with a prior PTB are at risk for recurrent PTB. Treatment with 17-alpha hydroxyprogesterone caproate (17OHP-C) has become standard of care for women with prior PTB to help reduce this risk. Factors that affect a woman’s decision to use this medication are largely unknown.
Objective
The objective of our study was to investigate patient-level barriers to 17OHP-C. We studied a cohort of women eligible for 17OHP-C with the hypothesis that 17OHP-C is underutilized and certain patient characteristics, such as obstetrical history, influence its use.
Study Design
A cross-sectional study of all women seen at a specialty prematurity clinic from 2009 through 2013 was performed. Women with a singleton pregnancy were included if they had a prior spontaneous PTB (sPTB). The χ 2 tests were performed for univariate analyses. Multivariable logistic regression was used to control for confounders.
Results
In all, 243 women had 17OHP-C recommended to them based on obstetrical history. There were 218 women with a pregnancy during our study period that were included in our analysis. A total of 163 (74.7%) had documented 17OHP-C use. Women were more likely to accept 17OHP-C if they had a history of a second-trimester loss only (odds ratio [OR], 2.32; 95% confidence interval [CI], 1.17–4.58) or received recommendation for cerclage due to a short cervical length (OR, 4.12; 95% CI, 1.55–10.99). Women with a prior full-term birth were less likely to accept 17OHP-C (OR, 0.48; 95% CI, 0.26–0.89), especially when the prior full-term birth was subsequent rather than prior to the PTB (OR, 0.19; 95% CI, 0.08–0.47). Race, obesity, and insurance status did not impact 17OHP-C use. There was no difference in the rate of sPTB between those who used and did not use 17OHP-C (37.2 vs 34.0%, P = .7).
Conclusion
Obstetric history impacted 17OHP-C use. This study identifies biases regarding 17OHP-C at the patient level and can be used to develop strategies to increase its use. However, the similarity in the sPTB rate between users and nonusers highlights the importance of identifying specific populations where 17OHP-C is and is not effective in preventing PTB.
Introduction
Preterm birth (PTB) is a leading cause of immediate and long-term neonatal morbidity and mortality, posing a significant burden on health care resources. Despite the recent decrease in the rate of preterm delivery in the United States, PTB remains a noteworthy problem. One of the strongest risk factors for PTB is a history of a PTB. In 2003, the Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine (MFM) Units Network published a multicenter, randomized, placebo-controlled trial that demonstrated a 34% reduction in recurrent preterm delivery with the weekly administration of 17-alpha hydroxyprogesterone caproate (17OHP-C) beginning at 16-20 weeks’ gestation in women with singleton pregnancies and a history of spontaneous PTB (sPTB). Since then, the American Congress of Obstetricians and Gynecologists has issued 2 Committee Opinions supporting and encouraging the use of 17OHP-C among eligible women. The Society for MFM also provided evidence-based clinical guidelines recommending both the use of 17OHP-C as well as cervical cerclage placement for short cervix in women with a history of sPTB.
Despite its known benefit in reducing the rate of recurrent PTB, there are many obstacles to ensuring the use of 17OHP-C in clinical practice. These barriers occur at the patient, provider, and health systems level. Patients may not perceive themselves at risk for PTB, may not know this intervention is available, or may be concerned regarding the risks and side effects of the medication. Providers may not be aware of the availability or effectiveness of this intervention. Lastly, at the health systems level, women may not be seeking prenatal care at an early enough gestational age to initiate the medication, may have difficulty in obtaining it and arranging weekly administration, or their insurance may not fully cover the medication. In a survey of general obstetrician-gynecologists exploring attitudes regarding the use of 17OHP-C, respondents reported that they prescribed 17OHP-C to only 59% of eligible patients. While evidence regarding the efficacy of 17OHP-C in reducing the risk of recurrent sPTB continues to mount, it is of critical importance to understand what biases affect its use in clinical practice.
To that end, the objective of our study was to investigate patient-level barriers to 17OHP-C use. Patient characteristics that impact the use of 17OHP-C were evaluated among eligible women with the hypothesis that 17OHP-C is underutilized and certain factors, such as obstetrical history, influence its use.
Materials and Methods
We performed a cross-sectional study of all women seen in our prematurity prevention program (PPP) from November 2009 through June 2013. Approval was obtained from the institutional review board at the Hospital of the University of Pennsylvania prior to initiation of the study.
The PPP was established in 2009 to allow focused counseling regarding possible interventions to reduce the risk of PTB among high-risk women. All women seen for consultation had their prior delivery records reviewed, when available, and a detailed history was taken. All records and obstetric history were reviewed by MFM subspecialists to determine whether the prior loss/delivery met the criteria for sPTB or second-trimester loss as defined in prior studies. Standard counseling at our institution includes the recommendation for weekly 17OHP-C if the woman had a prior sPTB <37 weeks, as well as serial cervical length screening with cerclage recommendation for shortened cervix (≤15 mm) if the prior sPTB was <34 weeks.
Women were included in our study if they had a prior sPTB between 16-36 6/7 weeks’ gestation and had 17OHP-C recommended to them at their PPP visit. Women were excluded from our study if they were seen for preconception counseling and did not have a pregnancy during the study period, if they were too advanced in gestation (≥24 weeks) to allow for initiation of 17OHP-C, and if there were no prenatal records available for review.
Our primary outcome for the study was the use of 17OHP-C as documented in the electronic medical record by: (1) the presence of 17OHP-C in the medication history, and/or (2) notation of its use in any prenatal or ultrasound notes. If there was no documentation of 17OHP-C use or if there was specific mention that a woman did not use 17OHP-C, it was considered not used. Our secondary outcome for the study was sPTB (16-36 6/7 weeks). We defined sPTB as spontaneous labor and delivery or spontaneous preterm premature rupture of membranes as has been defined in previous studies.
Data abstraction from the electronic medical record included women’s demographic information, and obstetrical, gynecological, medical, and surgical history. Recommendations for 17OHP-C use and cervical length screening were also collected, as were delivery outcomes.
The sample size was fixed (n = 316) based on the number of women seen in PPP during the study period. Based on the assumption that only 60% of eligible women used 17OHP-C, we would have at least 80% power to see the following differences: for exposure variables with a prevalence of 10%, we could detect a 2.25-fold difference in 17OHP-C use; 20% prevalence, a 1.25-fold difference; 40% prevalence, a 1.5-fold difference; and for 60% prevalence, a 1.5-fold difference.
The χ 2 tests were used to compare categorical variables in the univariate analysis, and Wilcoxon rank sum tests were used to compare continuous variables. Multivariable logistic regression was used to calculate odds ratios (OR) and adjust for confounders. The data were analyzed using software (Stata, Version 12.0; StataCorp LP, College Station, TX). Statistical significance of P < .05 was used.
Results
During the study period, 316 women were seen in PPP. Of those, 243 (76.9%) were eligible for 17OHP-C use based on obstetrical history and 100% of these women had 17OHP-C recommended to them. Among this group, 218 met inclusion criteria for our final analysis ( Figure ).
Demographic information for the entire cohort is seen in Table 1 . As noted, the majority of women in this study were African American (83%), had Medicaid insurance (61%), and were overweight or obese (65%).
| Characteristic | Cohort, n = 218 |
|---|---|
| Maternal age, y, mean (±SD) | 28.8 (±5.9) |
| Race | |
| African American | 82.6 |
| Caucasian | 11.5 |
| Other | 6.0 |
| BMI, kg/m 2 | |
| <18.5 | 1.4 |
| 18.5–24.9 | 33.3 |
| 25–29.9 | 29.2 |
| >30 | 36.1 |
| Parity, median [interquartile range] | 1 [1–2] |
| Prior FTB | 44.5 |
| Insurance | |
| Private | 35.8 |
| Medicaid | 60.6 |
| None | 3.7 |
| Tobacco use | 11.9 |
| 17OHP-C use in prior pregnancy | 11.0 |
| Cerclage recommended based on short cervix | 23.9 |
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