Background
Although a weekly injection of 17-hydroxyprogestone caproate is recommended for preventing recurrent preterm birth, clinical experience in North Carolina suggested that many eligible patients were not receiving the intervention.
Objective
Our study sought to assess how well practices delivering at 2 major hospitals were doing in providing access to 17-hydroxyprogesterone caproate treatment for eligible patients.
Study Design
This retrospective cohort analysis studied all deliveries occurring between January 1, 2012, and December 31, 2013, at 2 large hospitals in North Carolina. Women were included if they had a singleton pregnancy and history of a prior spontaneous preterm birth. We extracted demographic, payer, and medical information on each pregnancy, including whether women had been offered, accepted, and received 17-hydroxyprogesterone caproate. Our outcome of 17-hydroxyprogesterone caproate coverage was defined as documentation of ≥1 injection of the drug.
Results
Over the 2-year study period, 1216 women with history of a prior preterm birth delivered at the 2 study hospitals, of which 627 were eligible for 17-hydroxyprogesterone caproate eligible after medical record review. Only 296 of the 627 eligible women (47%; 95% confidence interval, 43–51%) received ≥1 dose of the drug. In multivariable analysis, hospital of delivery, later presentation for prenatal care, fewer prenatal visits, later gestation of prior preterm birth, and having had a term delivery immediately before the index pregnancy were all associated with failed coverage. Among those women who were “covered,” the median number of 17-hydroxyprogesterone caproate injections was 9 (interquartile range, 4–15), with 84 of 296 charts (28%) not having complete information on the number of doses.
Conclusion
Even under our liberal definition of coverage, less than half of eligible women received 17-hydroxyprogesterone caproate in this sample. Low overall use suggests that there is opportunity for improvement. Quality improvement strategies, including population-based measurement of 17-hydroxyprogesterone caproate coverage, are needed to fully implement this evidence-based intervention to decrease preterm birth.
Each year in the United States, nearly half a million infants are born before 37 weeks gestation. In 2006, the US preterm birth (PTB) rate reached a record high of 12.8%. Since that time, it has declined significantly to 11.32% in 2014, with the reductions thought to be due to changes in elective deliveries before 37 weeks. The number of early preterm term births (<34 weeks) has not seen significant improvement in the past 20 years, and it is these infants who experience the highest rates of morbidity and mortality.
Ambitious goals have been adopted by the Association of State and Territorial Health Officials (ASTHO) and the March of Dimes for reducing the disease burden caused by prematurity. Central to these goals is a reduction in the national PTB rate to 8.1% by 2020. North Carolina, which has a preterm birth rate of 9.7%, received a grade “C” on its 2015 March of Dimes report card, which refers to states with a preterm birth rate between 9.3% and 10.3%. A national target of 8.1% can be achieved only through a systematic, multifaceted, and coordinated effort. Although there has been reasonable recent progress made toward mitigating some PTB risk factors (smoking in pregnancy, elective late preterm births), other areas still need attention. These include the complexity of addressing racial/ethnic inequalities in perinatal care and increasing coverage of known effective interventions such as use of 17-hydroxyprogesterone caproate (17OHP-C).
A history of a prior PTB is among the most important risk factors for spontaneous PTB in a subsequent pregnancy. Thus, women with a history of PTB have been the focus of interventions. In 2003, Meis and colleagues published the results of a multicenter randomized trial showing that, among women with singleton gestations and history of a prior spontaneous PTB, a weekly intramuscular injection of 17OHP-C (starting between 16 and 20 weeks and administered through delivery or 36 weeks’ gestation) reduced the risk of recurrent PTB by 34%. Numerous professional organizations in the United States, including the Society for Maternal–Fetal Medicine, the American College of Obstetricians and Gynecologists (ACOG), and the American Association of Midwives, have endorsed the use of 17OHP-C treatment in eligible women. The most recent 2012 ACOG Practice Bulletin on preterm birth recommends tracking the “percentage of women with a prior spontaneous preterm birth who are offered progesterone supplementation” as a way to monitor implementation of 17OHP-C. Yet, the document does not specify how to carry out such monitoring, which populations to evaluate, or appropriate data sources.
North Carolina has had a strong, statewide 17OHP-C initiative for almost 9 years, and the UNC Center for Maternal and Infant Health has disseminated guidelines for the use of 17OHP-C based on the ACOG/SMFM eligibility criteria on the Center’s website ( www.mombaby.org ). However, there are no coordinated efforts to monitor statewide coverage of the intervention. In an effort to characterize 17OHP-C use in NC, we sought to assess what percentage of eligible women had received at 17OHP-C at 2 major hospitals.
Material and Methods
We conducted a retrospective review of all deliveries 20 weeks and above occurring between January 1, 2012, and December 31, 2013, at the University of North Carolina (UNC) Women’s Hospital (Chapel Hill, NC) and at Mission Hospital (Asheville, NC). Both facilities have perinatal databases that can be queried for basic indicators, such as parity, gestational age, and birth history. We used these databases as a first pass through the study population to identify women whose medical records should be further evaluated, specifically those deliveries occurring during the study period to women whose obstetric history indicated a prior preterm birth (≦37 weeks). We then evaluated the full (paper) medical record for all women who were identified as potentially eligible for 17OHP-C through this initial screening process.
We define index pregnancy as the pregnancy that occurred between January 1, 2012, and December 31, 2013, and the pregnancy in which the woman would have been eligible for 17OHP-C. Our study cohort included women whose index pregnancy was a singleton gestation and who had a history of ≥1 singleton birth characterized by either premature rupture of membranes or spontaneous labor, occurring between 20 0 / 7 weeks and 36 6 / 7 weeks’ gestation. We excluded women whose only “qualifying” prior preterm birth was indicated for maternal reasons (eg, induction for preeclampsia), indicated for fetal reasons (eg, fetal growth restriction with abnormal testing), or associated with placental abruption. We also excluded those whose index fetus had a major structural anomaly. Finally, we excluded from our primary analysis those women whose prenatal care for the index pregnancy was provided outside North Carolina, because we had limited access to those prenatal records. We categorized cases in which there was not enough available information to determine the cause of the prior PTB as “unknown.”
We examined the prenatal records of the index pregnancy to determine whether the patient had been offered 17OHP-C by evidence of documentation of a provider discussing 17 P with the patient. We also documented whether the patient who had been offered 17 P accepted or declined it. We extracted information on the number of documented 17OHP-C injections received by each woman. In cases in which there was no documentation of whether or not a woman had been offered the drug, but there was evidence of her having received injection(s), we assumed that it had been offered. In some cases, women opted to self-inject 17OHP-C at home, and in those instances we assumed that she received it because in most cases there was no record of actual receipt in the chart.
We also extracted characteristics potentially associated with non-receipt of 17OHP-C, such as maternal age, race/ethnicity, gravidity, smoking status, and type of insurance from each chart. Prenatal care data from the index pregnancy, including gestational age at the start of prenatal care and number of prenatal visits were collected. Finally, we extracted detailed available information on all prior pregnancies. We classified each participant represented in the sample as urban or rural according to her county of residence using definitions from the North Carolina Rural Economic Development Center.
Our primary outcome was “17OHP-C failed coverage” defined as the proportion of eligible women who had not received ≥1 dose of 17OHP-C. We also investigated in additional analysis the outcome of “not offered 17OHP-C,” which we defined as the proportion of eligible women who were not offered the drug by their provider and “refused 17OHP-C,” which we defined as the proportion of women who refused the medication.
We fit logistic regression models to estimate odds ratios (OR) for the association between selected correlates and 3 dichotomous outcomes: failed 17OHP-C coverage, not offered 17OHP-C, and refused 17OHP-C. We used a stepwise regression approach with backward elimination to select an adjusted model. Main effects were retained in the model if P values were <.2. We performed all analyses with SAS version 9.4 software (SAS Institute, Cary, NC).
We planned our sample size around a balance between precision of the primary outcome estimate and projected feasibility of the medical record review. We anticipated that our time and resources available would allow detailed record extraction from approximately 600 charts. Assuming 50% 17OHP-C coverage among participants, a sample size of 600 eligible patients would provide 5% precision around this estimate (ie, 17OHP-C coverage = 0.50; 95% confidence interval [CI], 0.45–0.55). We estimated from prior experience that approximately 5% of women in the hospitals’ birth cohort would be eligible for 17OHP-C, and selected our study period to provide approximately 600 eligible patients. The study was approved by the Institutional Review Boards of the 2 delivery hospitals.
Results
Between January 1, 2012, and December 31, 2013, a total of 14,725 women delivered at the 2 hospitals ( Supplemental Table ). Of those women, 1216 (8.2%) women had a prior preterm birth. We excluded 577 women (47%) for 17OHP-C noneligibility or unknown eligibility after medical record review ( Figure 1 ). Once exclusions were applied, we were left with 627 women who were classified as 17OHP-C eligible.
Characteristics of women with a prior spontaneous preterm birth are presented in Table 1 . Of the women who were eligible to receive 17OHP-C, the majority were of white ethnicity, and more than half (56%) were covered by Medicaid in the index pregnancy. Approximately two-thirds (64%) presented to their first prenatal visit before 14 weeks’ gestation, and nearly half (46%) had >10 prenatal visits. The mean gestational age at delivery of the index pregnancy was 36 weeks (interquartile range [IQR], 35–39). Slightly more than half of the women (55%) had ≥1 prior full-term birth, whereas 25% reported ≥1 prior extremely preterm birth (≤28 weeks).
| Characteristic | Total | Covered | Not covered | P value | |||
|---|---|---|---|---|---|---|---|
| Age, y, n (%) | .59 | ||||||
| <24 | 130 | 22% | 61 | 22% | 69 | 22% | |
| 25–29 | 165 | 27% | 75 | 26% | 90 | 28% | |
| 30–34 | 191 | 32% | 97 | 34% | 94 | 29% | |
| ≥35 | 118 | 10% | 51 | 18% | 67 | 21% | |
| Missing | 23 | 12 | 11 | ||||
| Race/ethnicity, n (%) | .03 | ||||||
| White | 314 | 52% | 153 | 53% | 161 | 50% | |
| African American | 114 | 19% | 65 | 23% | 49 | 15% | |
| Other | 20 | 3% | 8 | 3% | 12 | 4% | |
| Hispanic | 161 | 26% | 63 | 22% | 98 | 31% | |
| Missing | 18 | 7 | 11 | ||||
| Type of insurance, n (%) | .48 | ||||||
| Medicaid | 352 | 56% | 166 | 56% | 186 | 57% | |
| BC/BS | 70 | 11% | 32 | 11% | 38 | 12% | |
| Tricare | 9 | 1% | 5 | 2% | 4 | 1% | |
| Self-pay | 101 | 16% | 42 | 14% | 59 | 18% | |
| Other | 92 | 15% | 50 | 17% | 42 | 13% | |
| Missing | 3 | 1 | 2 | ||||
| Gravidity, n (%) | .38 | ||||||
| <3 | 133 | 21% | 66 | 22% | 67 | 20% | |
| 3 or 4 | 286 | 46% | 140 | 47% | 146 | 44% | |
| ≥5 | 208 | 33% | 90 | 30% | 118 | 36% | |
| Smoker, n (%) | .83 | ||||||
| Yes | 121 | 20% | 59 | 20% | 62 | 20% | |
| No | 487 | 80% | 232 | 80% | 255 | 80% | |
| EGA at first prenatal visit, weeks, n (%) | .0001 | ||||||
| <14 | 373 | 64% | 204 | 72% | 169 | 57% | |
| 14–20 | 117 | 20% | 53 | 19% | 64 | 22% | |
| >20 | 92 | 16% | 28 | 10% | 64 | 22% | |
| Missing | 45 | 11 | 34 | ||||
| Prenatal visits, n (%) | <.0001 | ||||||
| <4 | 55 | 10% | 18 | 6% | 37 | 12% | |
| 4–10 | 259 | 44% | 94 | 33% | 165 | 55% | |
| >10 | 268 | 46% | 172 | 61% | 96 | 32% | |
| Missing | 45 | 12 | 33 | ||||
| GA (weeks) at delivery of index pregnancy, mean (SD) | 36.2 (4) | 35.7 (4) | 36.7 (4) | .002 | |||
| Delivery type of index pregnancy, n (%) | .01 | ||||||
| Vaginal | 441 | 72% | 192 | 66% | 249 | 77% | |
| Cesarean | 165 | 275 | 95 | 33% | 70 | 22% | |
| Assisted vaginal | 10 | 2% | 5 | 2% | 5 | 2% | |
| Missing | 11 | 4 | 7 | ||||
| Place of delivery, n (%) | .002 | ||||||
| UNC | 346 | 55% | 144 | 49% | 202 | 61% | |
| Asheville | 281 | 45% | 152 | 51% | 129 | 39% | |
| County of residence | .002 | ||||||
| Urban | 454 | 77% | 238 | 82% | 216 | 71% | |
| Rural | 139 | 23% | 52 | 18% | 87 | 29% | |
| Missing | 34 | 6 | 28 | ||||
| Any prior full-term births, n (%) | <.0001 | ||||||
| Yes | 343 | 55% | 131 | 44% | 212 | 64% | |
| No | 284 | 45% | 165 | 56% | 119 | 36% | |
| Number of prior full-term births, n (%) | <.0001 | ||||||
| 0 | 284 | 45% | 165 | 56% | 119 | 36% | |
| 1 | 181 | 29% | 78 | 26% | 103 | 31% | |
| 2 | 105 | 17% | 39 | 13% | 66 | 20% | |
| Number of prior preterm births, n (%) | <.0001 | ||||||
| 1 | 477 | 765 | 206 | 70% | 271 | 82% | |
| 2 | 106 | 17% | 62 | 21% | 44 | 13% | |
| ≥3 | 44 | 7% | 28 | 10% | 16 | 5% | |
| Earliest GA of prior preterm births, n (%) | <.0001 | ||||||
| 20 to <28 | 156 | 25% | 117 | 40% | 39 | 12% | |
| 28 to <32 | 57 | 9% | 31 | 11% | 26 | 8% | |
| 32 to <36 | 247 | 39% | 121 | 41% | 126 | 38% | |
| ≥36 | 167 | 27% | 27 | 9% | 140 | 42% | |
| GA of most recent pregnancy before index pregnancy, n (%) | <.0001 | ||||||
| <20 | 89 | 14% | 40 | 14% | 49 | 15% | |
| 20–36 | 370 | 60% | 207 | 70% | 163 | 50% | |
| ≥37 | 163 | 26% | 47 | 16% | 116 | 35% | |
| Missing | 5 | 2 | |||||
Of the 627 women eligible to receive 17OHP-C for prematurity prevention, only 296 (47%; 95% CI, 43–51%) met our definition for coverage (ie, documented receipt of ≥1 dose of the drug). 17OHP-C coverage varied significantly by hospital of delivery: at UNC Women’s Hospital, 144 of 346 of eligible women (42%) were covered, compared to Mission Hospital, where 152 of 281 eligible women (54%) were covered ( P = .002).
We recreated and quantified the steps along the critical path that each woman with a prior PTB must negotiate to benefit from 17OHP-C ( Figure 2 ). Of 627 women who were eligible to receive 17OHP-C, 409 (65%) were offered it. Of the 409 women who were offered the drug, 301 (74%) accepted it, and of those 301 who accepted, 296 (98%) received ≥1 dose of the medication ( Figure 2 ).
In multivariate regression, factors associated with failed 17OHP-C coverage included the following: delivery at UNC Women’s Hospital compared to Mission Hospital (adjusted odds ratio [AOR], 2.4); presenting at >20 weeks’ gestation for the first prenatal visit compared to <14 weeks’ gestation (AOR, 3.1); attending <4 prenatal visits (AOR, 4.5) versus >10, and attending between 4 and 10 prenatal visits compared to >10 (AOR, 3.9) ( Table 2 ).
| Not covered (vs covered) | Not offered (vs offered) | Not accepted (vs accepted) | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| OR | 95% CI | AOR | 95% CI | OR | 95% CI | AOR | 95% CI | OR | 95% CI | AOR | 95% CI | |
| Age, y | ||||||||||||
| <25 | 1.00 | Reference | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | ||
| 25–29 | 1.06 | 0.67–1.68 | 1.42 | 0.87–2.32 | 1.55 | 0.74–3.24 | 0.71 | 0.38–1.32 | 0.54 | 0.24–1.22 | ||
| 30–34 | 0.86 | 0.55–1.34 | 1.11 | 0.68–1.80 | 1.00 | 0.49–2.01 | 0.73 | 0.41–1.32 | 0.51 | 0.23–1.12 | ||
| ≥35 | 1.16 | 0.70–1.92 | 1.97 | 1.17–3.33 | 1.95 | 0.89–4.27 | 0.60 | 0.29–1.25 | 0.24 | 0.08–0.72 | ||
| Race/ethnicity | ||||||||||||
| White | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | ||||||
| African American | 0.72 | 0.47–1.10 | 0.84 | 0.52–1.34 | 0.58 | 0.31–1.10 | ||||||
| Other | 1.43 | 0.57–3.58 | 1.43 | 0.57–3.60 | 0.96 | 0.25–3.75 | ||||||
| Hispanic | 1.48 | 1.00–2.18 | 1.65 | 1.11–2.44 | 0.97 | 0.56–1.68 | ||||||
| Type of insurance | ||||||||||||
| BC/BS | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | ||
| Medicaid | 0.94 | 0.56–1.58 | 0.99 | 0.48–2.06 | 1.10 | 0.63–1.91 | 0.76 | 0.39–1.48 | 0.94 | 0.38–2.31 | ||
| Tricare | 0.71 | 0.38–1.32 | 0.84 | 0.36–1.93 | 0.91 | 0.46–1.78 | 0.55 | 0.24–1.27 | 0.70 | 0.25–1.97 | ||
| Self-pay | 1.18 | 0.64–2.19 | 0.49 | 0.19–1.25 | 1.75 | 0.93–3.32 | 0.55 | 0.23–1.31 | 0.16 | 0.04–0.61 | ||
| Other | 0.67 | 0.17–2.72 | — | — | 1.75 | 0.43–7.14 | — | — | — | — | ||
| Gravidity | ||||||||||||
| <3 | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | ||||
| 3–4 | 1.03 | 0.68–1.55 | 0.74 | 0.39–1.39 | 1.16 | 0.74–1.80 | 0.98 | 0.56–1.74 | ||||
| ≥5 | 1.29 | 0.83–2.00 | 1.41 | 0.68–2.93 | 1.54 | 0.97–2.45 | 1.02 | 0.55–1.87 | ||||
| Smoker | ||||||||||||
| Yes | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | ||
| No | 1.05 | 0.70–1.56 | 1.63 | 0.89–3.00 | 1.42 | 0.92–2.20 | 2.17 | 1.11–4.26 | 0.76 | 0.45–1.29 | ||
| EGA at first prenatal visit of index pregnancy | ||||||||||||
| <14 | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref |
| 14–20 | 1.46 | 0.96–2.21 | 1.10 | 0.59–2.05 | 1.41 | 0.91–2.20 | 0.93 | 0.48–1.81 | 1.23 | 0.69–2.19 | 0.69 | 0.32–1.51 |
| >20 | 2.76 | 1.69–4.50 | 3.08 | 1.49–6.37 | 2.99 | 1.87–4.77 | 3.47 | 1.72–7.00 | 1.55 | 0.77–3.12 | 2.00 | 0.81–4.93 |
| Prenatal visits | ||||||||||||
| >10 | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref |
| 4–10 | 3.14 | 2.20–4.49 | 3.85 | 2.35–6.31 | 3.02 | 2.05–4.44 | 3.19 | 1.86–5.48 | 2.38 | 1.47–3.87 | 3.11 | 1.67–5.81 |
| <4 | 3.68 | 1.99–6.82 | 4.47 | 1.95,10.26 | 4.11 | 2.24–7.54 | 5.09 | 2.21,11.76 | 2.24 | 0.94–5.37 | 3.50 | 1.20–10.21 |
| Place of delivery | ||||||||||||
| Asheville | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref |
| UNC | 1.65 | 1.20–2.27 | 2.41 | 1.42–4.10 | 1.72 | 1.23–2.41 | 1.46 | 0.86–2.47 | 1.20 | 0.77–1.87 | 3.15 | 1.58,6.28 |
| County of residence | ||||||||||||
| Urban | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | ||||
| Rural | 1.84 | 1.25–2.72 | 2.32 | 1.57–3.43 | 1.80 | 0.97–3.35 | 1.07 | 0.60–1.92 | ||||
| Any prior full-term births | ||||||||||||
| No | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | ||||
| Yes | 2.24 | 1.63–3.09 | 2.39 | 1.69–3.38 | 1.63 | 1.04–2.54 | 3.31 | 0.87–12.54 | ||||
| Number of full-term births | ||||||||||||
| 0 | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | ||
| 1 | 1.83 | 1.26–2.67 | 1.75 | 1.16–2.62 | 0.91 | 0.47–1.79 | 1.57 | 0.94–2.62 | 0.33 | 0.09–1.22 | ||
| 2 | 2.35 | 1.48–3.72 | 3.06 | 1.91–4.89 | 2.90 | 1.36–6.18 | 1.30 | 0.65–2.60 | 0.32 | 0.07–1.35 | ||
| ≥3 | 4.26 | 2.23–8.14 | 3.99 | 2.21–7.19 | 2.15 | 0.83–5.60 | 2.85 | 1.21–6.70 | 1.00 | 1.00–1.00 | ||
| Number of prior preterm births | ||||||||||||
| ≥3 | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | ||||||
| 2 | 1.24 | 0.60–2.57 | 1.33 | 0.57–3.12 | 1.25 | 0.44–3.52 | ||||||
| 1 | 2.30 | 1.21–4.37 | 2.40 | 1.13–5.11 | 1.93 | 0.77–4.83 | ||||||
| Earliest GA of prior preterm births | ||||||||||||
| 20 to <28 | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref |
| 28 to <32 | 2.52 | 1.33–4.75 | 1.71 | 0.65–4.50 | 2.04 | 1.00–4.20 | 1.13 | 0.36–3.53 | 3.20 | 1.27–8.09 | 2.08 | 0.58–7.45 |
| 32 to <36 | 3.12 | 2.01–4.85 | 6.37 | 3.33,12.20 | 2.07 | 1.70–2.77 | 3.95 | 1.87–8.35 | 4.19 | 2.13–8.25 | 7.21 | 2.99–17.37 |
| ≥36 | 15.56 | 8.99,26.93 | 38.3 | 17.5–83.7 | 9.34 | 5.49–15.91 | 20.31 | 9.24,44.64 | 11.33 | 5.19,24.74 | 22.98 | 8.52–61.96 |
| GA of most recent pregnancy before index pregnancy | ||||||||||||
| <20 | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref | 1.00 | Ref |
| 20–36 | 0.64 | 0.40–1.02 | 0.44 | 0.22–0.88 | 0.55 | 0.34–0.89 | 0.27 | 0.13–0.53 | 0.95 | 0.48–1.89 | 0.92 | 0.36,2.38 |
| ≥37 | 2.01 | 1.18–3.45 | 3.22 | 1.50–6.93 | 1.64 | 0.97–2.77 | 1.45 | 0.66–3.19 | 1.93 | 0.89–4.18 | 4.35 | 1.35–14.03 |
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