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There is an association between maternal comorbidity and cesarean delivery, according to a recent study published in JAMA Network Open.
- A recent study in JAMA Network Open found an association between maternal comorbidity and cesarean delivery rates, which have been rising since the early 2000s.
- Higher cesarean delivery rates are linked to an increased risk of severe maternal morbidity (SMM) and complications in future pregnancies, such as placental abnormalities.
- To reduce cesarean delivery rates, interventions should focus on nulliparous, term, singleton, vertex (NTSV) pregnancies, but factors like maternal age, obesity, and comorbidities have increased among first-time mothers.
- The study identified a significant relationship between maternal comorbidity, as measured by the OB-CMI score, and cesarean delivery risk, with a 3-fold increase in risk for patients with a score of 4 or higher.
- Non-Hispanic Black patients had the highest risk of cesarean delivery, while public insurance was associated with a decreased risk, and English as the preferred language was associated with an increased risk of cesarean delivery.
Higher cesarean delivery rates, which have been observed since the early 2000s, have been associated with an increased risk of severe maternal morbidity (SMM). Cesarean delivery also increases the risks of complications in future pregnancies, such as placental abnormalities.
Interventions to reduce cesarean delivery rates should target nulliparous, term, singleton, vertex (NTSV) pregnancies, which are believed to have the most favorable conditions for vaginal birth. However, maternal age, obesity, and other comorbidities have risen among first-time mothers in recent decades.
While it is known maternal comorbidity is associated with SMM risk, it is unclear how maternal comorbidity impacts the mode of delivery among first-time mothers. To evaluate this association, investigators conducted a retrospective cross-sectional study. Maternal comorbidity was measured using the obstetric comorbidity index (OB-CMI) screening tool.
Participants included all patients with NTSV pregnancies at 7 hospitals among a New York health system with a reported delivery between January 2018 and December 2021. Exclusion criteria included multiparous patients, preterm birth, multiple gestation, nonvertex presentation, intrauterine fetal demise, and contraindications to labor identified early in pregnancy.
The inpatient electronic medical record system was evaluated for clinical and demographic data. This included public health insurance, preferred language English, self-identified race and ethnicity, cesarean delivery and indication for cesarean delivery, hospital, and limited perinatal outcomes.
Maternal comorbidities were determined using International Statistical Classification of Diseases, Tenth Revision, Clinical Modification codes. Cesarean delivery was the primary outcome of the analysis, measured as a binary variable.
The OB-CMI score was measured based on 24 weighted maternal comorbidity indicators, with a score of 0 to 18. As more than half the pregnancies had a score of 0, the variable wasrecorded with 1 category of patients with a score of 0 and the remaining patients in quartiles of 1, 2, 3, and 4 or higher.
There were 30,253 patients with NTSV pregnancies included in the analysis, 43.7% of which were non-Hispanic White, 16.2% Hispanic, 14.6% Asian or Pacific Islander, and 12.2% non-Hispanic Black. Private health insurance was reported in 72.8% of patients, English as the preferred language by 94.4%, no comorbidities in 56.7%, and being aged under 35 years at delivery in 81.2%.
Common maternal comorbidities included maternal age of 35 to 39 years in 15.6% of patients, preeclampsia, general hypertension, or chronic hypertension in 12.8%, asthma in 6.7%, body mass index of 40 to 49.9 in 6%, and preeclampsia with severe features or eclampsia in 5.1%. An overall NTSV cesarean delivery rate of 28.5% was reported.
The onset of the COVID-19 pandemic was associated with an increase in cesarean births, from 27.4% to 29.2%. Comorbidities impacting the OB-CMI score were not reported in 56.7% of patients. However, OB-CMI score group was significantly associated with cesarean delivery.
An increased risk of cesarean delivery was observed with each successive OB-CMI score group, with the risk of cesarean delivery increased 3-fold in patients with a score of 4 or higher compared to those with a score of 0.
Except for American Indian or Alaska Native patients, those of other race and ethnicity groups had an increased cesarean delivery risk compared to non-Hispanic White patients. The highest risk was observed in non-Hispanic Black patients.
Additionally, public insurance was associated with decreased cesarean delivery risk and preferred language English with increased cesarean delivery risk. Abnormal fetal status, seen in 53.7% of patients with an OB-CMI score of 0 and 43% with a score of 4 or higher, was the most common indication for cesarean birth.
These results indicated a direct association between comorbidity burden and NTSV cesarean birth risk. Investigators recommended research be conducted to determine why the vaginal delivery rate is low among the highest-risk patients.
Wetcher CS, Kirshenbaum RL, Alvarez A, et al. Association of maternal comorbidity burden with cesarean birth rate among nulliparous, term, singleton, vertex pregnancies. JAMA Netw Open. 2023;6(10):e2338604. doi:10.1001/jamanetworkopen.2023.38604