Evaluation of cesarean delivery rates and factors associated with cesarean delivery among women enrolled in a pregnancy cohort study at two tertiary hospitals in Thailand
Authors: Patamasingh Na Ayudhaya Orada , Kittikraisak Wanitchaya , Phadungkiatwatana Podjanee , Hunt Danielle Rentz , Tomyabatra Krissada , Chotpitayasunondh Tawee , Galang Romeo R. , Chang Karen , Brummer Tana , Puttanavijarn Lunthaporn , Malek Parker , Dawood Fatimah S. , Mott Joshua A. ,   for the PRIME Study Group, Kaoiean Surasak , Asavapiriyanont Suvanna , Srisantiroj Nattinee , Rawangban Boonsong , Rongsak Sirichat , Kanjanapattanakul Wiboon , Suntarattiwong Piyarat , Chotpitayasunondh Bajaeee , Sinthuwattanawibool Chalinthorn , Sakornjun Waraporn , Ellison Damon , Klungthong Chonticha , Hussem Kittinun , Fernandez Stefan , Macareo Louis , Wesley Meredith G. , Azziz-Baumgartner Eduardo , Hombroek Danielle 
Published: February 2024

Background
Cesarean delivery rates have increased globally resulting in a public health concern. We estimate rates of cesarean deliveries among Thai women using the World Health Organization (WHO) Robson Classification system and compare rates by Robson group to the Robson guideline for acceptable rates to identify groups that might benefit most from interventions for rate reduction.

Methods
In 2017 and 2018, we established cohorts of pregnant women aged ≥ 18 years seeking prenatal care at two tertiary Thai hospitals and followed them until 6–8 weeks postpartum. Three in-person interviews (enrollment, end of pregnancy, and postpartum) were conducted using structured questionnaires to obtain demographic characteristics, health history, and delivery information. Cesarean delivery indication was classified based on core obstetric variables (parity, previous cesarean delivery, number of fetuses, fetal presentation, gestational week, and onset of labor) assigned to 10 groups according to the Robson Classification. Logistic regression was used to identify factors associated with cesarean delivery among nulliparous women with singleton, cephalic, term pregnancies.

Results
Of 2,137 participants, 970 (45%) had cesarean deliveries. The median maternal age at delivery was 29 years (interquartile range, 25–35); 271 (13%) participants had existing medical conditions; and 446 (21%) had pregnancy complications. The cesarean delivery rate varied by Robson group. Multiparous women with > 1 previous uterine scar, with a single cephalic pregnancy, ≥ 37 weeks gestation (group 5) contributed the most (14%) to the overall cesarean rate, whereas those with a single pregnancy with a transverse or oblique lie, including women with previous uterine scars (group 9) contributed the least (< 1%). Factors independently associated with cesarean delivery included age ≥ 25 years, pre-pregnancy obesity, new/worsen medical condition during pregnancy, fetal distress, abnormal labor, infant size for gestational age ≥ 50th percentiles, and self-pay for delivery fees. Women with existing blood conditions were less likely to have cesarean delivery.

Conclusions
Almost one in two pregnancies among women in our cohorts resulted in cesarean deliveries. Compared to WHO guidelines, cesarean delivery rates were elevated in selected Robson groups indicating that tailored interventions to minimize non-clinically indicated cesarean delivery for specific groups of pregnancies may be warranted.