A Segmented Logistic Regression Approach to Evaluating Change in Caesarean Section Rate with Reform of Birth Planning Policy in Two Regions in China from 2012 to 2016.

Objective: This study evaluated change in caesarean section rate with reform of birth planning policy in China from one-child to two-child policy.

Methods: Study data were collected from patient-level hospital records of 59,668 pregnant women who visited three major urban hospitals in Jiangsu Province and Inner Mongolia Autonomous Region of China between January 2012 and December 2016. A segmented logistic regression approach was developed to evaluate the changes in caesarean section rate in these regions with the launch of China's new partial and universal two-child policies in January 2014 and January 2016, respectively.

Results: Jiangsu Province had a significantly lower non-emergency caesarean rate (Jiangsu 8.15% vs Inner Mongolia 34.03%, < 0.001) and a much lower percentage of minority population (Jiangsu 6.99% vs Inner Mongolia 21.76%, < 0.001) than Inner Mongolia Autonomous Region. In Jiangsu Province, no change in caesarean section rate was detected with the two-child policies (all -values > 0.05), although the unadjusted trend change (0.038, 95% confidence interval or CI: [0.016, 0.060], < 0.001) in log odds after the implementation of the partial two-child policy was statistically significant. In Inner Mongolia Autonomous Region, an immediate jump in caesarean section rate was discovered by the segmented logistic regression with the implementation of both the partial (unadjusted level change 0.297, CI: [0.105, 0.489], = 0.002) and universal two-child policies (unadjusted level change 1.945, CI: [1.277, 2.614], < 0.001); but the rate reverted to the previous level thereafter. Ethnicity, maternal age, maternal reproduction history, insurance coverage type, infant weight, and infant gender were the significant factors associated with caesarean section rate (for odds ratios, all -values < 0.05). However, the significance of infant gender may stem from the large sample size of the study and is not clinically meaningful.

Conclusion: Change in caesarean section rate was not observed with the launch of two-child policy in China.